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Beyond the benefits, what other effect(s) of deeper wheels?

5K views 32 replies 21 participants last post by  Notvintage 
#1 ·
I have read the reviews, recommendations and the comparisons between most upgrade wheels. I am not a serious rider for whom marginal gains matter a great deal, so i am at least as interested in the less desirable consequences. I am looking at modest depth (eg dura ace c40). Can anybody speak to extent of wind effects, durability, maintenance hassles or other?
 
#2 ·
FWIW, deep section wheels may make you look sexy and you may pick up more chicks. Then again, they may make you look like a poseur.

You don't want these if you are going to be on roads with fast moving traffic when 18-wheelers barrel by at 60mph.
 
#4 ·
I recall that scene from Braking Away...

My dentist, who does tris, jumped at some Zipp 808 wheels and really regrets it. Deathly in crosswinds. I expect him to at least change the front wheel to a 404 for next season. Loves the wheels as long as there's no wind, but really, when is that?
 
#3 ·
Wind effects vary with depth and profile.

I have seen people bring 60-80mm rims on Tour de Nebraska....and LOL'd....those folks learn their lesson quick about Great Plains surface windage.
 
#5 ·
Generally speaking there's nothing depth specific about "durability, maintenance hassles or other"

What there is a correlation with is replacement cost though. If you break or wear out brake track with a non proprietary rim we're talking maybe $150 replacement including labor. If you trash a deep carbon rim we're talking big bucks. I don't even know if Shimano sells c40 rim only but you can bet it would be pricey if they did.

Not to imply needing a replacement any time soon would be likely but it's far from one-in-a-million type chance for sure so replacement cost is something to factor in.
 
#8 ·
Thanks

Thanks for the suggestions. It’ll take more than fancy wheels to delude spectators about my sexiness but the caution about very deep wheels is appreciated. I wonder then if a rim depth in 40s would typically also catch enough cross wind that it might push me significantly offline (either far off line, or quickly/unavoidably offline). I am 175 lbs and ride a few thousand km per yr on roads driven by lots of lumber trucks. Getting blown or drawn into one would be fatal. Thanks in advance if anybody can describe
 
#9 ·
Thanks for the suggestions. It’ll take more than fancy wheels to delude spectators about my sexiness but the caution about very deep wheels is appreciated. I wonder then if a rim depth in 40s would typically also catch enough cross wind that it might push me significantly offline (either far off line, or quickly/unavoidably offline). I am 175 lbs and ride a few thousand km per yr on roads driven by lots of lumber trucks. Getting blown or drawn into one would be fatal. Thanks in advance if anybody can describe

Anything 45mm and over can get you blown into traffic, depending on your weight.

35mm is the limit of what's safe and not effected much at all by the wind.
 
#12 ·
Some of the newer rim shapes perform really well in crosswinds, even in the deeper depths.
Here is South Carolina during the spring time we have races around an industrial airport which could pretty much be nicknamed the factory of wind. Races are regularly ran during 25mph winds (groups of 2-5 riders all over the place) and I have always used 60mm depth for those races.
A lot of it has to do with tire size as well. If you are running a 28mm tire that is going to have worse crosswind handling and stability compared to a 23mm or 25mm tire.

If you are going with a good mid depth rim under 50mm that has good aerodynamics at the higher yaw angles (above 10degrees) you will likely see the crosswind stability is ok with those. It's certainly not going to steer you off the road.
 
#14 ·
yes, we can measure that in the wind tunnel and we can see it in the CFD software when designing the rim shapes and the tire to rim interface.

Crosswind stability is all about the center of pressure. When the wind blows from the side it hits the rim both in front of the fork and behind the fork. Lets take the older V shape rims as an example. When you have a crosswind you have a good airfoil shape on the front of the wheel and a poor airfoil shape on the backside of the wheel. This puts the center of pressure towards the back of the wheel. So when the wind blows it will push on the backside of the wheel and will try to steer the wheel.
If you have ever been riding in a heavy crosswind and felt like you were steering into the wind, this is why.

With the newer shapes that are aerodynamic in all wind angles (most modern rim shapes), you have a good airfoil shape on the front and back of the wheel. This takes the center of pressure and moves it forward over top of the skewer. In the CFD software you can plot where the pressure hits. With the center of pressure over top of the skewer, you are still getting hit by the wind, but it's pushing the wheel versus steering it. This is what everybody talks about when they say "having better crosswind stability".

Now, when the air flows over the backside of the wheel and onto the tire, tire size can affect how the air hits that area. On a 23mm tire, with a wider rim profile, the air will flow over the rim and over the tire. However, introducing larger tires creates a "pocket" and the airflow gets disrupted. This will create a situation where instead of flowing over the rim and over the tire, the wind will push on that tire. This brings the center of pressure backwards from the skewer and introduces crosswind instability again.

This is purely for crosswind handling and a lot of times in situations like descending or crits, the larger tire is still better to have. However, when I am looking at situations like Kona tri for example I recommend the riders to use a 23mm tire up front and a 25mm tire in the back. With Kona being windy from the side a lot, that narrower tire up front will give the better stability and aerodynamics.
 
