Do Deep Section Wheels Climb Faster? | GCN Does Science

Do Deep Section Wheels Climb Faster? | GCN Does Science

– These are the brand
new wheels from Shimano. They’re gonna become available
a little bit later this year. And we’re gonna use them
for a little experiment. Now, this one here is the
C40, and this one is the C60, and both are completely new
to Shimano’s wheel lineup. This one, the C40 has been
designed as an all-around wheel. Super-light, just 1,355g
but yet, also aerodynamic. Shimano tell us in fact
that it is two watts faster than their previous
aerodynamic wheel, the C50. And they’ve achieved that partly through a new rim
profile, and partly, they say, because they’ve made it much, much wider, so it sits much better
with modern wider tyres, so it’s actually 28 millimetres
wide, so wide in fact, that they’ve produced their
own slimline brake pads for it. This one, the C60, however, is the out-and-out aerodynamic wheel. If this one creates two watts
less drag compared to the C50, this one creates 16 watts less drag, so that is significantly faster, although Shimano haven’t
actually told us exactly how they have tested those
wheels, but what I want to know, and what I’ve always wanted to
know, is just to see how much difference there is between
shallow wheels and deeper wheels when climbing. We’re told that this is a climbing wheel. But yet this one is just 125g more, and creates 14 watts less
drag at higher speeds. So, we’re gonna find
out exactly what happens when we put the two head-to-head. Our climb of choice today
is the Coll de Rates, which is in Alicante in Spain. It’s 6.5 kilometres long,
and 5.6% average gradient, so it should be reasonably quick. Any guesses? Run number one, it’s the C40s. (exhilarating music) (exhaling) You ready? Run number two, C60s. All right. (stimulating music) (exhaling) With two runs of the Coll
de Rate under my belt now, it is time for some results. I’ve not seen these yet,
so I’m just gonna click into the lap function. Right, here we go. So the C40s were 16 minutes, 52 seconds, and the C60s, 16 minutes and 55 seconds, so actually, two and a
half seconds between them. I can’t quite believe that. That’s unbelievable. An average power for each one was 326 watts. Now that’s not guaranteeing
that those watts were laid down in a completely even manner, so there could be a bit
of discrepancy in there, but that is uncanny that
they’re almost exactly the same speed at that climb. I suppose you could extrapolate that and say that if the climb is
any steeper than this one, which is 5.5%, then the C40s
are gonna get progressively faster and faster compared to these, but you can bet your bottom dollar that these C60s are now gonna
be a heck of a lot faster down the other side. Which one matters to you,
I suppose ultimately, is a decision for you. But, I can’t believe that. That’s almost slightly weird, isn’t it? Right, well. If you have enjoyed this
little dip into science, then make first of all
that you subscribe to GCN. We regularly try and tackle
some of your burning questions about cycling and cycling
equipment with the help of helpful brands like
Shimano that lend us this amazing stuff. And then, once you subscribe,
back here on the globe, why not check out a couple
other GCN Does Science videos, where firstly, we test
out how much of an effect bike weight has on climbing speed. That’s just up there. Or, Matt and Dan put on
fat rucksacks to find out how much body weight
affects climbing speed, and that one is just down there.

About the Author: Michael Flood


  1. should have measured going down and along the flat as well to see if the 'claims ' work in the 'real world' as well

  2. Maybe you can try a similar test with an amateur rider power. I believe the majority here averages between 200-250w on most of the rides.

  3. When Si' tells us "you can subcribes" and Dan appears down there …I must recognice that I love the Dan's sexy Face looking us as telling .. come on baby … get in and buy some clothes here in our web XD

  4. I only just had a shot for the first time last week with a bike with a power meter on it all I can remember is that my best sprint I could produce was 923w so too sustain 325w for 16 minutes is crazy to think of !

  5. I would really like it if you could devote some of these tests for ensuring that there is as little measurement error as possible. For instance, if you could somehow ensure that the avg wattage of 325W is distributed similarly for every round, and that the wind conditions are not too different. I would guess that there would be some pretty smart experts in, e.g., universities, that could help you try these things.

  6. No aero effects climbing. Lighter wheels would have more benefit.Why didn't you test going down hill where aerodynamics play more of a role?

  7. Why am I watching this ? I'll never have wheels like that . Every video like that makes me feel sad about my bike 😩

  8. Well Simon thank for your experiment but what about Aero against conventional rims. It might be the latest fad to go Aero but does science back up that fad, you have the less Aero wheels the C40s that go faster than the C60s so it would be interesting to see if conventional rims climb faster than C40s!

