I will be selling my Tiagra 4500 group soon, but there are some scratches on the drive side crank which i want to remove. The strange thing is that the scratches are only on the drive side.
1. Is it safe to assume that the scratches are in fact caused by the few times the chain has dropped off into the crank spider? I sort of wrestled with the bike when the chain dropped because i was pretty new to road biking. I think that's how the scratches were caused.
2. Could the scratches possibly be caused by clumsy clipless engagement? My shoe has no metal pieces and also the non-drive side is clean. The angle required to scratch it with my mtb cleat is quite hard to achieve actually.
3. How do i go about polishing to remove the scratches?
1993 XO-1, early 1980s witcomb fixed gear, 1993 MB-1 singlespeed, a Surly 1x1 with pugsley front end, trek 520 converted to 650b, Coppi lugged road bike, Schwinn Crisscross townie
unfortunately for you, the crank is anodized, so lightly sanding and polishing is out of the question, more or less. if you were nuts, you could remove the anodization and then take some fine 400 then 600 grit sand paper, sand out the scratches, and then polish the crank with some simichrome or mother's aluminum polish. but if you did that, it would look like you did that, and the other parts wouldnt look the same, and that would be bad, from a selling stand point.
leave the scratches. its tiagra, not a mint condition 1960s record grouppo.