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Rear Suspension Designs That Failed, and, of course, More! Trending
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00:00:00Hello, everyone, and welcome back to the Cycle World Podcast. I'm Mark Hoyer. I'm with Kevin
00:00:04Cameron. If you've never joined us, thanks for joining us. If you have joined us, like
00:00:08I said, welcome back.
00:00:13So we recently did a podcast about rear suspension, principally the swing arm. Had a few little
00:00:19chit-chats in there, but we're going to talk about failures of rear suspension, things
00:00:23that we possibly pondered and looked at the sky and thought, what if
00:00:29the wheelbase never changed? What if, what if, what if?
00:00:36Constant steering geometry.
00:00:40Imagine perfection.
00:00:43Exactly. Imagine perfection and then imagine getting into the dyno cell and putting a
00:00:49connecting rod in the roof, for example.
00:00:52Yes.
00:00:54But yeah, we're going to talk about suspension, the failures of different types of rear suspensions
00:00:59and all the implications of what we're working on motorcycles here. Very quickly, if you
00:01:06haven't found us on Patreon, go find us on Patreon. You can get every episode that we've
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00:01:22too bad. And, you know, YouTube's great to join us here if you want. Just know that you're paying
00:01:28YouTube a lot more than you're paying us. Oh no, did I say that? Anyway, thanks for joining
00:01:34us. Let's get right into rear suspension, Kevin.
00:01:37Okay. Front suspension came first because if you hit a bump and it's tall enough, it acts
00:01:51as it tries to wrestle the steering out of your hands.
00:01:56Well, I think there's more natural padding on the other end, too, compared to your hands.
00:02:01Well, that's true. Yes, that's true. Except for my maternal grandmother. But front end needed
00:02:12suspension because otherwise bad things happened right away. So people learned to ride with front
00:02:22suspension only, so-called rigid frame. But there were efforts made to add suspension to the rear,
00:02:30most notably Indian in 1912, who made an effort in that direction, was an option, wasn't a popular
00:02:40one. And there were a number of attempted swing arm revolutions which failed because, well, I should
00:02:50say giving rise to the wisdom of the ages, which was nothing steers like a rigid. Now, the reason for
00:02:59that is a rigid allows the rider a monopoly of control. You turn the bars, causes the machine to flop
00:03:10over right or left at your choice. But if you have a swing arm bike with a weak swing arm,
00:03:20then there's a
00:03:23second opinion on steering. Is the throttle causing the chain to pull strongly on the swing arm? Are you hitting
00:03:33bumps? Is the frame flexing? So what was the good compromise in that period from the creation to 1935 was
00:03:50the large
00:03:50section tire? The same revolution had occurred in automobile tires. They had learned the comfort
00:04:02producing qualities of not blowing the tires up to 100 PSI. And they began to build thinner walled,
00:04:11larger section tires operating at lower inflation pressure.
00:04:15I'm a big fan of bringing back the Moore sidewall. We need tall tires. None of this 30 series, 20,
00:04:2340 series, low profile. Oh man, sidewall. That's where it's at.
00:04:28Yeah, well, near the end of Goodyear's participation in road racing in 1984, and right at the end of the
00:04:40two-stroke era, there was created, and Dunlop did it too, tall sidewall tires. Because it was believed that
00:04:51if you added some lateral flexibility that the motorcycle would be more stable. There would be
00:04:59an opportunity for the flexing rubber to provide damping force. But that diverts us from our subject,
00:05:07which is rear suspension. Then came 1935, and two big things happened. One,
00:05:17Phil Vincent in 1929 had bought the name and a few bags of frame lugs from Howard Davies,
00:05:31who had made his own motorcycle and won the TT on it. He won the TT on a bike he'd
00:05:38built himself.
00:05:39So Phil Vincent buys it. Phil Vincent as a schoolboy was drawing pictures of motorcycle frames. And what he
00:05:48built was a rear suspension that was triangulated so that the two beams of the suspension were more
00:05:58resistant to this motion, which would cause the rear tire to tilt from side to side.
00:06:06One of those bikes finished seventh in the 1935 TT. And remember, Vincent was never really a factory. It was
00:06:15more like
00:06:17two creative guys with a lot of helpers. And the other creative guy, of course, was Phil Irving.
00:06:24So here's this bike in seventh with nothing but factory Norton's and a couple of factory NSU's,
00:06:33which were just German Norton's, some would say, ahead of it. Distinguished finish.
00:06:44Well, aside from the first place, which was Stanley Woods on the factory,
00:06:53120-degree V-twin Moto Guzzi with a triangulated swing arm.
00:07:02And this was a shock because nothing steers like a rigid. People don't like to find that,
00:07:09you know, thou shalt not kill. Well, actually, it's okay if the right people tell you to,
00:07:14you know what I mean? People like to nail down these home truths.
00:07:25So, no less an authority on everything motorcycle-wise than Joe Craig, Norton's long-serving
00:07:35racing manager. In a 1942 magazine article, he proclaimed that Stanley Woods could not have
00:07:42achieved his stunning last lap in the 1935 TT on a rigid frame. Suddenly everybody's got to have
00:07:51rear suspension. Rear suspension. Rear suspension is hot. It won the TT. Well, how can we do this on the
00:07:58cheap? How can we, you know, like make it look like rear suspension or something like that?
00:08:04And this gave birth to things like sliding pillar. Here comes the two members, triangulated
00:08:14members of the rear suspension, the hard tail, down to the axle holders. And instead of just putting the
00:08:26wheel into the axle holders, you make room, weld on some brackets and put the sliding pillars there and
00:08:33attach the rear axle to them. Presto. Suspension. Not much of it.
00:08:39It's there. And I got to say, my experience with those types of frames is, you know, it's possibly more
00:08:46comfortable, but perhaps also more unsettling. Yeah. Yeah. Well, of course, one of the things is,
00:08:55I noticed that detective dramas on television tend to be better put together because so many people
00:09:05are working on them. And then along comes a family comedy and it's, I think I'll go get a sandwich.
