Classic & Vintage - Is this chrome or some other finish? Ciocc rear triangle

I have a question regarding the finish of the rear triangle of my Ciocc San Christobal. I decided to polish the chromed front fork and rear triangle with some Simichrome. I finished polishing up the front fork and it looks great. I went to polish the rear triangle, and I noticed that the polish wasn't leaving the black residue its supposed to and the polish didn't do much. The rear triangle obviously has a different finish than the front fork. The fork takes polish nicely, almost as though it were aluminum (its not.) I rub the polish in and black resdue appears, I wipe off the residue, and buff to a shine. The rear triangle doesnt respond to the polish at all. I'm just curious if anyone knows what the difference in finish is. Thanks!

I'm pretty sure the rear triangle is chrome also. At least the two I used to own were. I would suggest using an actual chrome polish. Semi-chrome is an aluminum polish.
Why does it work on your forks and not the rear triangle?...I got nothin'!

Check the fork with a magnet to see if it's steel or aluminum.

I'm pretty sure the rear triangle is chrome also. At least the two I used to own were. I would suggest using an actual chrome polish. Semi-chrome is an aluminum polish.
Why does it work on your forks and not the rear triangle?...I got nothin'!

"Simichrome is the world's finest all-metal
polish. Any uncoated, non-ferrous metal
surface – brass, gold, silver, aluminum,
magnesium, pewter, chrome, sterling, copper, stainless steel – can be brought
to a brilliant shine using Simichrome."

I'll bet that fork is aluminum. Chrome doesn't make black stuff.

.....I'll bet that fork is aluminum. Chrome doesn't make black stuff.

I agree.

According to the decals and the magnet currently stuck to the fork, its made of Columbus Sl. Steel.
This would be odd, but could the fork be polished stainless?

I would say yes. It's either chrome, or something else. ;)

Could the rear triangle have been clear coated at some point?

The decals are all under clearcoat. I guess thats the only explanation for the rear triangle.

But why does the fork, which is also presumably chromed, react to polish the same way aluminum does? I've never gotten the black residue when polishing chrome before, but I do on the fork. I also used some mothers on it and I got the same results.

Actually, Simichrome brand polish is recommended for aluminum, AND chrome, as well as brass and bronze. But you'll find the black residue coming up much more on metals that are more reactive to the oxalic acid in this and similar (Fliz, Super 7, stufflikethat) polishes. I think the deal with your Ciocc is the chrome on the rear is clearcoated (typical on Italian chrome) and somebody (or time and the elements) has removed it from the fork. Try a little solvent on some VERY fine (0000) steelwool and see if you can get any indication of clear coming off that chrome...then polish with Simichrome and apply wax for the protection you no longer will have.