- 8 hours ago
WEIGHT TRANSFER and Motorcycle Handling--To wheelie or not?
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00:00:00Welcome to the Cycle World Podcast. We appreciate you being here. Share it with your friends.
00:00:07Thanks. Thanks for joining us. This week's topic is weight transfer and motorcycle handling.
00:00:14Weight transfer in the most extreme forms. Wheelies and stoppies. Very exciting.
00:00:19Yes.
00:00:20I've had a stoppie at Mugello in an area where you would not want a stoppie.
00:00:24And I managed, because it was one of the early awesome radial brakes, I was able to be up and
00:00:33being breathless.
00:00:34So you go through a chicane at the top of Mugello when you go up the hill, there's a little
00:00:39chicane, and then you accelerate hard to the downhill.
00:00:42And boy, that was exciting. But the brakes, it was one of the early radial mount brakes, I think top
00:00:48and bottom, Aprilia Miele 1000 factory, the V-Twin.
00:00:53And it was a great, it was a great case for ultra precise modulation because I was able to, I
00:01:00was able to release precisely in enough to get the bike to stop from continuing.
00:01:05Because once you get over that center, past the balance point, you're done on the other side, there's no, especially
00:01:11a stoppie because you can't, you know, wheelies, you can maybe stab the brake or.
00:01:15You need front drive then.
00:01:17Yeah. Yeah. So.
00:01:18Gas the front.
00:01:20But very important. We've seen a lot of experiments with this, and we've had so many different ideas of where
00:01:27the rider sits.
00:01:29Gosh.
00:01:31It's a good topic, and that's why we're using it.
00:01:34Yes.
00:01:35So.
00:01:36Yeah.
00:01:37Here it goes.
00:01:38Here it goes.
00:01:39I've just thrown the pitch, Kevin. Swing.
00:01:41Yes.
00:01:42Swing and a miss.
00:01:43Anyway, we've all seen automobiles squat down at the rear while they're accelerating.
00:01:50We've seen automobiles dive at the front when they're braking.
00:01:53And motorcycles do these things much more than cars do because their center of mass is higher.
00:02:03At least it's higher than the center of mass of racing cars.
00:02:09And their wheelbase is roughly one half that of a car.
00:02:13So, here's what causes weight transfer.
00:02:19We know that braking or accelerating force takes place at the pavement surface.
00:02:25So, its height is zero.
00:02:29However, the inertia force, if you're braking, the inertia force of the vehicle's kinetic energy
00:02:40is acting at the center of mass height, the CG height.
00:02:47And on a motorcycle, this is 20, 22 inches or so.
00:02:56That is the lever.
00:02:58The force acting on the lever is the braking force.
00:03:03And when that torque, CG height in feet times the force, gives you foot pounds, just like with a wrench.
00:03:11When that equals the, let's say we're braking here, the wheelbase times the load on the rear wheel
00:03:23is the torque level we have to reach in order to just get the rear wheel up a little bit.
00:03:32And the same thing for acceleration.
00:03:38So, we're just looking at a little arithmetic here.
00:03:43The basics are the force acts at ground level.
00:03:46The vehicle acts like its mass is focused at 20 or 22 inches above the pavement.
00:03:52So, you apply the brakes or you hit the gas and you're going to transfer weight from one wheel to
00:03:58the other.
00:04:01And some practical examples are useful.
00:04:07Years and years ago, the late Hurley Wilbert, America's great rider tuner,
00:04:16he actually got one of those 750 air-cooled Kawasaki two strokes to finish second at Daytona.
00:04:23So, that was the highest finish at Daytona of any of those bikes, those 750s.
00:04:31And Hurley did that because he was a practical man and he was a thinker, as I will now reveal.
00:04:39He called me to tell me that he'd ridden two bikes back-to-back.
00:04:43He had built his own bike's chassis and setup in the old English style.
00:04:51Weight as low as possible.
00:04:52Weight, low center of gravity is the key to handling.
00:04:58People worshipped in that church for years.
00:05:01And I must say, I did more than had a look in the front door, too.
00:05:05So, mea culpa.
00:05:08But, he said, the other bike, which was prepared by Randall M. Hall,
00:05:15who was a controversial figure at Kawasaki, had a noticeably taller, higher engine position.
00:05:24And he said, I rode those bikes back-to-back, same day.
00:05:30And, I have to tell you, I was quicker on the tall bike.
00:05:38And he said, at first, I just wanted to reject that idea because we don't want to have built a
00:05:45slow bike intentionally.
00:05:47It can't be true, right?
00:05:49Let's make this thing slow.
00:05:50Oh, success.
00:05:51It's a, it's a.
00:05:54Anyway, he said, I've, I've thought about this a lot and I want to tell you my conclusions.
00:06:00He said, if you're accelerating on a low bike, lower center of mass, it has less leverage to lift the
00:06:10front or to unweight it.
00:06:13And he said, and less effect of transferring that weight to the rear tire.
00:06:20So, he said, on my low bike, the symptom was, it, it wasn't accelerating as strongly off corners.
00:06:28It was tending to maybe slip and slide a little.
00:06:33But, on the tall bike, hooked up and accelerated.
00:06:37And, what was going on here, he said, was that the taller bike transferred more weight onto the drive wheel.
00:06:46And, provided that there was enough on the front wheel to steer, it made that bike accelerate.
00:06:54So, quicker lap times on the taller bike.
00:06:59Then, we have the example of Yvonne Duhamel at a closed Kawasaki test at the old Ontario Speedway in Ontario,
00:07:11California.
00:07:13And, this was 1972, just a year after the peak of the mania for long swing arms.
00:07:20You buy candles bad, put on a long swing arm, it'll settle it right down.
00:07:26So, Yvonne goes out on this bike, which has a longer than usual swing arm.
00:07:33And, he's just not getting down to lap times that he's done previously.
00:07:38What can be the trouble?
00:07:39Round and round, he goes.
00:07:41He said, when I try to gas it, it spins instead of accelerates.
00:07:47It doesn't go forward, it goes sideways.
00:07:51And, Yvonne always spoke in a kind of charming nasal whine.
00:07:57And, he was a man of considerable humor.
00:08:00He enjoyed life's little contradictions.
00:08:04Oh, Miguel was the same way.
00:08:06He was very funny.
00:08:07Covering Miguel when I was doing some race coverage back in the day.
00:08:11And, the other guys were doing more of that.
