Originally Posted by
ColonelSanders
There were a lot of problems with that video before it can be taken as gospel.
Leaving aside the more aero wheels of the rim braked bike, in both instances the rider went first on the disk brake bike, meaning he would likely know the lay of the land better on his 2nd run, which in both instances was on the rim braked bike.
Additionally, I would like to know if the results that one gets from such "experiments" changes much, if the rider weighs 220lbs/100kgs vs 154lb/70kgs.
Also, is there any difference in how many miles you can rack up before you have to change your pads in either style of braking?
When I get around to building my next bike, as it will be rim brake equipped, it will give me a chance to do some very rough comparisons myself, but unfortunately it will be on two different frames and two different sized wheels.
All good questions. Although a few are the opposite for me. I'm usually faster the first time down a hill because I overestimate the grip of my tires. After a good scare or 3, the second time I wise up and go slower. haha
Also, I'm pretty sure the rims are the same, just with different decals. The black tire + black rim of the rim brake bike makes the rim look "larger" and more aero, but I think they're the same depth. If anything I could argue that the disc rim SHOULD be more aero because of the lack of a brake track.
My question is this.
When considering the downhill AND the resultant 20-50k flat ground before or after it, which bike would come out on top? My guess is the more aero one. Disc brakes help for the very limited amount of time when you are actually braking. There are very few road races where the entire race is downhill with sharp curves. (However, that IS why disc brakes are superb for mountain biking, because it's really just one big downhill race with lots of curves.)