Hi, wondering if anyone could offer me some advice please, I have no idea what to do next!

Back in May I bought an XL Yeti 575 and I absolutely love riding it. I have one problem though, chain suck.

Within a few weeks of purchase it began. At first I thought it was just mud and dirt getting in the chain. I distinctly remember it happening on the Hit The North race in July, which I’m sure we all remember was tremendously muddy. I’ve struggled with it since then, particularly in muddy conditions.

It doesn’t happen all the time though, which means if I take it to a bike shop they can’t find anything wrong with it. With a clean well oiled chain, I can generally ride for a couple of hours without a problem. After a couple of hours I’ll be on a climb in the lowest gear and the chain will attach itself to the granny ring and not release, trapping it inbetween the frame and the chain rings. Then that’s it, it’ll do it for the rest of the ride.

It only ever happens when the chain is on the granny ring on the front and either of the 2 largest rings on the back. Shift on to the middle ring on the front and it’s fine. I can deal with it at a trail centre but on a day like today, 4 hours in on a loop around the peaks you don’t want to not be able to use the granny ring. How much pressure I put on the pedals possibly also seems to have an effect. Get out of the saddle and go for it and there seems to be more chance of it happening.

Everyone told me “it’s your drivetrain, it’s worn and needs replacing”. 2 weeks ago I replaced the entire drivetrain – cassette, chain, granny ring and middle ring. It was fine for 3 hours round Betws-Y-Coed last weekend and I thought I’d fixed it, but today it was as bad as ever.

Does anyone have any ideas? Is it simply that the Yeti doesn’t like the wet & muddy conditions? I was talking to another rider today who was on his first ride on his 575 and had already had a couple of instances after a similar ride time.

Any adive would be much appreciated.

Thanks

check your chainline. Each bike design is different. You may need to change the spacer on the bottom bracket to a thinner one, or more, if the shell is 73mm you should use one, but if the chainline is shonky, you might need to play with this (all assuming you have an external BB)

You could try adding mre tension to the chain? either the rear mech tensioner or removing links ( making sure you have enough chain for all rings.)

KMC chain 9SL is great!

I’ve not had a problem with mine – I’ve got an X9 front mech with 08 xt crankset on a medium 07 575.

Chainsuck IS a drivetrain issue. When riding your bike the chain/rings do not touch your frame, or mech at all. Chainsuck is the chain not releasing from the chainring properly.

Usually solved by replacement, which you already have done.

New shimano granny rings have a tooth profile to stop chainsuck appearing as the ring wears. Rings as fitted to the current XT chainset (not the 760 cheese one) are very good. Crappy cheap rings are usually not manufactured to very high tolerances and are more prone to chainsuck

Thanks guys. When I replaced the drivetrain I made the chain the same number of links as the one I took off. I’ll try shortening it a little and have a look at the bottom bracket.

My friend also has a medium 575 and he hasn’t had any problems, the guy I met yesterday was on a large. Could it be a design thing?

All I can suggest is you could have stretched the chain whilst using the big ring if its worn. But I can’t imagine that would have happened in a three hour blast round a trail centre…unless you’ve been doing some road miles as well?

Probably worth checking the bb spacers as suggested above as well.

how much clearance is there between the stay and the rings as fitted ? if less than a chain width, then there’s increased chance of damage !

What chainlube you running?

Also bear in mind, once it’s done it, it’ll keep doing it again and again and again, getting worse, as the rings become hooked and the chain may have a slightly bent link or two.

Currently using Prolink Lube, seems to be OK.

Don’t think I’ve been on the big ring since changing the transmission so don’t think it’s stretched the chain.

Plenty of clearance between the stay and the rings, it’s damaging the chainstay protector, but not too badly and that’s what it’s there for.

Thanks guys