50mm or 38mm deep?

vegas76

Hi folks, I'm contemplating some new wheels. Can someone in the know explain what the main differences are in use between a 38mm deep & 50mm deep wheels?

pblakeney

If you often ride in cross winds you will probably prefer the 38mm rims.

stueys

Deeper equals more aero benefit but at the expense of more weight and more susceptibility to cross winds. As ever, that's a broad generalisation, the modern designs have made crosswinds pretty much a non-issue.

Matthewfalle

Crosswinds have been a non issue for years.

50mm works perfectly everywhere and looks and sounds the best which is, tbh, the main reason most people buy these things.

First.Aspect

12 mm

norvernrob

Depends where you ride. My mate and I have both had 50mm (actually several from 46-52mm) wheels and ditched them due to getting blown all over the place in the Peak District. Anyone that says they aren’t affected by wind either weighs 100kg+ or is talking rubbish. He’s now got 38mm and I have Fulcrum Zero Nite that are lighter, stiffer and handle far better than deep wheels.

stueys

NorvernRob wrote:

Depends where you ride. My mate and I have both had 50mm (actually several from 46-52mm) wheels and ditched them due to getting blown all over the place in the Peak District. Anyone that says they aren’t affected by wind either weighs 100kg+ or is talking rubbish. He’s now got 38mm and I have Fulcrum Zero Nite that are lighter, stiffer and handle far better than deep wheels.

I ride Enve 4.5’s, they are as stable (if not more so) than my box c24’s. A gust at a certain angle can sometimes catch them but it’s always a very manageable torque loading. I took them to Mallorca this year and had no issue with the gusty afternoons where the wind bounces around the mountains. You can certainly feel the wind on a windy day but it’s never been a problem for me.

cycleclinic

cross winds are a non issue with the right rim profile. Dura Ace C50 7900/9000 rims are an example of the wrong profile and it that kind of rim where the problem has arisen.

with clinchers the depth of the rim does not effect the weight much, it does affect spoke longevity and the aero gain so there is no point in shallow. you might as well spend less on the kinlin XR31T and get near enough all the gain.

norvernrob

Stueys wrote:

NorvernRob wrote:

Depends where you ride. My mate and I have both had 50mm (actually several from 46-52mm) wheels and ditched them due to getting blown all over the place in the Peak District. Anyone that says they aren’t affected by wind either weighs 100kg+ or is talking rubbish. He’s now got 38mm and I have Fulcrum Zero Nite that are lighter, stiffer and handle far better than deep wheels.

I ride Enve 4.5’s, they are as stable (if not more so) than my box c24’s. A gust at a certain angle can sometimes catch them but it’s always a very manageable torque loading. I took them to Mallorca this year and had no issue with the gusty afternoons where the wind bounces around the mountains. You can certainly feel the wind on a windy day but it’s never been a problem for me.

Maybe I’m being a bit unfair, as I’m talking about big gusts of crosswinds when high up in the Peak District. I was once actually blown off the road onto the grass on Holme Moss, but that was probably a 40mph+ gust. I’ve had a few sets, from Planet X 52mm which were horrendous, to Zipp 404 and Syncros 46mm which were better but still took some handling in gusty crosswinds.

StillGoing

Have had 50mm tubs and 50mm clinchers with both suffering with cross winds, particularly when riding along hedgerow lined roads shielded from the wind until you went by a field gated entrance. Didn't have any issues when I moved to 38mm front and 50mm rear. I now ride 40mm Mavics and suffer no problems.

MiddleRinger

Unless you ride somewhere super hilly or super windy, go deep. 8)

vegas76

Thanks for all the replies. Thinking of treating myself to Primes RP-50 or RP-38 wheels. That would be to replace the stock giant PR 1 wheelset which I think is 28 deep, so arguably not a lot of point going 28 to 38, might as well just go 50.

imposter2.0

Vegas76 wrote:

Thanks for all the replies. Thinking of treating myself to Primes RP-50 or RP-38 wheels. That would be to replace the stock giant PR 1 wheelset which I think is 28 deep, so arguably not a lot of point going 28 to 38, might as well just go 50.

You haven't really said what your expectations are for these new wheels. If you are expecting them to turn you into a cycling god, then you may be disappointed. If, on the other hand, you just like the idea of cool deep section wheels which look awesome, then get the deepest you can find.

vegas76

Just looking for something a bit more efficient, and lighter. The current wheels on my bike must be at least 2kgs!

DeVlaeminck

Vegas76 wrote:

Just looking for something a bit more efficient, and lighter. The current wheels on my bike must be at least 2kgs!

Well lighter would suggest you are looking for some shallow rims. If you don't race and want an everyday wheel I'd go for the shallower option - some people seem fine on 50mms in quite gusty conditions and others not - part of that is probably due to the wheels and part the rider's mentality.

fenix

I had 50mm deep rims - I swapped to normal depth after we had a lot of windy rides.

As has been said - if you ride in windy areas then it's no fun going past a farm gate. Sure they're nice on fast descents - but for most roads - there''s no real benefit.

vegas76

DeVlaeminck wrote:

Vegas76 wrote:

Just looking for something a bit more efficient, and lighter. The current wheels on my bike must be at least 2kgs!

Well lighter would suggest you are looking for some shallow rims. If you don't race and want an everyday wheel I'd go for the shallower option - some people seem fine on 50mms in quite gusty conditions and others not - part of that is probably due to the wheels and part the rider's mentality.

Would you say it's worth it if I'm coming off 28mm deep wheels? I.e. Is it enough of an upgrade? I'm 85kgs,mostly ride in South West London / Surrey so it's not awfully windy...

StillGoing

The Prime RP38s are good wheels. My wife has a set of carbon disc on her Hybrid (I won them but got the Mavics at the same time so were surplus to requirements) they look good, light and enough of a balance between looking aero profile and not being affected by cross winds.

vegas76

philthy3 wrote:

The Prime RP38s are good wheels. My wife has a set of carbon disc on her Hybrid (I won them but got the Mavics at the same time so were surplus to requirements) they look good, light and enough of a balance between looking aero profile and not being affected by cross winds.

Do they look aero or is there actually an aero benefit?

BikerGroveish

50mm rims look nicer than 38mm and there are aerodynamic advantages in a straight line. 50mm rims take a bit more getting used to if you ride in windy conditions.

svetty

Another reason to think about handbuilt wheels is that you can specify. I have found that 50mm on the front wheel does make it prone to sidewind esp gusts. On the other hand deeper section rear wheels are less of an issue. There's a reason TT bikes have discs in the rear but not the front. Going handbuilt means you could run a less deep - say 38mm on the front and deeper - say 60mm on the rear.

cycleclinic

having riden in the on the tops in the north on a windy day with shallow rims gust are a problem on those so it not the wheels but the wind. so it again is all in the rim profile. the better deep rims are not much more a=of a handful than a shallow rimmed wheel.

This is the problem with generalisations. different rims behave differently in winds and you can tgeneralise that easily.

StillGoing

Vegas76 wrote:

philthy3 wrote:

The Prime RP38s are good wheels. My wife has a set of carbon disc on her Hybrid (I won them but got the Mavics at the same time so were surplus to requirements) they look good, light and enough of a balance between looking aero profile and not being affected by cross winds.

Do they look aero or is there actually an aero benefit?

They look aero and have the added benefit of being tubeless ready. They accommodate a 25mm tyre without any bulging of the sidewalls too. You can see from the images in the link that they look aero.

https://cyclingtips.com/2017/01/prime-r ... et-review/