Thread: chain question
View Single Post
Old 07-30-04, 07:36 AM
  #16  
a2psyklnut
Senior Member
 
Join Date: Mar 2000
Location: Parrish, FL
Posts: 7,963

Bikes: Lots

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by iamthetas
my chain keeps falling from the mid front sprocket to the small one when I am doing serious bumpage but not pedaling. has anyone else had this problem and how did you solve it? it does fine when pedaling it just seems to slip when it is slack and I hit big bumps,jumps,roots etc. it is painful to think I am in one gear going downhill and finding out Im in a much smaller one when I start to pedal again. its a Shimono XT crank,sprocket and Im not sure what Shimono chain.Ive had the chain checked and it is not stretched out of specs. can a weak spring on the rear der. cause this? thanks for the help.
Kona was right and your front derailleur is out of adjustment.

Here's how to adjust it and minimize the problem.

What the end goal here is to center the front derailleur over the middle chainring.

Shift into the middle chainring(front) and into your largest cog(back). Then using the barrel adjuster at the shifter, turn it out (counter clock wise) until the chain starts to scrape the inside plate of the front derailleur. Then turn it back in 1/2 turn (or until the scraping stops). Then shift into the small cog in the back. Check to make sure the chain doesn't scrape the outside plate. If it does, turn the barrel adjuster back out. Go back and forth finding a "happy compromise" between the big and the small cogs and the chain scraping.

If the chain still drops, you may want to consider letting the chain scrape the inside plate when in the big cog. (This will mean keeping the front derailleur over to the outside).

L8R,
Have a good ride this weekend, I'm heading out on Sunday with a crew!
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger
a2psyklnut is offline