Chainring / chain compatability?

[BERGS2]

So - i've just spent the last day doing up my tired old commuter hack -

i'm very much a fair weather bike mechanic so hopefully someone with more know how will be able to help with the below:

I replaced the rear wheel cassette and chain (was 8 speed Shimano from about 15 years ago) with a new 9 speed shimano set up.

I know that the widths of 8 & 9 speed chain are slightly different but the front chain is slipping and sticking on the chainring - almost as if the chain link pitch was wrong?

Its also sticking to the chainring and being 'sucked up' as i ride..

i cant imagine its a worn chainring, as this was replaced last year and the teeth would wear consistently...

genuinely bemused - any ideas?

(Crank & Chainring is an FSA Vero)

[MDMA .]

Is it possible the old chain was 1/8 inch ( single front chainring ) and your replacement chain is 3/8 inch?

[BERGS2]

MDMA . said:

Is it possible the old chain was 1/8 inch ( single front chainring ) and your replacement chain is 3/8 inch?

the old one was an 8 speed Shimano, which would be for all manner of chainset combos

as i understand it 9 speed chains are narrower, but they have the same 'internal' spacing for the teeth on the chain ring...its almost as if the brand new chain is the wrong size for the chainring (longitudinally) which it can't be, as these are the same from 6spd - 7spd - 8spd etc etc...

most odd

[gazza285]

It might have been new, but if you have used the chainring with an old chain then it'll soon wear out.

[BERGS2]

gazza285 said:

It might have been new, but if you have used the chainring with an old chain then it'll soon wear out.

But thats the bit that's foxing me -

is its is worn, then it should be consistently worn & the chain should still 'seat' correctly on the 'ring, no?

this is almost as if its trying to line up 12 links on 11 teeth (if that makes sense?!?)

I'm gonna buy a new chainring to see how that changes things but am confused as to whys its grabbing and generally being ste at the mo!

[TheInternet]

I'd guess worn chainring. Cheap enough to replace and good practice.

[HardtopManual]

BERGS2 said:

is its is worn, then it should be consistently worn & the chain should still 'seat' correctly on the 'ring, no?

No. What you have there is probably a worn chainring and a worn (stretched) chain. Chain link pitch is just about the last remaining universal standard in cycling - it's always half an inch; only the width varies. Measure across 6 or 7 links with a steel rule. If your chain is OK, your chainring has had it, otherwise it's time for a new chain. It may be time for both - easily possible for a neglected winter hack to go through a chainring in a year.

[Barchettaman]

OP stated that he had replaced the chain.

That looks bloody weird to me.

[TwilightJohnny]

Is the chain too long? You will almost always need to remove some links from a new chain.

Did you remove and replace the rear derailleur? If so are you sure it's been put back on correctly? If not it may not take up the chain slack.

[TwilightJohnny]

Also, zooming in on your image it does look as if the teeth on the chainring are quite pointed so it does seem to have quite a bit of wear.

[yellowjack]

Chainring replaced last year but no mention of a new chain at the same time?

Sounds like the old chain has worn the new chainring prematurely. The way the new chain is sitting 'high' on the teeth? That suggests to me that the teeth are already worn to excess. Non-salvageable if so. The teeth will be 'hooked' which is why they are picking the chain up (chain suck). Basically the teeth on the chain ring now match the pitch of a (badly?) worn chain, not a new one.

Now that there's a new chain and cassette on there, it's time for a new chainring too, I'm afraid...

[BERGS2]

Cheers for the responses fellas -

TwilightJohnny said:

Is the chain too long? You will almost always need to remove some links from a new chain.

chain is def too long - have a new chaintool arriving tomorrow - so will be able to shorten it - i thought that a lower tension bottom half of the chain wouldn't help matters - but not the cause of the weird mis-alignment

TwilightJohnny said:

Also, zooming in on your image it does look as if the teeth on the chainring are quite pointed so it does seem to have quite a bit of wear.

i think - from the sum of responses - its the combination of a wider worn chainring that worked OK with a old (frankly, knackered) 8 speed set up, that is now not playing ball with the (assumably tighter tolerance) and newer 9 speed chain... that is a not aided by the chain being a bit slack, as i've not been able to shorten it yet...

So thanks so far chaps - most helpful - final call for advice: if i need a new chainring and the one that would have been fitting is a shimano 'middle' (39T or so) - will this work bolted on to a single chainring crank set up? (i'm thinking the hyperglide noggins might get in the way.....)

or should the be fine on a normal 130 BCD set up: http://www.wiggle.co.uk/shimano-sora-fc3403-triple...

thanks again guys - & Happy New Year!

[gazza285]

If you get a chainring from a standard double, a 39 tooth 130 pcd one, then there won't be any shift pins on it.

[BERGS2]

gazza285 said:

If you get a chainring from a standard double, a 39 tooth 130 pcd one, then there won't be any shift pins on it.

this kinda ting:

https://www.ebay.co.uk/itm/SHIMANO-GENUINE-105-570...

[gazza285]

That'll do you.

[lufbramatt]

To me it looks like the narrow chain isn't sitting down deep enough into the teeth, possibly due to the chainring being too wide. This will make the effective diameter of the chainring bigger so the teeth are too far apart compared to the pitch of the chain, making it ride up the teeth around the bottom of the chainring.

[gazza285]

Looks to me like it's worn out.

[The Rookie]

lufbramatt said:

To me it looks like the narrow chain isn't sitting down deep enough into the teeth, possibly due to the chainring being too wide. This will make the effective diameter of the chainring bigger so the teeth are too far apart compared to the pitch of the chain, making it ride up the teeth around the bottom of the chainring.

Lots of words amounting to drivel....width and pitch are two different measurements, a 9 speed chain is the same (3/32") internal width as an 8 speed and it doesn't make the effective diameter bigger!

As others have said, when you fitted a new chainring with the old chain, it was worn by the old chain, now you've fitted the new chain the two won't mesh properly. If things are badly worn its a false economy to not change it together.

[WarrenG]

The Rookie said:

lufbramatt said:

To me it looks like the narrow chain isn't sitting down deep enough into the teeth, possibly due to the chainring being too wide. This will make the effective diameter of the chainring bigger so the teeth are too far apart compared to the pitch of the chain, making it ride up the teeth around the bottom of the chainring.

Lots of words amounting to drivel....width and pitch are two different measurements, a 9 speed chain is the same (3/32") internal width as an 8 speed and it doesn't make the effective diameter bigger!

As others have said, when you fitted a new chainring with the old chain, it was worn by the old chain, now you've fitted the new chain the two won't mesh properly. If things are badly worn its a false economy to not change it together.

That's a bit harsh. I knew exactly what he meant. I fitted a single-speed chainring to an 8 speed bike and found the same problem, it acts "as if" the chainring was larger than it really is. The chain tries to ride the tops of the teeth and never reaches the bottom of the hollows between them.
The solution for me, because I was being cheap, was to make the chainring into a narrow-wide configuration by filing the sides of alternating teeth and then setting the chain onto it in the right sequence, just like an official 1x setup.

If OP doesn't want to do that, get a wider chain.

[gazza285]

WarrenG said:

The Rookie said:

lufbramatt said:

To me it looks like the narrow chain isn't sitting down deep enough into the teeth, possibly due to the chainring being too wide. This will make the effective diameter of the chainring bigger so the teeth are too far apart compared to the pitch of the chain, making it ride up the teeth around the bottom of the chainring.

Lots of words amounting to drivel....width and pitch are two different measurements, a 9 speed chain is the same (3/32") internal width as an 8 speed and it doesn't make the effective diameter bigger!

As others have said, when you fitted a new chainring with the old chain, it was worn by the old chain, now you've fitted the new chain the two won't mesh properly. If things are badly worn its a false economy to not change it together.

That's a bit harsh. I knew exactly what he meant. I fitted a single-speed chainring to an 8 speed bike and found the same problem, it acts "as if" the chainring was larger than it really is. The chain tries to ride the tops of the teeth and never reaches the bottom of the hollows between them.
The solution for me, because I was being cheap, was to make the chainring into a narrow-wide configuration by filing the sides of alternating teeth and then setting the chain onto it in the right sequence, just like an official 1x setup.

If OP doesn't want to do that, get a wider chain.

It's not a single speed chainring though, it's an eight speed one that was changed a year ago and used with a knackered chain, and now won't work with a new nine speed chain because it is too far gone. A new wider chain isn't going to be any good, the chainring is still worn, and the wide chain won't work with his new nine speed set up. Harsh maybe, but correct.