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Crank spacing

Old 05-28-13, 05:59 PM
  #1  
krobinson103
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Crank spacing

My grocery getter is running a square taper triple. At some point I managed to kill the crank arm on the chain wheel side so I changed it out for a second hand part from the LBS's parts bin. It actually works great. But, it sits too flush with the BB and thus the FD can't push the chain to the granny gear, Almost there. It gets to the clickity clackity I want to move stage and stops. Lower limit is as low as it goes. I need another few mm. My first though was simply to put a few washers in against the BB face then reattach the crank. Thing is I've never seen square washers. Would large round ones do the job? They would be ugly but I care not what it looks like. The uglier the better - then fewer will want to steal it.
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Old 05-28-13, 06:02 PM
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Your method would ruin the crank.
It has to fit TIGHT on the sq. taper.
Get a longer BB.
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Old 05-28-13, 06:08 PM
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... or a tighter fitting chain wheel and crank arm setup. The previous one sat a bit further out on the BB thus working fine.
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Old 05-28-13, 06:13 PM
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That's the way it goes. You match the BB TO the crank. Period!
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Old 05-28-13, 06:17 PM
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Thanks. I think I'll rummage around the box of parts first before I replace the BB. It was new not so long ago and I kind of like it. Maybe I'll luck out with a crank that does fit.
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Old 05-28-13, 06:31 PM
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"...I managed to kill the crank arm on the chain wheel side..."

How so? If you stripped the pedal threads they can be economically repaired, better than new, with a Helicoil insert.
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Old 05-28-13, 06:43 PM
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No the actual crank arm started to flex back and forward. Too much carrying 50kg of groceries up hills I suppose. It wasn't a good one to start with and asking it to propel me, heavy racks, and groceries up and down hills at 20-50kmh was a bit much for it. Thing is I need my granny gear because I want to take my grocery getter on a 600km tour next month which includes a fairly substantial hill or two. I could ride up in the gears I have but why suffer unless I have to? Yes, I have other nicer bikes but this one rides so smoothly and has so much luggage capacity that I want to give it a chance to do more than go to the store and back.

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Old 05-28-13, 06:59 PM
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"Too much carrying 50kg of groceries up hills I suppose."

More likely insufficient crank mounting bolt torque, allowing the crank to move and wear out its taper. Best to get a torque wrench and do it right lest your new crankset suffer the same fate.
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Old 05-28-13, 07:06 PM
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What type of bottom bracket do you have? If it's a cartridge with a non-drive side cup that does not have a lip, you can place washer/spacers under the drive side cup and just thread the nds cup in further.
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Old 05-28-13, 08:29 PM
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No it was the crank arm. The area that fixes it to the chain wheels died. The taper however was fine. When I removed it it still rocked forward and back in its housing.
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