40mm or 55mm wheelset?

If there’s negligible weight penalty would you get 40mm or 55mm rims?

I’m looking to get a pair of 9velo carbon wheels. Road Rim Brake RV Series. Options are - 40mm at 1430g or 55mm at 1467g

Mostly for riding myself, Strava segments, keeping a decent average speed. Like climbing. May do the odd race - once or twice a year. I don’t care about the tiny weight difference, and obviously the 55mm will be faster, so my main concerns are -

  • will stability with the deeper rims be an issue
  • will 55mm rims look a bit silly on alloy endurance bike (giant contend sl)
  • the weight difference seems a bit unrealistically small for the difference in depth

Deeper wheels look cooler, thats all you really need to worry about, everything else is irrelevant :smiley:

I run 60s at 53kg and don’t really have a problem on windy days. Love the whoosh whoosh noise too.


Maybe the wrong time of year, but I think you’d be better keeping an eye out for an Advanced TCR/Defy with their 42mm SLR wheels… I’ve seen full bikes go for not much more than you’re going to pay for wheels.

Looks and sound - thats all I came here to say :grin:


I also dont think crosswinds are a huge concern on modern deep section wheels with a “U” shaped cross-section rather than the older “V” types - I certainly don’t ever consider not riding my WTO60s on windy days.

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I think I’d struggle to just get the slr wheelset second hand for £520 these days, and these are a fair bit wider. Good review for the carbon spoked version by Hambini too.

But if you see a tcr at that price with any wheels let me know! :slight_smile:

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What frame size is your Contend?

The walls of the rims will be really thin so not much material needs to be added to make them deeper - also the spokes can be shorter - so the 37g difference between the two sizes isnt completely unbelievable.

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I’m not certain. I think small (but maybe extra small)

Ah, cool, thanks. Have asked them anyway and if they’ll do 40mm front 55mm back

Not sure where you’re located, but there’s bargains out there.

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It entirely depends on where you live. I got 50mm wheels when I lived in NM (often windy and gusty). Many days, I wished I had gotten the 38mm wheels. Then I moved to TN where there is always tree cover. In two years of riding there, I never once wished I had bought the 38s.

That said, 40mm is a nice all-around size and I’ve also noticed the top pros riding less deep wheels these days. The difference between 40 and 55 is only going to be a handful of seconds in the best of situations.

Most of these wheels test very similarly in 0 yaw situations (wind coming head on). Deeper wheels only really shine when it’s windy and you have a side wind (think the Kona triathlon course). I don’t think most buyers realize this. The “save 30 seconds in a 40k tt” is usually a best case 12 degree yaw side wind simulation. Who ever experiences that unless you are racing Kona?

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Except that Propel is so ugly. I wouldn’t buy it at any price!


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Thanks, that is indeed a bargain. Actually thinking about it and getting it stripped and sprayed

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Cheers, leaning towards the 40mm mostly as I just think they’ll look better on my bike

I won’t ride over 45mm where I live. Seems like every other weekend we have winds gusting to over 30 mph. Gusty winds, high speed descents, and deep rims are not combo I enjoy.

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I’d definitely go with 55 mm. Deep wheels are very benign. Yesterday I was out for a ride along the coast with strong and unsteady winds. With my 45 mm deep wheels I felt nothing from my wheels. When I got pushed around by the wind, it was the wind acting on my entire body + bike rather than giving spurious, unwanted steering input.

(We sometimes have really strong winds where I live. I did not feel uncomfortable on my 45 mm deep wheels once. I’d definitely go deeper next time.)

In my experience that advice is outdated. We also frequently have winds of similar strength, especially along the coast line, but also on top of mountains. (Near the top of mountains, the winds tend to be more steady, but can be stronger, along the coast they can be gustier.) When winds are extremely strong, then in my experience the problem is not the wheels, but that my whole body + bike gets pushed around. Unwanted steering input is not part of the equation.

At a certain point riding becomes dangerous, and that has nothing to do with wheels. I remember one time when I had my kids in tow with my mountain bike (= no deep wheels), I had to be in my easiest gear (30:46) to make progress on the flats.

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How many different pairs of deep wheels do you have experience with? The feeling entirely depends on the particular wheel. The market has not reached the point where all wheels are good no matter how windy it is.

It’s really not debatable that a deeper rim is more affected by wind. Yes, I might still get tossed around on a shallow rim on a bad enough day. But it’s worse with deeper rims.

I have extensive experience with 3 and ridden a fourth:

  • A pair of Bontrager wheels on a 2015 or 2016 (?) Trek Domane SL6 Disc: these were horrible in the wind. It was a loaner, and I really didn’t get along with them. I don’t remember how deep they were, but I could feel steering input. I had the bike for several weeks.
  • 3T Discus C60: I do not have extensive experience, but these worked great. No issues with wind steer. These were the only wheels that went whoosh. :slight_smile:
  • 3T Discus C35: I have ridden them for a bit over 2 weeks. Zero issues with wind. These wheels had the nicest ride feel of any of the wheels I have tried, although that had nothing to do with wind steer.
  • 3T Discus C45|32: I have had these wheels for 2 years now, and I have spent many, many hours on them. I think I remember two occasions when I felt a bit of wind from the wheels, but even then it was not strong, more of a reminder I was riding into a strong side wind and I did not veer off course. My whole body acted like a sail on top of a mountain, I had to fight against 50+ km/h winds, no issues really.

I am sure I have test ridden some other carbon rims, but those are the ones I remember specifically.

In addition, I have friends with other 45 mm deep wheels and everyone seems very happy with them. None with new wheels (e. g. Zipp 303s) mentioned wind steer when asked, they were super happy.

I would have gone wider, but 3T discontinued its wider C60s and the C45s came with my Strada as a package deal for a steep discount.

Not in my experience: the surface area of your body is way larger than that of your rims, and my whole body + bike get pushed by the wind before I can feel steering input on my front wheel. On these days, I should have rather stayed home anyway, it isn’t fun to creep back home on a road bike. In my book, that makes wind steer a complete non-issue with the wheels I have. The conditions I encounter are on par or worse than what you mentioned (50+ km/h winds are not unusual, and especially along they coast the wind can get gusty).

I can literally count the instances where I felt steering input from my front wheel on one hand and two fingers, and even then it wasn’t anything to worry about. My experience with the Bontragers many years ago was very different, but these rims are outdated by today’s standards.