# shifting from 3rd to 1st sprocket



## Burbage (Apr 5, 2010)

I have a DA 7900 groupset. The levers can shift to a larger sprocket (lower gear) 2 gears at a time, except when on the 3rd sprocket. If I try to shift directly to the 1st gear in a single sweep of the lever, it intially changes to 1st gear, but then jumps back onto the 2nd. Shifting a single gear at a time is no problem. I've read about this issue on one or two other forums. I don't think this is a set up issue and adjusting the inner derailleur limit screw doesn't make any difference.

However, I've had chance to look at several bikes equipped with DA 7900 and they appear to have the same problem. I've also tried a bike equipped with new Ultegra, but that was different - that shifted the two gears perfectly well. I've returned my levers under warranty, but the replacement ones are just the same - shift perfectly otherwise, but won't shift two gears from 3rd to 1st. 

Any ideas? Is this just a quirk of DA 7900?


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## Wheelman55 (Jul 10, 2009)

Strange...this was not an issue for me on the 7900 bike that I rode last fall...200 miles or so. Are you sure about your setup? Maybe one of the "pro" mechanics can chime in on this


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## Burbage (Apr 5, 2010)

Thanks Wheelman55. I've since got one or two other riders to check their shifting and they report the same issue - bizarre! The shifting is otherwise brilliant, so I suspect it's not likely to be a set-up issue. The same thing is happening on 6 different bikes now (only one of them mine).


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## jasjas (Dec 16, 2009)

Very odd!
Just tried it on my 595 DA7900 and its perfect.
Gotta be setup?:blush2:


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## Burbage (Apr 5, 2010)

Thanks Jasjas. Maybe it is, then. I can't understand it. It shifts perfectly otherwise. I bought my groupset from a large retailer and they said they would contact Shimano for advice. I'll keep you all posted.


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## jasjas (Dec 16, 2009)

I set up my 7900 gears exactly the same as any other shimano groupset, no difference at all, no slack fd cable, made sure rd shifter on highest ratio, rd pulleys aligned over top an bottom spockets, pinched up cable and away i went, in fact its needed less post fitting adjustment than my previous Ultegra/da7800 setup, 
oh and i use the 7900 chain as well, no difference what make of quicklink fitted.


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## Wheelman55 (Jul 10, 2009)

you might be missing the thin spacer behind the cassette...give it a check.


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## Burbage (Apr 5, 2010)

Thanks again, Wheelman55. I have the spacer there, on both sets of wheels I use. The gears will shift to the largest sprocket, it's just that they won't shift 2 gears with a single sweep of the lever. It's fine if you go one gear at a time. I've looked at 4 other bikes fitted with 7900, belonging to other riders. Theirs are just the same as mine. It's really odd, especially as some people appear to be able to double shift without any problem. 

I've tried changing the inner derailleur stop, cable tension, cables - everything I can think of, but it's still the same. I would ignore it, but I do sometimes need to shift 2 gears at a time at that end of the cassette. I ride hilly cyclosportives, with gradients over 30% on some of the rides and a rapid shift to the 25 sprocket is sometimes essential!

It's a bit puzzling. Hopefully, I'll hear back from Shimano soon.


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## AFS (Sep 15, 2004)

My 7900 shifter has the same problem. It’s about 1 ½ years old. A few others noticed the same problem, i.e. mds & bdaghisallo1 (http://forums.roadbikereview.com/showthread.php?t=157593), but not everyone.

I sent mine back to shimano Feb’09 and was told that it was an inherent characteristic of the current ST-7900 design and they were working on eliminating it in the future. I don’t know what the others ended up doing, but I didn’t follow up any further with shimano. I can see how it would be a problem with cyclocross type riding.


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## Burbage (Apr 5, 2010)

Thanks AFS, that makes sense. I've seen this on a number of bikes now, including my own, of course. My replacement levers were supposed to be from a newer batch and they still won't double shift, though. Maybe they're not quite the latest model. It does seem as though some riders aren't having a problem. I'll check with the supplier where I bought the levers.


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## jasjas (Dec 16, 2009)

just played around with gears, if i turn my lo adj screw on rd 1/8 turn , i get same probs as you, it seems that it needs to be very very slightly set to over shift to work, because of all that float in top gear pulley?
hard to believe shimano QC is that bad????? my groupset bought in autumn last yr.
Best of luck!


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## Burbage (Apr 5, 2010)

I've tried that previously, much more than 1/8th of a turn. It's not making any difference, unfortunately. Whatever I do, the shift mechanism won't engage that second click unless I push the levers so hard it feels as though the cable will snap - then it will just about engage and shift the two gears. The advice is much appreciated, though.


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## Wheelman55 (Jul 10, 2009)

There's always Di2


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## Burbage (Apr 5, 2010)

Try telling my wife that!


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## Wheelman55 (Jul 10, 2009)

Burbage said:


> Try telling my wife that!


Have you tried flowers?


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## Burbage (Apr 5, 2010)

I would try flowers, if there was even the remotist chance that would work - but it wouldn't. She's looking over my shoulder as I write this, so I do know.


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## Burbage (Apr 5, 2010)

I now have the answer. Shimano have replied to my supplier. It's a rolling change, so newer levers will double shift to the 1st sprocket, whereas older levers won't be able to. They will exchange under warranty for those concerned by this anomaly in the rear shifting. I think I will return mine, as I do have to use my bottom gear quite frequently (unfortunately!).

Thanks to those who've offered their advice.


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## AFS (Sep 15, 2004)

Thanks for the update Burbage. I'm not sure what I'll do, since I only have one bike right now.


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