shifting problem on old Beast

[Philly]

Hello hopefully you can provide some help

When I'm on the bike and I put some serious torque on the pedals my chain will just pop [smiley=doh.gif]right off of the front (middle) chainring.  What I'm not sure of is what to replace.  Front derailluer, chain, chainrings?  I'm at a loss here.

[Simon]

I'm assuming that there is no play in the swinging arm bushes or at the B/B etc and you are sure that when you are pedaling using alot of pressure  that the chain rings are running in line, then I would replace the middle chain ring along with the chain, if you've been running with a worn chain you will also probably have to replace the cassette as well, unfortunatly you may find after replacing these parts that the other chain rings may not mesh well with the new chain and you may have to replace these as well.Simon.  

[Old Proflexer]

might try this first  -

slip the chain into the small chainring and examine the teeth on the middle chain ring.  usually that's the ring of choice for 3 ringers and it gets worn the most, first.

check the teeth at or just behind the crankarm and compare them to the others.  rings will wear the most when the pressure is applied to the cranks and the teeth engaging on the chain at that moment.  you'll probably show wear on the opposite side of the ring as well for the left crank pressure.

if the teeth are badly worn, broken, bent etc. yeah, you may need a drive train overhaul but i once got a few extra miles out of a set up by removing the middle ring and rotating it 90 degrees.  this gave some fresh teeth on the chain at the pressure point and put the worn spots at a point with minimal crank pressure.

it's easy on the rings with 4 bolt patterns, but you might want to give it a try anyway and do the best you can on a 5.

just some thoughts


OP

[Philly]

Thanks for the suggestions.  I was affraid that it may come to replacing the whole setup.  I'll try some things this weekend and I'll fill you in on what's up.