  9. Your conclusion indicates that you think the C40s really are faster in climbing, but hold on a second. You have one sample of each and didn't account for potential sources of variance such as tire pressure, weight (other commenters have noted the differences in water bottle contents), temperature, wind, your line through curves, etc. They may seem small, but 2.5 seconds over 16:22 is around 0.5% difference. I would guess a margin of error to be closer to 2% (FYI – the accuracy of your power meter is +/- 2%). So it's not at all clear there is any difference, much less that you have the right difference, ceteris paribus. It is nice to see a real world comparison, but don't indicate that it's potentially indicative of anything other than the difference between 40 and 60 mm rim depth on a 5.6% grade climb is negligible. Fun to watch nonetheless.

  10. Without doing multiple tests and apply a little statistics, these numbers are useless. Please do multiple runs with the same rims, minimum of 3, next time.

  11. I can't quite believe it either 😂😂 2 secs dif over a 16 ish min climb 😂😂 How convenient. Did Shimano supply the time dif? 😂😂

  12. My five year old Specialized Roubaix can't take 28 mm tires due to the narrow throat at the BB. How can these 28 mm rims work? I guess I need a new bike.

  13. Having climbed hardest Climbs regularly for 2 years in Hawaii on C35. Ill take my new C24 any day with a half lb less of rotational mass over a deep section wheel not to mention crosswind drag which is substantial in Hawaii also C40 are identical to C35 not an upgrade at all Shimano should be ashamed saying any different ! 😤

  14. That 14w less drag is going to be at something stupid like 60km/h. I bet at climbing speeds it's not even 1/4 of that. I also think that your margin of error on your timing is probably +/- 2seconds anyway.

  15. I don't think a 1355 gm wheel is all that light for climbing. Lots of wheels go lower – my corima's are 1130 gm. So I am not sure how fair the comparison is. Of course, if I could generate 325 watts I probably wouldn't care.

  16. good luck descending on c60' s in the mountains when the wind gets up, which it always does 😀.

  17. I love these videos, don't get me wrong. But in this particular case I can't help but think that this was not a very scientific study. One run on each wheelset, one after the other … would like to have seen a couple of runs on each wheel and maybe even have someone like Dan or Tom also ride…

  18. nah nah, the wheels are too similar in depth. You'd need a 20mm rim with say a Tune hub and Sapim spokes to compare – or to answer the question.

  19. Is the effect the same when using a Climbing bike / light Aero bike (eg Ridley Helium vs Noah SL, Specialized Tarmac/Venge, Trek emonda/Domane)  #torqueback

  20. Meaning you're better of getting aero wheels if you don't do any serious gradients….. hummm interesting…

  21. I don't care about deep or low section on my wheels. I care how I can ride climbs at an average of 326 Watts.

  22. wait, you only did one run on each?? wouldnt a scientific approach would be to test, test, test, and then test some more? I would think more than one run (multiple riders (all GCN guys), multiple days, multiple runs (fresh and fatigued), maybe a baseline with stock wheels, etc) would be needed for a more scientific approach and, well, MORE data.

  23. Before you even consider getting the deep section wheels for climbing, ask yourself; are you able to churn out 324 watts for a 6.5km climb with a gradient of 5.6%.

  24. If a pro bike is under weight, is it better to add weight to the frame, or to put heavier aero wheel on and add thw eight there?

  25. 2watts! I save that by putting my gel wrappers in the bin rather than in my pocket when I have eaten them!

  26. It would make for a boring video but… bike gear/component comparisons would probably yield truer results if you could use one of those infamous "mechanical doping" battery powered bikes. 😉

  27. What were the wind condition for both runs, at least qualitatively? This make a large difference in the aero performance, as newer-model wheels are wider to allow for more side winds withour stalling and consequentely adding more drag.
    Are these tubulars or clinchers?

  28. The trajectory and the wind can be different between one test and the other!!You should repeat test 10 time!And in different roads with more difficult climb!!

  29. So if these are aero wheels, why not test them on aero? Any straight descent fast enough to not demand pedaling will suffice

  30. I don't care if the extra deep dish wheels make you a couple of seconds faster, since I don't compete. They are ugly and look like lorry tyres (A.E. truck tires). Medium disc is the best compromise of looks, weight and "aero".

  31. yeah, sure… very accurate… he followed exactly the same line in the two climbs, is it?

    NO, it's not. These tests say basically nothing.

  32. Does anyone know if my bontrager at-750 can fit a 11 speed cassette? And if I can't what are some budget wheels I can upgrade to without breaking the bank?