00:08:14But, quotes from Miguel in a road race story from Road Atlanta or whatever were always great.
00:08:19Like, oh, he's going to be.
00:08:20I thought the guy in front of me was going to put the kickstand down because they were trying to
00:08:23avoid being drafted.
00:08:25You know.
00:08:26God, he's good.
00:08:27Very funny guy.
00:08:28And, obviously, massively talented.
00:08:30Just like his dad.
00:08:32So, they have a little conference about this.
00:08:35Mom, mom, mom, mom.
00:08:36What's different from the last time we tested here?
00:08:39Swing arm.
00:08:40Hmm.
00:08:42Okay, what do we got here?
00:08:43Is there anything in the truck?
00:08:44Somebody nimbly hops up in there.
00:08:47And, in a manner that white-haired guys like myself can no longer do.
00:08:53And, there's crashing and banging.
00:08:57As you expect when people are looking for something in a hurry.
00:09:00And, he comes out holding up a stock H1R swing arm in one hand.
00:09:04They had piles of those things.
00:09:06They had piles of the special 35-millimeter VM carburetors made for the 500.
00:09:12They had boxes of them.
00:09:13I think they had to buy a minimum quantity.
00:09:15There's probably still some.
00:09:19Anyway, they put the stock swing arm on.
00:09:24Take care of the details like ride hide, blah, blah, blah.
00:09:27Yvon goes out.
00:09:29And, immediately, his times come right down.
00:09:33And, he comes in beaming.
00:09:34He says, how's that?
00:09:36And, they show him the board.
00:09:38All is well.
00:09:40So, what was happening?
00:09:43By shortening the wheelbase.
00:09:45See, dragsters have long wheelbases.
00:09:48To avoid wheelies, what they're trying to do here to get Yvon's bike to hook up and accelerate is to
00:09:56transfer more weight onto the rear tire.
00:09:59If you push the tire forward, it's easier for it to do that.
00:10:05I'm sure dirt trackers do it all the time because the surface they race on is constantly changing.
00:10:11Oh, here comes the water truck.
00:10:12Oh, here comes the sunlight.
00:10:14Oh, it's cooling off in the evening.
00:10:17So, that was a success.
00:10:25That change worked.
00:10:27So, that shows the value of putting weight on the rear tire so that it doesn't spin but instead hooks
00:10:39up and drives.
00:10:41See, I want to ask Yvon how the front was with the long swing arm.
00:10:46Was that better or was that worse?
00:10:49Well, he wasn't getting enough power down to make the front have a problem.
00:10:54So, another example here is, and I've used these examples before, but Valentino Rossi in 2008 switched from Michelins, which
00:11:12he had used for a long time, to Bridgestones.
00:11:17And the reason that everyone was in a mad scramble to do so was that Michelin had made an incorrect
00:11:28response to a rules change.
00:11:30The rules change said, no, you can't wait until Saturday to make the tires for Sunday.
00:11:37The tires all have to be here Thursday beforehand or whatever day.
00:11:43Explain that, because that was a time to be alive.
00:11:46Oh, man.
00:11:47Overnight tires, based on the weather and what had happened up to that point, and then back in the factory,
00:11:54okay, mixing up the tire and then putting it in the machine and then knocking out the race tires and
00:11:59flying them to the track.
00:12:02Amazing.
00:12:02That's what they did.
00:12:03Or they drove them to the track if it was sort of within the compact part of Western Europe, swaying
00:12:10over the highways.
00:12:13And, of course, what they were trying to do was to have the right tire compound for the temperature expected
00:12:18on Sunday.
00:12:21And Bridgestone, well, Michelin, always compounded in a very temperature-sensitive way.
00:12:30They had family of rubber compounds that the peak grip, if you were at the temperature that they were made
00:12:37for, was fantastic.
00:12:39But if the grip was five degrees centigrade different, there might not be very much of it.
00:12:45But Bridgestone, being half a world away, said to themselves, we can't fly our tires out there Saturday night.
00:12:58It's too far.
00:12:59So we're going to have to make a wider temperature range family of tread compounds, which they did.
00:13:07So here's Valentino, and he's on Bridgestone.
00:13:11And he's rushing up from turn six to the top of the hill at Laguna Seca and braking.
00:13:18And in order to get down to corner speed, he finds he has to brake 40 feet sooner than he
00:13:25had done on the previous tire.
00:13:27Now, you have to realize all these race teams carry digital histories of everything that's ever been done.
00:13:33It's all on the computer.
00:13:36And there's more than one copy.
00:13:38So what's going on here?
00:13:47So Jerry Burgess, Valentino's crew chief at that time, tries all the things you try.
00:13:55Nothing worked.
00:13:56Nothing.
00:13:57And as Burgess likes to say, paralleling Sherlock Holmes, when the obvious solutions turn out not to be the answer,
00:14:13what is left must be the answer.
00:14:16So they raised the bike.
00:14:20And the 40 feet disappeared.
00:14:24And based upon what we've said here so far, you can see that a taller bike has a higher center
00:14:32of gravity, more leverage to transfer weight quickly onto the front tire.
00:14:37Now, tires are at a disadvantage at the beginning of braking because they have cooled all the way down the
00:14:44straightaway to that point.
00:14:48Tire grip is very sensitive to temperature.
00:14:51So this is why the tire guys are always asking the rider about initial grip versus mid-braking grip.
00:15:01Because if initial grip is too low, then they've got a problem.
00:15:07And in this case, raising the bike a few millimeters added enough weight transfer to make the front tire to
00:15:15load it hard enough to grip so that he could then get the bike down to corner speed in the
00:15:23normal distance, braking distance.
00:15:27So I think that's a valuable lesson right there, because here you might think, well, dragsters are low to keep
00:15:37the front end down.
00:15:39Maybe we should lower the bike to improve braking, which is just the opposite of acceleration.
00:15:44But no, it doesn't work that way.
00:15:49So that's getting some weight on the front.
00:15:56So a few years later, I'm watching a super bike practice at Loudoun, New Hampshire.
00:16:02And there's a rider having trouble getting off 13, which is the turn out of the infield onto the little
00:16:09dinky straightaway they have there.
00:16:11And I see him trying to accelerate, and the bike is going wide, and with a kind of resentful shake
00:16:22of his shoulders, it was like, oh, all right, then.
00:16:25He leans forward and pulls himself forward to move weight over the front tire.
