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PostPosted: Sun Nov 16, 2014 7:27 pm 
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Hello,
I’m new to this forum and I’d like to make my first post on aerodynamic wheelsets.
I always heard good things about aerodynamicity of Rolf wheels compared to others out there and would like to share my concern about this issue.

At the time, probably in 2004-2005 I was riding a road bike which was about 10 kilos with 105 and Tiagra gruppo and an alu frameset with Shimano WH-6500 wheels. These wheels share the same pattern with rolf wheels, 16 spokes and 30 mm deep rim.
At that time, I thought those wheels a bit flexy but I was really liked them when riding on windy roads, easy to accelerate
and keep my body balance and weight stable enough to ride along. I was probably 1,67 m and 60-62 kilos then.

Now I’m riding a 2007 model Trek Madone 6,5 SSL carbon bike with full DA 7800-7900 gruppo and DA 7900 C24 CL wheels with Michelin Latex 700*20 tubes
and Conti Grandprix 4000 700*20 tires (I keep tire pressure up to 140 psi) and total weight of the bike is 6,824 kg (DA 9000 pedals inc).

As regards weight, I’m totally satisfied with my bike and when it comes to performance, I think it lacks a little bit of aerodynamicity when riding in windy weathers.
I ride mostly on dry roads but the place where I live is all the time get windy so I’m not sure if I have any problem keeping my bike stable while riding under these windy conditions but I do 100% sure that these DA wheels lack stability regarding headwinds coming and sometimes with crosswinds and it gets sometimes pretty hard to control my bike.
BTW, now I’m 1,72 m and 67 kilos. I thought I should add some weight to my bike and change my wheels with some deeper profile wheels.
I can afford up to 1700 $ for wheelsets and my question involves some comparison among wheelsets.

Currently, I’m thinking of these models to compare: Shimano WH-7700-7701, WH-R540, Bontrager Race X Lite Aero (2005 model) and Rolf Prima TDF 58 Clincher, including some of the rest Rolf models like Vigor or Vigor Alpha etc…

What I’m looking for is a stable and fast wheelset to keep my pace high while I train or race under windy conditions on mostly flat roads.
At first, I thought to take WH-R 540 wheels for training and Rolf’s TDF 58 for race purposes by making the weight of my total bike up to 7,2-7,4 kilos..

Do you think this is a good idea? If you were to mine situation what would you do and choose? Also could you share some of your personal tests on aerodynamic wheelsets if any available…You can also give me an advice of any other brand’s wheelsets regarding aerodynamicity.

I included those wheels here because of their low spoke count and frequently i heard about wheels with low spoke count are more aero than the others.
Sorry for my long explanation to my question but I just needed to make sure myself finding a pair of good aero wheelset for my purposes.
Thank you in advance for your responses and comments.. :thumbup:


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Posted: Sun Nov 16, 2014 7:27 pm 


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PostPosted: Sun Nov 16, 2014 8:00 pm 
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Location: Glermsford, Suffolk U.K
First of all wider tyres 25mm and 100psi or less will actually make you faster. First of all the tyre deforms better to the road surface which normally improve the speed you can sustain unless the road you ride are very smooth. Also the wider tyre at lower pressure will allow faster cornering.

For racing I use 50mm deep 25mm wide carbon clincher rims (I bought these as rims and built them up myself) which I have mounted Vittoria Open Corsa 23mm tyres which spread out to 25mm. The tyre and rim are the same width which helps aerodynamics abit and the torodial shape of the rim means even in side wides I don't get blown about so that means they have to work. You can spend alot more of Dura Ace C50 wheels for example but I am no faster on those than the one I built. With nearly 3000 miles on them with no rim wear to speak of I think I am doing alright.

Any brand offering a 25mm wide carbon rim is worth looking at. Narrow rims (20mm wide) are bettered. You can buy this kind of performance for $1700 or alot less depending on wheather you go for an unbranded chinese rim (the one I have used or farsport e.t.c), gigantex do some good rims (BHS sell these), or a branded rim from the bigger names but buying them is the issue.

