hi there...i'm a longtime reader, first-time poster...yada yada...
anyways, i've got a bit of a problem
my left crankarm (and possibly my right one, i can't tell yet) has started to come loose/develop rotational play recently...when i first noticed it, last wednesday, it was pretty bad, not to the point of "flopping about in the wind," but to the point where i didn't feel safe riding on it, and i don't exactly have the greatest sense of self-preservation. fortunately, i had a 15mm socket wrench with me, (for the rear wheel) which happened to be the right one for my crankarm bolts. so i tightened both (the right was also rather loose) and was on my way...so then on thursday, i was cleaning my bike and found that the left one had once again loosened up a bit (over about 20 miles of riding)...this time, since i was cleaning the bike anyway, i removed both arms, and after cleaning them, reinstalled them, making sure both were on pretty damn tight...once again both felt secure...now this morning, i tightened up the left again (as is becoming routine), and, while it feels like it made an improvement, there is definitely a bit of play in that arm (something like 2-3 mm at the end of the arm, if that makes any sense)...
now i do realize that this topic has come a few times before:
Chronic crank looseness
Loose cramk arm!
loose / stripped crank typical when riding fixed?
however none of these really gives me enough information, so i'm trying to see if anyone out here knows a bit more that they could tell me. specifically, how i managed to cause this, if there is any cure, (that doesn't involve permanently bonding it to my BB spindle--does an aluminum foil shim really work?) are left arms more prone to this, are fixies (particularly brakeless ones) more prone to this, and, if it can't be cured, how long do i have before i'll need to replace the arm.
and lastly, if it makes any difference, here's some background info:
-it's on a brakeless fix
-i ride ~80-100 miles a week
-i've used the cranks for about 4 months
-i installed a new BB about 2 months ago
-they are a Sugino double chainring model from sometime in the 80's
-i do a fair amount of skid-stopping
-i weigh ~160#, and usually carry ~5-15# of whatever
-i clip in with my left foot first
-i start up with my left foot forward, and skid with my left foot back
i think that's everything relevant, and probably some extraneous crap, too
any replies will be greatly appreciated...hell, i'll be grateful if anyone even reads all that