Chain slip

roscoe
roscoe Posts: 525
edited November 2008 in MTB workshop & tech
Apologies if this has been covered before, however, I am new to the site and couldn't find anything.

I recently fitted a SRAM chain to my Trek 2700. Sunday was the first time I've been on out the bike for a good session. All was fine until I was on the road on my home. I was on the middle chain ring on gear 6 or 7 and stood up to get some power. On pedalling hard, the chain seemed to slip, so sat down and came back down the gears a bit. Tried again in gear 6 and the same thing happened.

Didn't happen at any other time during the ride, only when I stood up in 6 or 7 and tried to push hard.

When I fitted the chain, I wondered if it was slightly long by one link, but, as a novice, didn't have the confidence or wit to take a link out.

Could it be that the chain is slightly too long? Do you think taking a link out would help?

The previous chain actually snapped, hence the replacement. The bike's 2 years old, but hasn't had a huge amount of use, so would be disappointed if something had worn out.

Comments

  • nicklouse
    nicklouse Posts: 50,675
    new chains come too long.
    what sram chain was it?
    how many gears do you have?
    how old is the cassette? as old as the bike? and the bike is what year?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • roscoe
    roscoe Posts: 525
    I'm pretty sure it was PC951?

    The bike has 21 gears- 3 x 7

    The cassette is the same age as the bike, bought in Feb 2006.

    I measured it against the old chain before fitting, hence the reason I thought it was perhaps one link too long. I have only ridden it maybe twice since changing the chain and this is the first problem I've had, however, maybe haven't pushed as hard as I did when it slipped.

    Apologies for the lack of info on my first post, I'm new to this!
  • Andy B
    Andy B Posts: 8,115
    If it is a PC 951 it's the wrong chain, the PC9xx series is 9speed

    You need a 7 speed chain
    2385861000_d125abe796_m.jpg
  • roscoe
    roscoe Posts: 525
    I may be wrong on that. I'm sure I checked the compatability on-line when I ordered it.

    Is the product code stamped on the chain so that I can check it at the weekend?
  • Andy B
    Andy B Posts: 8,115
    the product code will be on the chain.
    2385861000_d125abe796_m.jpg
  • roscoe
    roscoe Posts: 525
    Thanks for the help guys.

    Checked the chain and it's a PC850, so hopefully the right one.

    Took a trip to the LBS this morning and bought a chain tool. Removed a link and refitted the chain. Will test it out tomorrow, weather permitting.

    Quite pleased I've actually replaced the chain and now managed to remove a link, not something I would have tried a few years ago, I'm a complete mechanical novice.

    Feels good trying to do some maintenance on the bike and if all else fails, LBS is 5 minutes away.

    Think I'll be asking for Zinn and the Art of Mountain Bike maintenance from Santa.

    Again, thanks for the advice.
  • I had the same problem a few months back, I fitted an new SRAM chain (correct length) and it slipped on the middle front chainring, but not the outer or inner. Turned out the middle ring had worn - classic sharks teeth look on closer inspection - and the new chain juut wouldn't work with it when the power was applied (like standing up). It was the stock Shimano Deore that came with my Rockhopper and wore after about 2 yrs.
  • stubs
    stubs Posts: 5,001
    Think I'll be asking for Zinn and the Art of Mountain Bike maintenance from Santa.

    A wise choice I have been mucking about with bikes for 35 years and I earn beer and bike parts money fixing bikes and I regulary consult this book.
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap