Milessio wrote:
Note that Fulcrum's Racing Quattro Carbon DB disc braked wheel has 21 spokes front & rear, so disc braked wheels don't seem to be particularly handicapped compared to rim braked wheels.
We don't really know much about the durability of that setup yet, do we? In comparison, my front Hed Jet 6 has a mere 18 spokes.
Milessio wrote:
With triathlon bikes not needing to meet restrictive UCI rules, the use of disc brakes should allow companies to produce designs that wouldn't be possible with rim brakes, e.g.
- A front 'fork' with a monoblade/lefty for aerodynamics, and no need to remove wheel when puncturing.
I don't think it's been shown that sort of fork configuration is actually more aero. A traditional fork makes a nice triangulated structure. A mono-fork would necessarily need more structure to accommodate the same forces. So...that's all pure speculation on your part.
Milessio wrote:
- If the road surface is poor - fit 650b wheels with (even) fatter tires.
One could argue that if you're doing timed races in conditions that require tires fatter than 28-30mm, you might want to reconsider if you should be doing it on a Tri/TT bike in the first place :-/
Milessio wrote:
- Automatic pad wear compensation, so no awkward, dirty under bottom bracket adjustments needed.
- No loss of power with convoluted braking line routeing.
- No cable stretch requiring extra lever travel.
There is no reason why a hydraulically actuated rim brake couldn't have those exact same properties. Those aren't a function of brake configuration (rim vs. separate braking disc) but of brake lever/caliper system design.
Milessio wrote:
These and other factors are in addition to whether discs are better at braking. So, where are rim brakes better - tradition?
Well...according to SRAM's own data, their hydro rim brake actuating on an aluminum surface is only ~10% less braking torque for a given lever force as compared to their disc brakes on a 160mm rotor. If one then considers the fact that HED claims "25% shorter stopping distances in dry conditions, or 70% shorter stopping distances in wet conditions" for their Turbine brake track equipped wheels as compared to regular aluminum tracks, one can logically conclude that any gaps in braking performance really aren't there. I would really like to see independent data on this...but sadly, nobody in the media appears willing to take it on.
So, after that, they're better in regards to aero, mass, complexity, and backwards compatibility...none of which should be dismissed out of hand considering it's
possible for their to be no performance difference.
Food for thought...there are 2 well-known custom tandem manufacturers (Santana and Erickson) who recommend rim brakes (V-brakes) instead of separate braking discs for the front end of their tandems. One should probably contemplate why this is so...
http://bikeblather.blogspot.com/