Front Derailer
 

I purchased a new Giant OCR-1 Tuesday nite. Ultegra derailer and shifterswith 105 front derailer. On it's maiden voyage last nite I threw the chain off the front derailer 2/3 times. Grrr. Tonight on outr local ride I was going to stay off the big ring and ride the middle only, but I forgot about my problem. It jumped off the little ring when downshifting to it. Now I don't have to worry about scratching the paint because it did a number on it, talk about sick... The rear gears feel like their missing teeth or something now. Kinda like a car with a miss in the engine. Where I bought it at is 63 miles away or I would of took it right back, I might have to do this anyway.

Is their a trick when shifting the front sprocket that I don't know about. It's like I hit the lever and man it goes from big ring to little ring or off real quick. The store where I bought it was very good at checking everything twice. He ran it threw the gears on the rack and it ran flawless.

Thanks in advance for any help.

It's not your technique.

It sounds like the deraileurs are improperly adjusted. It needs to be tuned up and the stop screws adjusted to keep from throwing the chain off of the chain rings. Hopefully you didn't ruin the chain or rear cassette when you sucked the chain.

If you know how to do it, have at it. If it was me, I'd bring it back and see what they will do for you. Good luck.

Thanks for your insight. I will take it back Sat.

It should have been set up right before it left the shop. Just because it shifts on the workstand doesn't mean it will in actual use. They should have test ridden it.They owe you a new one that isn't all buggered up.

Definately, if they didn't test ride it, they didn't do their job.

I would understand if it was lever or twist shifters, but this is a new roadbike, which has neither of those, so there is no excuse for that kind of maladjustment. Test rides on any cable adjustment, especially derailers should be done religiously. It annoys me to no end seeing folks not used to working on bikes adjusting brakes and thinking it works right without an actual test. My test for my mtn bike is I find a way to put all my weight in a 45 degree angle to the wheel while the brake is engaged...if it makes ANY movement...then it's maladjusted. That works fine for brakes, but for derailers the only way to be sure is to actually ride it, no exceptions.

This is the exact reason I picked up the Zinn book and started doing my own maintanence.

STI triples can be tricky to set up. I think that the most frequently made mistake is to assume that the derailleur is mounted to the frame corrrectly and consequently to start the adjusting process somewhere in the middle. Park Tool has a site that gives excellent directions on making adjustments such as this. If you can follow directions and have average mechanical ability, you should have no trouble adjusting both of your derailleurs by yourself.

A couple of times I've ran across 105 front triple derailleurs that sometimes seemed to "hang up" a little and then shift hard enough throw the chain over the granny ring. It looked to me like the momentum of the chain carried it over the granny ring regardless of the derailleur adjustment. I eventually installed a gizmo called a "Third EYE Chain Watcher" which solved the problem on those bikes.