I have until this year been a big fan of rim brakes, but after having ridden nearly 1,500 km with a disc brake bike (and frequently switching between disc and rim brake bikes), I have a few thoughts that I wrote about on my blog (click here if you can read Norwegian) - summarized here:
Myths busted:
- Weight. Disc bikes often come with a weight penalty, but it may not necessarily be significant (e.g. S-Works Tarmac SL6 Disc weighs in at 6.8 kg with pedals and bottle cages in size 56).
- Rub. The rotors don’t rub as much as I feared, and is for all practical purposes not an issue.
- Looks. Esthetically speaking, disc brakes are less pleasing to the eye than rim brakes, but this is a subjective opinion, not a fact.
Arguments pro disc brakes:
- Effortless braking - especially useful in wet and cold conditions and on long decends. The braking power is significant and allows for harder braking at a later point, which has led me to descend faster.
- Better wheels in terms of braking - when the quality of the braking surface is less dependent on the manufacturer.
- Broader tyres - disc brakes allow for frames built with wider clearance.
Arguments against disc brakes that are valid:
- The pros will win races regardless of brake technology. 2 out of 5 wins in the Giro, Tour, Vueta, the 5 classics and the Worlds came on bikes equipped with discs, but if you look behind the numbers, you’ll see that 16 out of the 25 wins with disc brakes were on a Specialized. The guys riding these bikes would probably have won regardless of bike or braking technology.
- Fat, lumpy hoods. The hoods on the mechanical Shimano Dura Ace are significantly bigger than those on the Di2 version. This is a personal preference, but I dislike lumpy hoods.
Arguments against disc brakes that don’t hold up:
- Changing wheels/tyres takes more time. I actually spent 10-15 seconds less time taking off and on a disc wheel, and the actual procedure of replacing a tube is the same regardless of brake technology. It may be faster for a pro mechanic in a race, but for us mere amateurs there is no practical difference.
- Compability. Sure, in a race it is beneficial to be able to safely mix and match wheels, but this isn’t an issue for the most part.
- Spinning rotors, aka “spinning blades”, present a mortal danger. Years after disc brakes were introduced, we still don’t have a single rider whose legs or arms have been sliced off.