Carbon deep-section wheels

TOM

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#1
I've always been attracted by the good looks :cool: of deep-section carbon wheels. I know some TCC people are using them to advantage in race events.

Just how big is the aerodynamic advantage and what would be the ideal rim depth for long fast runs on a flattish stage? Should I be looking at a 50mm rim?

Also what are the downsides - if any besides their weight - of such wheels?

Finally, can anybody recommend a budget-friendly (i.e. under 10-man :warau:) pair (preferably with alu rims ;)) based on actual experience ?
 

FarEast

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#2
GS ASTUTO 50mm wheels - I've been testing these for Tim for sometime and I have HAMMERED them. I'm using the carbon clinchers andI have to say theseare amazing wheels not just price point but also quality and build as well.

Although remember the depth of the rim is dependant on several things.

Wind conditions- strength and direction
Wattage output
Type of racing / riding you are doing.


Right now the Pro Tour is favouring either 50mm or 38mm in multiple stage races while 24's for the climbs. Remember though they will switch wheels mid race
 

GSAstuto

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#3
Thanks for the plug, James, I appreciate it. To add a little for Tom's benefit

Why is a deep dish wheel <better> aerodynamically? Mainly because it allows a smoother, laminar flow across the surface. This is obviously more significant as you raise the velocity. In cycling, wind resistance will account for a large part your wattage requirement as you go above 35kph. So - if you can reduce the effects of wind resistance, you will be able to go faster with the same wattage.

How deep of rim is recommended? This depends on many factors especially the prevailing wind conditions, weight issues, ride quality desired and route. As wind increases and you involve more hills, the use of a disc wheel becomes disadvantageous and smaller sectional wheels will outperform especially in heavy cross wind situations.

An interesting factor is that if you ride a grade more than 3 % or so, the aerodynamics advantage will become negligible compared to the weight advantages. Unless, of course, you have strong wind conditions - then you could raise the grade effectiveness up a degree or 2. But at the end of the day - the lighter wheelset will offer much more advantage than the heavier in extended climbs over 4-5% under nearly any condition.

If you are riding in general conditions that oftentimes require extended TT type riding, then I'd suggest a 50mm or 60mm rim section. If you are doing TRI type events where drafting is not allowed, then even going to 80mm is good. The 50mm or 60mm is a real workhorse wheel and offers good aerodynamics and superb stiffness for strong riders. Put these into a peloton and you will barely even notice cross wind effects. So - for example, the Itoigawa event - you'd find me on 50's or 60's in a heartbeat. Or, even for crit events where you have longer intermediate sections - I'd probably favor the 50's.

If you are riding alot of 'rouler' type of routes involving combination of hills, technical descent, rapid acceleration and deceleration, then I'd suggest a 38mm rim section. This will result in a high performance wheel with acceptable weight for most shorter duration climbs. The 38's make a great 'Greenline' wheel. You have some nasty rough descents and lots of smaller, sub 10km climbs.

For truly Alpine use, then you want sub 25mm wheels. The goal is just getting the rotating mass as low as you can. Just a few grams off and you start shaving seconds over km. As an example, our Alpine standard wheelset is under 1000 gr complete with skewers. Add a couple of 135gr Tubulars and DA cassette and you'll barely tip the scales at 1400gr with the front wheel a svelte 485gr or so complete.

What is the real effect? In my direct experience - which somewhat correlates with formulaic studies :

1) Aerodynamics do count. I descend faster without pedaling using my 50mm than my 20mm. And I can average higher steady state velocity on relatively flat routes like Arakawa, etc. The aerodynamic gain is biggest, in my opinion.

2) Weight does count, if it's seconds you are after. As the hills become steeper - weight matters even more. Below 10% grade it matters much less. Where I notice the advantage of super light wheels is especially on switchback sections where I need to 'push up' over a relatively short, steep (15%+) curve. With the lighter wheels I can make this jump and gain advantage on every switchback. O Toge is good example here - I did pretty good and I was using very lightweight wheels. Had I gone to my 38's or 50's , I would have been probably a minute or 2 down from my best effort there.

