sfleuriet

Is there a way to get these crank arms cleaned up?

Front and back look pretty nasty. They're bothering me, as the dullest looking parts of the bike right now!

If not, maybe it's worth it just to replace the whole crank. It's a FSA Tempo 50/34 175mm.

FBinNY 

It's hard to tell, but these are probably anodized (light silver color when new). If you polish them, you'll still have the pattern of darker bare metal where it's scratched showing out against the lighter anodized finish. You could polish out the anodizing entirely, but then you'll have a crank much more demanding of constant cosmetic attention. Polished aluminum quickly darkens to a dull gray color, and is very vulnerable to things like salt, which is why it's anodized in the first place.

Burton

I guess there's really two questions here
(1) Can these cranks be polished?
(2) Can I polish these cranks?

(1) Yup - buffing wheel and a couple grades of polishing compound and the anodizing is gone, and an oil finish or a few coats of car wax and it'll be low maintenance but still need occasional attention.

(2) In absence of a bench mounted buffing wheel, a drill and buffing wheel can do a pretty good job but this is a messy operation at best and should be tackled outside.

Personal skills, materials at your disposal etc you'll have to answer yourself. Having it done at a finishing shop will be close to the cost of a new one.

Jeff Wills

Well, he's in Texas, so I'm going to assume the bike's not going to see much salt.

I've polished a couple bike parts like this: sand smooth with 600 wet sandpaper. You want to smooth the whole surface and remove all the anodization. Follow this with red rubbing compound (either by hand or machine), then white polishing compound, then Mother's mag Polish. They'll come out pretty, but will dull over time (like FB said), but I find a semi-annual touchup with the Mother's is adequate. I'm not super-picky about my bike's appearance, though... the whole frame is polished aluminum, so when I start it takes an hour or two to finish.

sfleuriet

I don't mind occasional re-polishing - that would certainly be better than having it look as is. I have a huge arsenal of automotive cleaning supplies (including waxes), so that would work fine.

Is there any chance in retaining the black lettering, or should I assume any polishing (esp. sanding) will remove it?

Also, I've never done maintenance to the crank or bottom bracket area - is removal of the crank arms pretty straightforward with hex bolts?

fietsbob

they're probably anodized , sure you can polish them, but then you can never stop re polishing them
because you will go through the corrosion protective anodizing layer. are you ready to be a permanent polisher ?


you will just be removing the bolts, not the crank arm,

to remove the crank arms , after removing the bolts,

you need a Crank arm Extractor. a special Bike tool.

Bill Kapaun

I started polishing mine when I was about 12.

HillRider

The hex bolts do have to be removed along with any washers behind them (some cranks have them and some don't). Then you need a specific tool known as a "crank arm puller". It is a screw press that threads into the center hole of the arms and has a center bolt that pushes against the end of the spindle and pulls the arm off. Park Tools and numerous other makes sell them and any bike shop can do the job for a small charge.

dinobyte

I'll second the wet sanding as being a very necessary step, gotta do that before you go straight to polish.

After it's polished, you can put some some caranuba/auto paint wax to protect it if you want. So far it seems to have worked ok for me.

Kimmo

Sorry, but



...Um, throw a whole bunch of photons at it before you start?

reddog3

The anodizing must absolutely be removed before polishing. You can sand it off, or strip it off. Search "stripping anodizing." It's all there. If you are into a bit of labor sand it off yourself. You need to get it off completely from all the nooks and crannies, or it will look as bad after polishing as it does now. I've polished out quite a few cranks. If you're into the "showbike" appearance it's definitely worth the effort. A buffed aluminum finish is pretty tough, but does require some maintenance. Like Jeff Wills, I use the Mothers mag polish.

bradtx

sfleuriet, This is the first set of crankarms I cleaned up using 600 grit wet/dry sandpaper and Never Dull. I've since worked on a couple of others using up to 2000 grit wet/dry sandpaper that look better. It took awhile as I didn't have any power tools to speed the process.

Brad

TampaRaleigh

Oven cleaner will strip off the anodizing. No need for sanding.

Booger1

Oven cleaner to remove anodizing.....600/1000 sand any scratches out........buffing wheels and compound to make it easy......Mothers'/Semi-chrome aluminum polish if you need to build hand strength.

I hope black is your favorite color....

TomCat_Ford

I could be wrong, but I don't think that the OP's crank arms are anodized. I have a FSA Tempo crank set, and the crank arms appear to have a polished chrome finish from the factory.

JTGraphics

Yes they can and with out much trouble and its not hard to actually get it to look like chrome shiny if you wanted or a more polished flat look with no power tools. I have my own way of polishing aluminum that works quite well and quick you would loose the name on it.

Maukaman

Just use some Mother's Aluminum Polish and a micro fiber rag. You can find that in the automotive section at stores like WalMart or automotive shops like O Rileys. I buffed mines till it became pretty shinny and clean. It looks like the aluminum is a bit faded and needs a good polishing. You can try wet sanding with a very fine paper or even use very fine steel wool. The wording will probably be taken off, so I would start with the Mother's Aluminum Polish first and see how that goes. The small jar goes a very long way.

Maukaman....

DannoXYZ 

There's no anodizing that needs to be removed on that crank due to the corrosion pattern. Yes, all you need is a chemical polish like Mother's or Blue Magic. Look for "contains ammonia". Don't use the abrasive polishes such as Simichrome.

Apply with soft rag and rub for 1-2 minutes. Wipe off with clean portion of rag.

The black painted lettering & logo will be unharmed by the polish.