Originally Posted by
Scheherezade
Besides actual frame size, it seems like tire clearance is one of the most limiting factors on the bicycle frame. You might be able to change out every component on the bike, but still be stuck with 25mm tires.
How come the vast majority of consumer bikes in the US have such tight clearances on anything that isn't a mountain bike? Is this a result of the racing industry's effect on the other 99.9% of riders? Even many bikes geared towards commuters, tourists, and weekend riders have limited tire clearance.
Cheers.
I guess it depends on what you mean by limited. Most touring and cyclocross bikes can take 32s or 35s + fenders. That's generally adequate for street use. Hybrids have a similar amount a clearance, sometimes more. There are commuter oriented things like flat bar road bikes which may have very limited clearance. I scratch my head at those sometimes too. It might just be laziness. It's cheaper to take an off the shelf frame design and tweak it a little bit for flat bars than to do something completely different.
As for sportier, non-CX road bikes? Of course I'm only speculating but I think part of it has to do with the brakes. It seems that most road bikes with wider tire clearances come with cantis. With those you need cable hangers and canti posts on the frame + fork. Carbon forks are very popular on road bikes these days and I'm sure constructing carbon forks to work with cantis is a more expensive proposition.
Longer reach brakes are an option too put they don't work as well as short reach brakes unless they're made alot stouter which adds to the expense and the weight.
From the manufacturers perspective, they don't expect people to be putting 32mm tires and fenders on race oriented bikes. They well gladly point you in the direction of their touring bikes.
Personally, I'd like to see an aluminum framed touring/CX bike that could take 40mm tires + fenders for winter use. But I'm a pretty small market.