In a message dated 2/9/01 9:37:24 AM Eastern Standard Time, sachs@erols.com writes:
> To me, the key is to avoid hammering on a cotter when the crank is not
> supported. If you do that, the impact blows are transferred through the
> spindle to the ball bearings to the cups, increasing the likelihood of
>
According to Jobst Brandt and my own experience, this is incorrect. It sure seems like it should be correct, but isn't - at least if the bottom bracket is properly pre-loaded so more than one bearing is in play at a time. That said, it still makes perfect sense to support the crank arm when driving out the cotters - since otherwise you might break out the bottom bracket shell from the seat or down tube ! :-)
As an aside to this issue, a cute Jeunet "Franche Compte" mixte frame was in for repair Thursday. You know, Mafac Racers, Atom hubs, Simplex red-label, steel Rigida rims and a steel cottered crank (Nervar ?) The left crank arm was loose to the point of being able to turn 1/4 way around freely. When I removed the cotter key for replacement, it was notched over half way through ! Inserting a new cotter of the largest size that would fit resulted in the arm still not drawing tight because the flat on the BB axle was deformed from its work as a key-cutter.
Is it possible for a shop to still order replacement axles for such cottered steel cranks as found on cheap French gas-pipe 70's bike boom bikes ?
Glenn Jordan - Durham, NC