# Aero Benefit of 38mm vs 50mm +



## chocy (Feb 4, 2009)

Is there a significant benefit between 35~38mm and 45~58mm rim depth?
I am looking at carbon clinchers for all purposes (mostly training rides and occational racing on rolling hills),

I think the weight of 35-38mm rims are more of my liking for climbing rolling hills but I do spend good amount of time doing mid 20 MPH on flats also. (My ave, speed for last century 18MPH, shorter trips can be 20MPH +) i go downhill portions usally around high 20s to mid 30s.

I am not looking to spend a lot of money to get light deep wheels (budget around $1000)
so usually sub 1600g of 35-38mm rim seems like a decent compromise unless 50mm+ depth adds considerable benefit on flats. 

I weight 185lbs and I ride about 500 miles on good months.

Also I right now ride Neuvation R28 with 27mm depth aero and tell me if I am crazy for wanting to go deeper if that is the case.


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## Guest (Nov 10, 2009)

I think you'll find rims like 38's and 45's are pretty good all rounders. Some of the stuff deeper than that can be a bit of a handful in crosswinds, that being said I have Edge 68's that I use all the time. I'd love to have sets of their other rims as well, but for now I either ride something pretty shallow and alloy or go all in with those. They are pretty light for their depth though.

As to the aero advantages I'll leave that alone.


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## Argentius (Aug 26, 2004)

In short, yes, there does seem to be a difference.

It seems to be pretty linear, within a given rim style -- the deeper the rims, the more aero the wheel.

For century speeds and times, the aero advantage will not be tremendous.

For racing speeds -- those sections when you're red-lined in the break doing 30mph -- you will notice it more. 

$1,000 is quite a lot of money. You'll find something you like. If your goal is speed, go as deep as you can.


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## Fixed (May 12, 2005)

*Zipp*

Zipp seems to be the best at actually documenting this stuff; dig around on its website for a while.

http://www.zipp.com/_media/pdfs/technology/revolutionary_speed.pdf

http://www.zipp.com/technologies/aerodynamics/aerodynamics.php


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## Zen Cyclery (Mar 10, 2009)

Fixed said:


> Zipp seems to be the best at actually documenting this stuff; dig around on its website for a while.
> 
> http://www.zipp.com/_media/pdfs/technology/revolutionary_speed.pdf
> 
> http://www.zipp.com/technologies/aerodynamics/aerodynamics.php


I disagree there is FAR too much bias. Here is a source that is not full of sh*t.
http://www.rouesartisanales.com/article-15505311.html


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## rruff (Feb 28, 2006)

chocy said:


> Is there a significant benefit between 35~38mm and 45~58mm rim depth?
> I am looking at carbon clinchers for all purposes (mostly training rides and occational racing on rolling hills)


Without knowing the specific wheels you are looking at, generally it would be less than 0.1 mph on your top end... seriously. 

If you aren't a racer, then I'd just get whatever will feel best to you... and that sounds like the lighter ones.


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## cpark (Oct 13, 2004)

With a budget of $1,000, I think the Reynolds wheelset fits the bill.
I heard a lot of good things about Edge wheelset and love to buy a set but it's little out of my price range.....


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## Guest (Nov 11, 2009)

cpark said:


> With a budget of $1,000, I think the Reynolds wheelset fits the bill.
> I heard a lot of good things about Edge wheelset and love to buy a set but it's little out of my price range.....



They are nice, maybe save till they're within reason? I waited and finally got a set and love them.


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## team_sheepshead (Jan 17, 2003)

There's a lot more to wheels than just rim depth and price. You've also got to look at durability and ability to service. So after you have narrowed down your choices, ask those questions, too, before you buy.

For example, I got a beautiful set of handbuilt wheels assembled by someone a few states away. Well, I tweaked one of the rims, a Velocity Aerohead. So the builder offered to look at it for me...if I paid shipping both ways. I wanted to try and avoid that cost, so I looked at every LBS in my neighborhood for a Velocity Aerohead front rim. Nobody had one. One shop called QBP and Velocity--out of stock. 

I finally found a shop with a good relationship with BTI in New Mexico. They were able to source a rim for me. This search process took me about two days, and now I have to wait 3-4 days for delivery. Frustrating.


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## Guest (Nov 11, 2009)

team_sheepshead said:


> There's a lot more to wheels than just rim depth and price. You've also got to look at durability and ability to service. So after you have narrowed down your choices, ask those questions, too, before you buy.
> 
> For example, I got a beautiful set of handbuilt wheels assembled by someone a few states away. Well, I tweaked one of the rims, a Velocity Aerohead. So the builder offered to look at it for me...if I paid shipping both ways. I wanted to try and avoid that cost, so I looked at every LBS in my neighborhood for a Velocity Aerohead front rim. Nobody had one. One shop called QBP and Velocity--out of stock.
> 
> I finally found a shop with a good relationship with BTI in New Mexico. They were able to source a rim for me. This search process took me about two days, and now I have to wait 3-4 days for delivery. Frustrating.



