Tuesday, July 9, 2013

Volagi, Disc Brakes, and Shifting

A series of interesting reads in this season's Bicycle Quarterly.

First Jan Heine absolutely pans Volagi bikes. It's not clear what he has against them; he stresses even subjective measures that he must realize are woefully imprecise.  One example:  the bikes are problematic because when not paying attention his speed dropped off.  They would not be good for long distance riding because not paying attention is par for the course.  An odd observation, to say the least.

The primary thrust is an important point:  Volagi's entire business is built on the idea that comfort in the seat is the most important part of cycling.  As Heine points out, the front end is where bikes really get uncomfortable after many hours pedaling -- and he does not like Volagi's front end one bit.

Second Jan Heine pans mechanical road disc brakes.  This short feature seems to have been driven by his disappointment with the performance of disc brakes on the Volagis -- and his decidedly non-scientific test involved taking the Volagi to a braking hill and comparing the stopping results against stopping results from an earlier test of Sram rim brakes.  A few obvious problems: the bikes weren't the same (should that matter?); the tests were done on different days with presumably different atmospheric conditions; a full stop test may not be the best demonstration of brake quality (how often is that how you use your brakes?); and by the time Heine got to testing the brakes he was already hating the Volagi.  That said, the difference -- ~2 meters, or 15% -- was substantial.  Heine gave some thoughtful intuition underlying that difference, including that rim brakes are literally disc brakes with much bigger (i.e. better) discs than the modern disc brakes.

Third is a long and fascinating discussion of bicycle shifting systems.  Sorry to say that it killed my desire to build a bike with an internally-geared hub anytime soon.


sam said...

I thought he was a bit harsh on the Volagi, but I do appreciate that he holds no punches in his reviews, and generally makes it clear that his conclusions are only his. It does sound like there's a build quality issue to be dealt with. If his comments about the Volagi's suitability for distance have any merit, that's a shame for Ragsdale given his recent use of them.

Ditto on your thoughts re internally geared hub. I had thought of building up an internally geared bike with hub generator, but I think I'll pass on that now.

While I don't recall the specifics of his arguments in the disc brake article, generally I'm in agreement with him that disc brakes on a road bike are a solution looking for a problem. On a tandem they may make sense (to keep braking heat away from the tire). But otherwise, aside from additional fender clearance, I'm not sure what they buy. Braking 13" from the hub should give you more advantage than 3" from the hub, and the twisty forces on the fork can't be a good thing, particularly with lightweight CF forks. While it's common to whack a MTB wheel out of true, seldom has my road bike wheel been so out of true that opening the brake couldn't get me home. etc.. etc...

Unknown said...

I think the fact that disc brakes are less likely to lock up a wheel is a pretty big selling feature, and I sure would have appreciated their all-weather functionality when descending off the mountain in a monsoon last weekend. I quite literally could not stop my bike no matter how hard I worked the brakes. Matt Roy, a guy who knows some bikes, spec'd discs on his recent bleeding-edge Seven dirt road/randonneuring bike.

Max said...

Heine said about discs (perhaps among other things): (1) they don't stop as well. (2) They put torsional forces on the fork, requiring heavier-duty forks, which in turn makes the forks harsher on the hands (hence the Volagi problem. (3) The rotors warp. (4) They lock up. (5) The rationale for preferring them seems to be "but they are better in cars" -- but in cars the alternative was drums, not rim brakes.

I've never ridden discs and have a hard time seeing why I would. After all, the lord did sayeth, "thou shalt not ride knobby tires." On top of which, until you've bled a few brakes (and as a past British car owner I've definitely bled a few brakes), you can't possibly appreciate the displeasure of working with hydraulic fluid.