00:16:35Now, there's a little 1950s book by Piero Taruffi, who was so important in making the Jalera 4 happen, because
00:16:47he was the man who knew everything.
00:16:48He wrote a book, a little book, called The Technique of Motor Racing.
00:16:52And in one of the pages, there's a curve of tire load versus tire grip.
00:16:59And it goes up linearly, and then it softens, and it starts down.
00:17:06What's happening there with the softening is that increasing load is increasing the area of true contact between the rubber
00:17:17and the fine details of the pavement texture.
00:17:21Notice what I'm not saying.
00:17:25I may have to just say it.
00:17:28Asperides.
00:17:30Asperides, yes.
00:17:32So, it starts to soften because the tire has filled in, has deformed to the maximum that it can.
00:17:50And now what's happening is, is the rubber strong enough to transmit the force, or have we just made a
00:17:57cheese grater?
00:17:59And that's how a blackie is left in a corner.
00:18:05The tire is turning into a cheese grater situation.
00:18:08So, that business meant that this rider had not yet reached the peak.
00:18:20He just didn't have enough load on the front tire to get the grip he needed to keep turning while
00:18:25he was accelerating.
00:18:26So, he, oh, all right, I'll lean forward.
00:18:30My arm doesn't feel good now.
00:18:32It reminds me of Nicky Hayden going into Turn 11 at Laguna Seca.
00:18:36I don't remember what year it was.
00:18:38But he was going in deep and trying to, I think he was trying to make a pass or block
00:18:42a pass.
00:18:43But he went in and you could see it in slow motion.
00:18:45They went back.
00:18:46It was beautiful.
00:18:47He's braking super hard, right?
00:18:48So, you watch the front end.
00:18:50So, when you're applying the brakes in a racing situation, and even on the street, you want swift and ultra
00:18:55-precise from no braking to zzzz.
00:18:58So, you're squeezing the suspension, whatever that sag is going to be, that braking force.
00:19:03And then you squeeze the tire.
00:19:05And that's all you have.
00:19:07And so, you could see him zzzz, and then the tire squeezes down.
00:19:12And there he is.
00:19:13And he's a little bit, maybe he's somewhere else in the track, but there's a small bump.
00:19:16And there was nothing left to give.
00:19:19He was going in as deep and hard as he could.
00:19:22And that little bump, there was no more, the tire couldn't take it.
00:19:27Nothing could absorb it.
00:19:28And it just, you watch the light appear under his tire, and down he went.
00:19:36So, what a feeling.
00:19:39Yes, indeed.
00:19:40Yes.
00:19:41What a feeling.
00:19:44Near the end of the 1980s, the people were getting a lot more experience with four-stroke race bikes.
00:19:54And a problem was appearing.
00:19:59Squat and push.
00:20:03Bikes whose riders were trying to accelerate early in a corner.
00:20:10So, as to make the straightaway as long as possible.
00:20:15We're noticing that, as they tried to accelerate, if their chassis setup was such that the bike squatted down at
00:20:23the back, it made the front end push.
00:20:28And I saw a classic example of this, again, at Turn 11.
00:20:32I've spent a lot of time there.
00:20:37At Laguna.
00:20:39And here comes Alex Barrows on the Kajiva.
00:20:47What a comparison with Wayne Rainey.
00:20:50Wayne Rainey is approaching this turn, and he's making all sorts of preparations.
00:20:55You can see him moving on the bike.
00:20:57He lifts his inside knee just in time to clear the border bricks or whatever it is, a raised curb.
00:21:07And he is pulling himself forward on the bike and moving his elbows and knees away from the motorcycle because
00:21:15he's expecting the motorcycle to be doing all sorts of violent stuff.
00:21:19And he doesn't want the steering interfered with by those gyrations.
00:21:24So, he's basically hanging from the high bar with his arms bent.
00:21:31He's holding himself forward like that.
00:21:33But poor Barrows, he's 19 years old or whatever he was at the time.
00:21:38Not very experienced.
00:21:40His butt is back against the seat stop.
00:21:43And you can see he's trying to dig the front in, and it won't.
00:21:48And he comes in from that practice, and he's talking to his team.
00:21:55And he's making the air motorcycle with his hands.
00:21:59And he's showing – he's digging it in.
00:22:03And it closes, as they say.
00:22:05You want me to see that?
00:22:06There's, like, there's chatter, and then there's crossing the front, like, losing the front.
00:22:11Oh, boy.
00:22:12We've seen various hit videos where we string all those gestures together.
00:22:17What are they saying?
00:22:18It's good.
00:22:19What are they saying?
00:22:19I love the paddock gestures.
00:22:21It's good stuff.
00:22:23And, well, it's actually a language that is useful because there's a lot of noise trackside.
00:22:29Yeah.
00:22:32And Freddie, at one time, was not too good at remembering different things that they wanted him to do on
00:22:43the racetrack.
00:22:44And you come in, and they ask him, well, did you look at the tack in Turn 8?
00:22:50Oh, I'm sorry.
00:22:52I forgot.
00:22:54Because he had other things to do.
00:22:56He didn't keep a scratch pad with a pencil on a string taped to the tank.
00:23:02He had work out there.
00:23:04Well, that's what I like about the test pilots and the, you know, your Chuck Yeagers and all those guys,
00:23:09they get into some horrific flat spin that they're never going to recover from.
00:23:14But he's riding on the clipboard that's strapped to his leg, you know, cross control, not functional, whatever.
00:23:23And then, okay, eject.
00:23:27Farewell.
00:23:28Yeah.
00:23:29Our hands are too busy.
00:23:30If you're in a flat spin on a motorcycle, there's no riding.
00:23:34Yes.
00:23:37Well, this squat and push thing was a real bother because it didn't seem to afflict everyone.
00:23:48And it was finally, it was finally analyzed properly by, among others, Olien's.
00:23:58And they published a little four-page paper on it, which became a treasured item.
00:24:04Hey, anybody seen a copy of that?
00:24:06Because you could see that there were teams going to the Olien's truck asking for really stiff rear springs.
00:24:15And, of course, what they were trying to do is prevent the motorcycle, forcibly prevent it from squatting.
00:24:21And, of course, the stiffer your suspension is, the greater the height that a bump will toss you, the more
00:24:28airtime you get, and the farther you move sideways, possibly enough to lose grip altogether.
00:24:34So we don't want extremely stiff.