00:09:13So the fact that large numbers of people were working on these concepts eventually made them
00:09:22made them workable. There was a thing in 1919 called Coulson B. Coulson B, instead of attaching
00:09:33stick slip prone sliding pillars, had little dinky vestigial swing arms at the end,
00:09:42ends of the hard tail. And the axle, I think was supposed to somehow prevent this whole thing from
00:09:49flopping to side to side. Footnote to history, Coulson B. It went nowhere. So
00:10:03this was pretty much the state of affairs from 1935 onward. Although Velocet enthusiastically adopted
00:10:11rear suspension in the form of three pieces of pipe, not welded together, but mechanically fastened,
00:10:18make those joints good and tight. And you might have less of this.
00:10:27Never having ridden a Velocet, I will have to defer to Mark, who has not only ridden them, but
00:10:34to an extreme.
00:10:36Well, the ridges were, I had a 37 KSS with a girder fork and it was, um, it was a
00:10:42pleasure to ride
00:10:43on a winding road. And you can see there was, for me, it was the education that took me from,
00:10:47um, I'd already owned the KSS or the MSS, which is the push rod 500 single. It was the first
00:10:54swinging
00:10:54arm 500. I had the 19th bike off the line, in fact, for swinging arm bikes. And, um,
00:11:02it's a pretty good handling bike of the, of the early fifties, mid fifties British bikes that I've
00:11:07ridden much better than a sprung hub that Triumph was doing. We'll get, we'll get to that. And that's
00:11:13a, that's a quite a, that's quite a contraption, but, um, Velocet swinging arm was pretty good.
00:11:19And as Kevin was talking about earlier, getting some of the action, you know,
00:11:24not, not rigidly connecting the steering head to the axle. Nothing steers like a rigid they're
00:11:32connected. And that means they're not having a twist, which Kevin's talking about introducing
00:11:36rear steering, whether you're breaking hard or accelerating or hitting bumps in the corner
00:11:41and starting to get cycles going where you just, I wrote a Norton 500 twin that was a model
00:11:49seven. And it was, uh, it was, yeah, it was exciting. It was, it was, uh, it was not bad,
00:11:59but I mean, the Velocet for the Euro works pretty well. Although getting back to it, the single,
00:12:04it had a vestigial seat post in the middle of the frame. Oh yeah. Which is what came up between
00:12:11the gear box and the engine. Yeah. And there's, and there's a lug for the, uh, swing arm pivot,
00:12:17which is a pipe through a lug. That's about this wide. And then you clamp on the swing arm arms.
00:12:24They have little pinch clamps on them. So you have to pinch them, get them lined up,
00:12:30you know, so that they're not out of a skew. So there's some setup there and then you clamp them
00:12:36on and it can't have any play in it. And I've, you know, it's sometimes you got to sleeve them
00:12:41and
00:12:41then you clamp the thing. I don't know. There's like a kit. Norton's having.
00:12:46Participatory motorcycling. Yeah. You got to really work at it. I mean, that's,
00:12:49that's why we're here. You know, there's plenty of stuff you can buy. You never think about the
00:12:54swing arm pivot for the life of the motorcycle. In any case, they worked okay. Velocets worked
00:12:59pretty, the swing arm Velocets worked pretty darn good. It was a step and it was, um,
00:13:06it took some courage. I'm sure. Well, the crew, I want to give also one more little bit of credit
00:13:12to Velocet was that you could adjust the position of the upper shock mount. They had an arc in the
00:13:19frame. We'll, we'll throw a, an image of that famous arc. Yes. Um, and what you can do is basically
00:13:26change how compliant the suspension is by tipping them forward or making them more vertical. And it
00:13:35it's, uh, it's useful. I mean, look at the size of me, it's, uh, it improves the bike. And it
00:13:44was a,
00:13:44a method of adjustment that no one else had at the time that around 1950,
00:13:49Edward Turner did something very characteristic of Edward Turner. He was the man who, when he designed
00:13:57a parallel twin for triumph, uh, made sure that it would slip into the frames that were made for
00:14:05the single. Now this is not lavish manufacturing, uh, backed by the courage of an enormous market.
00:14:15This is, uh, mind the pennies and the pounds will take care of themselves.
00:14:20So what did he do? He designed the rear suspension into the wheel hub so that it could simply be
00:14:30slipped into the, uh, axle carriers of the stock frame, no modifications, no extra costs.
00:14:41Now this has been, the spring hub has been referred to as a jack in the jack in the box,
00:14:49because if it happens accidentally to open something will spring out, namely the springs.
00:14:56Well, I was very much told by my friend, like Bill Getty, who's run JRC engineering. He's, he's an
00:15:02incredible British bike mechanic in his historical knowledge. He's worked on everything. He used to run a
00:15:06shop, uh, for a long time. And now it's aftermarket parts for, uh, British motorcycles. But, uh,
00:15:13he said, you know, Mark, if you ever own a spring hub triumph, don't open it.
00:15:20As Kevin points out, there can be explosive.
00:15:23The big, the other big development in 1950 was of course, the Norton Featherbed frame, which was
00:15:33developed by Rex and Chromy McCandless in Northern Ireland as a result of actual testing.
00:15:41And, uh, rather than, uh, armchair platonic theorizing, such as we want a constant wheelbase,
00:15:51we must have constant steering head angle. We must have purity in all things and perfection.
00:15:59So Norton were so impressed with this thing. They contracted with, uh, the McCandless's to build
00:16:07the frames for the 1950 TT bikes for Norton, the factory Nortons. And they won the TT.
00:16:16And not only that, they gave the Italian four cylinder bikes, uh, a terrible scare
00:16:25because they could get on the gas earlier in a corner. They were stable. They braked well.
00:16:33And, uh, in Norton's testing, the featherbed version could be written around the outside of their
00:16:45previous bike, the so-called, uh, uh, garden gate frame, which was a single plane frame,
00:16:52similar to that of a bicycle. Uh, the featherbed frame had, had twin loops and the swing arm was
00:17:01placed between them at the aft end so that it had a broad base for, uh, stiff mounting, not a
00:17:10lot of
00:17:11flopping and flexing. And Jeff Duke would have won the world championship on that bike first time out,
00:17:19except for tire failures, chunking and high speed. So, and then in 1951, he did win the world championship.
00:17:29The last one that Norton would win in 500 or other classes that the singles were not finished, but almost.
00:17:42However, the terror felt by the Italians resulted in a widespread Nortonizing campaign.
