00:00This is the bike that I've been riding for the last few weeks. It's the new Cervelo S5 and it
00:05is very good. It's more aero than the last one, it's more comfortable than the last one, and it's
00:12lighter than the last one. There is just one thing about it though which I'm not too sure about.
00:18You see, you can choose the new S5 with either a Dura-Ace groupset, an Ultegra groupset,
00:24a SRAM Red groupset, a SRAM Force groupset, or this, a Gravel groupset. Now this might seem like
00:34a little bit of an odd choice. This is about as race bike as race bikes get and yet it
00:40has a cassette
00:41that is quite literally bigger than the one on my Gravel bike. It's a 1046 in fact. Now Cervelo
00:49aren't the only people offering this either. 3T are offering something similar and if you
00:53project 1 a Trek you can also spec this groupset onto the latest Madone.
00:58But should you? Is 1x13 the future of groupsets? Does it offer any meaningful advantages over a 2x
01:06system or indeed a 1x12 speeds groupset? And should more road bikes start offering it?
01:13Well, this is Cycling Weekly and I've been finding out.
01:21I've been wanting to test this groupset out on the road for a little while now,
01:25ever since Lidl Trek used this groupset at the Spring Classics. More on that later.
01:30Why? Well, I'm a self-confessed fan of 1x. I think that it adds simplicity,
01:36I like not having to switch between front rings mid-climb and I also like the clean looks.
01:42In fact, I like 1x so much that I now not only run it on my gravel bike, but also
01:47on one of my road
01:49bikes. I've found it great for the criterium racing that I do and the rolling terrain around where I
01:54live, but this isn't all about me. I think that it has benefits for lots of other riders too. Riders
02:00just getting into the sport for example. Riders who can't help but cross-chain. And anyone who wants to
02:07get rid of the seven or so gears that are literally overlapping. Let me explain. But before I do,
02:13make sure you're subscribed to the channel because it really does help us out.
02:17So, this bike here. Right, it's got a 50 tooth ring at the front. Now that is fairly big by
02:241x standards,
02:25but fairly small by usual road race bike standards. And these are the gear proportions that you get
02:31when it's paired with that 1046 tooth cassette. You can see that there are 13 unique gear combinations.
02:4013 gear combinations that give me the following speeds when ridden at 100 rpm. So, the easiest gear
02:48down here gives me a speed of 14 kilometers an hour when peddled at 100 rpm. Obviously I can comfortably
02:54pedal a fair bit slower than that if I need to, but 100 rpm does make the maths a fair
02:59bit easier. In the
03:00hardest gear, so using the 10 tooth cog up here, I can get to a speed of 64.3 kilometers
03:07per hour,
03:08again when peddling at 100 rpm. In a sprint finish, I might be able to pedal a bit faster than
03:13that. And
03:14so this can be stretched depending on what cadence you find comfortable. So now let's compare that to
03:20a more conventional setup. As you can see, there is a lot more gears going on here. Now I rather
03:27like
03:28the look of this Cervelo S5 with the Dura-Race groupset. And that has quite a generous 11 34 tooth
03:35cassette at the back. And then at the front it's got a 54 tooth big ring and a 40 tooth
03:42little ring.
03:43Now type in those numbers and we can see that in the big ring at the front and the smallest
03:47cog at the
03:48back I can now travel at 63.1 kilometers per hour, again in the hardest gear at 100 rpm. Now
03:56that is
03:57about 1.2 kilometers per hour slower than on the 1x13 system. So maybe I get an easier gear as
04:06a result.
04:07Well actually no. When peddled at 100 rpm, little ring at the front, in the 34 at the back, you
04:14can see
04:15it gives me a speed of 15.1 kilometers per hour. 1.1 kilometers per hour faster than on the
04:231x setup.
04:24What this means then is that without a doubt, the 1x setup offers me more range than the 2x setup
04:32that
04:32I would go for. And there's more. So if you look at these gear ratios, you can see there's loads
04:37of
04:38overlap. In fact, 9 out of the 24 gears are overlapped. And what that means is that you're lugging
04:45around some gear combinations that you will quite literally never use. This one for example. That
04:53would be a horrendous cross chain. I'm never going to use that. All of these, Shimano won't even let me
05:00use these ones because my chain will be too baggy. What this comes down to is the fact that if
05:05we've been
05:05using 1x since the dawn of time, I don't think that anyone would come along and invent such an
05:13overcomplicated and, frankly, inefficient system as 2x and manage to convince anyone that it's the
05:19way to go. So why is it still so popular in 2025? Well, the way I see it for three
05:27reasons. Number one,
05:28it's not actually any heavier than the 1x setup. Despite adding a front mech and a chainring,
05:34the rear mech is much, much smaller and lighter, and this 13-speed cassette is not that light. I mean,
05:41it is light for how big it is, but it's not that light. In fact, it's about 100 grams heavier
05:47than
05:47the one you might see on SRAM's 2x setup. Number two, efficiency. Now, I don't have any figures,
05:54but I will be trying to get some. But we do know that big cogs are more efficient than little
05:59ones,
06:00and that a nice straight chainline is more efficient than a cross chain. That's why,
06:04in time trials, we see such massive chainrings. Whichever way you look at it, I just don't think
06:10that a 1x system is advantageous from a purely efficiency point of view. Feel free to disagree
06:17with me in the comments, though. And finally, and this is the kicker, the jumps in between the gears
06:22are much bigger on the 1x system than they are on the 2x group set. So what's that like to
06:29ride with?