00:24:37We want just stiff enough.
00:24:39Great Alan Girdler quote.
00:24:41I was talking to him about my Liberta 3CL, which is a 1970s Italian motorcycle with 1,000cc triple.
00:24:48And I said, you know, man, the suspension on this thing is really stiff.
00:24:52It's kind of brutal.
00:24:53And he said, well, in the 70s, the best way to make suspension to work was to not let it.
00:24:59So he ended up with no movement.
00:25:01And that was probably the best solution at the time.
00:25:08Well, this needed a solution, and the solution was found.
00:25:14It turns out that the angle between the top run of the drive chain and the plane drawn through the
00:25:28swing arm pivot and rear axle, the central plane of the swing arm,
00:25:33that angle, working, powered by the tension in the chain, produces a lift force, tending to push the swing arm
00:25:44down.
00:25:46Hmm.
00:25:48Maybe we could use that to cancel the squat.
00:25:53And if we cancel the squat, that ought to cancel the push.
00:25:57And then we'll win the race and be heroes.
00:26:02Well, like it says in the song, fighting the girls from off in my back.
00:26:08So that's a 50s song.
00:26:10So you have to apologize for their lack of sensitivity.
00:26:13A moment of silence for them.
00:26:18But the question was, how do we change that angle?
00:26:22Well, every time you change the sprockets, you're changing the angle between the chain and the swing arm,
00:26:28which is why some places the rider would have this problem and other places not.
00:26:34So it was like it was like Zeus's thunderbolts striking at random amongst us mortals.
00:26:42It couldn't be understood.
00:26:43But this new understanding showed that it could be conquered.
00:26:47Because if you change the height of the swing arm pivot, you would change the angle of the central plane.
00:26:55So by raising the swing arm pivot, you would increase the anti-squat force produced by the chain angle.
00:27:06Also, if you put on a bigger rear sprocket, etc.
00:27:10So it became possible this way to fight, squat, and push right out of the picture.
00:27:23And that's why early 90s bikes, super sport, and superbike homologation jobs were given adjustable swing arm pivot height,
00:27:38usually in the form of a little metal box on either side.
00:27:42And you could put plates into that box that had the pivot hole at different heights,
00:27:49which would be stamped into the plate so you'd know.
00:27:56That's all you wanted as a kid, at least when I was a kid.
00:27:59It's like, oh, the homologation special would come out, and you're like, I want that.
00:28:04I don't know how to use it, but it's got to be good.
00:28:07Well, mysteries are very cool.
00:28:10We love mysteries.
00:28:12We watch them every evening, in some cases.
00:28:19Anyway, this sort of got the thing under control.
00:28:25But I went to the Olin's Tech, and I said,
00:28:31doesn't everybody have a copy of your little dissertation?
00:28:36Oh, no.
00:28:37He said, we had a subscription list.
00:28:39And I put you on there because I thought you'd like it.
00:28:42I did like it.
00:28:45I got to find a copy of that.
00:28:47Yeah.
00:28:47So that made it possible to, for some people at least,
00:28:54to give up using super stiff springs at the back in an attempt to conquer squat and push.
00:29:02Well, now, somebody turned this idea around and said,
00:29:10well, I wonder if this would work at the front.
00:29:14If we made a device that kept a constant ride height at the front during braking,
00:29:20maybe everything would be, you know, better.
00:29:22So there was a period of error.
00:29:29And during this period, all sorts of mechanical and hydraulic anti-dive systems were made really quite ingenious.
00:29:40You can see them in photographs from that time.
00:29:46Rods, levers, heim joints, external hydraulic lines.
00:29:50We're going to level this thing off, and we're going to have wonderful braking.
00:29:56Nope.
00:29:57Didn't work.
00:29:59Oh, it was all over production bikes?
00:30:04Yamaha did some testing, and they found that a bike that dived,
00:30:11particularly if the rider first applied the rear brake somewhat,
00:30:16when you apply the rear brake, the torque is applied not to the chassis, but to the swing arm.
00:30:22So the rotation of the wheel tends to produce a squat effect to lower the rear of the bike.
00:30:33And when Skip Axelon went to talk to Kenny, who'd been hurt in practice, 1980, I think,
00:30:44Skip said, people are out braking me at Daytona.
00:30:49And Kenny said, do you ever think of applying the rear brake the instant before you apply the front?
00:30:56It was like wonderful words from Olympus, but what do they mean?
00:31:04It's like when the Persian army was approaching in Greece,
00:31:14with the Olympians, the words were, the Greeks, the Persians shall subdue.
00:31:27That could mean either thing.
00:31:31Amphiboli, they call it.
00:31:34Anyway, so...
00:31:36Are we adding that to the vocabulary list?
00:31:41In many cases, though, you can tell people something,
00:31:46and because they've heard so many rumors in their lives, paddock rumors, you know,
00:31:51they just come, oh, they did this, and here's what happened.
00:31:55It's great.
00:31:57Got to try it.
00:31:58It's easy to dismiss this stuff.
00:32:00If I had some bread, I'd make a sandwich.
00:32:02If I had some meat.
00:32:03Yes.
00:32:05So, Yamaha's experiment showed that letting the bike dive,
00:32:13particularly if the rear end was squatted by applying the rear brake,
00:32:18too, lowered the center of mass,
00:32:22giving the deceleration force less leverage with which to lift the rear wheel.
00:32:29Well, BMW did a similar experiment with their telelever when they were, you know,
00:32:35looking at how to build telelever.
00:32:37Telelever is the lower A-arm on the fork.
00:32:41So, you know, you have an upper crown,
00:32:43and, you know, it puts the braking force into the chassis.
00:32:47It's a big A-arm and has a ball joint.
00:32:49And telelever, you know, it's pretty good suspension, does a good job,
00:32:53but you can tune anti-dive into it just like you can with a Hasek front end.
00:33:01And they experimented with, well, like dive, let's get rid of dive.
00:33:05And it was a big indication for riders.
00:33:08How hard am I braking?
00:33:10How far is the front going down?
00:33:12And also putting the weight on the front as we're talking about weight transfer.
00:33:18Perhaps there's something going on with geometry, Kevin, doing the math.
00:33:21But you want the front.
00:33:23I mean, you know, I want the front, and everybody else wanted the front.
00:33:26So they've tuned in dive to give riders.
00:33:28As a way of control, as a measurement.
