I am currently in the process of building a Cross Check using the drivetrain from an old bike. So far everything works as expected except the rear derailleur. It is some sort of old Shimano "Altus" which comes with an adaptor claw (which I believe cannot be removed from the derailleur) that I use with Dura-Ace 9 speed barcons in friction mode and a 8 speed 11-28 SRAM cassette.
I've attached pictures of the derailleur (please don't mind the dirty chain).
First problem: when I shift on the smallest cog, the chain rubs on the adaptor claw's bolt. I've read in another thread that this could be solved by adding a washer each side of the hub. It should be easy because the Cross Check has 132,5 mm spacing, but it would make my second problem even worse.
Second problem: the dropouts are thicker than on my previous frame, so the derailleur is further right from the cassette on the Cross Check (by a millimetre or two). Even by adjusting the limit screws, the derailleur cannot engage the chain in the first cog (it could on the old frame because the metal on the dropouts was thin enough).
My question is: is there a way to mount the derailleur directly on the frame's derailleur hanger? I think it would solve both my problems at once. However, I think my derailleur is riveted or similarly attached to the claw adaptor (i.e. without a screw).
Or should I buy a new derailleur? In that case, is it better to find one on eBay/craigslist or at my LBS? Should I use a mountain or road derailleur (I have a standard double in the front)? Weight is not an issue, but reliability is.
Thank you, I'll post pictures of the build once it is complete.