On a route like Tomin No Mori - then I notice not so much difference between my 38's and 20's . Mainly because I am climbing at higher speed and the aerodynamic actually give me more benefit than the weight. So, typically my 'go to' wheelset in the mountains will be a 38 or a 50 because my routes involve a significant amount of transiting and descending. But for hill climb event where descending and transit is not so important - then I prefer the 20 or 24mm.

BTW - if anyone wants to try a set of wheels, just shout out. Maybe we can arrange a group testride out at Otarumi or something like that where you can try both uphill and downhill repeats with different combos. I have several sets of wheels and it's quite fun to compare on the road where it really counts. Regardless of the actual brand you end up getting, just riding on differing profiles will give you a very good indication of relative performance and suitability.
 

AlanW

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#4
I've switched to using deep section rims all the time....

My everyday wheels are Dura Ace 7850 C50 (clincher), which can be had for around ju-man en if you look around. I've been super impressed with these wheels. The 50mm rims are noticably faster once up to speed. I can reach higher speeds and sustain them with much less effort than the Ksyrium "windmills" that came with my bike. They are a bit heavier than the Ksyriums (1700g vs 1550g) but the advantages on the flats, downhills and shallow gradients is clear, and I'm pretty sure they're faster overall. They certainly feel that way. Other nice things about these wheels is that they are quite stiff, so feel good when sprinting/climbing, and they have an alloy brake track. I enjoy pushing hard on the descents and with these wheels I can brake super-late into the corners, rail round and launch off down the next straight. Full carbon rims are gradually getting better for braking but still can't hold a candle to a metal brake track for power and modulation. The Dura-Ace hubs are very high quality as well, and the build quality seems excellent; my wheels have been 100% round and true for several thousand km with no need for the spoke key. Downsides, as I said, they are not the lightest, and they do get buffeted a bit in really strong crosswinds so you have to be ready for that, particularly on fast descents. The long valve stem needed seems to throw the balance off, and I'm thinking of adding a small weight opposite to compensate and further stabilise the ride at very high speeds. Finally, you need to be a reasonably fast rider to get the benefits of a deep wheel....just pootling around they don't really feel special.
For the hillclimbs and road races, I splashed out on a pair of Zipp 303 tubular wheels, mostly for the weight saving. These are very nice indeed but only come out to play on race days. There's just no need unless I'm going against the clock. They are a nice "all round use" wheel at 45mm deep but only 1170 grammes. These do feel special, even at slow speed, the accelerative kick due to the light weight is addictive :D (on sale too from ChainReaction)
 

GSAstuto

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#5
Couldn't agree with Alan more - this is exactly what you get with high quality deep(er) rims. What I'm doing differently is providing the same kind of performance at about 35- 50% cost savings over even top brands like ZIPP. And, of course if you want even MORE weight weenie insanity - we have a new set coming in that tips the scales at about 750grams - FRONT and BACK! You know what I'll be rocking at Ryusei.
 

m o b

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#6
Daily Use

In addition to the statements about aerodynamics and racing capabilities and I would like to highlight some points concerning daily usage of carbon wheels

1. Braking Performance
Even "good" carbon wheels with optimized braking surface and carbon-specific braking pads do not come close to the braking performance of standard alu rims. The whole experience is rather disappointing on descents.

Some wheels are available with alu rims, however this is a compromise in design which increases the weight of the wheelset substantially. Shimano uses a mix of materials.

2. Clinchers
Most carbon wheels are designed for glued tubeless tires. They are more expensive than clinchers and more difficult to exchange. On rides you either need to carry a spare tire or repair spray with you. Another weight disadvantage.
Carbon clinchers need thick crabon rims so anothr weight disadvantage.

