Worn chainring??

glassdoc

Hi guys,
Two weeks ago I replaced the chain on my bike with a brand new one but right away I started having trouble with it slipping on the big chainring under pressure....(was leading a sprint finish in a race at the weekend when it slipped 50metres from the line:( )

I automatically blamed the chain so put back on the old chain this week and hey presto, no more slipping. But had a clubmate look at my bike and he's come to the conclusion that the big chainring is worn. Apparently the old chain is worn enough to not cause a problem on the worn chainring. The teeth are pointed rather than flat/rounded on the inner chainring. The wear seems to be on the "hollow" between the teeth.

It's an Ultegra 6700 compact chainset with around 12000kms done. Just wondering if it would be a standard problem and anyone know where I could pick up a replacement chainring or would I be better replacing the whole chainset. Cheers

funkyjebus

glassdoc wrote: »

Hi guys,
Two weeks ago I replaced the chain on my bike with a brand new one but right away I started having trouble with it slipping on the big chainring under pressure....(was leading a sprint finish in a race at the weekend when it slipped 50metres from the line:( )

I automatically blamed the chain so put back on the old chain this week and hey presto, no more slipping. But had a clubmate look at my bike and he's come to the conclusion that the big chainring is worn. Apparently the old chain is worn enough to not cause a problem on the worn chainring. The teeth are pointed rather than flat/rounded on the inner chainring. The wear seems to be on the "hollow" between the teeth.

It's an Ultegra 6700 compact chainset with around 12000kms done. Just wondering if it would be a standard problem and anyone know where I could pick up a replacement chainring or would I be better replacing the whole chainset. Cheers

Worn chainrings look like this as oppose to these perfect chainrings .

Absolutely no need for a new chainset, just new chainrings like so.

Assuming you use a standard chainset (not a compact) afaik you can use any chainrings (except campy) that have a 130 BCD.

Also, replacing you chain more often will improve the life of your chainrings and cassette (which might also need to be replaced if not done recently, again look at the teeth)

glassdoc

Cheers for the info funky. It is a 50-34 compact chainset so I'll have a trawl online to see what I can get. Did a good hilly 80k this evening and the old one is going grand though I don't know how long it's going to last. Thanks again.

clog

Hi I have a 50t fsa pro road chainring for a shimano 7900/ 6700 chainset, I bought it by mistake and it has done about 500 meters (half a kilometre). will post pic tomorrow. looking for 25 euro

FISMA

I always change the rings, cassette, and chain at the same time. They wear together and likewise, should be replaced together.

Beasty

FISMA wrote: »

I always change the rings, cassette, and chain at the same time. They wear together and likewise, should be replaced together.

Never found the need to change the chainring on any of my bikes however many times I've changed the chain and/or cassette. With care you should be able to get 2 or even 3 chains per cassette and several cassettes per chainring.

glassdoc

Might be interested in giving that a go clog if it would suit. A pic would be a help. cheers

glassdoc

Beasty wrote: »

Never found the need to change the chainring on any of my bikes however many times I've changed the chain and/or cassette. With care you should be able to get 2 or even 3 chains per cassette and several cassettes per chainring.

Have been told it's very rare for a chainring to wear. I've changed the chain twice and regularly cleaned the drivetrain. Am wondering if I've just been unlucky with a poor chainring or could it be too much use of the big chainring in the hilly terrain we have here?

ford2600

glassdoc wrote: »

Have been told it's very rare for a chainring to wear. I've changed the chain twice and regularly cleaned the drivetrain. Am wondering if I've just been unlucky with a poor chainring or could it be too much use of the big chainring in the hilly terrain we have here?

Do you cross chain? When in big ring do you use larger sprockets on back?
I never use 3 biggest sprockets on rear when in big ring

clog

Glassdoc sorry for delay in getting pics as I was on Holiday. See attached The Chainwheel is specific to Ultegra 6700 or Dura ace 7900 chainsets where the bolts are behind the spider

glassdoc

Thanks for the pics clog, am mulling over whether to replace the chainring now or save up for a new chainset. At the minute the old chain is doing a grand job and I don't think its going to do any harm to the rest of the bike. I'll be in touch if I decide to go for the chainring.

ford2600 wrote: »

Do you cross chain? When in big ring do you use larger sprockets on back?
I never use 3 biggest sprockets on rear when in big ring

That's a habit I would have been guilty of up until the last 3 months and it's probably a valid point. I've come to realize that using the small ring more can be easier on the drivetrain and my legs!!:D