What rim depth do you recommend for me?

[Beaver]

If height was more important then my 38mm deep tubular would be more stable in winds but they are not. Profile it seems to me is more important than height.

Your info however is interesting. The tyre width thing is quite important, its that 105% rule again.

How wide are the rims you compare and how wide are the tires mounted on them? Spokes and spoke count are the same?

[fromtrektocolnago]

My current wheel for climbing is the Dura Ace C-24. I could not be happier. If you are looking to improve on the flats the aero benefits of positioning and being lean and strong will far outweigh any benefits of a deep rim, but if you are inclined to go there recognize the trade off. Maybe a wheel like a 35 mm gets you there. Also understand deep rim wheels are terrible in cross winds. For me I have no desire to go deep rim, and prefer to focus on fitness being very pleased with my C-24 wheels that i can pretty much use for any style riding.

[pdlpsher1]

I'm 62kg and as such my strength is also climbing. But I have a full aero bike with 50mm deep rims. I couldn't be happier. I even think the aero advantage helps me on climbs of less than 5% gradient. I'm sure the calculations can prove this. In conclusion one should look for equipment to address his weakness and not the strength. One would find a higher level of satisfaction and happiness with this approach.


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[bm0p700f]

beaver this is my point exactly.

My 50mm deep clinchers are 26.2mm wide but have 27.5mm wide tyres mounted to them. I do have narrower tubeless tyres I can mount but once I have worn out my old stock of IRC 25mm out first.

The 38mm tubulars are 20.5mm wide and have 22mm tubs mounted to them which are 21.5mm wide. They are very light though.

So profile is very different and the deeper rim is more stable due to the profile.

Profile is more important than depth by itself.

[kaguri]

I guess the bora one 35 mm is good for you

[hambini]

I have some 80mm Zipp 808's, the alleged improved handling in cross winds is rubbish. They are a nightmare. Anything more than 35km/h and I go to Shimano C60's (50mm). They are not as good as my old Shimano C35's in cross winds but they are at least manageable. The worst time is when trucks go past me.

[Beaver]

I have some 80mm Zipp 808's, the alleged improved handling in cross winds is rubbish. They are a nightmare. Anything more than 35km/h and I go to Shimano C60's (50mm). They are not as good as my old Shimano C35's in cross winds but they are at least manageable. The worst time is when trucks go past me.

Tour test 8/2016 steering moment on bars at 12.5° crosswind:

Mavic Ksyrium Pro Exalith SL | 0,0001
Fulcrum Racing Quattro | 0,0025
Mavic Cosmic Pro Carbon SL C | 0,0035
Reynolds 58 Aero | 0,0045
Mavic CXR Ultimate 60 | 0,0060
Zipp 404 Firecrest | 0,0070
Zipp 808 NSW | 0,0125

Your Shimano C60 were also tested, but without concrete numbers - the rating of crosswind stability was a little worse than the Mavic CXR Ultimate 60 though.

The NACA teardrop shape seems the way to go, but as stated, with a slight aero penalty at high yaw angles.





But even with the Reynolds, 80mm stay 80mm. Maybe the 65mm on front will be the best choice for you:



But only for 23mm tires and good roads. I need 25mm on 21C here.

[Shrike]

What do those numbers above mean in layman terms. I just got the 404s and been gradually upping the wind speeds I take them out in. Am definitely curious about how they handle when things get rougher. Worst crosswinds so far have been around 14mph.. seem fine so far.

[Beaver]

In general the higher the rim, the lower the crosswind stability, but width and shape play a role too.

The teardrop shape will be a bit better than the U shape but with a slight aero penalty at high yaw angels. But the faster you go, the lower the yaw angels are.

But don't overestimate the differences. Here from blogger Steve (https://intheknowcycling.com/2015/07/10 ... ke-wheels/):

"And, what about all that noise about their V-profile rims? Well if you don’t ride in an area where you get strong crosswinds, it won’t matter. If you do, these 58 Aero wheels handle them better than most – it feels like more of a quick light tap to the front wheel than the smooth light push you get from the better round-nose designs. It’s a differentiating characteristic similar to the way Campy, SRAM and Shimano components shift differently. Both the Reynolds 58 Aero V-shaped wheels and the better round-nose rims get the job done but you may prefer the Reynolds way over the Zipp, HED, ENVE, etc. way. At the end of the day, I’m not sure its worth all the attention Reynolds gives it.

