Bicycle Mechanics - Refurbishing cranks

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View Full Version : Refurbishing cranks


Big H
04-24-04, 08:19 AM
Hi

This should actually be posted under "Tandems" but being a common item I hope to get many and varied answers to my problem. We have a mixed set of cranks on the tandem being, three CPi cranks (two for captain and left hand for stoker) and a stronglight triple crank (for the stoker). We are in the process of "rebuilding" the tandem. There were some scuff makes on the Stronglight crank. I sanded the crank with 800/1000 and 1200 grit carborundum paper and polished the aluminium alloy with Brasso. It ended up looking much better than the crank originally was. The CPi cranks looked like it was a brightly polished aluminium alloy. I thought sanding out the scuff marks would be easy. It now seems that the cranks has some coating (chrome??? or anodizing) on it. I seems that I now will have to sand down all three cranks to obtain similarity, a very labourious process. If it has a coating would it be ok to leave it uncoated or would they wear down??? Can I stop where I am now and have all three anodised??? Is there an easier way to get rid of the anodising or chrome???? Help and suggestions would be appreciated.

Big H


sch
04-24-04, 02:29 PM
Shimano liked to paint cranks with a pearl gray that looked metallic until scratched.
Anodizing would be hard to remove, compared to paint which could be stripped off.
A bit of heat or paint stripper should distinguish to two surface preps. Longevity
of aluminum is unaffected by surface treatment. Surface treatment is strictly cosmetic although in theory anodizing will enhance resistance to wear as Al oxide
is much tougher than Al metal/alloy. If you want to anodize yourself, do a google
search on "anodizing aluminum" for a bunch of links to DIY sites. All you need is
a battery charger and analine dye for coloring. Also, if anodized, you dont need to
strip/grind/sand it all off, just polish the scratches and and wear spots then
reanodize the whole thing. Steve