Originally Posted by
mcours2006
The standard recommendation for fender size is usually 10 mm bigger than your tire. So if you're using 28 mm tires you can do with 40 mm fenders. However, I've find that aesthetically having larger fenders much wider than the tires is odd. I've got a set of 35 mm SKS Longboards on a set of 35 mm tires and it works quite well. I've also got a set of 45 mm SKS's on 38 mm tires, and it looks okay, but not as nice as the 35-35's.
So for 28 mm tires you could get away with 30 mm fenders if you mount them a bit tighter.
Standards-shmanders. I used 28s with my Berthoud 40mm fenders and it worked fine for 2-3 years of commuting and a 200k and 300k brevet with the attendant training rides. No rattles, no rubbing, but there is very little room for error.
I'm running 23s and 25s with those 40mm fenders now and am much happier. Some fenders basically ride over the tops of the tires (longboards)and width is not much of an issue. Some fenders wrap around the tire more (Berthouds) and clearance is more of an issue. In London, I would like as much coverage as possible.