Pro's Using 25mm Tyres

JustinLeeAtkinson

Just read this in the BR review of Mark Renshaw's bike at the Tour Down Under:

Pro riders - Blanco sprinter Mark Renshaw included - are quickly switching to wider tubular tires such as the 25mm Vittoria prototypes shown here. Wider rims mean there's little aerodynamic disadvantage with the move, plus the riders get improved ride quality and cornering traction

So what counts as a wider rim?

danlikesbikes

I know blanco ride Dura-Ace but Zipp wheels have the following profiles which are fat, though am sure the marketing people would prefer are more scientific description.

JustinLeeAtkinson

Thanks, so does deep section equate to bigger width then? Is that what I've missed (not owning any deep section, but thinking of getting some and wondering what tubs I want to go with them for racing).

pkripper

depends entirely on the rim / brand. Some are fat, some are thin. At the sharp end of racing they're going fatter, but there's plenty of designs out there that are still 19mm or so.

thegreatdivide

I think Zipp Firecrest wheels only really work with tubs up to 23mm. After that you lose the smooth ‘teardrop’ shape of the rim and tyre combination. I’m sure Boonen and co rode fatter tyres on their FC 303’s during Paris-Roubaix but that’s probably an exception.

Lots of deep rims are not fat. If you compare a 303 FC to a Gigantix 50mm the 303 will look massive!

Wamas

Gigantex now do 24mm wide clinchers as well as their standard 20mm wide ones.

thegreatdivide

303 FC's are 28.5mm at their widest point

JustinLeeAtkinson

Just reviving this. I may not go for deep sections having decided that I am not fast enough to justify them (another story).

My current wheels (Ultegra 6700) which are fine, bombproof, and coped well with some racing last year have a rim width of 20.8 mm according to Shimano. Is that too narrow for 25mm tyres?

displacedaussie

I use 25mm GP4000s with the RS80s (which I think are reasonably similar to the Ultegra 6700 wheels). They work great for me.

luomatey

good idea, Gigantex now do 24mm wide clinchers as well as their standard 20mm wide ones.thanks

thegreatdivide

The new Gigantex wheel is trying to replicate the Zipp FC, so taking a 24mm wide rim and sticking a 25mm tyre on it will do the opposite of the rim's purpose - to be aero. You may as well just buy the standard 20mm rim and stick a 25mm tyre on it.

racingcondor

Justin -

You'll be fine with a 25mm tyre on a 21mm rim. The trend towards wider rims is new and fat tyres for winter riding etc have been around a lot longer than that.

The recent issue around this is how different tyre widths impact on the aerodynamisc of deep rims and how to get the most out of the tyre/rim combination. Worth worrying about if you spent a couple of £k on your wheelset but for most of us it's a tiny aero impact not worth worrying about.

JustinLeeAtkinson

Thanks all

Racing Condor, thanks I understand that, it's not just the marginal gain in aerodynamics, if indeed there is any with a cheapish, shallow section rim, but also the added benefit in terms of handling with a wider tyre. if indeed there is no trade off in speed.

Grill

Hed Stingers can handle them. They use a 28mm rim.