Skipping front Chain Ring (the middle one)

[TonyG]

Hey guys,

I have just got my bike (08 Reign) back from a full service, in which I had a new XTR chain fitted. I've been for two rides now and my front chain ring is really causing me grief. It jumps out of the middle chainring (down to first) under load or over hard bounces..
I've done a search on this, and found a thread back in 2006 which had exactly the same issue, unfortunately no one at the time could actually pin point the problem. As with that thread it seems to come down to 3 things,
1 - the chain has loosened and needs to have a link removed. - the guy in the original thread tried this and it didn't sort his problem
2 - the front chain ring has worn so much the rings need to be replaced - possibly, but it wasn't picked up in my service
3 - a manual adjustment of the front derailer - I don't know how to do this.

Anyone else here had a similar problem, it seems funny that it only happens on the middle ring and always jumps down not up.

 

[Lard]

Do you still have your old chain? Try putting it on and testing it. it'll probably be fine. Sounds to me like the middle ring is worn and a new and old combo will never work well. I had a similar problem with a new chain on old rings slipping all over the place, I've had to go back to all the old drivetrain until new rings arrive.

 

[lemonpeeler]

Just commenting from my experience. I have an 07 Reign 0 and I took the bike into my LBS as the chain was slipping off the chain rings recently.

I personally run a 2x9 Saint setup on it, and the largest chain ring had worn to the point it was letting the chain slip.

After replacing the largest chain ring as well as the chain, I took it for a ride and the issue was still apparent. Next thing replaced was the cassette, which made for perfect shifting on the large ring, but not the small one. On the small ring the chain wouldn't slip, but it was very graunchy (if thats a word).

Finally, the small ring was also replaced (although it didn't seem that worn) and the bike finally shifts as it should. So basically all sprockets and the chain were replaced to rid of the issue.

Now I'm personally not sure what your problem could be, so I'll let others give you some pointers there, but my similar issue was sorted with the above.

 

[0psi]

Pretty much just an elaboration on the 2 above posts but I'd wager some new chain rings are in order. I usually change chain, cassette and rings when ever I do mine. I bit of a pain but it just works so much better. Chains stretch over time and as they do they'll wear the rest of the drive train in a very specific way so when you put a new unstretched chain onto those cogs and rings it usually doesn't work too well. Especially true of the middle ring as it's the most used.

I'd very much doubt it's the alignment of the derailluer as you'd notice rubbing on the cage before any skipping.

 

[0psi]

but it was very graunchy (if thats a word).

I don't think so but I know exactly what you mean and it describes it perfectly! I think we should pass a motion to make it part of cycling terminology.

 

[Propagate]

Sounds like a worn ring to me, (that sounds sordid as!).

Just had the exact same issue. New chain and shifting turned to shit, new rings and all is great.

Moral of the story, replace your chain every 3 months if you ride hard, saves odd ware on your rings & your cassette. That's what the LBS back in the UK always used to drum into us.

Or get a chain ware tool and replace your chain once it's too stretched.

 

[Nerf Herder]

before you lash out for a new ring ... try the barrel adjusters on the front shifter first ... as its dropping to the granny ... put a few turns of tension on (visualising I think thats still righty tighty).

Note: if you put too much tension, you'll hear it when you shift from middle to big as you'll get more chain grindage or rub ... just back off the barrel adjuster a little to fine tune.

2ndly the trick to the limiters is "L" = Low speed ... or Granny ... "H" = High Speed or Big ring (it is opposite for the rear mech L = big cog, H = small cog).

I don't think its the limiters anyway ... as it seems to be more the indexing in the middle.

Lastly, as its just been serviced ... I'd take it back to the LBS. They should fix it for free.
(note: the reason I don't think its a worn ring, is the LBS would have checked and that would have been the first thing they'd try to sell you ... along with a new cassette)

 

[Propagate]

LBS do miss things. Mine went in for new chain, got home and it was literally unrideable. Took it straight back, checked the middle ring and it was totally worn out. Replaced it and all was great.

The problem is, I guess most gears are re-tuned when clamped in the LBS workshop stand so under very little load. I wonder how many mechanics change a chain then razz the bike round outside to make sure all is good.

 

[0psi]

the LBS would have checked and that would have been the first thing they'd try to sell you

Assumptions are a dangerous thing Nerf Back when I was young and less wise I bought a bike from a 'reputable' shop in Cronulla. Went out for my first ride and there was an odd screeching sound coming from the front wheel. Turns out that in the pre-delivery service they thought that the correct way to set up the front brake was with the caliper body pressing into the disc. There's always a chance you'll get the work experience kid.

 

[TonyG]

Thanks for the feed back guys. A new set of front rings was discussed at servicing, but the two guys looking at my bike formed the view they still had a bit of life left in them. I think by the way it's riding now that they did require replacing. I'll head back this weekend and request a change of all three rings. I'll keep you posted on the success of this for future reference for others.
Nerf, the bike is pretty old now and this is the original set of rings, so although I do appreciate your advice on alignment it will be due for a new set of front rings soon anyway. May as well tick this off now, if that doesn't work I'll be around for you to fix it!!

Thanks again all.

 

[Nerf Herder]

no probs ... happy to be wrong and hopefully you get it sorted TG.

And anytime for a visit ... I don't mind experimenting on other people's rigs ... wah wah wah ... good to see your getting out again Dood

 

[madstace]

I've only had 1 or 2 instances of load slip on my Reign (chain was ready for retirement), but it definitely likes throwing the chain off over bumps. It was worse at new, so I had a few links taken out (sorry can't remember how many, think maybe 6 out of a 116 link chain), and this helped a lot. My first replacement chain was a XTR and only now is it starting to give me grief, but only with bumps, no slippage. I've actually found that once it starts dropping the chain, it's a good signal that it needs replacing.

Before you start spending more money, if you have the old chain, count how many links were on it, then compare to the new chain (with the new chain already installed, this might be a bit painful). If the new chain has more links, maybe get your LBS to drop it back to the same amount. Also, have a play with your B adjust screw at the back of the derailleur, I know my Reign likes a good amount of tension of it. Just be careful not to go too far one way or the other.

 

[John U]

Thanks for the feed back guys. A new set of front rings was discussed at servicing, but the two guys looking at my bike formed the view they still had a bit of life left in them. I think by the way it's riding now that they did require replacing. I'll head back this weekend and request a change of all three rings. I'll keep you posted on the success of this for future reference for others.
Nerf, the bike is pretty old now and this is the original set of rings, so although I do appreciate your advice on alignment it will be due for a new set of front rings soon anyway. May as well tick this off now, if that doesn't work I'll be around for you to fix it!!

Thanks again all.

The chain wear tools basically measure the point at which the chain is too stretched to be able to be replaced with a new chain and mesh with the rest of the drive train (chain rings and casette).
If the chain hasn't stretched too much a new chain should be able to be put on and mesh with the rest of the drive train no worries. Replace chain and rock on.
If the chain has stretched too much then the stretch of the existing chain will only mesh with the existing cassette and chainrings. If you have this scenario keep these elements together and use them until they won't shift properly any more. When they no longer shift properly you'll be up for chain, casette, and chain-rings.

The bike shop should have checked the stretch in your chain and explained the above.

Get one of these and keep an eye on it yourself
http://www.parktool.com/product/chain-wear-indicator-CC-3
Its a great time to be buying tools from the states.

One last thing, if there are chain rings you never or very rarely use then you may not need to change them even though the rest of the drive train needs to be replaced.