3. Sensibility
Well, they are made of carbon. One has to accept the fact that the risk-free lifetime is rather short. Unintentionally one rides over a pothole and the question remains forever in the brain if the integrity of the wheel is still OK or not.

4. Design
Yes, they are good looking.

I own a pair of Toppolino VX4.0 which are very good looking (4) but I hardly use them (1,2 and 3). About 8ManYen in Germany.

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GSAstuto

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#7
In addition to the statements about aerodynamics and racing capabilities and I would like to highlight some points concerning daily usage of carbon wheels

1. Braking Performance
Even "good" carbon wheels with optimized braking surface and carbon-specific braking pads do not come close to the braking performance of standard alu rims. The whole experience is rather disappointing on descents.

Newer carbon rim actually have good braking performance. With basalt impregnation and Hasselhoff approved compounds.

Some wheels are available with alu rims, however this is a compromise in design which increases the weight of the wheelset substantially. Shimano uses a mix of materials.

Shimano? Non e vero!

2. Clinchers
Most carbon wheels are designed for glued tubeless tires. They are more expensive than clinchers and more difficult to exchange. On rides you either need to carry a spare tire or repair spray with you. Another weight disadvantage.
Carbon clinchers need thick crabon rims so anothr weight disadvantage.

Not so much , actually - most of the extra weight is in the crappy clincher tires and axillary tube thingy.

3. Sensibility
Well, they are made of carbon. One has to accept the fact that the risk-free lifetime is rather short. Unintentionally one rides over a pothole and the question remains forever in the brain if the integrity of the wheel is still OK or not.

I have hit speedbump followed by a series of the Japanese brick reflectors (6) at 'speed', watch my 20mm wheel warp into a pretzel, then snap back - following which I sprayed some latex into it - pumped it up and rode another few hundred km (tomorrow I ride it again) something I could never do on my alloys, which would be permanently 'bent'. Carbon kicks .

4. Design
Yes, they are good looking.

Even David H. would agree!

I own a pair of Toppolino VX4.0 which are very good looking (4) but I hardly use them (1,2 and 3). About 8ManYen in Germany.

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'Topolino' means 'Mickey Mouse' in Italian - Is this a MOBism???
 

TOM

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#8
Thanks James M., Tim, Alan, MOB for all the super insightful advice! Immensely thankful :).

I'm a lazy person and a bit of a chicken when it comes to descents. Tim with his incredible pretzel anecdote :warau: almost convinced me that 100% - rim and all - carbon is the material to go but it is such a pain to change brake pads all the time with each wheel swap. Also, I am looking for a daily use (not race) pair at a democratic price.

Right now, I am seriously considering these...they (non-series WH-RS80-C50-CL) seem to be new on the market and reasonably-priced too. Shimano has rarely (only once broke a spoke) let me down so I feel ready to give these a try...
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Sikochi

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#10
There`s a lot of information floating round about wheels and my best recommendation would be to read some of the information Flo cycling have been publishing on their way to produce their own cheap aero wheels - aluminium with carbon fairing.

http://www.flocycling.com/aero.php
http://flocycling.blogspot.com/

Basically, rim shape (e.g. toroidal) is more important than rim depth, due to the crosswind problem - see Zipp`s new Firecrest design. Also, rim width.
Carbon`s biggest problem is the heat dissipation and there`s an article on the Zipp website showing that even their best wheels can`t match aluminium for this.
Spoke count (and shape) comes into play.
The interplay between the rim and the tyre is also vital, so you can negatively affect your aero benefit by choosing the wrong tyres e.g. tyre width.
Rotating mass effects aren`t an issue when cycling.
Aero beats weight on gradients, I would go steeper than GSAstuto here and say more like 10%+ (but I don`t know the exact figure)

Basically, the RS80-50`s would have marginal improvement over the standard RS80`s that I have. Also, remember that what riders use is partially dependent on the situation they use them in - i.e. riding in a peloton. Unless you are going to ride in a peloton all the time, looking at what pro-triathletes use would be a better guide and pretty much standard advice is the fastest option is a Hed tri-spoke or Zipp 404 up front and a disc on the rear.
 