00:33:34Assigned.
00:33:35It allowed them to say, oh, I'm braking pretty hard here.
00:33:39And Luca Catalora was one of the people that complained particularly about that.
00:33:43People were saying, oh, I want this really stiff suspension
00:33:46because it makes the bike respond quicker to your control inputs.
00:33:52Luca Catalora didn't want that.
00:33:53He wanted the front end to dive a bunch.
00:33:56So he couldn't put, you know, springs with inch-thick wire in there, stiff ones,
00:34:03because he wanted the front dive to measure for him his braking level.
00:34:09And this is one of the things that's hardest for engineers to understand,
00:34:14because when they talk to riders, they don't hear – it doesn't sound like the physics professor.
00:34:21It sounds like a layperson.
00:34:23Meatbags.
00:34:25They dismiss it.
00:34:27Meatbag full of feelings.
00:34:28We're feeling things.
00:34:29We have emotions.
00:34:31And as you've always said, the safety net, you know, you've done things over and over,
00:34:36and you've found a way to do it that is repeatable,
00:34:38and you don't end up on the pavement, and you're going fast enough.
00:34:42And then when you try to go faster, you have to experiment with new things.
00:34:45But, yeah.
00:34:47I'm a third-place rider, so I just relax back here.
00:34:50It's emotion.
00:34:51Well, you know, Freddie Spencer's got a book out.
00:34:53I've got to get a copy of it, but it's called Feel, and it's about him.
00:34:56Oh, very good.
00:34:57Yeah.
00:34:57It's about him, you know, riding and, you know, something to do with intuition,
00:35:04and, you know, he's really into it.
00:35:06It's cool.
00:35:06I want to check that out.
00:35:12Well, so much for anti-dive.
00:35:15Now we can move on to some other examples leading to new technologies.
00:35:21Well, I think I would like to bring up, unless you have it somewhere in your brain pan on the
00:35:28list,
00:35:28but 1984 NSR 500.
00:35:32Oh, yeah.
00:35:33That was a wonderful experiment by Honda in center of gravity, and, you know, Kevin was there.
00:35:40So, Kevin, tell us about that bike.
00:35:42Well, what they did was they used an idea that Elf, who were their partners in building a line of
00:35:54what people today call high-tech front ends,
00:36:01alternative front ends, and Honda supplied engines, and Elf built chassis.
00:36:09And the problem was that, well, one of the concepts that they raised was along the lines of the key
00:36:20to superior motorcycle handling is the lowest possible center of gravity.
00:36:24They decided to move the fuel from above the engine to below the engine.
00:36:33This was supposed to be hot stuff.
00:36:38And why didn't the test riders catch it?
00:36:41I saw this bike at Daytona.
00:36:43It also had carbon fiber fork tubes that were an unspeakable price, and they had metal jacketing for the friction
00:36:54surface.
00:36:54So they were just marvelous things.
00:36:58I want unlimited budget.
00:37:00Wouldn't it be nice?
00:37:01I just want unlimited budget, whatever it is, Arma, Racer, magazine stories.
00:37:07I want all the budget.
00:37:08But when people get the big money, they're so tired from the effort that all they can think of is
00:37:13Olympic-sized swimming pools
00:37:14and blonde ladies with cash register eyes and dancers' legs.
00:37:21And just let me alone.
00:37:23I don't want to do anything.
00:37:26Well, motocross.
00:37:29Find me in the shop, Kevin.
00:37:31Just bring the budget and find me in the shop making bushes.
00:37:34I'll look there.
00:37:35Yes, sir.
00:37:36I'll look there.
00:37:39Motocross and dirt track have been the most fertile fields in which to grow innovation for suspension.
00:37:50Now, somebody had the bright idea.
00:37:54Let's compress the front suspension on this motocross bike and hold it down with a latch such that the next
00:38:03time the rider applies the front brake that it will unlatch and let the bike up to the normal ride
00:38:10height in the front.
00:38:10The purpose of this, because these are bikes with 10, 11, 12 inches of suspension travel.
00:38:21It's like Tom Mix getting on a horse.
00:38:24You can't just throw your leg over something that's this tall.
00:38:28So they pull the front end down.
00:38:30That lowers the center of mass considerably, even though the front is still where it normally rides.
00:38:37And you get the whole shot.
00:38:39You can accelerate harder without lifting the front with the center of mass lower.
00:38:48Well, soon everybody was doing it.
00:38:51So it was of no advantage to anyone.
00:38:53It moved to MotoGP.
00:38:56And the wonderful thing about MotoGP is that within certain broad limits, they do have the money.
00:39:08So they built the whole shot system and they tried it.
00:39:17Well, that was good.
00:39:19That was good.
00:39:20What about the next turn that we accelerate off of?
00:39:25Now the bike is at normal ride height.
00:39:28Why can't we lower it so we can accelerate harder?
00:39:33Why don't we keep it low all the way down the straightaway so we can brake harder, provided that the
00:39:38initial braking is strong enough to transfer weight to the front brake, enough to brake maximally.
00:39:47So they get to work on this.
00:39:49But there's a rule.
00:39:50The rule says that electrical or hydraulic means cannot be used.
00:39:56Oh, powered electrical or hydraulic means cannot be used to alter ride height.
00:40:02Because previous to this, there had been an era when, had you been able to record MotoGP bikes entering and
00:40:12leaving corners, you might have heard, you might have been able to detect a waveform of little motor humming away.
00:40:21Little electric motor is rotating the preload ring and raising and lowering the rear suspension.
00:40:31In order to gain the advantage of a lower center of gravity, lower CG height in certain circumstances, the bike
00:40:40has to be high to have cornering clearance.
00:40:43It ideally should be lower.
00:40:46It should turn into a dragster for acceleration.
00:40:49It should turn into a brakester for braking.
00:40:55So, this was done.
00:40:58And I suspect that it is self-powered, that the motion of the suspension pumps up some kind of accumulator.
00:41:08And the hydraulic pressure in there, which has not been achieved by electrical or mechanical power sources.
00:41:19Well, suspension motion is mechanical, but you get the idea.
00:41:25And there's enough such power available to do these ride height changes.
00:41:32And I asked John Cornwell, who recently survived a horrific, he and his daughter survived a horrific accident with minimal
00:41:43injuries.
00:41:44Oh, my.
00:41:46And I asked him, so, I see pictures, I see stills and videos of these bikes, but I can't always
00:41:54make out what's going on.
