Bicycle Mechanics - Front STI Derailer Jam

Has anybody had their front derailer jam? My reason for asking is, I rode my new bike for the second time on Sunday. About 4 miles into the ride, I found that my front derailer was stuck on the biggest chainring. As I was riding, I kept trying the shifter, but it would not work. About 2 hours after I finished my ride, I put the bike on the repair stand and lo and behold, the shifter worked!

I guess I should say exactly what equipment is on my bike. It is a 1997 Cannondale R500 with Shimano STI shifters and a triple front chainring.

Was it the shifter or the derailleur?

If the shifter moved but the derailleur didn't it could be a stuck cable, that wants cleaning/lubing/replacing.

Richard

For part of the cable run, the cables are exposed. When it happened, I feared that I may have broken a cable so I reached down to feel if it was still there. The cable was tight.

The outer brake lever would not move to the side. The inner lever would move the full range but not move the shifter or the cable.

Besides that, I don't know if the derailer itself was stuck, if the cable needed lubing, or if it was something in the shifter. This is my first experience with STI shifters.

Kobyj,
I just had a similar, if not identical, problem with brand new Dura Ace STI and front der. The small lever just didn't seem to ratchet at all, much less move the der, and the cable seemed really taut. I stopped at the LBS for a quick check. My regular wrench told me sometimes the STI front small lever can be a little hard to actuate when new. He did adjust the tension a little, but mainly he said you just have to push it really hard, past where you think it should. You feel a soft false click that you think is the real thing, but you have to really PUSH it past that point to get it to shift. He said this breaks in very quickly. Mine is getting better after just a few rides. Hey, who needs the small ring anyway, right? :D (Uh, me, for one.) Easing up pedal pressure slightly as you shift helps. That's a good idea anyway.

Having said all that I would still take it to your LBS for a check before going gorilla. I'm always afraid I might break something.
Regards,
Raymond

I've seen this a couple of times. I'll second the break in period for STI levers, but! Your shifter/lever may be on too tightly! If you overtighten the lever onto your handlebars you can compress the lever. You don't need it "Gorilla" tight, just snug and then 1/4 turn more. It may mean having to unwrap you bar tape a little, but it may be worth it! The clamp screw is on the side of the lever and is accessed by inserting an allen wrench(5 mm I believe!) between the lever and the boot! There is little indentation (groove) on the side of the lever. Loosen it up, then tighten it to where it's snug, try to move the lever back and forth it should move, but only with effort, then tighten another 1/4 to 1/2 turn. Rewrap you bars and go for a test ride!

Try that first.

FWIW, If your levers are "Gorilla" tight (BTW, I like that term) something will break if you crash! If they are only snug, (no movement during normal operation) they will move in the event of a hard landing and will only be cosmetically scuffed!

L8R

When shifting down and moving the lever past where you think you need to, have any of you experienced a hard popping? I've been experiencing the same issue and basically chalked it up to BIT (break in time) but I still want to make sure that I'm not forcing it tooo much.

Seeing the bike is 7 years old, the break in period should be over with. The shifter may need to be lubed, as does the cable under the BB. Just spray a good teflon lube into the shifter housing. Also spay the same lube on the exposed cable under the BB. Wipe clean after letting it sit for a while.

Wow. This post is old.

I have determined what the problem is. There is a little lever that drops down into a groove when you are shifting one way. When it gets cold, it just doesn't drop down. I think if I spray it out with WD40 and then lube it, then it should work fine.