00:17:50What is it about this bike that makes it so, uh, able? We'd like to have some of that.
00:17:59And of course, uh, the, the great ambition of English riders was to be summoned to Italy and be well
00:18:07paid
00:18:08to arrive and to ride the frightening force. And they would bring with them in their suitcases,
00:18:18British made, uh, telescopic coil over, uh, rear suspension dampers inspired by those made by hand
00:18:27by the McCandless brothers, which included remote reservoirs, not to be seen again for 20 odd years.
00:18:37So this was, this was a movement of goalposts. Uh, this set the scene for 20 years of convention
00:18:52in which if you wanted a good handling motorcycle, you would buy one of these Nortons with the featherbed
00:18:57uh, chassis and you would try to understand it. And of course it wasn't so mysterious.
00:19:06McCandless moved the rider and the engine forward almost three inches, big change.
00:19:14And, uh, uh, I've spoken to you before about the, uh, JSME article, which in which they ran motorcycles
00:19:25stationary on a moving belt highway. And they tested them for stability and they found out that loading
00:19:34the front tire rather than the European practice of backing the engine up against the rear tire produced
00:19:43stability and steering that did what you expected.
00:19:50So this was the new standard and it would rule the world until the coming of Antonio Cobas and his,
00:20:00uh,
00:20:01inventions in the early 1980s, which culminated in the twin aluminum beam, um, establishment of the present
00:20:11moment. Uh, not to, uh, overlook the significance of so-called trellis frames as practiced by Ducati.
00:20:22Um, KTM also, uh, wasn't adherent of multi-tube space frames. So one of the very important things that
00:20:35Norton added was supple, smooth acting hydraulic dampers, front and rear telescopic fork in the front,
00:20:43twin shocks in the rear. No more stick slip from scissors type dry friction dampers.
00:20:52Which had been the world standard for, since there was rear suspension.
00:20:57Sort of like a clutch.
00:20:58And before that it was used on, on girder forks.
00:21:01Yeah. You sort of, sort of like a clutch, except it had two arms on it that were attached to
00:21:05different
00:21:05elements. And that was your, you know, attached to the front wheel, attached to a fixed area.
00:21:10And then in some of them, there was a big wing nut by which you had adjustable damping.
00:21:15Steering dampers were, were like that. Uh, for a time you had a big knob,
00:21:20you could turn on your steering head and the rod went right into the sixties.
00:21:23Yeah. Uh, to a sense, essentially the same friction pack underneath the, uh, steering pivot.
00:21:30So, well, in 1973, uh, there was an explosion of rear suspension innovation from motocross.
00:21:41And this is where, uh, suspension is so badly needed. So it's not a surprise that innovation,
00:21:48uh, should come, should well up out of the dirt, so to speak. And
00:21:59what had been the norm for many years was the three to three and a half inches of travel
00:22:04of a pair of trusty old black curling shocks with a variety of springs that you could get
00:22:11at your nearby stockists. Stockists. I've always liked that. I'm not going to say it again. Don't worry. Uh,
00:22:24riders rode as hard as they could with those short travel units. When they began to extend the travel,
00:22:32they found they could go much faster. Now, one reason is that the energy absorption ability of
00:22:40a suspension is proportional to travel squared. Double the travel, you can absorb four times
00:22:53the, uh, uh, energy of the shorter travel unit. And the other thing was that as pointed out by former
00:23:02Honda, American Honda racing manager, Gary Mathers, riders push as hard as they can, but they are stopped
00:23:12by what they call harshness. And whether that means that your brain is being jarred into foolishness
00:23:21or that your muscles are unable to go any further in the direction they're going or your peripheral
00:23:30circulation shuts down. I don't know what it is. I'm sure that, um, sports physiologists could tell you
00:23:38what harshness is, but what happened was that as they extended travel at first, everyone enjoyed the
00:23:45softer suspension and the ability to magically travel at great speed over rough terrain.
00:23:56But as usual, people rode to their limit, the harshness limit. So Mathers noted, they ended up with
00:24:07the same spring rate with 12 inches of travel that they had had with three and a half inches.
00:24:15And I find that fascinating.
00:24:18Well, racers, you know, the good, the good racers, what do they do? They, or any tester,
00:24:23you ride the bike until it does something wrong. You push it harder and harder until it does something
00:24:29wrong. That's actually the job. Cause most things are good. It's at 70%, 80%. Most things are pretty
00:24:36darn good. But it's when you start asking more. Long travel, um, hit road racing too. And, um,
00:24:49one rider told me that with his long travel Honda with suspension, uh, that had the latest in low, um,
00:25:02rigidity compression damping.
00:25:06Traditional compression damping was just a hole through which oil was pumped by the moving piston
00:25:13in the damper. What a suspension damper does is it converts bump energy into the velocity of oil rushing
00:25:23through a limited area. In this case, a drilled hole and the resistance to that flow goes up as the
00:25:33square
00:25:33of the flow, which means at some level, the resistance, it becomes essentially rigidity.
00:25:43And there's, there's, there's all kinds of wonderful stories about riders throwing, uh, shocks into,
00:25:52into lakes or, uh, abusing them in other ways. But what this led to was a new type of compression
00:26:01valve that was progressive and that whose resistance more was more nearly proportional to shock rod velocity,
00:26:11uh, than to the square. And so, uh, this made it possible for the rider I'm talking about to hit
00:26:21the
00:26:21banking at what used to be turn five out of the Daytona infield up onto the banking without timing
00:26:28it to coincide with an upshift. He could just ride through there on the power with this innovation.
00:26:35So this is not engineers playing with pencils and papers. This is, let's try this.
00:26:47Be sure to wind your stopwatch. Okay, here we go. Oh, that's much better. Let's talk to the rider.
00:26:54And so on. This is how it actually goes. We are not sitting in Plato's cave,
00:27:03looking at mere shadows of reality. We're getting in there and messing with it. So
00:27:12we get results this way.
00:27:15Now, there are some, uh, exceptions. The atomic bomb worked perfectly the first time.
00:27:22Um, although there have been some fizzles since.
00:27:26Well, the atmosphere didn't even catch on fire either. That was one theory, right?
