Bikerumor Monday Mystery Pic

bikerumor monday mystery bike part picture

Photo from the collection of Rustybicycle. If you think you know what this is, post your answer in ‘comments’ – the answer will be posted there on Tuesday!

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Me - 09/05/11 - 7:16am

Crank extender for a cotterpin crank? Thats all I can think of.

tim bateman - 09/05/11 - 8:39am

Looks like a linkage from a Schwinn Air-dyne that helps connect the crank-arms to the moving handlebars. Probably one of the last hold-outs for cotter pin usage.

Charlie - 09/05/11 - 8:46am

It looks like it could be an extender, but it it would run perpendicular to the crankset. You’d have a 90 degree bend in your crankarm, I think. that might look cool.

JON - 09/05/11 - 8:47am

Cottered crack from a clown bike

JON - 09/05/11 - 8:47am


Derric - 09/05/11 - 8:48am

This is a Schwinn Airdyne Eccentric Arm for the Left side. Still used today on new Airdynes.

Mr. C - 09/05/11 - 8:48am

It’s an extension piece to make a cottages crank longer!

Mr. C - 09/05/11 - 8:50am

Spell checker! That should have read: it’s an extension piece to make a cottered crank longer.

Jason Aven - 09/05/11 - 8:50am

It is an old Cotter pin that is designed to attach the crank to the bottom bracket spindle

JON - 09/05/11 - 8:53am

Think your right! Or to get past some funky frame shape

Matt - 09/05/11 - 9:48am

Crankarm eccentric

CJ Anten - 09/05/11 - 10:43am

Spring retainer for an old Singlespeed retention system.

fleche1454 - 09/05/11 - 11:42am

airdyne eccentric crank pin

JimmyWu - 09/05/11 - 4:20pm

…no hands air-hanky.

Chris Michaels - 09/05/11 - 4:30pm

Totally Airdyne! Work on these all the time! Good one, maybe post some esoteric dropouts next time.

JON - 09/05/11 - 5:19pm

meh, not even a real bike part!

KDAY - 09/05/11 - 5:41pm

It’s what Derric said. Excentric for a Schwinn Airdyne. Fixed many in my day’s a the bike shop.

q-rim - 09/05/11 - 6:56pm

IKEA assembly kit?… j/k
Looks like a piviot joint for an old bike? A rod driven brake part?

Kristibee - 09/06/11 - 8:34am

Answer: “This is a part a Schwinn dealer will readily know.
It is a coupling(eccentric) for the arm pivots and crank on a Schwinn Airdyne.”

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