OUCH! chain slip after new cassette/chain install

[chwoodiv]

Hi -
I recently got a new rear cassette and chain installed and was happy at first. It was smooth and quiet and shifted real purdy-like.

Then I cranked (I weigh 230 lbs) on a short steep hill and the chain seemed to skip off under torque and my huevos were introduced to parts of my bike that should have stayed strangers. I figured at first it was user error, but then I made sure I was a in an easier gear for climbing and it happened again, and again, and again. Luckily, the only real incident where I was injured was the first, other than a little pedal/shin deal.

Can I tighten the slack in the chain via rear derailer adjustment or other, or do I need to take a link out of the chain? Thanks in advance.

[ezdoesit]

(07-18-2010, 02:21 PM)chwoodiv Wrote:  Hi -
I recently got a new rear cassette and chain installed and was happy at first. It was smooth and quiet and shifted real purdy-like.

Then I cranked (I weigh 230 lbs) on a short steeep hill and the chain seemed to skip off under torque and my huevos were introduced to parts of my bike that should have stayed strangers. I figured at first it was user error, but then I made sure I was a in an easier gear for climbing and it happened again, and again, and again. Luckily, the only real incident where I was injured was the first, other than a little pedal/shin deal.

Can I tighten the slack in the chain via rear derailer adjustment or other, or do I need to take a link out of the chain? Thanks in advance.

Was this installed by a local bicycle shop?

[chwoodiv]

kind of local. It is about a 30 minute drive. I have no doubt they'd fix it, but time is precious and any free time I have I would rather be on a trail. So please drop a little knowledge on me, I can fix it in the wee hours, and get it back on the trail a little faster.

[trevgbb]

As you have had a new chain and cassette, it is unlikely the slippage is here, unless you have a serious mis-alignment of the rd or a stiff link, you can test for this by putting the gear in top, smallest, ring at the back and backpedaling, any jumping or skipping indicates a fault in this area. A stiff link can be seen as a vee shape in the chain as it runs through the rd, and can be easily solved with a chain breaker, see videos on this site, or the freehub is faulty, although these problems would probably have been detected by the mechanic and warned you about them.

The most likely cause, and a common problem when fitting a new chain, is that the teeth on your chainset are badly worn and the chain is slipping over them.

Exaimine the teeth critically, if they look slightly hooked you need a new chainset, or if you have a chainset with replaceable rings, you can replace the worst one only.

This is such a common problem when fitting a new chain, I am surprised the lbs didn't warn you about it.

[chwoodiv]

Hi. Thanks for the replies. I took a quick look at the chain rings and they were good. I forgot about the chain checkout but will do that tomorrow.

[chwoodiv]

(07-19-2010, 04:11 AM)trevgbb Wrote:  ... a serious mis-alignment of the rd or a stiff link, you can test for this by putting the gear in top, smallest, ring at the back and backpedaling, any jumping or skipping indicates a fault in this area. A stiff link can be seen as a vee shape in the chain as it runs through the rd, and can be easily solved with a chain breaker..

ding ding ding WINNER

Stiff link! thanks again