Installing vintage crank arm

[jrippah]

I was wondering if anybody knows how to install a 1980's model Raleigh crank arm. It fell off of my friends bike while he was riding. The square bolt is still attached to the bottom bracket. Any help is appreciated.

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[nfmisso]

if it fell off, it probably has been loose for a long time and is damaged beyond useable.

That said; unscrew the round cap (a coin works as a screw driver); underneath you will find a loose nut or bolt. Put the crank back on the bottom bracket (BB) axle, re-install the nut or bolt (usually takes a 14mm socket), tighten until the crank is fully seated (no wobble).

If there is any wobble, a new crank is required.

[jrippah]

Awsome thanks that helps a lot. If a new crank is needed, what style/size crank would i look for.

[nfmisso]

(06-27-2013, 06:54 PM)jrippah Wrote:  .... If a new crank is needed, what style/size crank would i look for.

one the same length, for the same side of the bike, same interface to the BB.

For example:
http://www.amazon.com/XLC-Alloy-Crank-Arm-Diamond/dp/B005YO157O/
is 170mm long, for the left side, for a square taper BB.

Note: some cranks for square taper have diamond holes, and some have square; the have to match on both sides of the bike.