Originally Posted by
Dave Mayer
I spent much of today riding a current $5k road bike with discs and 32mm tires (GP 5000s). The bike is a boat anchor; at over 18 pounds it weighs about 2 pounds more than a similarly spec'd and priced rim brake bike from 5 years ago.
Reason for the extra weight: the frame and fork reinforcements required to handle disc braking forces, and the much heavier wheels - again required to handle the forces from the ends of the fork to the rider. The farm tractor tires didn't help with my speed on pavement either.
Wouldn't it be much more efficient for wheel rims to secure tires, and double as braking surface? I'm guessing that 5 years from now the industry will roll this novel concept out with great fanfare. And big price increases.
Anyway, you can get sub-800 gram rim-brake road frames direct from Asia. The big brands have abandoned high-end rim brake frames? I've abandoned the big bike brands.
Being objective, the overall increase in weight with disc brakes is only a couple of hundred grams. It certainly isn't 2 lbs. Disc specific wheel rims are actually lighter by the way, which offsets a bit of extra hub/spoke weight. As for frame and fork weight, it's a wash. The fork is a little heavier, but there are savings around the frame where rim brakes would have been mounted.
For sure if you are an obsessive weight weenie then you could build a slightly lighter rim braked bike and save some cash. But there are plenty of other reasons to choose disc brakes - like actual braking performance and consistency!
As for 32 mm GP5000 tyres slowing you down on pavement. The same tyres that have won Paris Roubaix. Maybe try the 28 or 30 mm versions next time?