TM-17 is the rear & side belt. That and the SP-50 (pulleys) is what I used to wear out. If you run on the slightest bit dirty track, you will tear them up.
No idea where to find a manual for the GP Spider, but here is a link to an exploded view of the Spider MKII. Some parts are the same and others will interchange.
If you were close, I would send you a gear. But I think the shipping would cost more then the gear. I still have most of the part #'s, if your looking for something just ask.