!6, 18 or 20 spokes does not make a big difference to how aero a wheel is. Rim depth, tyre/rim width and rim shape does.

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PostPosted: Sun Nov 16, 2014 11:18 pm 
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Joined: Tue Nov 11, 2003 9:47 pm
Posts: 1760
Location: Santa Cruz, California, USA
140psi is crazy. You will be more comfortable and have better cornering traction with 95-100psi in 23 or 25mm tires. 140psi is way too much for carbon clinchers. I use 95 front/100 rear for most riding but for especially bumpy roads (we have one race here billed as the "Paris-Roubaix of Northern California") I use 85/90 on 23mm tires. I weigh a couple kg less than you.

Modern rims are designed around 23mm or 25mm tires. That includes their aerodynamics.

I have yet to spend time on wide high profile rims but I've had plenty of riding on narrower ones. Their being affected by wind is something you get used to. It's like riding on sand- you let the bike move around a bit under you rather than fighting it, which gets tiring. If you are having problems with low profile rims I don't think that a high profile rim is going to be significantly better... just not as bad as older narrow high profile rims.


Adding weight isn't going to change how much you get blown around by wind. However for better performance on flat ground you're on the right track to go more aero even if it means more weight.


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PostPosted: Sun Nov 16, 2014 11:50 pm 
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Corning is improved on the wide rims eric well worth a new wheelset and given your propensity to break wheels (your own admission) you can't be that far away from another set.

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PostPosted: Mon Nov 17, 2014 6:34 pm 
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the shimano c24's have actually been tested as pretty aero, and I am surprised that you are bothered by sidewwinds with them. they are my everything wheel for years, and with 25c tires I have no complaints about aerodynamosity, aerodynamicity, or aeronessicosityness.


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PostPosted: Tue Nov 18, 2014 12:17 am 
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Location: Santa Cruz, California, USA
I've got a set of wide rim wheels and they don't corner signficantly different than the narrow ones. Same 23mm tires, same pressure. Different bike though. I should probably swap wheel sets on the same bike to make a better test.

I think my next rear wheel will use the offset spoke bed XR270 from BHS.


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PostPosted: Tue Nov 18, 2014 10:55 am 
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Thank you for your precious views on this issue. Actually, I have been riding on rough roads pumping my tires up to 100 psi in the past and I have used both 23 mm and 25 mm tires, along with 19 mm. What I tested was that on smooth roads higher pressure and narrower tires helped me get speed as much as possible. I don't know if this is a placebo effect but I can't ride with 23 mm in terms of high speed. The weird thing is latex tubes are needed to be pumped up to 120-130 psi in order to have much smooth controlling on asphalt. I have tested this occasion several times and provided me with the same result every single time. On the other hand, 23 mm tires with 100 psi definitely works very well on rougher roads and help cornering very well as you stated...As for DA C24 wheels, they are also my favourite wheels for 3 years by now and I don't have any problems concerning sidewinds. I normally ride with an average 35-38 km\h and when it is windy my speed lowers to 20-28 km\h depending on the wind speed. In particular, I tested my bike when the wind was blowing about 35-38 km\h and what I found is that with DA C24 wheels I cannot ride 24-25 km\h and on this occasion a friend of mine had some speed gain comparably higher than me even he was riding with a normal wheelset with 30 mm deep. I was definitely having problem with headwinds.. His bike weighted more or less 9-9,5 kilos, 2,5 kilos heavier than mine...I guess, there should be some explanation for this difference..Thank you..


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PostPosted: Tue Nov 18, 2014 4:04 pm 
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undisputed27 wrote:
The weird thing is latex tubes are needed to be pumped up to 120-130 psi in order to have much smooth controlling on asphalt.

That's very weird you found that...at your weight (as other have stated) you're better off with closer to 100 PSI. Latex tubes are great because they deform more easily than butyl - no idea why you'd max them out at such a high PSI. Especially as you don't really have the weight to deform them.

