Are my chain rings knackered?

[Marin Maniac]

I'm about to replace my 9 speed chain (to dura ace) and cassette (to ultegra) and I am considering changing my chain rings too. My reasoning is to prolong the life of the cassette and chain as long as possible.

Below are some piccies of the suspect. I've also included some pictures of the chainrings on my old hybrid which look in better nick!

How easy would it be to replace the rings. Is it a case of undo the allen bolts and unhook rings and replace with new?

To me my larger ring looks more knackered than the smaller one. The large ring as 4x teeth which resemble shark fins and some of the others are very "pointy".

What do you chaps think?

 

[spence]

They've seen better days.
As you're changing the chain and cassette it'll be wise to change the rings as well otherwise it'll start to slip.

 

[kyuss]

They look okay to me. There's no obvious shark finning on the teeth. Just looks like the anodising has worn away a bit on the teeth. How old are they?

If you want to prolong the life of the drivechain you'd do worse than to get yourself a ti-nitride coated chain. Similar price to dura ace but it'll last longer.

 

[02GF74]

How easy would it be to replace the rings. Is it a case of undo the allen bolts and unhook rings and replace with new?

I';ve seen worse but they are on their last legs.

yep - undo the alen bolts - you would need a special to get away with screw driver to precent the reverse sied from turning.

usually the big 2 rings can be slipped over the crank but the ,ittle ring would need the crank to come off.

 

[Marin Maniac]

They look okay to me. There's no obvious shark finning on the teeth. Just looks like the anodising has worn away a bit on the teeth. How old are they?

If you want to prolong the life of the drivechain you'd do worse than to get yourself a ti-nitride coated chain. Similar price to dura ace but it'll last longer.

Nice chain, however I've already put my order in!

usually the big 2 rings can be slipped over the crank but the ,ittle ring would need the crank to come off.

Bearing in mind mine is a double do you think I would get away with slipping both over the crank arm?

 

[Marin Maniac]

I've been looking at replacement chainrings. My current set are 50/36 110BCD. Does anyone know if I purchased say these

http://www.ukbikestore.co.uk/produc...ring/fsa-road-compact-110-bcd-chain-ring.html would they fit my cranks.

My other question is, are sets of rings made to go together i.e. if you look at the 50T ring in the link, on the side of the ring it has stamped 50/34. Does that mean you should only put the 34 with it? if so why to they make a 36t ring?

I'm thinking of just replacing the big ring as the small one doesn't look that bad. Is this wise?

 

[spandex]

As long as the BCD is the same and the same number of bolts they will be fine. But what you can do to save you buying new ones is turn the chain rings you have by 90 deg's in doing so you will change the power point to the part of the ring that has had little wear.

 

[Dave Davenport]

If you do change the rings get the tool (Park one's good) to hold the 'nuts' with, you can get away with using a screwdriver but it's hard to get them tight enough without the proper tool.

 

[Marin Maniac]

As long as the BCD is the same and the same number of bolts they will be fine. But what you can do to save you buying new ones is turn the chain rings you have by 90 deg's in doing so you will change the power point to the part of the ring that has had little wear.

Interesting. Will turning it 90 degrees really make that much of a difference?

 

[yello]

If I recall correctly from another of your posts, you were running a 10 speed chain weren't you?

 

[Marin Maniac]

If I recall correctly from another of your posts, you were running a 10 speed chain weren't you?

True. Was.

I've just put a 9 speed dura ace chain on.

 

[yello]

Okay. Just thinking that maybe the internal width of the 10sp was slightly narrower than a 9sp and causing wear.

I only mention this because I noticed something similar when I changed my 9sp chain rings and cassette recently (campagnolo mirage) and saw that the original chain was a 10sp. There was a significant amount of wear on the sides of the cassette teeth, to the point where the metal plate of the cassette was flaking off.

I keep meaning to find out if a campag 10sp chain has the same internal width as a 9sp chain.

 

[Marin Maniac]

Okay. Just thinking that maybe the internal width of the 10sp was slightly narrower than a 9sp and causing wear.

I only mention this because I noticed something similar when I changed my 9sp chain rings and cassette recently (campagnolo mirage) and saw that the original chain was a 10sp. There was a significant amount of wear on the sides of the cassette teeth, to the point where the metal plate of the cassette was flaking off.

I keep meaning to find out if a campag 10sp chain has the same internal width as a 9sp chain.

Thankfully I've only done about 50-100 miles so I would hope that the 10 speed chain hasn't really had time to wear/bed in. I am absolutely astounded at the difference in shifting the new chain and cassette make.

If the chain rings aren't slipping, is it really worth replacing or am I just making more work for myself in the future not replacing them/one now?

 

[spandex]

Interesting. Will turning it 90 degrees really make that much of a difference?

Yep it will all most be like a new ring

 

[spandex]

If you have a look at the ring you will be able to see two wear points if you think of the ring being a square it will be the left and right hand sides. That is where the power is going into the chain not the top or bottom. So if you turn it 90 degrees you are in some ways giving the chain a new set of teeth to play with.