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bottom bracket taper question(2 posts)

bottom bracket taper questionnaff geezer
Jan 15, 2002 12:17 PM
my riding buddy is reticent to spend any money on his bike but his crank has a bent spider (hence chainring) and no amount of front derailler fettling seems to still the griding beast.

i am looking for a cheap crank arm but am not sure what will fit .

he has an old torpado with ofmega cranks, and simplex derailleurs. (6 speed). the bottom bracket is very smooth though and i doubt i can convince him to fit a new one. i need a best guess on what crank arms will fit.

shimano pattern cranks are about the cheapest i can find (chucks bikes $15 175mm sugino) but i am worried that the taper profile will be wrong as its likely to be an ofmega unit (it was bought unknown).

and also where can i get new brake blocks to fit (modolo calipers - old skool campy like).

remember he is cheap!!! he rides with dot gloves, lubes his chain with gear oil and uses plastic bags to keep his feet warm in winter. its a nice bike and he is a good rider but the continous noise while riding with him is killing me although he doesn't mind. i respect him for his thriftiness but its pissing me off.

i respect him for his thrifty ways but now even i find it challenging trying to get this right. should i just use ear plugs?

advice appreciated.
Probably don't need a new crankKerry Irons
Jan 15, 2002 4:51 PM
You can easily straighten a bent crank spider. Place the bike on its side, with the opposite crank supported by a block of wood right at the BB spindle. Using a dowel or 2X2, pound the bent spider back to its correct position. Start easy, and constantly check for movement. You need to support the BB to prevent your hammering from damaging the BB cups or bearings. You can do this repeatedly till you get it right. Alternatively, you could have bent chain ring (confirm this by measuring the distance from the spiders to the seat tube at the chain ring bolts). You can straighten a chain ring by sliding a large adjustable wrench over the chain ring and bending it straight.