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visits member for 2 years, 7 months
seen Feb 9 at 2:16

I'm a commuter cyclist and mechanic. I occasionally enter collegiate races.


Aug
17
comment Can the Tensioner Spring go Bad on a Rear Derailleur?
Essentially, yes. All bike chains are 1" pitch (center to center of the pins), but the chain stretches out with use, and the cogs also wear. So after a while, neither is what it is supposed to be. Often a chain and cogs will wear together, so the old chain will fit the cog better than the new chain. Sometimes replacing an old chain also forces you to also replace both the cogs and the chain rings.
Aug
16
answered Can the Tensioner Spring go Bad on a Rear Derailleur?
Aug
14
revised Why are roadies concerned about weight?
copyedit: the -> to
Aug
14
answered Why are roadies concerned about weight?
Jun
10
awarded  Yearling
Mar
8
answered How long will a battery last in a Garmin GSC 10?
Sep
29
awarded  Scholar
Sep
29
comment Are there any high power bicycle generators?
@lmre, The source you cite gives the efficiency of a pedal-powered generator system (with a bad topology and worst-case sub-system efficiencies) as 30%. The source claims the generator itself is 80% efficient at turning mechanical work into electricity. 80% is in line (though at the low end) with what I've seen in other literature. Assuming 90% efficient converters is reasonable given the static load in this application, so I would expect the mechanical power to be under 15W, including the drive train.
Sep
29
accepted Are there any high power bicycle generators?
Sep
29
comment Are there any high power bicycle generators?
This is good information, but we're going to have to agree to disagree on the issue of power. The ultimate purpose is for night commuting, which passes through some unlit areas with potholes. Car headlamps output 1500Lm to 2000Lm (two incandescent or Xenon on low), so I fundamentally can't get behind the position that a bicycle light should be restricted to below half that (I can back the idea that each element of the light should be below 800 Lm, though)
Sep
27
comment Can cars legally drive in the bike lane down the street?
The questioner says he's in LA. If he's in the city of Los Angeles (as opposed to Los Angeles County) the anti-harassment ordinance might come in handy: articles.latimes.com/2011/jul/21/local/…
Sep
27
awarded  Student
Sep
27
asked Are there any high power bicycle generators?
Aug
23
awarded  Analytical
Aug
23
answered Are Hövding helmets safer than regular helmets?
Aug
23
awarded  Supporter
Aug
23
answered Is it possible to perform tricks with 100% safety during commuting?
Jul
16
answered Can I damage my brakes by testing them vigorously?
Jul
15
awarded  Teacher
Jul
15
answered Converting crankset from 28-38-48 to 30-39-53