Unless you're building with a 32 hole Mavic Open Pro, I don't know that there are any other rims around right now that I would expect to be able to find quicker than that in an LBS.


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## foofighter (Dec 19, 2008)

thanks for posting this as i've been thinking the same thing...


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## twinkles (Apr 23, 2007)

I'd also check out the HED website. There's alot of info on rim depth, rider speed, wind speed & wind direction. You've got to be really moving to get aero advantages from deep rims and quite often deep rims are slowing people down. I do so much climbing that wheel weight is way more important than aero. I also notice that sub 1500 gram wheels accelerate quite a bit faster than 1800 gram wheels. The only aero wheels I'd consider would be tubulars, cause they're so light compared to aero clinchers. But tubulars aren't practical for most everyday wheels.


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## cpark (Oct 13, 2004)

kytyree said:


> They are nice, maybe save till they're within reason? I waited and finally got a set and love them.



My budget is around $1,800 so I may have to go with a set Reynolds DV46.
I had a set of DV46 a few years back and I really liked them.
But the set I really like to have is the Edge 68 with Alchemy hubs.......oh well.


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## spade2you (May 12, 2009)

I think everyone is on the same page. I think ~38mm rims are pretty good all around wheels and I'd think most riders would start to have crosswind issues with a 50mm, although at 125lbs, even my Mavic CCUs assist in crosswinds throwing me around. 

I'm not bashing the idea of deeper dish rims for training, but clinchers generally add weight and it's hard to find clinchers that roll like tubulars. In my book, making them "everyday wheels" takes a little away from high performance.


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## cpark (Oct 13, 2004)

spade2you said:


> I think everyone is on the same page. I think ~38mm rims are pretty good all around wheels and I'd think most riders would start to have crosswind issues with a 50mm, although at 125lbs, even my Mavic CCUs assist in crosswinds throwing me around.
> 
> I'm not bashing the idea of deeper dish rims for training, but clinchers generally add weight and it's hard to find clinchers that roll like tubulars. In my book, making them "everyday wheels" takes a little away from high performance.


Agree with everything you said here.
I will also add that the shape of the spokes has a huge affect on cross wind, IMO.
In a windy day, my Fulcrum Zero (fat AL spokes) feels like it gets blown around as much as my old DV46 wheelsets....


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## spade2you (May 12, 2009)

cpark said:


> Agree with everything you said here.
> I will also add that the shape of the spokes has a huge affect on cross wind, IMO.
> In a windy day, my Fulcrum Zero (fat AL spokes) feels like it gets blown around as much as my old DV46 wheelsets....


Very much so! I'm looking at ordering some Zen Enligthenments with the tiny stainless steel spokes mostly for climbing, but also because I misunderestimated (favorite Dubya word) the impact of flat spokes with my CCUs. Heh, my last ride with the Mavics about a week ago pissed me off THAT much, although it tends to be notoriously windy in my area when winter is approaching. Every once in a while, I've debated gaining weight. Fortunately, I can hide in the pelaton on most races and the most frequent TT route has minimal crosswind issues. Every once in a while, I've debated trying to gain weight....then I climb and calm down.


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## Zen Cyclery (Mar 10, 2009)

spade2you,
What you need is a build like this. Then you can ride the CCUs in a hurricane.


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## spade2you (May 12, 2009)

Zen Cyclery said:


> spade2you,
> What you need is a build like this. Then you can ride the CCUs in a hurricane.


Ha! At that weight, I could use full discs on both wheels!


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## chocy (Feb 4, 2009)

Thanks everyone for interesting insights.

As for the cross wind. Neuvation R28 I own has seriously fat bladed spoke and it does effect me in cross wind conditions quite a bit but it is something I can deal with (after all I am not exactly light at 185 lbs) 
it seems that the deeper rim with less of a bladed spoke will be similar 

Looks like reynolds are nice, I have been looking at following wheels to be speciic

35 ish wheels

SOUL C4.0 (40mm depth) $820 1390g claimed -- everything sounds awsome + cheapest but supplier to far for A/S
Williams 38 Carbon clincher $999 1596g claimed -- Interesting balance for 38mm is the shallowest of the bunch
SRAM S40 under $1000- ebay 1615g claimed -- looks great but heavy for relatively shallow wheel.

