Christopher86

A little history of my bike:

I Ride a 2008 Specialized Tarmac Elite. After about 11-12k miles the drive train started to take a beating. One day the chain broke... got it fixed guy tells me to come back in a few weeks for a full tune up and that i will need to replace the rear rings soon. A couple weeks later I was cruising across a bridge, the derail-er snaps off at the drop out and gets pulled by my chain snapping the plastic arch in it. I brought it back to the same bike shop and had the entire drive train replaced. With the exception of the front crank and chain rings. And a full tune up for the bike.

The Problem:

For some reason when I crank really hard while in the smaller chain ring. The chain will just clip off. It always happens when there is a small hill that I want to charge up and I stand up to crank the living hell out of it. (scared to do this now).
-Dosn't matter what gear its in in the back. I've got it to pop off in almost every one.
THIS IS VERY FRUSTRATING


Venting(reason for my frustration):

The first time I went to pick up my bike.... the BRAND NEW chain SNAPED. this took 12k miles to happen on my last chain.. not to mention how badly i treated the the old chain. I WAS FURIOUS!

Brought it back to the bike shop had them fix the chain. They were very unwilling to put a regular chain link on and now i have a "master link" on the chain.

Took it for a test ride: Chain pops off... bring it back... they adjust it... test ride.. again chain pops off... this happened about 5-6 times before it got better.. YET the chain still pops off.

I've been back 2 more times since then and they say it looks perfect.. do not know what is wrong.. They told me the front chain rings are not worn enough for them to be the cause as they keep the chain snug and dont need replacing yet. However every time I try to ride up a hill in my small chain ring.. the chain fall right out.

The bike shop is no help to me. Any suggestions are welcomed.

I WANT MY BIKE FIXED ;(

Shimagnolo

Likely cause: Improperly installed pin. They did you a favor with the master link. I won't even use the antiquated manually installed pins anymore.

Likely cause: Improperly adjusted low limit screw in FD. Trivial to adjust. https://www.parktool.com/blog/repair-...ur-adjustments

jimc101

In addition to Shimanglo's suggestions, you can get chain catchers, K-edge, Rotor, Deda & Token all make them, which will stop the chain from falling off the inner chain ring, by physically stopping it.

You haven't given any detail about the spec of your bike, but you can look at the Tech Docs from SRAM or Shimano for the relevant components to adjust yourself, in addition to the Park guide linked to above.

For the distance you have got out of your chain, 12000 miles is alot, you may want to invest in a chain checker, and replace the chain more regularly as it needs it, before it snaps in future.

FBinNY 

It could be any number of things, including sever chainring wear, but the fact that it only happens under load may be a clue. It could be that flex under load is moving the top of the chainring outward with respect to the FD cage, causing a ghost shift to nowhere.

Try this experiment. Shift to low. Hold both brakes (or pit the front wheel against a wall) and put the right pedal at the forward horizontal position. stand on the pedal and load it while watching the chain in the FD cage. Does it move outward enough to touch the cage? If so, that's why it's shifting.

It might help to adjust the inner limit outward a but, but the real solution is finding out why it flexes so much. Some may be normal frame and crank flex, and can't be fixed, but there may also be play in the BB which needs to be eliminated.

pierce

did you EVER replace the chain rings? I see where you said you were told to, then blah blah, and blah blah, and new everything BUT chain rings and.... same symptoms.

a badly worn front small chain ring will be happy to toss your chain off

and it sounds liek you really stand up and power this bike. now, if you're already in the lowest gear and climbing a steep hill, there's not much choice, but otherwise, you should be spinning faster in a lower gear.

jimc101

This would be highly unlikely for this to happen the Bottom Bracket would need to be a square taper type, which for high end bikes has been obsolete for over a decade, the 2008 Tarmac Elite was spec'ed with an FSA Gossamer MegaExo, 39/53 / FSA MegaEXO Bottom Bracket, which is an External BB type; and the OP indicated that these were still stock.

oldbobcat

Something is wrong with the chain ring. It's either bent or worn. Chain rings get bent from shifting mishaps. Sometimes they look wavy and definitely not flat. And sometimes a single tooth or two or three will simply get bent out of line.

12k miles without replacing the chain is hard on cogs. Chains should be replaced at 2-3k mile intervals, more frequently if you're in the habit of running the chain dry or dirty. Cogs wear out, but significantly more slowly than chains, but only if you replace chains as soon as they're worn.

The chain the key link in your drive train. Treat your chain well and replace it when worn, and everything runs smoothly and problems are easy to diagnose and fix. Treat your chain badly, and it abuses the rest of the system--cassette cogs, chain rings, and derailleur pulleys.

Either way, that chain ring should be replaced.

I might be looking for a different bike shop,too. The failure of your first new chain could have been caused by an improperly installed connecting pin or link, the chain having been cut too short, or "chain suck," what happens when a new chain isn't properly released after passing around a worn out chain ring.

Billfreemanii

Christopher86,
Have you been able to find out a solution to your problem? i have the same problem with my bike.
I recently just bought a used orbea aqua dama for my wife. It also has the Fsa gossamer 53/39 crank.
the front derailleur is adjusted properly, but the chain will fall off when she puts a lot of pressure on the crank and the chain is in the small chainring. Like when climbing a hill.

any help would be much appreciated.

FBinNY 

see the 2nd paragraph in post #4 . This may NOT be the cause, but deflection is such a common cause, that you need to do this simple test and rule it out before moving on to complex issues.

pierce

check the chainline to be sure its square. maybe her frame is too whippy. is she in the lowest gear when she's standing on it? spin always wins.