  33. Why I see different coments when I am logged and not?

    Rims are not quit high tech=(

  34. it would have been interesting if to see then use a non aero wheel and see what the differences were between all 3. This might have given more clarity to how much is gained by aero wheels when climbing

  35. As per other comments, it would be useful to also compare times for a basic set of wheels (though the manufacturers of carbon bling may not appreciate the results!)

  36. You should have done the same test with a shallow box rim 32 spoke conventional clincher road wheel. I'd wager good $$$ that if your wattage output is the same and the environmental conditions are the same you would see almost no meaningful difference in your times. A small incremental gain of a few seconds at best perhaps? But neither of those wheels, nor any cute wheel from Enve, Zipp, Lightweight nor any other maker is going to suddenly make you climb even 15-30 seconds faster on that run.

    Damon Rinard has published great analytical data on all this stuff. The conclusion: all these high zoot wheels eek out very, very small relative incremental gains that might be necessary for a paid pro, who does not buy their gear nor ride it for a very long period of time. For the typical recreational cyclist most of this stuff is a laughable joke purchased and ridden by posers and pretenders. You can literally go on any number of cycling blogs and listen to all the lies and complete BS from this crowd of clownsters. "Oh, I just dropped a pound off my wheels and now I'm climbing 3 miles per hour faster…." Oh, I went to an Enve carbon wheel and now I'm riding 3 miles per hour faster on the flats…. blah, blah, blah…" All a bunch of BS and hype babbled mostly by clueless clowns, who have no clue how ridiculous most of their claims are. Nonsense designed by the bike industry to continually pry money from the wallets of fools and amateur posers.

  37. Shimano specifies a rim width of 20.8mm for WH-R9100-C40-CL-F, are you talking about another version of the C40? Because I didn't find a 28mm width on any C40.

  38. That time difference is probably within margin of error, making the difference meaningless and results suggest that there is no difference in speed between the two wheels.

  39. Haha, I did a 6km climb at ~6% and I was like 22 minutes 😀 I think 325W is my maximum, not an average going up a climb!!!

  40. After I watched this video, I got some idea about tire & wheel in rear & front. How about deeper wheel in rear with 25c & less deeper wheel with 23c in front??

  41. Cool! And I second how it’s interesting that shimano didn’t say how they tested to get the differences they got out of the two wheels. Proof that aero is everything in modern cycling! I’d get either super deep or super light rather than in between though. Go out and have super fun hitting your favorite terrain.

  42. So 5 1/2% is climbing now is it !? That's a lot of production effort for a useless test scenario. Surely climbing starts at 9% or thereabouts ? C60s faster is a straight line down the other side, but throw in some bends and I'll take the C40's please.

  43. Hey guys, a long time cyclist here but new too cycling science but I've seen a couple of GCN "VS" video's and the main thing that puzzles me is that you guys never take fatigue of the rider into the equation. Or do I overlook something?

  44. comes to climbing the lighter wheel of course wins out. I did a triathlon as an amateur and I found myself alongside the pros in the climbs w just regular wheels lol. However, the pros w their pricey 2K wheels will just pass you on their descents that's for sure.

  45. So last year this video made me order the C60… I loved the look and with the Ceramicspeed OSPW and rotor oval 50/34 crank my SuperSix Evo climbs wickedly through the BC Rockies

  46. So basically I should keep my 2005 Mavic Ksyrium ES 700c wheelset (1470 grams) and save my hard earned money instead of buying a pair of Zipp 404's?

  47. Can we use 80mm wheels in mass start races or is there any rule of uci to not use them in mass start or criterium.plz reply thanks.

  48. Did anyone at GCN measure those Shimano C40 wheels I have been reading (no personal experience yet) that they are indeed the older 9000 series wheels (less deep). Reason I ask is I was interested in purchasing them after your review and found several blog sights making this accusation. I love the channel keep up the good work!

  49. Hey GCN people!

    Can you travel to Serbia real quick and smash the Venac climb (near the city of Novi Sad) record(10.21 by some Belgian dude)?


  50. Stiff lightweight wheels are only really beneficial for hill climbs, and they generally look cack. Aero do have the draw back of wind issues but they look cool. In reality if you aren't competing just get what looks best on your bike and brake well and ride nicely. If you are using c40's / c60's then you are competing . Unless you are a big money weekend warrior then nobody likes you and spend your money on buying everyone a drink.

  51. Yes, but what if your climbing into a stiff wind. Which does happen! I think the aero would help a lot

Leave a Reply

Your email address will not be published. Required fields are marked *