Reynolds has announced a new Aero line for 2017 with rounder, wider, and deeper rims yet still with a pointed V spoke edge. The 46 and 58 Aero will disappear and the shallowest in the new rim brake line will be the 65 Aero."

This is a very subjective matter after all - maybe you are fine with your 404s and others would definitely prefer a Reynolds rim in the same crosswinds. Very high rims and disc wheels are time trial material though. The aero benefits of a 80mm rim to a 60mm rim are marginal and without a closed off race track you will loose the power you gained every time you have to get the wheels going again after a stop in normal traffic. And in addition to the higher weight you will also loose comfort.

[Stueys]

I ride enve 4.5's, I find them fine in a crosswind, you can sometimes feel a gentle pull but it's very rare that this becomes disconcerting. 40-50mm deep is a great all rounder depth, no real weight penalty but plenty of aero benefit. I also find the 4.5's build into a nice stiff wheel, which makes them good climbers. Braking is ok but I think the gen 2 rim has moved the game on further now.

[Hexsense]

I used to have 45mm Ebay chinese carbon fiber front rims. It is ~27.5mm wide in the middle and ~25mm at brake track (AKA U-shaped). Then I replace front rim due to accident with a 46mm-deep Light-bicycle 28mm wide at brake track which is their widest point (AKA V-shaped). And the new rim (V-shaped) is way more stable in crosswind especially noticeable when a truck drive pass me on other lane. Since years of believing in Zipp's Marketing that bash V-shaped and praise toroidal U-shaped, i don't know what to believe anymore. But only thing i believe is, i'll choose wide rim rather than narrow rim every time.

[mpulsiv]

Zipp is making some bold claims. Let's take a look at 10 degree yaw, despite the fact that we spend most of the time between 1-7 degree yaw. Tire that sits flushed with a wheel exhibit ~ 7 watts advantage next to wider tire (2.2mm wider than rim). I find this very hard to believe because ~ 7 watts delta is substantial in aero world. Last time I looked at wind tunnel, wider tire had a marginal penalty of ~ 1 watt. Now, how is Zipp pushing sales of deep 404 wheels when shallow 202 wheels have a penalty of ~ 2 watts? Why in the world would a consumer invest more money for deeper and heavier 404? Oh wait, how could we forget, it's all about aesthetics. We try too hard to mimic Pro's and look fast.

[Shrike]

You actually believe there's only a 2 watt difference between Zipps 202 and 404? A 32 v 58.

Really?

[alcatraz]

I found chinese (i live in china) toroidal shaped rims with the same size and shape as 404's. It's a modern production so they can withstand more heat.

Right now I'm trying to decide tubular "404" vs clincher. If I go tubular I can't affort riding any other tire but the Tufo S33 Pro's but if I go clincher I can stretch to the Vittoria Corsa Speed tubeless, which I hear are very fast tires.

At the size of the "404's" it seems the weight penalty of going clincher is small. Under 50gr.

I'm just crying that my otherwise very light build is being compromised by the heavy wheelset. I will be going from 1300 to 1550 on the wheels. Before looking around I was hoping to build me a 900gr wheelset with shallow carbon tubular rims. The more I look at my frame though (FM066SL) the more I realize it's not that bad in the aero department.

I'm trying to justify the deep heavy rims by thinking that wheels are not a good place to save weight at the expense of aero performance. The velocity at the rim is too fast to ignore the aero benefits. Even for a climbing bike.

I've been thinking 303's but the weight difference is not huge anyway. If I change my frame in the future the 404's will be a better fit probably.

So I'm leaning towards taking the weight penalty of 404 clinchers so I can run vittoria corsa speed tubeless setup. I will end up with around 200gr more rotational weight in the end and around 6kg bike weight. But hopefully gain in the air and rolling resistance department to add 2-3 km/h to my average speed which would be nice.

(I build my own wheels. I will just get the rims and spokes. Around 300usd investment.)

Am I crazy or what?

[dvearn]

Interesting data points.
I wonder what the trade off and tipping point is for aero vs rolling resistance of different tyre sizes is.
Thinner being more aero, thicker being lower rolling resistance.

The other thing that struck me is the -5 to +5 yaw angle for all the Zipps gave similar drag, so head on the depth seems to make little difference. Granted you will rarely get direct head on wind in the real world