Either way, your wheels...

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PostPosted: Tue Nov 18, 2014 9:07 pm 
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Location: Glermsford, Suffolk U.K
C24 maybe fairly aero but they could be alot better. If the rim was 23mm wide and did not have the "sharp edges" it does then I am sure it would perform better. A stiffer rim would also allow the use of Cx-rays instead of CX-sprints to complete the package. I don't know how much difference this woulld make but as these wheels are all about marginal gains I feel they have gone for the lowest weight they can wothout making them un relaible at the expensive of aerodynamic performce. Letting the weight climb by 50g to produce a stiffer more aero rim would help the wheelset perform better.

Stilll the OP tyre pressures must reflect the flat landscape he must ride in and the ultra smooth roads. Either that or he can tap out 350W hour after hour in which case this thread is irrelevent as he will always be fast no matter what he rides. Your friend undisputed may have been able to ride in the headwind faster than you because his wheels are either more aero or he can sustain a higher power output maybe both. I doubt the weight of the bike would make much difference except on a good long hill. 2.5kg is not alot. Your friend maybe 10kg heavier that would make more a difference to the bike stability.

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PostPosted: Wed Nov 19, 2014 5:34 pm 
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Location: around Paris
I think you're asking yourself way too many questions. It's all about sensations/feeling.
Those 23mm not carrying speed as your 20mms...
Your friend faster with headwind... and you blaming the wheels in that precise conditions.

I don't want to be rude, but man, it's all in your head.


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PostPosted: Mon Nov 24, 2014 12:05 pm 
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I understand your views and appreciate them but the very characteristics of speed I was searching through the net for the info about speed differences b\w narrow wide rim n narrow tire vs. wide rim and tire at appropriate air pressures, let's say I want to run a wheelset with 19mm rim and 19mm (170-185 gram) tires at 140-160 psi depending on tire's max air pressure characteristics versus a wheelset with 25mm rim and 25mm (230-265 gr) tires at 100-130 psi bearing in mind that the road will be smooth silky asphalt regarding time trail purposes and just focusing on high speed max average 42 km\h at a distance 45-50 km..Is there any data available in the net proving that wider rim and tire combo will be faster than the narrower ones??


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PostPosted: Mon Nov 24, 2014 12:15 pm 
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Samuel Sanchez Gonzalez wrote:
I think you're asking yourself way too many questions. It's all about sensations/feeling.
Those 23mm not carrying speed as your 20mms...
Your friend faster with headwind... and you blaming the wheels in that precise conditions.

I don't want to be rude, but man, it's all in your head.


Actually, I'm not blaming the wheels man, indeed. What I'm trying to find out is that differences b\w wheelset weights and tires width in terms of high speed and aerodynamics, once you are riding with 40 km\h it concerns aerodynamics mosly wind resistance not only low rolling resistance of tires. DA C24 wheels are my favorite so far and I'm quite happy with them, they accelarate quite fast and they are responsive at high speeds but I also found out they become pretty slack in headwinds when the wind speed is 30 to 37 km\h...I asked myself maybe my bike is too light for such weather conditions ultimately wheelset is quite light..Wheelset is around 1440 gr. (i use titanium skewers to shave some weight) and total bike is 6,824 grams and that's why I was skeptic about this headwind issue thinking about if i add some weight to my bike or change wheels with more aero ones with more weight...That's it.. :noidea:


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PostPosted: Mon Nov 24, 2014 12:19 pm 
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You need more power to overcome the headwind..your friend might be putting a lot more power than you hence he's gaining speed better, perhaps.


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PostPosted: Mon Nov 24, 2014 4:59 pm 
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To ride faster you need to put out more power simple as that.

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PostPosted: Mon Nov 24, 2014 10:12 pm 
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http://aerogeeks.com/2014/04/03/aeromail-tire-size/

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Posted: Mon Nov 24, 2014 10:12 pm 


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