00:27:30No, but nitrogen and oxygen failed to rush into each other's arms. Yeah. But it was a sort of
00:27:39nagging itch until they actually saw the fireball through their smoked goggles.
00:27:47So when long travel hit, um, road racing and street bikes, of course, what people noticed was these bikes
00:27:58have powerful brakes and pavement has more grip than dirt, which means you break and the bike
00:28:07noses over rather radically.
00:28:11And for each inch that the front suspension compresses, you lose roughly one degree of your
00:28:17steering head angle. Now this is, uh, there are people who say that this can be a terrifying thing.
00:28:24And then there are others who, uh, dismiss it, but I've not risen to those heights in my own modest
00:28:32motorcycling.
00:28:36So people began to say, let's put a stop to this, um, extreme attitude change.
00:28:43We don't want to go back to short travel. Let's put anti-dive onto the front end.
00:28:50And hydraulic, mechanical, there was a wide variety of, of devices. You may have seen, um, the
00:29:02Kawasaki ones that had all these levers, which used the, uh, effort of the brake caliper to follow the
00:29:10brake disc to generate a force that lifted the front of the machine.
00:29:17Now, uh, Udo Giedel has commented that it could brake nicely or on a rough surface, it could stutter horribly.
00:29:29Then in the end, um, once again, reality prevailed because it was found, wait a minute,
00:29:37these guys over at Yamaha are out braking our guys and they don't have any anti-dive on their bike.
00:29:43What do they know that we don't?
00:29:46Well, what they knew was that when the front of the bike sinks dramatically, it takes the center
00:29:54of gravity down with it. And that makes the lever, the height of the center of gravity over the
00:30:01pavement, by which front brake torque can lift the rear wheel into a stoppie, makes the lever shorter.
00:30:10So you can brake harder and not lift the rear wheel.
00:30:16And so overnight, anti-dive just disappeared, went off the street bikes. It was all gone.
00:30:23Oh, so embarrassing. And this is how things go.
00:30:31Uh, there was initial resistance to monoplanes. I mean, where are the bracing where? Well,
00:30:38they're inside the wing, so to speak. Yeah. But I don't, I don't really trust that. I mean,
00:30:43the biplane is built like a box kite, you know, you can trust it. They didn't like a canopy
00:30:51over the pilot because he couldn't feel the slide slip on his cheeks and judge how the turning was going.
00:31:01Well, I mean, imagine a Cessna 195 in the late forties with no wing braces, no, it just,
00:31:08it just was a straight wing sticking out and there was no, nothing visibly holding it.
00:31:16Well, uh, anti-dive disappeared. Okay. Uh, there were various
00:31:28strange anomaly, uh, anomalous, um, suspension proposals from like 1970s onward and US Kawasaki
00:31:43played with what they called the FUBAR rear suspension. There were, uh, two swing arms
00:31:51going up and down together. Their aft ends joined by an upright
00:31:57that was perforated for the rear axle.
00:32:02When they described this to me, it sounded like someone slightly familiar with the A-arm
00:32:09geometry of race cars had fallen in love with the idea of the virtual pivot that is far away in
00:32:20space.
00:32:21And so what was hoped for initially from this design was that it would absolutely prevent wheelies,
00:32:28allowing you to just scoot out of corners and disappear.
00:32:33But in practical sense, I think they discovered anti-squat and they actually put this on
00:32:42on Yvonne de Hamel's race bikes, air-cooled and liquid-cooled from 73 to maybe 77.
00:32:51And then it disappeared. They, it didn't go any further, but they put a lot of effort into it.
00:32:59Another possibility, um, which I've never seen in the aluminum and steel is the, um, Chebyshev linkage.
00:33:09Um, in 1859, um,
00:33:16Pafnuti Chebyshev, a Russian mathematician was trying to devise a way to change straight line
00:33:24motion into rotary motion. And in the process, he came up with twin swing arms that were crossed.
00:33:35This was perfect for the constant wheelbase theorists because at last you could have the rear axle going
00:33:44up and down in a straight line, zero wheelbase change. Perfection is at hand.
00:33:56I don't even know if any prototype of this kind was built, but there was the idea.
00:34:06So what a lot of these ideas for rear suspension were trying to do can be broken down into three
00:34:16areas.
00:34:17One is people were beginning to be aware as engines grew more powerful. Remember the two
00:34:24strokes came to Daytona with a hundred horsepower in 1972. That got people thinking. Um,
00:34:33chain force had an effect on rear suspension. It might either cause it to rise up or to squat down.
00:34:40And so people were trying to negate this force so that it would be neutral.
00:34:47Hasek's rear suspension, he wanted the swing arm center plane of the swing arm to be horizontal.
00:34:53He wanted the chain above it to be horizontal and parallel with the pavement.
00:35:00Um, ATK came out with a similar idea. They placed two sprockets clamped
00:35:10one above the other to the chain side swing arm beam.
00:35:15And they were arranged at such a height that the upper chain run and the lower chain run,
00:35:22when either of them was under tension, would be parallel with the swing arm.
00:35:27So there would not be this tangent force tending to cause the swing arm to extend.
00:35:34The thing that I loved about ATK was that they made a demonstration toy was fascinating to
00:35:42play with you. You could, you could change the variables, uh, so that was bad, normal thing,
00:35:49where the rear suspension extends, or it would be super modern, uh,
00:35:55with no net force, no effect from the chain tension on rear swing arm height, suspension height.
00:36:06Then the, the second idea was no, rather than setting the swing arm free from chain pull,
00:36:13let's use the chain pull on these powerful motorcycles, which otherwise will squat down
00:36:20in the rear when they accelerate. Let's use it to generate the lift force just to the point that it
00:36:29cancels the squat. So that here you are in the turn, trying to accelerate. And as you twist the
00:36:39throttle and the rear end squats down, weight comes off the front tire and goes on to the rear tire
00:36:45and the front tire pushes you head for the outside. This is squat and push.
00:36:55And I remember seeing, uh, one of the South American lads who made it big in GP racing,
00:37:05come in to his, uh, crew and make the universal sign for push, which is,
00:37:15you know, Mars crossing. Yes. Yes. And which is now called, uh, something else. They call it,
00:37:23um, closing, closing the front end. And then the third, um, possibility was to, uh,
00:37:37completely ignore all of the above and focus only on constant chain slack because there are some
00:37:47peculiar motorcycles out there. Yamaha's TZ 500. Um, you had to be careful adjusting
00:37:55the rear chain slack because there was a place in the arc of the rear suspension where it got real
00:38:01tight. That's where you had to adjust it. And so these guys were going to, to nail down constant
00:38:11chain tension by making the swing arm pivot concentric with the output sprocket center line.
00:38:21Famous Spondin chassis got that. And then BMW was playing with that on their, uh, dirt bike,
00:38:26which didn't work out too well for them on the dirt bike. It worked out too well for anyone.
00:38:32Anyone. Because it completely ignores the chain pull effect on rear suspension height.
00:38:40And, and, but it's invented several times each year and it probably will be as long as the motorcycle
00:38:46exists. Hey, here's a good idea. Why don't they do this? But it's not a good idea. It works,
00:38:56it achieves its purpose, but it ignores effects that cannot be ignored on powerful motorcycles.
00:39:04Yeah. So all these, uh, well, then, then there's Hossack. Hossack was involved in formula one, um,
00:39:21development. And at one point they had a chassis bolted to the wall and they had a, a great big
00:39:28bar
00:39:28through the, the projecting end. And they were going to test that the twist resistance in pounds per
00:39:36degree. And this is good. This is, this is finding out stuff you want to know by lashing up something
00:39:44that doesn't cost a million and a half dollars and has to come from a German high precision outfit.
00:39:52Um, bathroom scale and a drill press, uh, test your spring rights. There's a famous
00:39:58picture of Dan Durney. Yes, or suspension springs. You got it. So, um,
00:40:11I once, uh, stood just off of, um, what used to be turn nine at Laguna, the left hairpin
00:40:19and watched the TZ 750s upshift off of that corner. As soon as the clutch went home,
00:40:28clunk, the bike, the bike rose up and hit the upstop. They had plenty of anti squat.
00:40:34This is why, um, in the early nineties,
00:40:41adjustable swing arm pivots began to be seen.
00:40:45Adjustable height, usually in the form of a rectangular opening on either side of the frame
00:40:51into which plugged a plate with a hole for the swing arm pivot at a particular height.
00:40:59And you had a fitted case of these like fine cigars.
00:41:04And you could select the ones that had the height change that you thought would put an end to all
00:41:11your
00:41:11problems and shut your rider up with all his complaining whiners.
00:41:19So, uh, that was, that was that when it came to FUBAR, uh, nothing is going to change the fact
00:41:30that the
00:41:31thrust accelerating the motorcycle is at ground level. Whereas the center of mass is maybe 20, 22 inches above
00:41:42that. What that means is the thrust is tending through this lever arm to exert a torque on the
00:41:51chassis and lift the front wheel off. So what you need to prevent this is either a chaparral like, um,
00:42:02big section fan up front that is pulling the front end down onto the pavement or winglets or a tiny
00:42:10rocket motor that fires only when you accelerate. Nothing else is going to stop wheeling. No complexity
00:42:18of linkage gears, cams and linkages. Forget that. Now here come the Elf alternative motorcycles.
00:42:27At first, Andre de Corton's Frenchman, uh, with formula one experience reasoned very reasonably.
00:42:36There must be with all the research done in formula one concepts that are immediately applicable to the
00:42:45motorcycle, that poor primitive creation, which will greatly improve it. And I will be a star. Well,
00:42:57one of their improvements was everyone knows that a motorcycle handles better if it has a low center
00:43:03of gravity, right? Wrong, wrong. Look at modern motorcycles. You will see that the rider is way
00:43:12up in the air above the rear tire. It used to be that the seat back, the underside of it
00:43:19was arranged to
00:43:20be barely greater than the suspension travel. And many a motorcycle had tire burns on the underside of
00:43:29the seat pan. They found that that didn't work well. Well, Honda bought into Elf because they wanted
00:43:39it to be, uh, uh, uh, uh, in a position of advantage and this looked like it. In 1984, they
00:43:46brought their, uh,
00:43:51NSR 500, uh, their new four cylinder bike to Daytona with the fuel carried under the engine and with the
00:43:59exhaust
00:44:00pipes rooted over the top protecting the rider by means of an insulated dummy tank.
00:44:08And it was found out they added, they used this concept on their, uh, uh, 500 GP bike, um,
00:44:17um, as their main, they, they placed all their bets on this. And Freddie Spencer said, I can't
00:44:29change direction as quickly on the bike with the fuel on the bottom as I can on my old three
00:44:36cylinder.
00:44:37And a test was arranged. Orange cones created a slalom. The three cylinder was sent through the
00:44:45slalom until Freddie said, that's about all I can do. Click. They had a measure.
00:44:53They sent the NSR 500 into the slalom at Freddie's entry speed and knocked all the combs down.
00:45:04Actual physical testing, not just sitting by at fireside in a comfortable armchair reading Plato.
00:45:15Actual testing. Revolutionary. So that was the end of that. It was also the end of the court.
00:45:24They brought in two other fellows instead. And this is an excellent story because it shows
00:45:36persistence, willingness to spend money
00:45:40and ultimately acceptance of the fact that it added up to nothing.
00:45:47But that's something learned.
00:45:50So what went on there was that, uh, the radical bike
00:45:59didn't go as well as some bikes modified to be somewhat less radical.
00:46:06And so they went in that direction.
00:46:09And all the hub center business with gears, cams and linkages gave way to a simple,
00:46:17almost like a McPherson strut.
00:46:19Um, and, uh, uh, the poor guy on the bike, um, is trying to give good feedback and get good
00:46:33finishes. And he was, uh, fifth or third, or he had some good finish positions in the championship
00:46:41in the middle eighties. Um, so it can't be, it was Ron Haslam.
00:46:51Very earnest, a corner speed rider. The bike's wheelbase kept getting longer and longer. They
00:46:57started at 53 inches and they ended up at 57 plus. And when, uh, what was it? Scott Redding.
00:47:06I'm not sure which rider it was told me about the difference, the physical difference in the
00:47:11motorcycle from a corner speed bike to a point and shoot bike. He said, the corner speed bike is
00:47:17long and low. And that's what Honda built for Ron Haslam.