00:41:55He said, low on the straightaway, high through the turns.
00:42:02And so, for 2027, all this will be banned, because they are reasoning.
00:42:09Everybody has such a system now, and so there's no advantage in it.
00:42:13It's like when everyone switched to titanium fasteners.
00:42:19Big deal.
00:42:20Three pounds.
00:42:23All it means is that you've all spent too much money for fasteners.
00:42:29Well, maybe if it's being outlawed, Kevin, we can make a deal with some team.
00:42:34We can call Claudio Domenicali and say, can we see that stuff?
00:42:38Can we see how it works, please?
00:42:39Can we go to a room with one of these bikes with no body work and look at all the
00:42:45jewels?
00:42:48So, this is, at present, this is the norm.
00:42:53And it is also possible to go to the wind tunnel.
00:43:01Ducati use tunnels that Ferrari has, I guess, or a tunnel.
00:43:08And vary the motorcycle's attitude.
00:43:14It has wings on it.
00:43:16Can we perhaps change the ride height at one end upward and at the other end downward to reduce the
00:43:27angle of attack so that the aerodynamic drag from the downforce-producing wings is at a minimum?
00:43:36This is what we hear is done.
00:43:39So, not only is there up and down, but there are also pitch changes that are scheduled into these systems.
00:43:47The rules insist that the rider must initiate the cycle for each turn.
00:43:54So, it's not something that says, oh, the GPS says that we're at position, so therefore, we must initiate CAN
00:44:05cycle number XYZ.
00:44:09Well, that's what riders need, more workload.
00:44:15But when the rules makers were racers, it was a long time ago.
00:44:20So, they're less sympathetic to these crazy kids who've never ridden a bad bike.
00:44:27There's the case of A.J.
00:44:29Foyt, I think it was Foyt, who said, modern race car drivers have never driven a bad car, so they
00:44:39don't know how to compensate for common chassis faults on the track as required.
00:44:49I had that same conversation with a racer who started in the 70s riding, you know, Libertas and other things
00:44:56that are not easy to ride.
00:44:59Forks were not figured.
00:45:00Forks were spindly.
00:45:02Swing arms were flexible.
00:45:03Everything, the weight transfer, weight, the overall weight on super bikes, whatever.
00:45:08And he said, yeah, these kids, you know, haven't ridden a bad bike, don't know how to compensate.
00:45:14And that was the one point I wanted to make, and this is how important the rider is, as we've
00:45:19already discussed here.
00:45:20But I remember, you've talked about Wayne Rainey riding a bike that, you know, he's obviously one of the greatest
00:45:29talents that's ever been on a racing motorcycle.
00:45:31And you could give Wayne a bad bike, and he would give you a good lap time.
00:45:36And part of that is that the percentage of his body weight versus the motorcycle can be moved around.
00:45:41And you were talking about entering the corner, exiting the corner, and hanging on to the bars and all of
00:45:47that.
00:45:48The really great guys are putting their bodies all over the place to influence what's happening.
00:45:52And if you have a problem where the bike's not doing a certain thing, you move your body.
00:45:57Kevin Schwantz, when he switched to, I think it was Busch Trucks, NAS trucks, he was, you know, racing pickups
00:46:05around ovals and stuff.
00:46:06And they'd switch to an in-car camera, and he would stick his knee out inside the truck because he's
00:46:12entering a corner.
00:46:13Like, it's there, man.
00:46:14It's not going anywhere.
00:46:16It is written.
00:46:17It's not going anywhere.
00:46:19So, the influence of the rider, you know, if you have a jockey-sized rider, maybe Danny Pedrosa has a
00:46:25harder time because he was like 120 pounds or something.
00:46:28But you get up into 160 pounds, and think of the 500 here at 286 pounds.
00:46:35Yes.
00:46:35You have a huge influence on that motorcycle.
00:46:39Certainly do.
00:46:40Yeah.
00:46:43So, then we look at dirt track, and as I commented earlier, the surface is constantly changing.
00:46:54So, in order to make the motorcycle hook up when it won't, you might have to raise it, as Valentino
00:47:02did with Jerry Burgess at Laguna that time, to make the Bridgestones work.
00:47:10You might have to change the wheelbase length and put a link in or take a link out because both
00:47:17of those things can alter the weight transfer to the rear tire.
00:47:24What you don't want is to find yourself rolling into the gas, and the back tire wants to go up
00:47:33and kiss the fence.
00:47:36So, people who really know that business are able to translate the rider's complaint or observation, a kinder way to
00:47:47say, into action to correct the vehicle's handling.
00:47:55And there are motorcycles on which variable ride height is an option, and one of them is Harley's Pan America.
00:48:07It has long been known to dealers that every dual-purpose bike you sell, which has longer than street bike
00:48:17suspension travel, the owner is going to come back and say,
00:48:23man, it's kind of embarrassing when I get to a stoplight, the contortions I have to go through to keep
00:48:29holding this thing up.
00:48:31So, I can fix that for you.
00:48:33Yeah, 35, 36 inches more on motocross bikes.
00:48:37They're in that range, though, up to 38.
00:48:40So, they just lower the bike a bit.
00:48:44The customer is happy.
00:48:46He didn't buy the motorcycle, in many cases, for its outstanding off-road performance, but because he likes the look
00:48:53of it.
00:48:55And that is perfectly legitimate.
00:48:58Yeah, the mechanical ride height change automated that has been going through the adventure space is a real boon.
00:49:06I mean, I'm big.
00:49:07I've never had an issue.
00:49:09Six-foot-two, 34-inch inseam.
00:49:11No problem.
00:49:12Like, put me on a tall bike.
00:49:13I don't really—it's not an issue.
00:49:16You are a downforce generator.
00:49:18Yeah.
00:49:19Yes, I am.
00:49:19I'm also good at compressing springs, especially now at this point in life.
00:49:23But it is a boon, and it's wonderful.
00:49:27Like, when you pull up, it's why that confidence on the dealership floor, the confidence of low seat height, that's
00:49:36why everybody, all the cruisers, low, low, low.
00:49:39People feel happy.
00:49:40They sit down.
00:49:41It feels—
00:49:4224 inches in some cases.
00:49:44Yeah.
00:49:44Yeah, on the most extreme case, yeah.
00:49:47So it's really good.