#16 ·
So this is your study? Until there are more than just 2 third-party analysis that come to the same conclusion, you're just talking out of your a$$.

Prove me wrong and provide at least 3 independent studies that conclude the same as you then I'll believe you.
 
#20 ·
We've seen the exact same thing when we've gone to the wind tunnel. It's valid. I have literally no dog in the aerodynamic fight here - whatever you want to believe about how much faster you're going to go is yours to keep yourself up late at night with, but wider tires consistently show more cross wind handling effects. This post from several years ago mentions it but doesn't go deep into it.

And again, if 1 or 3 watts is going to make someone blow by you, there are bridges in Brooklyn and London and various other places I'd be happy to sell you. There was one in Washington that had particular difficulties with cross winds if I recall...
 
#23 ·
The newer Shimano C40 rims are actually less than 40, they should be the same depth as the previous generation C35s. A little deeper than shallow rims, enough to definitely add some bling factor but not a huge danger in crosswinds.

I have had 3 sets of C24s (RS80-C24, RS81-C24, DA9000-C24) and just started using a pair of NOS DA9000-C35s that I got at a really good price. I've been happy with these Shimano carbon/aluminum blend wheels for the most part... I definitely like the aluminum braking tracks. Of all of them I liked the RS81-C24s the least. I would note that there are some complaints that there is braking pulsation that can be somewhat mitigated by toeing in brake pads... I did experience this with one set but not the others.

So far I'm liking the C35s but in all honestly I don't think they are doing anything for me performance-wise compared to the C24s other than weighing me down an extra 150g :) ...
 
#25 · (Edited)
Revised question

My 2nd post wasn’t clear and I don’t know how to delete it entirely but I am hoping to learn something about wheels in the tier below Zipp and Enve because I expect to make compromises at the C$ 2000-2500 price and want the compomises to be informed ones. Assuming all of the quantifiable variables are equal ( price, weight, rim depth around 35-40), is there a consensus that carbon is still preferable, or that carbon is to be avoided, and why? (I don’t ride in rain or descend mountains so braking conditions are generally optimal).
 
#29 ·
My 2nd post wasn’t clear and I don’t know how to delete it entirely but I am hoping to learn something about wheels in the tier below Zipp and Enve because I expect to make compromises at the C$ 2000-2500 price and want the compomises to be informed ones. Assuming all of the quantifiable variables are equal ( price, weight, rim depth around 35-40), is there a consensus that carbon is still preferable, or that carbon is to be avoided, and why? (I don’t ride in rain or descend mountains so braking conditions are generally optimal).
There is no consensus that carbon is still preferable or is to be avoided. The best advise I can give you is to ask your riding buddies who use carbon wheels. Maybe ask to borrow a set, or, rent a set from an LBS if they offer rentals.
 
#26 ·
I have read the reviews, recommendations and the comparisons between most upgrade wheels. I am not a serious rider for whom marginal gains matter a great deal, so i am at least as interested in the less desirable consequences. I am looking at modest depth (eg dura ace c40). Can anybody speak to extent of wind effects, durability, maintenance hassles or other?
If this is the case, I really don't see a reason to buy deep section wheels. A good quality alloy wheel with a modest depth of 24-28mm will serve your needs the best. Anything else and you are wasting your $$$.

If it makes you feel good to buy something expensive to hang on your bike, so be it. But if you think a new set of wheels will allow you to pass your buddies going uphill that you couldn't catch before, you will be disappointed.
 
#28 ·
The hubs Bicycle tire Bicycle wheel rim Bicycle wheel Yellow Rim
can affect the price considerably, but also contribute to a more reliable and enjoyable wheelset. Most carbon rims are very reliable. You will notice that braking power in the wet decreases considerably compared to alloy for any carbon rim. Also, many modern carbon rims are tubeless-ready which is nice, but it makes tires a little more difficult to take on and off. More expensive wheels have more expensive production, engineering, marketing and sometimes better customer service. The gains are sometimes marginal. 36mm Nox Carbon rims and DT 240 hubs may be in your price range.
 
#30 ·
Flywheel effect



With more weight out on the rims, there is a flywheel effect. So it takes a bit more effort to get up to speed but can hold it better. Not a big deal on the flats but when I tested a $2,000 35 mm wheelset on rollers, it was very noticeable. Good going down but when going back up and losing momentum, it took more effort to regain speed, that is , a little longer to accelerate. Since my area has lots of hills of all kinds, I opted to not go w the deep rim wheels.
 
#32 ·
Interesting post. Thanks

With more weight out on the rims, there is a flywheel effect. So it takes a bit more effort to get up to speed but can hold it better. Not a big deal on the flats but when I tested a $2,000 35 mm wheelset on rollers, it was very noticeable. Good going down but when going back up and losing momentum, it took more effort to regain speed, that is , a little longer to accelerate. Since my area has lots of hills of all kinds, I opted to not go w the deep rim wheels.
You have touched on a concern I have - I too ride in hills and am not a cycling prodigy who can ignore possibility of “lost momentum” uphill in order to realize uncertain gains elsewhere. I had assumed that if weight of wheels was sub 1500, and if 35 mm rim depth, I’d avoid weight and wind effects penalties. Thanks for your impression to the contrary.
 
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