00:47:24And of course, as the bike became more conventional, people had heard of McPherson strut and a lot of
00:47:31people were driving cars with it. The extremists squeaked and moaned because it wasn't radical enough.
00:47:42It was not true to the original concept of changing everything. Wait a minute. What are we trying to
00:47:49accomplish here? To annoy people or to win races? So, uh, that just didn't work. At one point,
00:48:04um, a quote on from a rider was directional stability, a problem at almost any speed.
00:48:11That's for elf to a for elf to see, uh, front pattern of terrifying proportions, but breaking was
00:48:21exceptionally good because you know that a telescopic fork side loaded by breaking force operating on a
00:48:32long leverage tends to bind, tends to cause stiction that prevents the front end from following
00:48:41the pavement surface during hard braking. But with a pivoted front end, no stiction, excellent grip,
00:48:50shortest braking distances. And when Harley built their, uh, retro leading link suspension,
00:49:00I went to interview the engineer who had done the project and he was sort of apologetic. And I said,
00:49:08well, I want you to tell me there's gotta be some point of superiority here. And I want you to
00:49:12tell
00:49:13me about it. Well, he said, um, it does have the shortest braking distance of any bike we make.
00:49:24Uh, and this is what you would expect from a pivoted front suspension. So
00:49:32there was a point of, um, advantage, but it wasn't enough to win races and Honda pulled out of the
00:49:42elf Honda thing and no more was heard about it. So tough one.
00:49:52Uh, then we have, uh, leading link, uh, BMW made long leading link Earl's forks for their, uh, flat twins
00:50:11in the early post war years. And for a number of years during that period.
00:50:17Uh, and the thing about leading link is that instead of going up and back the way, uh, the wheel
00:50:26does
00:50:26with the telescopic fork, it goes nearly up and down with very little wheel base change.
00:50:35Now, how you can stiffen this assembly of two little leading links. It's kind of like Coulson B so that
00:50:47the
00:50:47wheel doesn't cock from side to side as you go through a turn with bumps in it.
00:50:53I don't know, but Cootsie managed to win the 350 world championship five times in a row, 1953 through 57.
00:51:03And then they pulled out of racing and that was that BMW, uh, kind of like the emperor has no
00:51:13clothes.
00:51:14They finally realized marketing realized that the graceful waving of the front end on those leading
00:51:23link BMW is kind of like hand typesetting in an era of laser printing.
00:51:32So that came to an end. It's an historical footnote. It was an era,
00:51:38was an attempt to find a better way to do it.
00:51:45So then there was the Bimota Tezi, um, early 90, 1990. I think it was shown Cologne and it has
00:51:57a hub
00:51:58center front end on it. If you're not familiar with a hub center, imagine a drum like open at the
00:52:07ends, uh, ring that is spoked into a rim. Then imagine two large bearings inside that empty drum
00:52:19with another drum pushed through it. And the drum that's pushed through it has a kingpin
00:52:28and grasping the bearings from one or both sides by reaching in through the open ends of the drum
00:52:36is a front swing arm. Now, the only thing that steers is the wheel, the discs and the brake calipers.
00:52:44There are no ponderous fork tubes swaying from side to side with the wheel.
00:52:52And this is potentially a strong point of this hub steering because it is more resistant to wobble.
00:53:01Wobble is a rapid oscillation of the front wheel, which generally times out at about 40 or 45 miles an
00:53:10hour. Or if you put your hands back on the bars, if you have on certain motorcycles decided to, uh,
00:53:17do the snaps on your gloves. Oh, yes. I won't do that again. Um, life's little travails.
00:53:31So the, the Tasey, I wanted it to succeed because it looked right.
00:53:38We all did. And the frame, the frame is just a, a thing that went from the frame was the
00:53:45engine. It
00:53:45went from the front swing arm pivot to the rear swing arm pivot. There was no steering head up in
00:53:50the air with long poles going down to the front axle. Yeah, just little arms, delicate little
00:53:55steering arms to get down there. Of course, the, the front swing arm had to have elbows
00:54:01to provide clearance for the front tire. And this was a problem for, uh, Ron Haslam at one point
00:54:09on the number three Elf Honda bike, because going through, I think a left-hander,
00:54:16um, and he used a lot of lean angle. He was a corner speed stylist. He dragged the swing arm
00:54:24on the
00:54:24pavement. Not many can make this claim. So this stuff came to an end. Uh, Tasey,
00:54:43I encountered a man who liked the Tasey that he bought so much that he bought two more so that
00:54:51he
00:54:51would have one at each of his three residences. Hmm. And he was a, a cheerful guy who just
00:54:59loved his motorcycle. So he had three of them. Yeah, they're neat. They are cool. I, you know,
00:55:06yeah, I don't know if I need three, but they are, it is a charming way.
00:55:09You've got a V twin? Yeah.
00:55:11But, uh, the thing is there are a lot of ways to build a motorcycle that will chuck, chuck,
00:55:16chuck, chuck, chuck along the highway and get you where you're going and provide you with a sporty
00:55:22feeling. Um, but with that, I'm sure, for example, that we could build a lovely chassis of adequate
00:55:33stiffness out of steamed plywood. But when you push something to its limits,
00:55:41you learn other things and racing riders on racers on Tasey or similar bikes found the steering vague.
00:55:54They complained of lack of feedback. Well, the information, it was like that story about, um,
00:56:04owl, a tiny creature, a mouse went by owl's house and he heard a commotion. And he told his friend,
00:56:13owl was up in there throwing the furniture out of the windows and
00:56:17stomping in the bottoms of all his pots and pans. When the signal is transmitted through several repeaters,
00:56:25the signal at the end may not be the same as the signal at the beginning.
00:56:31And so they said, if there are gears, cams and linkages, heim joints, rose joints, uh, things that
00:56:40have to be lubricated with a grease gun, it's going to take the feel out of the front end.
00:56:47But like Mark says, it's a perfectly adequate motorcycle in other respects, but it failed to
00:56:55make a revolution. There was no reason to build it that way, having to do with superior performance,
00:57:02other than I'm sure it has a good braking distance.