00:49:48An instance in testing that we had was we were doing a large naked bike shootout, probably nine bikes, and
00:49:55it was circa 2001, 2002, and we had a Ducati Monster 900 or 1000.
00:50:01I think it was a 900 at that time.
00:50:03And what was great about that bike is it had a rod for ride height adjustment and then also spring
00:50:10preload.
00:50:12And we were out on the test, and I had a lot of seat time on Monsters, and I knew
00:50:16how the suspension worked, and I had a good feeling for how they should be.
00:50:19And everyone was slagging that Monster for handling.
00:50:23Like, oh, it doesn't want to turn.
00:50:24It just, you know, the front's not sticking.
00:50:26It just doesn't feel right.
00:50:28And I was—I got my turn on the bike, and I was sitting on it, and I'm like, man, seat's
00:50:32really—feels low.
00:50:34And I rode it, and I'm like, this is not what it should be.
00:50:36And I pulled her over, and we got out some tools, and I found the adjustable wrench.
00:50:41And it's just a long rod with opposite threads, so that when you screw it in one direction, it spreads
00:50:47the rod longer.
00:50:48And when you spread it to the other, it squirts it down.
00:50:49Well, it had come from a dealer.
00:50:51I think it's a turnbuckle.
00:50:52Yeah, we needed the bike.
00:50:55Like, there wasn't one available.
00:50:56Like, you know, it was like, here's one from the dealer.
00:50:59So we got one from the dealer, but the dealer had taken all the preload out and compressed the ride
00:51:04height at the rear to the lowest setting.
00:51:06So it was a really low, good feeling.
00:51:08Wow, this is great.
00:51:09It's low center of gravity, and I can put my feet flat on the ground.
00:51:13Wonderful, but it didn't work dynamically.
00:51:15And on the side of the road, you know, above Anza Borrego, wrench, wrench, wrench, take the lock nuts off,
00:51:21extend it, put it back together.
00:51:22It was transformed.
00:51:23And, I mean, that was the super bike frame, essentially.
00:51:26That was the – it was great.
00:51:28That's what I'm getting at.
00:51:29It was great.
00:51:30And, you know, so it's a vote for you folks out there with motorcycles.
00:51:34Measure your sag.
00:51:35Do that stuff.
00:51:36Don't just accept what you get.
00:51:38If you buy a bike, you know, get active and mess with your suspension and see how life feels, see
00:51:44if it improves.
00:51:45Doug Chandler was well known for wanting a steep rake angle.
00:51:51And you get that on an adjustable bike by saying you want it.
00:51:57The mechanics take out a bunch of stuff from the steering head, put in other stuff, and there you are.
00:52:03But that situation didn't occur until later.
00:52:08So what you did was you raised the back of the bike and possibly lowered the front as well, thereby
00:52:15reducing the steering head angle.
00:52:19And all these things have a bearing on what's going on.
00:52:24MotoGP riders say that they use the rear brake 70% of the way through corners.
00:52:32I'd like to have more discussion on that.
00:52:36But I did work with a rider, Ron Pierce, who he was riding the wild and crazy KR750 Kawasaki water
00:52:45-cooled triple.
00:52:46And he said the brake is a quicker way to control engine torque than the throttle.
00:52:52Oh, yeah. Dirt trackers.
00:52:56Always, yeah.
00:52:57Oh, yeah.
00:52:57I mean, anybody, you know, you name it, yeah.
00:53:00And because the ability of that water-cooled engine to pull strongly on the chain was so great,
00:53:11on one occasion, the rear disc, it was a, I think it was an AP disc, it was cast iron,
00:53:19got so hot that it melted all the grease out of the wheel bearings and I had to put an
00:53:24insulator between the brake disc and the hub.
00:53:29But the lesson here is that these problems have been solved by people thinking about the problem.
00:53:36Well, let's see, what is causing this?
00:53:39What, how can we get at it?
00:53:41Let's take the problem apart so we actually understand it, rather than just being the guys that say,
00:53:47oh, Garland's is doing this, let's do it.
00:53:52There's a lot of that in the world.
00:53:54And that is why the late, great Albert Gunter told Dick Mann,
00:54:02don't ever imagine you're going to beat those guys using what they're using.
00:54:08They've had it a lot longer than you have.
00:54:11You've got to have an edge, something that only you have.
00:54:17And that takes thought.
00:54:20You have to come up with something.
00:54:22And extraordinary riders like Freddie Spencer, Kenny Roberts, and others did just that.
00:54:36When Marquez did his two years in Moto2, Moto2 has spec engines.
00:54:44So forget tuning the engine.
00:54:46It essentially has spec chassis because when the Kalex came out, it worked well.
00:54:52Everybody bought a Kalex.
00:54:56And so what is he left with as an edge?
00:55:01There were plenty of daring people who could really throw her in.
00:55:07His edge was tire management.
00:55:11When he got to MotoGP in his first season, I think it was the German Grand Prix,
00:55:18his tire drop occurred laps later than that of Valentino Rossi, laps later than that of Lorenzo.
00:55:29Well, impressive.
00:55:33He learned how to get more from the tire without progressively destroying it as much.
00:55:42Using the tire, yes, it does destroy it.
00:55:46But the rider can have such an influence on how fast that happens.
00:55:51Oh, huge.
00:55:52Yeah.
00:55:52I mean, I think back to Jim Allen in the Dunlop truck and looking at the wear patterns of a
00:56:00rider who was an incredibly hard breaker,
00:56:04but also was constantly ruining his tires.
00:56:07Pushing the front, pushing the front, using the front.
00:56:10Just mash.
00:56:11Yeah.
00:56:11Just mashing it out.
00:56:12And he would just, he wouldn't have grip.
00:56:14He'd go incredibly fast.
00:56:16He'd be at the front.
00:56:16He could lead the race, but he couldn't finish winning the race.
00:56:19Yeah.
00:56:20And, um, man, it's just, it's so much like that.
00:56:23And I, what you were saying about having their, their own recipe, having a talented rider,
00:56:28like obviously these people see a completely different plane of what's going on.
00:56:32The sensitivity of the tire.
00:56:33You talked about, uh, riders talking about the noise that a tire makes.
00:56:37I know when the tire is changing because I, it sounds different.
00:56:40Not only is it going to feel different, obviously you get, sometimes you get vibration when it's about to chunk,
00:56:45you know, there's all the things that happen, but there was a sound and you had,
00:56:49I remember you had said to someone in the tire business, like, Hey, you ought to put some,
00:56:54uh, some microphones back there.
