Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Classic & Vintage (https://www.bikeforums.net/classic-vintage/)
-   -   Refinishing a crank arm (https://www.bikeforums.net/classic-vintage/1256009-refinishing-crank-arm.html)

robertj298 07-30-22 07:22 PM

Refinishing a crank arm
 
Recently picked up a 1989 Centurion Ironman Expert. I believe the
crank arm is a SuntourGPX.. Both crank arms have a worn matte finish
in the same spot. I'm wondering if I'd better off just trying to strip the
finish completely off to the bare metal instead of trying to match the matte finish.
https://cimg3.ibsrv.net/gimg/bikefor...ab333b11b9.jpg

plonz 07-30-22 08:59 PM

Looks like a painted or powder coated silver finish. Really no way to touch it up with anything durable. You could have the whole crank powder coated.

I’m assuming high-polish is not the right look in this case. Twer me, I’d strip and wet sand to a duller polish. Then I’d probably try steel wool to make it look more unpolished and more like matte silver.

madpogue 07-31-22 12:54 AM

FWIW, the bike would originally have had Shimano 105.

easyupbug 07-31-22 11:39 AM

I have a '89 Master and I recall when looking the '89 Expert they dropped the 105 and went to Suntour's new GPX group, crank, FD and RD, etc. If an '89 yours is white as shown but with beautiful (to me) smoked blue on the fork, HS area and the stays which I would rather have had than the smoked grey I got. The above advice is spot on for powder coating.

madpogue 07-31-22 11:48 AM


Originally Posted by easyupbug (Post 22593802)
I have a '89 Master and I recall when looking the '89 Expert they dropped the 105 and went to Suntour's new GPX group, crank, FD and RD, etc. If an '89 yours is white as shown but with beautiful (to me) smoked blue on the fork, HS area and the stays which I would rather have had than the smoked grey I got. The above advice is spot on for powder coating.

Interesting to know, esp. from a time when much of the industry was just starting to migrate FROM Suntour. I guess the vintage-centurion site could use an update.

wrk101 07-31-22 12:44 PM

When I get cranks with wear like that, I tend to strip the finish. At that point, you will have to polish it, repeatedly.

I am becoming a bigger fan of patina. That wear has no impact on functionality.

Mr. 66 08-01-22 08:43 AM

Did just that on a Suntour set for my Univega. This is sanded ruff, I would need to take it down and do finer grit to get a better finish
https://cimg1.ibsrv.net/gimg/bikefor...4e52e72fcc.jpg
These were a battleship color when I started.

RustyJames 08-01-22 08:58 AM


Originally Posted by wrk101 (Post 22593870)
I am becoming a bigger fan of patina. That wear has no impact on functionality.

I endorse this statement. Plus, it’s far easier!

merziac 08-01-22 04:29 PM

Full on coating, a PITA, warrants some kind of scorched earth stripping, stripper, drain cleaner, etc. Fast, effective, nasty.

Anodized can often be sanded some with a sanding sponge that will conform to the shape better, and then scrubbed with Scotchbrite and maybe rust/corrosion/cleaner.

I can usually get an acceptable happy medium. The trick is to stop before you make a too nice spot and have to keep going.

Elbow grease is quickly becoming harder to come by. :twitchy:


All times are GMT -6. The time now is 10:45 AM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.