45- 50 +

SOUL C5.0 (50mm depth) $1170 1465g -- Same as SOUL C4.0 and slightly above my price range
Williams 58 cabon clincher $999 1879g -- heaviest of the bunch
Neuvation C50 carbon clincher $970 1600g -- probabaly best balance between weight and rim depth however other wheels other than reynolds claim that they have addressed the brake surface durabilty and this gigatech rim doesn't have that (i.e durabilty not as good?)
SRAM S60 ~$1000 1750g -- Nice but again heavy
Reynold Assault ~$1200 1525g -- thanks for the suggestion (was not on my list) look interesting but there is a hub issue?? plus this also doesn't have as durable braking surface as others? Also slightly above what I am looking to spend.

To be honest the new wheel set will yield more bling factor than actual performance in my regular riding. But I would hate to think it would slow me down by being heavier than my current wheels.


Reynolds DV46C ~$1500 1460g ish - my my awsome combination but again way above what I am looking to spend.

If you have other suggestions let me know.


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## Slee_Stack (Jun 28, 2006)

Soul S4.0. Absolute cheapest at $420-$450. Weighs alot (~1900g), but you aren't exactly a featherweight and you admit 'bling' is key. Is the 'carbon' bling worth at least 100% more?


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## wetpaint (Oct 12, 2008)

chocy said:


> Neuvation C50 carbon clincher $970 1600g -- probabaly best balance between weight and rim depth however other wheels other than reynolds claim that they have addressed the brake surface durabilty and this gigatech rim doesn't have that (i.e durabilty not as good?)


I have these wheels, durability is fine, mine have 5000 miles on them and the brake tracts are fine, they survived some really really bad potholes too.


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## EMB145 Driver (Aug 17, 2006)

wetpaint said:


> I have these wheels, durability is fine, mine have 5000 miles on them and the brake tracts are fine, they survived some really really bad potholes too.


4,000 miles on my C50Cs since I bought them in June and they've been great, no problems. I rode them yesterday in 30mph wind gusts and they handle fine, but you can't go to sleep on them in that kind of wind, but you couldn't on any wheel.


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## chocy (Feb 4, 2009)

Slee_Stack, 

yeah I admit the bling factor but I do not want to pay a dime for something that weights a lot more than what I already have (Neuvation R28) I guess bling factor is there but it is not as important than compromise in performance that I have now.


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## team_sheepshead (Jan 17, 2003)

Call John Neugent at Neuvation and talk to him about his wheels. I rode a pair of the carbon tubulars for a while and they are the best wheels I've ever "felt" under me. Alas, I got tired of dealing with flats and buying new tires, so I sold them.

This is the kind of guy John is: I bought the Neuvations used on FleaBay. When I emailed John to tell him how much I liked them, he said that if I ever had any problems with them, he'd honor the warranty.

Speaking of which, if you are looking for aero wheels, you know you REALLY should go carbon tubular, right? You get three benefits:
1. Aerodynamic rims
2. Light weight (with light tires, you also save the weight of the clincher and inner tube)
3. Relatively low prices in the used market, because demand is lower


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## chocy (Feb 4, 2009)

The thought did cross my mind. especially with the price of tubular rims that neuvation seels make them very attractive.
However I am not sure I am really ready for the hastle of tubular world. I'd hate to be stranded 50 miles out in NJ or upper hudson as I, nor my wife own a car.... (we live in the city)


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## team_sheepshead (Jan 17, 2003)

I live in the city, too, over on 1st Ave. Riding tubulars 50 miles out in NJ was not the prob for me, it was getting through NYC streets with all the shards of glass and metal. I got four flats in four months on tubulars. I was able to seal up two of the flats, but ended up having to buy two new tires. I'm not paying $100+ every four months for tires.

Let me know if you ever want to ride.

PM sent.


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## Fixed (May 12, 2005)

*exactly*



chocy said:


> The thought did cross my mind. especially with the price of tubular rims that neuvation seels make them very attractive.
> However I am not sure I am really ready for the hastle of tubular world. I'd hate to be stranded 50 miles out in NJ or upper hudson as I, nor my wife own a car.... (we live in the city)


To me, tubulars are only for supported racing. I have several sets of tubulars, but I have been stranded so often with that 2nd flat that I have given up using them for training or even events like centuries. I only use them for races where there are neutral wheels or I have my own crew.


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## mendo (Apr 18, 2007)

Fixed said:


> Zipp seems to be the best at actually documenting this stuff; dig around on its website for a while.
> 
> http://www.zipp.com/_media/pdfs/technology/revolutionary_speed.pdf
> 
> http://www.zipp.com/technologies/aerodynamics/aerodynamics.php


Hed has quite a bit of info on their site as well, showing aero properties at different wind angles.

Whoops. Someone posted the same thing below.


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## Kerry Irons (Feb 25, 2002)

*Careful reading*



Fixed said:


> To me, tubulars are only for supported racing. I have several sets of tubulars, but I have been stranded so often with that 2nd flat that I have given up using them for training or even events like centuries. I only use them for races where there are neutral wheels or I have my own crew.


You must not have been reading this site carefully! There are numerous tubular users who post here and tell you that they "never" flat with tubulars. You must be doing something wrong  Me too, as I have had significantly fewer flats since switching to clinchers after 30 years on tubulars.


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## stevesbike (Jun 3, 2002)

I think HED has decent data on the merits of different depths - check out the link below. Personally, if you want aero I'd recommend Jet 60s clinchers. Aero is not just about depth but also shape - HED and Zipp co-own the patent on toroidal rim design. In real world riding yaw angle is a factor and shape + depth has an effect on drag under those conditions (see the link). You can use a Jet 60 as an everyday wheel

http://www.hedcycling.com/wheels/jet6.asp


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## Salsa_Lover (Jul 6, 2008)

Kerry Irons said:


> You must not have been reading this site carefully! There are numerous tubular users who post here and tell you that they "never" flat with tubulars. You must be doing something wrong  Me too, as I have had significantly fewer flats since switching to clinchers after 30 years on tubulars.


Murphy's law.

I am careful when I ride, look ahead, avoid shiny shings on the road, don't roll over metal things or potholes etc.

After almost 5 years without flats, I decided to leave at home the saddle bag with the still unused for all that time CO2 cartridges and tube.

On my third ride without the repair kit, bam ! flat the rear tire. 

Fortunately it wasn't far from home, but I had to push my bike for a while to the next train stop.

I carry the repair kit again.

Then, now this year after reading all that the Cyclocrosser's say about the tubulars being much more flat resitant and allowing you to ride at lower pressures, so I decided to try them.

After 2 seasons of riding on clinchers and not having a flat ( alas, with higher pressure ), I set up a set of expensive Challenge Cross tubulars. 

Bam ! a flat on the first testing ride.... not far from home again but then I had to push it all the way back from the forest to the civilisation.

There you go.


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## Duke249 (Apr 4, 2002)

For the speeds that you're riding, I don't think you'll get the benefit of going with a deeper rim section. After recently using a pair of the latest Dura Ace 50mm tubular wheels, I was really disappointed by them for similar riding. 

On a group ride through rolling countryside with a 19mph-ish average speed, they felt very sluggish. The extra weight on the outside of the wheel really was noticeable with the extra inertia. 

I could see the benefit of using these while racing where the benefits of the aerodynamics will help more (I'm thinking 25mph-plus), but for just tooling around at 18-20mph, I think you're setting yourself up for a disappointment if you select a wheel with a taller profile.


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## Salsa_Lover (Jul 6, 2008)

Duke249 said:


> For the speeds that you're riding, I don't think you'll get the benefit of going with a deeper rim section. After recently using a pair of the latest Dura Ace 50mm tubular wheels, I was really disappointed by them for similar riding.
> 
> On a group ride through rolling countryside with a 19mph-ish average speed, they felt very sluggish. The extra weight on the outside of the wheel really was noticeable with the extra inertia.
> 
> I could see the benefit of using these while racing where the benefits of the aerodynamics will help more (I'm thinking 25mph-plus), but for just tooling around at 18-20mph, I think you're setting yourself up for a disappointment if you select a wheel with a taller profile.


my Cosmics start to come alive north of 23mph then you can really go faster than with non-aero wheels. and that only without crosswinds, don't help at all when climbing because I simply can't climb at that speed and are heavier than the Ks... So I only use them on the TT bike now.


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## wankski (Jul 24, 2005)

this has been posted before, but the rouesartisanales site and the tour mag test should tell you your answer.

suffice to say, if i were to build myself an inexpensive carbon set, i'd go with 38mm tubbies. i feel you get the best of everything. if you're a bit richer, i'd go for the edge 45s... something in that range. aero and light - can't be beat.


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## tyro (May 15, 2005)

I wonder where the Edge 45 and 68 would fall on the Roues Artisanales aero chart?


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## jsedlak (Jun 17, 2008)

It looks like you get fairly minimal benefits from a 58 over a 38. It is roughly a .01 difference between 19 and 38, and then another .005 to the 58s

I still like the idea of the Edge 45/65 combo. Or a 404/808 combo.

But that graph also suggests that if the graph were continued, a disc wheel would provide an extremely small aero benefit over the 80/85mm range.

And yes - I did just accidentally bump this ancient thread.


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