Mountain Biking - Chain delimas

Hey guys, I have a quick question.

I rode my first mountain bike race this past sunday and did pretty well (7th out of 35). My chain came off the bike 3 times on the fast BUMPY decents. This cost me top 5 and maybe more.

My question is, what is the best solutions to this? I went to my big chainring but this course was a middle ring all the time sort of course so that was just extra shifting I coudl have done without.

Can I take a link or 2 our of my chain to increase the tension on the chain to keep that from happening? Do I need to move my derailer?

Trey

Probably both.

The thing to do is to cross chain your drivetrain and shift into big-big combo. Check the tension on your rear derailleur. If there is still slack you may be able to remove two "half-links" (one inside half-link and one outside half-link = one complete link).

Also, is the chain coming off to the inside of the cranks or off the outside? Chances are you need to adjust the limit screws on your front derailleur. If it's coming off the rear, likewise you probably need to adjust those limit screws.

Go to the "Bicycle Mechanics" forum and click on the "Sticky" thread at the top titled Barnette's Repair Manuals. Those are great. Also, www.parktool.com has a "how-to" home repair section that has good visual aides (graphics and pics) on how to do this. Here's the direct link: http://www.parktool.com/repair_help/FAQindex.shtml

L8R

The chain if falling off the middle ring to the inside. It isn't in the limit screws as I don't have the derailer at either limit. I could be wrong thouigh. It doesn't come off to the outside at all. No problem on the rear as I have the limit screws there dialed in.

I can take a link (2 halves) out no problem just wanted to be sure this was an advised step. I'd like to clear this up before I race again. Re-Chaining the bike while people fly by me sucked!

Without touching, feeling, seeing the bike it's difficult to diagnose, but from what you are saying try this:

Shift into the middle ring up front and the big cog. Using the barrel adjuster on the left shifter turn it CCW until the inside plate of the front derailleur starts to scrape the chain and then turn it CW 1/2 turn to where it stops.

This will recenter your front derailleur. Your cable may have stretched (lengthened) just enough to where the derailleur isn't centered on the middle ring.

L8R

The big guy a2psyklnut is correct. :p

I readjusted and it took a bit of turning to the outside so hopefully this will help. I will go test it tonight :)

i used to have a bike where teh chain fell off regularly...turns out i bent the whole crank when i landed a 6 foot jump onto flat... ouchie

^Dopefish...that bike was literally 20$ at a garage sale...it was a REALLY crappy BMX...i remember those days...hahah, good thing u got an MTB now