replacing a seven speed drive train?!"
I am a newbie apols for any stupid questions
I am attempting to restore an old orange aluminium mtb. not sure how old it is (if anyone is familiar it has an orange and white frame and currently has maybe original pace race rc35 shox).
I am replacing the drive train and having a brand new xt hg90 cassette I would like to keep it 21 speed. the mechs (xt xtr) are usable i think given a clean but may well have to replace them some time in the future. The shifters are fairly new 21 sp shimano rapid fire, the only ones they still make (stx-rc?) and in fine working order. If i need to replace the mechs what will be compatible?
More importantly I need to replace the crankset and I imagine the bb. The measurementd are 68mm and 35mm will this be compatible with new cranksets (e.g. truvatic and shimano). Are these cranksets compatible with the rest of my drivetrain?
I am also considering replacing the back wheel. As far I can tell the rear dropouts measure 138mm and the wheel measures 130mm. This is somewhat confusing but there is alot of flex in the rear dropouts and i have no reason to believ it isn't original spec. Is this bad news for the aluminum frame? Can I use a 8/9 speed rear wheel (what spacing) and still use the 7sp cassette?
Any advice will be gratefully recieved.
I feel like I've opened pandoras box