Chain slipping!

[NumbCheck]

Hi all,

I was wondering if this has been a common occurance for any others with their bikes. I just got my bike , a 2006 Blur LT, a few weeks ago. I took it into my LBS for a tune up, as the drive system seemed to be slipping in the gears such as 1on the front rings and the third cog on the rear. Also it slipped when it was on the second chainring on the front and the fourth cog in the rear. It only does it when I am climbing and have to apply some torque on the pedals. The LBS replaced the chain, but I wonder if the new chain is too loose or the derailer is not keeping it taught enough as these seem to be the gears that the chain is running striaght across from the front to the rear requiring the least tension on the chain or derailer. Any help or thoughts would be greatly appreciated.

Chad

[CalEpic]

It sounds like you just have cable stretch with a new bike. Adding tension to the rear derailleur cable should take care of it. This assumes the derailleur hanger didn't get bent in a crash. If it's a new bike I doubt the chain would need to be replaced.

[NumbCheck]

It's new to me. It was a rental in Vegas. I will have the LBS check the derailer.

Thanks

[tkblazer]

the chain may just have to wear a bit. i had the same problem when i used a new chain on my old rear cassette, the chain would keep skipping any time i put down a lot of torque on the pedals

[NumbCheck]

Thanks TK,
I hope that's it. It doesn't do any damage if I ride it and it is slipping?

[Waldo]

Run your hand along your chain to find tight links that might be jumping around. Also check the sprockets & chainwheels for bent or chipped teeth.

Then...

Ask the shop to check to see if the chain is stretched or if the derailleur hangar is bent. Any respectable shop will have the basic tools and should start with those steps.

If both of those check out OK and no parts are worn/stretched, then it's probably just a matter of cable length and/or adjustment. Incorrect cable tension (the most likely culprit) could cause the problems you describe, as could the wrong length or poor routing of the cable if it's a full-suspension rig. The suspension action can cause changes in cable tension, thus ghost-shifting.

At least that's my understanding. I'm not a mechanic, but I slept at a Holiday Inn Express once.

And if you want to learn more, check you local library or LBS for mtb maintenance books. There are several really good ones out there. I'm partial to Amazon.com: Mountain Bike Maintenance: The Illustrated Manual: Books: Mel Allwood

Amazon.com: Zinn and the Art of Mountain Bike Maintenance: Books: Lennard Zinn is very good also.

And Park Tools has a wealth of free repair info on their web site:
Park Tool Website

Happy wrenching

ps: Yes, if it's slipping it will absolutely do damage to the drivetrain (worn teeth & chain) and possibly to the rider (busted kneecaps from hitting handlebars and a long limp home after the whole thing breaks while climbing). Get it fixed!!!

[NumbCheck]

Thanks Waldo.

Your advice is much appreciated. I will definately heed your warning and get it in the shop right away.

Chad

[Waldo]

De nada.
Most of this is fairly straightforward stuff to do yourself too, whereas some LBS's may charge a good chunk for simple adjustments. If you have a stand and don't mind fumbling through it - better still, if a friend has a stand and doesn't mind teaching you - you'll save a lot of $$$ and hassle in the long run by DIY. A lot of what we're talking about in this thread is pretty common maintenance (or maybe it is for me cause I never quite get it right???)

[~ Pakiha ~]

This is a really common problem with New vs. Old Chain/cassette combos. Both parts when new wear on each other, the chain streches, and the cassette teeth wear. they eventually mold to each other. If you've have a chain / cassette for a couple of years, count on replaceing both once you replace one or that slip will continue.

[Edog]

Originally Posted by ~ Pakiha ~

This is a really common problem with New vs. Old Chain/cassette combos. Both parts when new wear on each other, the chain streches, and the cassette teeth wear. they eventually mold to each other. If you've have a chain / cassette for a couple of years, count on replaceing both once you replace one or that slip will continue.

[26'er Zen Master]

What kind of cranks are they? There was a run of Race Face Deus cranks which were machined wrong and cause a similar problem.

[NumbCheck]

Thanks to everyone for your advice. I brought it back to the LBS ands they replaced the cassette for new and the problem was solved. I checked my cranks just in case but they are bontragers. It is really great to have a place to go to where others have a wealth of knowledge and are willing to share it. Once again Thanks to all of you.

Chad

[Gabriel Zink]

Let me guess you had a 2006 SRAM x-9 casette with the black Ploycarbonet casette carrier in an 11-34 tooth combination, or an xtr, and if you do I get to tazer Dave.
So please post a reply. Thank You.

[NumbCheck]

Tazer away Gabriel. How did you know?

Chad

[Gabriel Zink]

Dave is going down.

[tkblazer]

Originally Posted by Gabriel Zink

Dave is going down.

YES! get him in the coin purse

[dirttorpeedo]

its what pakiha sed.the new chain isnt going to break into the old cassett.you've wrecked a new chain possibly,so now you'll need to get a new cassett and chain.if the bike was a rental its been very used.you'll proly need a new set of front rings too.be careful when chains slip they're a knee buster.

[NumbCheck]

Luckily I stopped riding when it first started slipping. I took it in and they replaced the rear cassette. I rode yesterday and no slipping. I think we caught it before any damage was done to the chain. Thanks to you all for the advice.

Chad

[26'er Zen Master]

thanks Nam good looking out. **** Gabe you know your shit. But I knew that already.