mountain bike chainsuck, replacing parts while thinking of future upgrades

Question

I have been having what I believe is called chainsuck for a while now. Chain will get stuck between first and second ring and have to stop and pull like "%&$* to get it out. It is always the between the first and second.

From reading a few posts it looks like the sensible approach is to (at minimum) replace the first and second rings as well as the chain.

My question is:

1) should I replace all of the rings or is it OK to only do 1 and or 2?

2) do I have to replace the rear cassette at the same time?

3) Is this pretty hard (just starting to learn how to do some mods, cleaning and maintenance my self).

EDIT

on further inspection, the middle ring has lost some teeth, got a nice bend in one bit and shark fin look to some of the teeth. This was replaced by "halfords" a while ago, guessing they put some rubbish ring on there. The first ring is a bit shark fin like, but the outer looks pretty good.

Answer 1

Sounds like you are going to be replacing the middle ring. 'Bolt Circle Diameter' is the measure of chainring compatibility. You need another ring of the same BCD and you can check the specifications for that on the Shimano website.

Personally I would go for another Alivio ring because they are made of steel rather than aluminium alloy, this will last a lot longer, cost a lot less and the weight difference will be marginal.

The shark-fin look to the teeth is deliberate, they are individually sculpted so as to make shifting that bit easier. The bent tooth is the problem - and the missing teeth.

You can order in confidence from Wiggle and return the item if it is not the one you want, albeit with some postage to pay.

The chainring bolts do need an allen key at the front and a proper tool at the back. See if your big-fat-screwdriver can be used instead of the proper tool - tightening chainring bolts is not an everyday task so you may be able to skimp on getting yet another tool.

Answer 2

Just a couple of notes: first of all, what you're thinking are missing teeth may well be intentional as well. Even on a brand-new chain-ring, some of the teeth are shortened (some of them a lot) to give the chain a spot to shift on to the next ring easily.

That being the case, the real problem may be just the bent tooth. It's at least worth trying just straightening the tooth that's bent as well as you can, and see if that doesn't fix the problem.