06:30Well, I've been using this bike for just over a month now on a range of rides, ranging from slow
06:36bimbals to races and fast group rides and chain gangs, like the bike's intended for. Towards the lower
06:43end of the gears, and it feels fairly normal, and there shouldn't be much surprise by that,
06:47because if you look, a lot of the gear combinations are actually very similar. 10 versus 11, 11 versus
06:5212, 12, 13, 13, 14, 15, 15, 17, 17, 19, 19, even 21, 21, 24, 24. It's this bit where
07:02things get
07:02slightly more weird. When you're on this bit, you're normally travelling at speeds of, let's say,
07:0830 kilometres an hour and less. The jumps, well, they just feel like they're a bit too much.
07:15Out on rides, I've found myself staying in gears longer, sometimes churning a big one,
07:21and other times spinning a smaller one than I ordinarily would. And that is not an efficient
07:26way of riding. And on rides where you're on your limit, the last thing that I want to be thinking
07:31about is my cadence. The truth is, I never normally think about my cadence, and yet on this bike,
07:41I've been forced to. And no, that's not just because I was making a video on it. It is, in
07:47fact,
07:47the reason I'm making the video on it, because I thought that 13 speed was going to be the answer
07:51to all my prayers, and was then, frankly, slightly surprised.
07:57The other thing I've noticed when out riding is the dragginess in the easiest gear. And I can show
08:03you what I mean now. So if I spin this and put it up to the biggest gear, you can
08:10almost hear it.
08:11You can hear how much drag is on that gear. And if I put it down here, it's much quieter,
08:19and the cranks spin freer. Now, like I said before, I really, really want some data to back this up,
08:26and I will be trying very hard to get some. But if I can feel the difference in the cranks
08:33with my
08:33hands, then I think that this is in magnitudes of full watts, rather than points of watts.
08:39Now, I said earlier that Lidl Trek had been using this groupset during the classic season in 2025,
08:45including at races such as Paris-Roubaix. They were extremely complimentary about it,
08:50and even went so far as to say that they'd never go back to 2x for those races.
08:56Whilst the likes of Mads Pedersen did use a 10-46 tooth cassette like this for some of the races,
09:02they too clearly wanted some closer ranges and less jumps in between gears when it came to races
09:08that are a bit flatter, such as Paris-Roubaix. And on those races, they modified their mechs,
09:13and they used a more conventional 10-33 tooth cassette. Now, I am all for tailoring your gearing to
09:21the terrain that you're riding, but I just don't think that switching out cassettes is as necessary
09:27on a 2x setup. And let's face it, cassettes really aren't cheap.
09:33As I said before, I am a big fan of 1x groupsets, and I really do think that they have
09:38a place on the
09:39road. This 13-speed Explore groupset though, it's exactly what it says it is, a gravel groupset. And
09:47although I've loved trying it, I would personally buy a bike like the Cervelo S5 with one of Shimano
09:52or SRAM's 2x options. Fair play to Cervelo though, for giving the consumer the choice,
09:58and speccing the 2x version with rings that suits the bike's purpose. Going fast.
10:04Circling back to 1x and the crux of it is that to get all this lovely gear range, I simply
10:09think that
10:10for me, the jumps in between the gears are too big for performance road use. I hope that we continue
10:16to see more endurance road bikes and all road bikes with 1x on them, and for select rides I will
10:22still
10:22be very happy on my 1x setup. For me though, the maximum size cassette that I want to be running
10:28on
10:28road is about a 10-36, not a 10-46. Anything above a 10-36, and I find that the
10:35changes in cadence
10:36are just too big of a sacrifice to make. Let me know if your next road bike will be 1x
10:41or 2x down
10:42in the comments below, that will be controversial I'm sure. Do you wish that more bike brands offered
10:47both? The full review of this bike will be live on Cycling Weekly shortly, and before you go,
10:53make sure you like, comment and subscribe. We'll see you next time.
Comments