00:56:57And then there's funny old Kev coming up with a, what the hell are you talking about, buddy?
00:57:01Why don't you go have a sandwich?
00:57:03You know, get out of my life.
00:57:05Well, uh, Kenny's contribution was to act on what everyone knew that motorcycles are lousy at turning
00:57:15and they're great at acceleration because two wheels, an engine and a place to sit.
00:57:21Whereas cars have all this extra stuff.
00:57:25They use one set of tires for going around right-handers and another set of tires for going around left
00:57:31-handers.
00:57:31What kind of a craziness is that?
00:57:34So, uh, these are, these are the innovators.
00:57:40And so it is with, with chassis and suspension setup and what have you.
00:57:45Um, the reason that people talk about MotoGP critics talk about it being a tiresome procession
00:57:53is because, um, the riders are all good at it and close racing is not achieved in any other
00:58:05way than by scripting or the occasional accident, like some memorable battles between, for example,
00:58:14Wayne Rainey and, um, Kevin Schwartz, where they, they went ding dong paint transfer time,
00:58:22uh, for long periods of the race.
00:58:25Rossi was always good at throwing something out, right?
00:58:29The creativity of Valentino Rossi, uh, I think of 2009 at, uh, Barcelona, Catalonia, where he does
00:58:37the, you're, you're at Catalonia, you're going this downhill and it's in a place where you
00:58:41wouldn't, you come out of a turn and you're kind of going into downhill and then it's a,
00:58:44a fast right onto the front straight and Catalonia's front straight is pretty long.
00:58:49And he passed between the two corners, the final corner and that corner beforehand down.
00:58:54And he just squirted by Lorenzo. It was, it was shocking and unexpected. And it is,
00:59:01it is wonderful to see that we, we like that creativity tactics. Yes. Yeah. It's, it reminds
00:59:07me of, of Nick Einach, what Nick Einach said once at a school, he was talking to a racer. I
00:59:12was at the
00:59:13school. He was talking to a racer. He was coaching as part of this school. And what he said was,
00:59:19I can only,
00:59:20I can only tell you as much as what would help you win second in the two 50 Grand Prix
00:59:26championship,
00:59:28fully realizing and fully knowing that that's every, every tool that he could apply at that time.
00:59:34That's the best he ever got racing in his career at, in the most competitive thing. And that was the,
00:59:40those were the tools available and it's up to the next person, the guy he's coaching, like I can get
00:59:46you here, but use these tools to, to find first it's, we all have to admit where we are and
00:59:54then try
00:59:55to be creative as we can. So. And of course the way handling is affected by a tire life, the
01:00:04need for
01:00:04extended tire life is that there are people who set up their bikes the way they would set up a
01:00:12dirt
01:00:12tracker. They scrub off speed with the front and the front is not destroyed in the process at such
01:00:18a fast rate. But if you try to ride that way on pavement, your front end, your motorcycle's front
01:00:24tire will look like somebody went at it with a, with a coarse wire wheel. It's just strings hanging off
01:00:32the
01:00:32rubber strings. So, uh, having a machine that's well set up to use its tires minimally, very desirable.
01:00:43Well, and the rider has a, has an influence, as you pointed out. I, I was terrible on fronts at
01:00:48Willow Springs cause I was always a person who rode the front. And then at Willow, you have all these
01:00:52incredibly fast rides, especially, you know, basically from, from six to the front straight,
01:00:59you're just, and I was brutal. Like I came in on a Ducati and experienced endurance racer,
01:01:06you know, came over and looked at my front tire and like feel felt the tire and looked at me.
01:01:11And I was, I just wasn't using the rear enough. You know, I wasn't, I wasn't balanced, particularly
01:01:15at that time I was, uh, better on the front than the rear. Like my exits were not that good.
01:01:21I learned
01:01:22it got better, but, uh, smoke a front buddy, especially that back then. I mean, the evolution
01:01:29of tires for what we get to test with, I mean, in nine laps, you could wreck a tire, you
01:01:35know,
01:01:35in like 2000, 1998, you could wreck a tire in seven laps at Willow, just destroy it. And then now
01:01:43you
01:01:43could go to almost any track and throw your Pirellis or Bridgestones or, or whatever. The compounding
01:01:49is so good. And the wear resistance, resistance to heat cycling. If you have tire warmers and you
01:01:54can keep your tires from heat cycling while you're at the track, boy, you get a lot of life out
01:01:59of
01:01:59these things and they're good. They're good for a long time. End of the day, they're good. It's,
01:02:05I think one of the great, one of the crucially important things there has been the, uh, adoption
01:02:12starting in 1992 of, uh, silica reinforcement in the tire tread compound in the past. Um,
01:02:24well, in the early days, they found that adding certain things to the tread compound made the
01:02:30rubber last longer. And the one that worked best was not the zinc oxide that made so many
01:02:37early, early, early tires white. It was carbon black. And, um, that's why tires were,
01:02:48were black forever. They still are black, but now grading off to gray because silica is not black.
01:02:56Silica bonds to rubber chains chemically, making the tire much, giving it more tensile strength.
01:03:08So that it broke the, the old, um, what do they call it? The magic triangle of, uh, tire life,
01:03:18tire grip. I forget the third one, but the great tensile strength conferred by silica has made it possible
01:03:25for, um, people to break in a, in a, in an apparently insane way because the, the curve,
01:03:37of tire grip versus tire load doesn't hook over down here. Now it hooks up, hooks over up here
01:03:46because of that higher tensile strength. So, um, racing does improve the breed, but people love to argue
01:03:58about it and I'll let them. Well, excellent. Thanks for listening, folks. We're, we're really glad to
01:04:06have you here as a subscriber. Uh, we appreciate that very much. Um, thanks for joining us. I do want,
01:04:12I did get a request for my dog. Someone requests chant lunch.
01:04:20So my dog has barked variously in, in other programs and she's come up and demanded attention
01:04:25before. I see a nose. I see a paw. There she is. There we are. That's champ. She's a real
01:04:35sweetheart
01:04:36and she's very quiet and very good dog this time. So thanks champ. Thanks for being awesome. Here's
01:04:42another one. Here's another one. Bye. Um, thanks for listening, folks. Thanks for joining us. Uh,
01:04:47that was champ and, um, we will catch you next time.
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