00:57:08So this is, uh, this brings us to the present moment when, uh, I was in the press room at
00:57:17Valencia once in a, a gentleman who came over to show me a project that, uh, he was, uh, I
00:57:23think
00:57:24a machine shop instructor and he and his lads were building a high tech front end for a motorcycle.
00:57:30And I said, well, now I'm puzzled because people call this high tech, but it has never been adopted
00:57:38at the highest level of motorcycling, which is, uh, uh, world supers, motor GP, et cetera.
00:57:45Oh, he said, I'm, I'm perfectly aware of that, but my class want to build this. Oh, okay, fine. That's,
00:57:52that's okay. But this continues. Journalism loves to call complex things, high tech, extra parts.
00:58:04Like the NASA guy said, if you have a million parts and the reliability of each one is a million
00:58:13chances, a million times it flies and one time it fails, you're going to have a failure every time.
00:58:19So reduce the number of parts, simplicity. Yeah, there've been, this was the lesson that I
00:58:26took from all of these complexities, which is that the motorcycle.
00:58:33Can't go too far from being two wheels, an engine and a place to sit.
00:58:41And what the McCandless brothers created hydraulic damping at both ends of a strong frame with a
00:58:52well-founded, uh, swing arm, telescopic fork up front. It's still not wrong.
00:59:02So all of these excursions have been instructive, but they have failed to produce a revolution.
00:59:12Some of these bikes, um, what was the name of the Yamaha that, uh, was built with a, with a
00:59:21strange front end?
00:59:22The GTS 1000 had the Omega frame and, um, I'm forgetting that fella's name who put it together.
00:59:29It was his idea. He was a big proponent. Um,
00:59:34my brain, my brain was actually recently diverted by thinking back to the Moto SIS with the,
00:59:39the variable trail inserts and the not tell the flex adjustable fork on that. That was an interesting
00:59:45time as well. Um, that, that could be part of a podcast in and of itself.
00:59:51Well, there, I, I, there are people who've, who've devoted years of their lives to these projects and we
00:59:58have to respect that. Um, but it does turn out sometimes like carrying the fuel under the engine
01:00:07that just doesn't work. Why didn't it work? Because people were confusing the sense of
01:00:15security that they have on a heavy motorcycle. If it has a low center of gravity, like a Harley big
01:00:21twin confusing that with a low center of gravity on some, a sporting motorcycle, because as it turns
01:00:30out, people imagined if this is the ground plane and this is the motorcycle, people imagined that
01:00:38the motorcycle pivoted around the line of contact of the two foot tire footprints. It does not.
01:00:46Instead, what happens is the bottom of the motorcycle goes one way and the top of the motorcycle goes
01:00:53the other. So what does it do? It rotates around its own center of mass.
01:00:59When I was learning to ride faster and riding more and more hours, I discovered that because
01:01:08you would see an object in the road you wanted to avoid and you didn't steer around it per se.
01:01:14The center of gravity can, could continue in very nearly the same direction it was going,
01:01:19but you would swing, you would actually swing the wheels out of the way. It reminds me
01:01:24of sports, the center of the center, the center of gravity of the motorcycle wants to travel in a
01:01:31relatively smooth line and things are pivoting around it. Your wheels are going out. The rider is
01:01:38doing things to alter where that center may be, but you're, you're trying to carry the center in a nice,
01:01:45smooth manner down the road. Well, it insists. Yeah. And it does. And you don't want to, well,
01:01:49you have to. And like, how do we best control it? It reminds me of sports. If you look at
01:01:55a surfer doing crazy things on a wave, if you follow the path, their head, their head is relatively
01:02:03stable because it's just like the squirrel. When the squirrel gets flung out of a tree,
01:02:08the first thing it does is it could be flailing about it's sighting it's landing.
01:02:15And then it's rotating. It's, it's head is everything. And that's just, that's sort of
01:02:20where the center of mass is. And in a bike, you swing the wheels out, just as, as you were
01:02:24describing,
01:02:25you need to miss a screw. You see something, you just go, you turn a little bit, you get the
01:02:31bike
01:02:31swung and then you allow it to get the wheels around the outside of it and hope you don't hit
01:02:37what you're trying to avoid. But yeah. And return to equilibrium. Yeah. And it's right back under his.
01:02:43Yep. So it's, uh,
01:02:48it's not intuitive unless you, um, have a little familiarity with Isaac Newton and his,
01:02:56his work. He seems to have been a peculiar fellow. Yeah. He complained once that all my friends,
01:03:05he said, are constantly trying to embroil me with women.
01:03:15So Newton's laws are just what we found happens most frequently. And we call that a law.
01:03:23It's more of an expectation. And so what was happening when they put the fuel on the bottom
01:03:29is they moved it away from the center of mass, therefore changing what was more like a cannon,
01:03:37a 24 pound cannonball into something that was more like a 12 foot long, 24 pound ladder.
01:03:45You're moving masses away from the center of mass so that Freddie's efforts to change
01:03:52direction produced less result. So then they took the gas out and put in two courts and they put 32
01:04:04pounds of ballast up among the pipes. And Freddie went sailing through the orange cones without knocking
01:04:13down one. So, um,
01:04:20good stuff.
01:04:24I, um, I'm pleased with that.
01:04:27Well, you know, we, uh, like in many things in life, mythology is very easy to, uh, say is,
01:04:34you know, yeah, that's how it is. That's how it is. Just like you talk about moving the engine to
01:04:39the rear.
01:04:39No, we got to get traction. We got to get traction and drive, you know, all that stuff.
01:04:44And, um, McCandless brothers doing science, testing actual things and really just
01:04:50check your prejudice at the door, forget your biases, look at what's going on
01:04:57and, you know, whatever it is, engine building, look at the marks on the bearings, look at
01:05:02measure the temperatures. I don't know. You just send the oil in for analysis. What's what where
01:05:11particles are in there?
01:05:14Truly. So companies do it all the time.
01:05:17I'm a firm believer. I got my little black bottles and, uh, I, you know, I rebuilt the engine
01:05:23of my Ford four 60 and it's relatively low miles. And I know what the service interval is
01:05:31recommended and I changed the oil and I've, uh, I've got a vial that I'm going to send in.
