"Gran Fondo" bikes but the wheels?

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WMW
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by WMW

MileHighMark wrote:What about something like this?

http://www.bikelugs.com/store/index.php ... ItemID=396" onclick="window.open(this.href);return false;

Maybe in a 28/32 combo.


I just built a set for a guy with CX-Rays. He says they ride smoother than his Campy shallow-rimmed carbon wheels... forget the name.

Even though most wheels have essentially no vertical flex, I'm convinced that there is something going on with vibration and harmonics that results in a noticeably different ride feel. A vertically flexible rim with lots of light spokes at low tension would vibrate at a lower frequency and feel the best.

However, if you really want to go fast the aero penalty you get with a shallow box rim and lots of spokes is not trivial. You gain more going from that to a ~25mm deep rim with 20f and 24r, than you gain by taking the additional leap of nicely made 80mm carbon rims. Plenty of data out there.
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WMW
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by WMW

fdegrove wrote:As most of you may have noticed quite a few manufacturers propose "Gran Fondo" frames. In a nutshell these are generally frames or complete bikes which are destined to be sold to those who'd like to endeavour in long rides: Centuries or more.
Not purely race oriented and not really tourist either but something inbetween. A bike that you ride for miles and miles more for fun than for mere racing, right?


Gran Fondos *are* timed. They are like mass group races for tourists. Normally they will time the climbs on a course rather than the whole thing, so you can cruise and recover and have fun in between "race" sections. The winner is the one with the lowest total time in the measured parts. I've never done one, but it is an interesting concept.

But... beats me what the marketing angle of a "Gran Fondo" frame is. Just capitalizing on the popularity, most likely. You know... you need 37 different types of road bicycle so everyone can express their unique individuality.
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by bm0p700f

The most comfortable clinchers I have are a set of 50mm deep carbon rimmed wheels 25mm wide with GP4000s 23mm tyres. Run at 100 psi (the tyres are 26mm on these rims) the ride is only equalled by 25mm Pave tubulars. so carbon wheel can be comfortable but it has nothing to do with the rim material. In fact wheel vertical stiffness does not effect ride comfort. If you think about physics for a moment (3000-4000N/mm) you will see why. also carbon fibre being a laminar material actualy absorbs sound vibration very well which is what most people are talking about when they talk about comfort. You can feel sound. Tyres and the thing you sit on do most of the sound absorbtion not the wheels.

My ideal 32 spoke count clincher would be using ryde pulse sprint rims (390g and wide) with Lasers or CX-rays on record hubs. 1460g or so I believe nice a light.

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by BobDopolina

What about disc brakes showing up on the GF bikes now?

This opens the door for some disc specific carbon rims which would be lighter than rims with brake tracks that would roughly offset the weight of 140mm rotors minimizing the weight penalty of discs.

You could also go with a wider rim with some areo benefits that many GF are not allowing now due to possible heat failures.

So you would get a disc brake with less weight penalty and the comfort and aero of a 23mm wide maybe 40mm tall carbon rim (not too tall so it is stable in crosswinds or gust).
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HillRPete
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by HillRPete

Bob, an approximate comparison of the potential weight savings can be made by looking at Enve's products, for example. The 25 Road / 29 XC clinchers for example are listed at 402g / 382g. Pressure rating for 23mm tyres is about the same. Of course the MTB rims are wider and taller, so shall we say 10% ballpark?

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by BobDopolina

wassertreter wrote:Bob, an approximate comparison of the potential weight savings can be made by looking at Enve's products, for example. The 25 Road / 29 XC clinchers for example are listed at 402g / 382g. Pressure rating for 23mm tyres is about the same. Of course the MTB rims are wider and taller, so shall we say 10% ballpark?


We can make a 400g 23mm wide rim that is around 38mm~40mm tall. I have the draw on my desk. Now it is all about pulling the trigger on the mold.
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by HillRPete

400g is also what Light-Bicycle quotes for their regular 38x23mm carbon clincher with brake track. No idea about relative strength, though. It certainly is interesting that the Enve 45 clincher, from a company often considered a benchmark in carbon manufacturing, weighs quite a bit more at 470g.

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