# 7900 FD/Shifter setup question



## P.D.E. (Oct 15, 2006)

I've been riding on 7900 for about a month and everything is great except the front shifting. In particular it seems like it takes a lot of force to go from little to big ring. There are two "clicks" and the second click where the chain will stay on the big ring is almost at the very end of the lever throw. Thus on little to big shifts I have to force the lever all the way to the end of its throw (which takes a lot of force), otherwise the chain will go up then immediately drop back down. This is very annoying as I miss a lot of shifts especially when wearing winter gloves which don't have a lot of grip.

Does this sound like a setup problem? (I read the FD cable needs to be pretty slack...in my case when it's in the little ring the cable can be pressed onto the downtube with light pressure but it does not appear to be slack enough to be flopping around very much...)

It possible to set it up so if the chain/FD goes up to the big ring position it will stay there every time?


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## Wheelman55 (Jul 10, 2009)

I'm not a professional bike mechanic however I got to spend some time with the local Shimano tech rep regarding DA 7900 and 7970. Several things that he told me...the cable does need a fair amount of slack...experiment a wee bit. Many OE set ups did not use a metal cable housing ferule inside the brifter. Peel back the hoods to check. Replace if you don't see the ferule. Some frames require a second ferule at the opposite end. He recomended routing the cable behind the bar if possible, or route for the smoothest bend You'll also see easier shifting if you upgrade to SP41 cables...he said something like 40% easier than the inexpensive OE cables.

Best of luck.


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## P.D.E. (Oct 15, 2006)

Wheelman55 said:


> I'm not a professional bike mechanic however I got to spend some time with the local Shimano tech rep reA 7900 and 7970. Several things that he told me...the cable does need a fair amount of slack...experiment a wee bit. Many OE set ups did not use a metal cable housing ferule inside the brifter. Peel back the hoods to check. Replace if you don't see the ferule. Some frames require a second ferule at the opposite end. He recomended routing the cable behind the bar if possible, or route for the smoothest bend You'll also see easier shifting if you upgrade to SP41 cables...he said something like 40% easier than the inexpensive OE cables.
> 
> Best of luck.


Thanks for the advice...so I got it looked at by yet another mechanic. Turns out most everything you mentioned was already done before (i.e. there is a ferule, the cables are SP41 and they're routed behind the bars), however he played around with the FD cable tension (loosening it slightly) and that resulted in lighter front shifting force. 

However I was told that with 7900 there will always be the possibility of a missed little-to-big ring shift if you do not push hard enough on the shifter, i.e. chain goes up, but FD hasn't reached it's click point yet, and thus chain drops back down. 

He said he could set it up to avoid that completely but then there would be chain rub issues. I guess one thing I miss about 7800 is you can shift to the big ring w/o worrying about whether you pushed the shifter hard enough.


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## Wheelman55 (Jul 10, 2009)

PDE..the advice that you got just doesn't seem right. I've been able to ride several 7900 bikes that were set up by the local Shimano tech rep and they shift perfectly. You should try some experimenting...adjust the FD yourself so that there is no rub in the big-big, then do the same in the small-small. Make sure to remember how many turns (or 1/4 turns), as well as the direction of the turns, so you can go back to the point where the LBS mechanic had it set...just in case. The tech rep said that when adjusted this way that there will be a fair amount of slack when in the small ring.

This is a really easy adjustment that you can and should do yourself. Get one of the books...either Zinn's or Park's. You'll save yourself time and money.


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