OK so the other day I asked about how to fix chain suck on an old bike...the answer was check the drivetrain for gunk and debris, put on a new chain, etc...

Well I did that (actually I made my girl do it since it is now her bike) and she test rode it and it still sucked the chain...

So upon closer inspection the front gears (small chain ring and mid chaing ring) are wasted. The chain is actually going between the little and big gear when it gets sucked. The gap between those two gears is much larger then the gap between med and large gears so I think the lower chain ring may have got bent (not that I can see) away from the mid gear one time when the chain use to get jammed in between the gears and then suck up into the frame.

The cranks are old and I figured I would just pick up a new set to toss on. Upon looking at the cranks available now...everything is for 9spd while this is a 7sp...whats the difference other then 2 extra gears in the rear? Will the modern cranks fit?

Heres a profile of the cranks and as you can see teeth are missing from the middle gear



Here you can see it wanting to jam inbetween the small in middle ring


Here you can see the derailer is already shift over but the chain just wants to get jammed between the 2 gears...


Here is the cassette


and her cleaning the thing...


so with all that said...are these cranks easily replaceable with any modern crank set even though the bike isnt a 9spd cassette?

Does it matter that I put on a sdram chain(minue a few links) even though it said compatible with 7,8,9 speed bikes?

The rear derailler cogs dont spin very freely...they are smooth but dont spin without effort...is that normal? Freewheeling backwards too fast will cause the chain to slack up.

I just want this thing to run good for her and eliminate the problems we are having on the trail...any help is appreciated.

Anybody got an old set of cranks that will fit this thing? They dont have to be fancy, just cheap and functional.