dura ace 7800 to 7900 upgrade question

[segalpin]

Looking for advise on dura ace 7800 upgrade to 7900 shifters. I want to pull this off with minimum change. After shifter change to 7900, it appears I must change front derailleur. Looks possible that 7800 rear derailleur will work and maybe brakes but with some performance trade off. Does this seem right? Anyone done this?

[Chris]

That's correct. I've done this exact thing.

[segalpin]

That's correct. I've done this exact thing.

How did the 7800 brakes work with 7900 shifters?

[Chris]

They say there is a difference in modulation, but frankly I haven't noticed any. I may just not pay that much attention. It certainly isn't a deal breaker. If you will watch the classifieds here and across the hall I have seen some newish brakes sell in the $150-175 range which is a great deal considering that cost is about $275ish. If you aren't interested in upgrading to 7900 brakes I don't think you will be disappointed with the performance of the 7800 calipers and the 7900 levers.

[PaulE]

I know someone who upgraded just the shifters from 7800 to 7900. Shifting front and rear was fine with 7800 front and rear derailleurs, cassette, chain and cranks. He subsequently also upgraded the brake calipers to 7900 as he wasn't happy with the braking with 7900 levers and 7800 calipers. He likes the braking much better with 7900 levers and calipers. And I got to buy his "old" 7800 brakes!

[segalpin]

They say there is a difference in modulation, but frankly I haven't noticed any. I may just not pay that much attention. It certainly isn't a deal breaker. If you will watch the classifieds here and across the hall I have seen some newish brakes sell in the $150-175 range which is a great deal considering that cost is about $275ish. If you aren't interested in upgrading to 7900 brakes I don't think you will be disappointed with the performance of the 7800 calipers and the 7900 levers.

This is a big help Chris and makes me feel better about the upgrade. I am assuming front shifts work fine with 7800 cranks and rings with upgrade to new FD?

[Chris]

Yes. Spacing is the same. So, bare-bones approach, i would say you need the front derailleur and shifters. Sweetest set up is to add the brakes, but I would try your 7800s first if you are trying to go simple and not do too much. If you don't like the modulation you can always find a deal on them later. The way I look at it on the brakes, so many people use aftermarket brakes these days anyway, that the 7800s have to be the second best alternative to 7900 anyway.

[segalpin]

Yes. Spacing is the same. So, bare-bones approach, i would say you need the front derailleur and shifters. Sweetest set up is to add the brakes, but I would try your 7800s first if you are trying to go simple and not do too much. If you don't like the modulation you can always find a deal on them later. The way I look at it on the brakes, so many people use aftermarket brakes these days anyway, that the 7800s have to be the second best alternative to 7900 anyway.

Great points, much thanks!

[54ny77]

or, you could just get ultegra 6700 shifters and keep your 7800 stuff.

i'm doing exactly that, just haven't gotten around to installing the shifters yet.

search for a thread on the topic by forum member dave thompson. it's very helpful & informative.

[rice rocket]

I thought most reviews considered it a downgrade in shift quality because of the extra stiction with cables routed underneath the handlebar tape? And weight savings is only ~40g.

Also, watch for the changes in the reach...someone has a pic of it here, but the reach at the hoods is extended 15mm or so iirc?

[Chris]

I have bikes with both and would consider the shifting to be equal if not a little lighter with the 7900. I definitely like the ergonomics better. I have heard about the reach issues, but in my personal experience my position stayed the same.

[segalpin]

Ergonomics is reason for change. I used to ride (last edition) campy with wide flat top to hood. Very comfortable on my hands. Sold bike and built dream bike Legend Ti with full dura ace. hate, hate, hate small narrow hoods of 7800 dura ace. New 7900 dura ace seems closet thing to previous campy. New campy has gone back to narrow. SRAM is thicker but seems round and not flat on top. Wow, am I picky.

[dave thompson]

Looking for advise on dura ace 7800 upgrade to 7900 shifters. I want to pull this off with minimum change. After shifter change to 7900, it appears I must change front derailleur. Looks possible that 7800 rear derailleur will work and maybe brakes but with some performance trade off. Does this seem right? Anyone done this?
Correct, the front shifting on the 7900 has different pull ratios and the correct derailleur is required. Braking with the 7800 calipers will be very good, with the 7900 calipers it will be great!

There is a difference in reach with the 6700/7900 if they are mounted at the same point as the 7800 were:

http://img257.imageshack.us/img257/503/67005.jpg

There is also other differences as shown on my two bikes with identical setup (bars, stems and positioning):

http://img143.imageshack.us/img143/1471/67004.jpg
http://img401.imageshack.us/img401/7702/67003.jpg
http://img169.imageshack.us/img169/7527/67002.jpg

I thought most reviews considered it a downgrade in shift quality because of the extra stiction with cables routed underneath the handlebar tape? And weight savings is only ~40g.

Also, watch for the changes in the reach...someone has a pic of it here, but the reach at the hoods is extended 15mm or so iirc?
Sticky shifting can happen if you don't use the recommended cabling, don't pay attention to making a clean end where the housing goes into the shifters or sometimes wrapping the bars too tightly causing a constriction in the housing underneath the tape. The installation is different that earlier Shimano gear and it has to be done correctly, not in the 'old way.'
http://img338.imageshack.us/img338/4407/67001.jpg

[54ny77]

bingo! thanks dave.

your pics and description sold me on the switch.

i'll bookmark this page for that cable/housing install guidance, maybe get motivated and do it this weekend....

[bearingpress]

where can i find those fancy 7800 carbon bits i see in the picture? Mine are all dented from cyclocross crashing.

[dave thompson]

where can i find those fancy 7800 carbon bits i see in the picture? Mine are all dented from cyclocross crashing.
This guy here: http://cgi.ebay.com/Veloflyte-Carbon-Nameplates-Shimano-Dura-ace-7800-/280540726912?pt=Cycling_Parts_Accessories&hash=item415187c680 Very nicely made, I've had several sets on different shifters.