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Recreational Cyclocross and Gravelbiking This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

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Old 11-06-09, 06:32 PM   #1
UBUvelo
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chain is jumping off: is it because...

recently took off the useless (or really, unused) front derailleur (reducing my cx conversion to a 6-speed!), but last week, after two hard training days, the chain jumped off....and off again.....and again......would keeping the derailleur on (though cableless) keep the chain from slapping off or was that just some hard riding?

it's down to 2 days before my first race...i feel pretty prepared, but i am already at a disadvantage as it is with being a cx noob on a 1990 steel schwinn with minimal modifications (front rim is finally alloy and not steel!). it's actually working pretty good these last 3 weeks with the tires on. but it will suck if i have to stop and get that chain back on every other lap.

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Old 11-06-09, 07:09 PM   #2
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If you're running a single ring with gears you need to either leave the derailleur on (you can remove the cable) or add chainguards.
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Old 11-06-09, 07:10 PM   #3
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if your chain is too long that will defeat a lot of chain retention devices
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Old 11-06-09, 07:24 PM   #4
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Originally Posted by funurdiesel View Post
If you're running a single ring with gears you need to either leave the derailleur on (you can remove the cable) or add chainguards.
i don't think my chain is having a slack problem, but...

but yeah, i guess i need to put my derailleur back on...cable is long gone...shouldn't really add any real weight back on...

of course, is it a matter of how i shift and keep pressure on the chain as i pedal?
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Old 11-07-09, 04:13 AM   #5
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Originally Posted by jonestr View Post
if your chain is too long that will defeat a lot of chain retention devices
+1,
also if you RD spring is weak.
also your chain or gear teeth could be too worn.
try a chain keeper and guard-
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Old 11-07-09, 06:58 AM   #6
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+1,
also if you RD spring is weak.
also your chain or gear teeth could be too worn.
try a chain keeper and guard-
though this is a vintage bike (nearly 20 years or so), i don't think anything is worn out yet...but not the greatest components either.

i think the 3rd Eye chain watcher will work...for the price it can't hurt to try it. thanks.
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Old 11-07-09, 02:01 PM   #7
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i would take a few links out of your chain before you go adding a bunch of stuff. A chain can look short enough without actually being short enough. It's less critical when you have your FD on, so you end up with a chain too long. Plus, assuming you took the big ring off, there's no need for the extra links that would allow it to go over that ring.

You may also want to adjust your chainline (as far as no weight/no money solutions go), but I bet too much chain is your issue--previous threads on this issue suggest that this is by far the most common problem.
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Old 11-07-09, 06:29 PM   #8
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Originally Posted by UBUvelo View Post
though this is a vintage bike (nearly 20 years or so), i don't think anything is worn out yet...but not the greatest components either.

i think the 3rd Eye chain watcher will work...for the price it can't hurt to try it. thanks.
dog fang works better
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Old 11-07-09, 08:47 PM   #9
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i would take a few links out of your chain before you go adding a bunch of stuff. A chain can look short enough without actually being short enough. It's less critical when you have your FD on, so you end up with a chain too long. Plus, assuming you took the big ring off, there's no need for the extra links that would allow it to go over that ring.

You may also want to adjust your chainline (as far as no weight/no money solutions go), but I bet too much chain is your issue--previous threads on this issue suggest that this is by far the most common problem.
thanks! i'll have to look into this after the race...i have finagl'd 'shimano shark fin' for the time being used in a way it wasn't quite intended...LBS had nothing in stock but one of those in the bargain bin for $3....
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