Sikochi

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#11
Newer carbon rim actually have good braking performance. With basalt impregnation and Hasselhoff approved compounds.

IS that THE Hasselhoff?

Not so much , actually - most of the extra weight is in the crappy clincher tires and axillary tube thingy.


Remember, Tony Martin just won the World TT on a set of clinchers.
 

GSAstuto

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#14
Of course, we ONLY use official Knight Rider approved technology.

As for clincher - to each his own.

How about you take your best pair of clinchers and I take my best pair of tubulars and we do a Wada showdown? 1 loop West->East starting at Takao and finish at Takao San guchi.

Just to make it fair (since I am an old man over 50):

1) I'll ride my Bidgestone RADAC circa 1980 with only 6speed and no FD.
2) I'll give you a 15min headstart.



Newer carbon rim actually have good braking performance. With basalt impregnation and Hasselhoff approved compounds.

IS that THE Hasselhoff?

Not so much , actually - most of the extra weight is in the crappy clincher tires and axillary tube thingy.


Remember, Tony Martin just won the World TT on a set of clinchers.
 
#15
:thumb:


How about you take your best pair of clinchers and I take my best pair of tubulars and we do a Wada showdown? 1 loop West->East starting at Takao and finish at Takao San guchi.

Just to make it fair (since I am an old man over 50):

1) I'll ride my Bidgestone RADAC circa 1980 with only 6speed and no FD.
2) I'll give you a 15min headstart.
 
Sep 2, 2009
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#16
Just to make it fair (since I am an old man over 50):

1) I'll ride my Bidgestone RADAC circa 1980 with only 6speed and no FD.
2) I'll give you a 15min headstart.
Haha, wicked. :)

Wheels; I use a set of Mavic Cosmic Carbone SR as my deep-section wheel. Love them, and have ridden them over all kinds of terrain.

They are the ones with the poncey carbon spokes. I have had them trued a couple of times, and each time the engineer has told me that I didn't need to get it done (meaning that they are tough wheels, considering how much bunnyhopping / trashing around I do).

If anyone is thinking of getting some of these, I would say go for it. There are loads of other wheels out there, for sure, and these are clinchers with an aluminium braking surface, so probably not everyones cup of tea.

I would love some of those Zipp 303s that Alan has too, but I don't think my banky will likey.
 

AlanW

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#18
Tom,
Those Shimano wheels are the same rims as my 7850s but use the Ultegra-grade hub. They should suit you well.
AW.
 

GSAstuto

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#19
I wonder what braking pads he had --- cause descending Azami even under severest situation should not be an issue. The main issue with carbon wheels and heating is in using high rubber content pads which generate extreme heating and can cause softening of the laminate. If you use dusting type pad which is designed for carbon rims, the heat is less because its part of the decomp process and friction is pretty darn good for controlling speeds at any reasonable descent.

Another MAJOR ISSUE is that people tend to mount their pads low on the rim. This is big NO NO for carbon clinchers. In spite of what you might think - you should mount the pads HIGH on the rim side - because that is the strongest (thickest) section. If you mount them too low you will certainly break the lamination between the sidewall and upper rim cross section.

Tubular rims minimize most of these problems, btw. They are stronger in the cross section and the carbon rim insulates the tire so the age old 'melting glue' syndrome doesn't occur. You end up with a far greater range of cornering footprint, better road 'feel' and safer overall system. Get a flat on a tubular? Who cares , just ride it! Get a flat on a clincher at speed? Good luck while you try to negotiate a tight corner at 50kph on a bare rim that is getting chewed up by the pavement.
Tom, don't forget what happened to Mike when he went down the Azami line with his carbon wheels...:eek:uch: