donhaller 

I have a 2006 Giant TCR C1 full carbon road bike with Dura Ace rear and Ultegra front.
It has been dropping the chain off the front rings a bit lately and I had the LBS install a new chain.
It still is dropping off the front occasionally and this is really getting me aggravated as it never used to drop chain.

I want to change up to Dura Ace front but I'm unsure of which one to buy. There are many Dura Ace part nos. for front Dérailleurs on eBay.

NoRacer

The "dropping" is probably more due to a maladjusted FD (limits) in conjunctuion with the trim adjustment. Also, problems could start to occur if the cable is ready to break.

If the FD is adjusted properly, then you may want to consider a "chain keeper". I use one on my TCR, especially when I switch to the compact crank where I seem to have more drops to the BB then when running the standard crank or running the 54x42 chain rings.

Between the DuraAce (7800) and Ultegra (6600) double there's not much difference other than weight/finish/added durability, these translating into premium $$$$. But, changing the FD will probably not correct the chain falling though.

Dura-Ace vs. Ultegra:
https://www.bikesportmichigan.com/fe...-ultegra.shtml

Another thing to look as is the chainline. Did you recently change wheels? Sometimes the position of the hub can cause the chain to fall off the big ring to the little ring. Using spacers between the cassette and freehub body may help correct this case.

donhaller 

Noracer,

Thanks for the reply.... the bike is going in for a complete look-see in a couple weeks to Bike Doctor Waldorf. I really like those guys a lot and they are worth the wait. I'll just have to be a little more gentle with it until then.

I'm glad you made the comments about the functionality of the Ultegra versus the DuraAce as I didn't realize they were that close. Saves me some $$$$. I'll just have them make sure they go over the front real good.

I know that sometimes I screw up and try shifting while in the wrong gears, like when I'm on the big ring up front and the big ring in back. Moving to the small ring upfront will cause it to drop on the BB if I'm not carefull. I have a 12-27 cassette in the rear and was wondering if that had anything to do with it also.

Thanks again

NoRacer

No, it shouldn't.

Try a chain keeper. It's one of those things you put on your bike, adjust it, and forget about it, but it really keeps the chain from falling down to your BB.

Here's a link to some of the ones on the market:

https://www.bikepedia.com/pa/List.aspx?catkey=6265

I use the "Third Eye" chain "watcher" on my TCR.

Al1943

Here's the fix. Do not run the chain on the big ring in the front and the largest cog on the cassette. When you shift to the smaller chainring have the chain on some other cassette cog.
Cross-chaining increases friction in the chain and between the chain and and other drivetrain components causing them to wear faster. It also reduces efficiency and makes you work harder. The chain won't drop if you have it more toward the center of the cassette when you shift the front.

Al

donhaller 

Al,

Thanks for the reply,... not to be a butt head, but I'm aware of that.
However, sometimes when I'm losing brain cells during high heat and exhaustion of a climb I might slip and change a gear when in a less than optimum position. This setup has always shifted perfectly and hardly ever dropped a chain in thousands of miles of riding. This is really a new issue that has surfaced.

I do appreciate your answer though