01:05:37And I did it at the interval and I'm going to see what happened, knowing how I drove it,
01:05:40knowing that it's relatively new, but I'll track it. And it's, it's relatively inexpensive,
01:05:46but it gives you actual information. It's not just, as you pointed out, we talked about oil change
01:05:51interval. And, um, I actually, I believe the first time I had this comment from you was reading
01:05:57your book, the sport bite performance handbook. It's a great book if you can find it. And, um,
01:06:03my first try, Kevin, it's a nice book. It's got hand-drawn graphs, all kinds of neat stuff.
01:06:09That's very artisanal. And I liked it. I loved it actually. It was a craft paper and, and, um,
01:06:16but one of the things that, one of the things that you said in that book about oil change interval
01:06:21was,
01:06:23well, you could change your oil every 10 minutes and wouldn't that be something. It was along those
01:06:29lines about frequency of oil change. So it's good to know the truth. If you, um, if you can go
01:06:35to the
01:06:35effort and spend the money, you know, spend, I think it's 40 bucks or something, you can send a nice
01:06:40big
01:06:41oil sample in and, and to get some actual data. The sensor that, um, causes the change oil soon
01:06:50light to illuminate. What does it measure? Is it measuring oil in this? Oh, this oil is terrible.
01:07:00Does it measure viscosity? Maybe the viscosity improver agency agents are, uh, which began life
01:07:08with long chains have now become little short things. No, what it measures is the presence of
01:07:15anti-wear because as long as there's anti-wear in the oil additive that has not yet been consumed
01:07:24in the process of protecting metals from each other, when they come very close,
01:07:31what that additive does is it produces a sacrificial solid lubricant layer, which is scuffed away,
01:07:41but it immediately reforms because that area is hot. And the additive is still in the oil says,
01:07:48Oh, here's my chance. And as long as there's anti-wear additive in the oil, uh, it is not worn
01:07:58out.
01:07:59Now there is another phenomenon called falling out of grade, which is exactly what I mentioned before.
01:08:04Namely, the VI improver is a long chain molecule.
01:08:12Viscosity index VI.
01:08:14Yes. Like, like, um, I think of, of oil as like a pot of boiling spaghetti.
01:08:23And when you want to thicken a light oil in order to have a multi-grade 5w20, for example,
01:08:33you start with five and you boost it to 20 by putting these long chain molecules into it.
01:08:43Now, if those molecules are not the high quality kind, and I forget which one that is,
01:08:51they can break, they can lose molecular length. And then what happens is called falling out of grade.
01:08:59It's becoming more like a 5w5 than a 5w20. And you don't really want-
01:09:06I think I took that out of my pressure washer because I bought a used pressure washer,
01:09:10and I don't think they ever changed the oil, but also I think the carburetor may have been
01:09:14putting fuel into the oil as well. So it was definitely out of grade.
01:09:19And we're, um, off the subject here, but-
01:09:23I was just thinking that, but you know, we, we were talking about trying to know the truth
01:09:28and that's what we, uh, that's why we send our oil in at least once in a while.
01:09:32And, uh, to find out what's going on, see what's in it. And, um...
01:09:38Well, there were those, uh, there was that B-29 crew who were refusing to fly,
01:09:44and a jeep comes up and screeches to a halt and a red-faced officer piles out,
01:09:49you will fly that airplane. And someone said, yes, but, uh, they gave us engines from Bengal Air Depot.
01:09:57I'll have you know that those Bengal Air Depot engines are just as good as the ones that come
01:10:03from New Jersey. And he's ranting and raving. Meanwhile, the pilot has said to the flight
01:10:11engineer, you want to go pull the screens on number three? And he's out there doing it.
01:10:17And the red face is getting redder and redder. Court-martial is about to convene,
01:10:23at least in his imagination. And here comes the flight engineer with the screen,
01:10:28with bolt heads and pieces of piston ring on it. And he...
01:10:37Oh, I'll fly that. No, I won't. I'll fly it myself.
01:10:42Yes, sir. In fact, no.
01:10:44I know I've told that story before, but it's a good one.
01:10:47Well, I haven't agreed... And it's much like oil. It's a crude form of oil analysis.
01:10:53Pull the screen and see what's on it. Well, cut open your oil filter.
01:10:59Yep. Yeah. The NASCAR guy's cutting the filter open.
01:11:03Oh, no. Yeah. I mean, you can send...
01:11:05Stretching out the paper to see what's on it. Oh, yeah. The lab, the lab that does the oil analysis
01:11:10for the stuff that I send in, you can also send a filter in. And they'll, they'll dismantle it for
01:11:16you. But you could just cut it open. You can get your big pipe cutter and cut your can off.
01:11:22I mean,
01:11:22I have the fortune of having so many canister filters in my life. I don't have to cut the
01:11:26can off because it just comes off and makes a mess anyway. Even the Toyota, the newer,
01:11:30the newer Toyota that we drive has a canister oil filter. I thought I'd never
01:11:35get away from it. And I guess I haven't. But it is, it's good to try and find the truth.
01:11:45Well, that's it. Yeah, that's it. We, we covered swing arms, both front and rear and alternative
01:11:52alternatives. We, we managed to skip Dr. John Wittner, a little bit of him on his slightly
01:12:00alternative. Oh, yeah. Well, we'll get to him. We'll get to him. I think John Wittner could be
01:12:04his own podcast. Well, he sure could. Yeah. There's so, so much going on there and the allegiance.
01:12:11His father was an aeronautical engineer and a very practical one. Oh, good. See, that makes sense.
01:12:16Doesn't that make sense? Yes. Indeed it does. But Hossack and there was the troll front end,
01:12:23uh, troll engineering. That was kind of like, uh, Oh, consider your tracks on your closet door,
01:12:31but for giant doors and the metal rollers. And it had this blade with these on either side of it.
01:12:37And it had wheels that located it and there were rolling elements instead of a linear bearing.
01:12:42Yeah. A linear bearing. And, um, I rode one of those that had a very rigid tubular front end and
01:12:47kind of like almost a miniature trellis. That was a fascinating too. We have, we have podcasted about
01:12:54some of that stuff, but, um, we'll see you soon, Dr. Wittner. Thank you for riding with us when you
01:13:01get
01:13:01to us. Thanks everybody for checking us out and, uh, we will catch you next time.
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