Dura Ace 7900 installation tips/tricks...

[SoCalSteve]

Hi all,

I'm gonna redo my Ottrott with a 7900 group and sell off the 7803 group that is on the bike now. I am also going to put a set of Reynolds DV3K wheels on it.

Any tips/tricks I need to know for installing the 7900 group? I have installed many a 7700-7800 and 7803 group on many a bike, but never a 7900 group.

In looking it over, everything seems to be the same except the routing of the brake and derauiller cable-housing.

As always, thank you all in advance,

Steve

[echelon_john]

make sure you save the 7800 stuff for when the 7900 doesn't shift right!?!?
:beer:

[SoCalSteve]

make sure you save the 7800 stuff for when the 7900 doesn't shift right!?!?
:beer:

Even if it doesnt shift right, it still is really pretty! (and, isnt that the MOST important thing)??? ;)

[dave thompson]

Steve, check your cockpit dimensions as the reach to the hoods on the 6700/7900 shifters is further. For me it was a bonus as I liked the extra room.
http://img257.imageshack.us/img257/503/67005.jpg

[godfrey1112000]

Let me know when you want to sell the old 7803 group

thanks

[Dan Le foot]

Congrats on the Group, Steve.
Have fun with the build. I know its not a guy thing to do, but read the directions if you get stuck. :confused:
Looks like you're replacing your triple with a compact. Did you go with the 11-28 cogset?
I also have the 7803 group that I bought just before the intro of the 7900.
(I really need a triple for the long 10%+ grades my wife is always dragging me to).
The problem I'm now having is finding a source for the 7800, 12/27 cassette.
I'm glad the 7900 doesn't have a triple. I'd be all over it. :crap:
Dan

[SoCalSteve]

Congrats on the Group, Steve.
Have fun with the build. I know its not a guy thing to do, but read the directions if you get stuck. :confused:
Looks like you're replacing your triple with a compact. Did you go with the 11-28 cogset?
I also have the 7803 group that I bought just before the intro of the 7900.
(I really need a triple for the long 10%+ grades my wife is always dragging me to).
The problem I'm now having is finding a source for the 7800, 12/27 cassette.
I'm glad the 7900 doesn't have a triple. I'd be all over it. :crap:
Dan

I have a few 12-27 cassettes that I have been hoarding. I will be using this with a compact crankset. I find it to be perfect for my needs.

Steve

PS: I HAVE read the installation manual! I still NEED help! :confused:

[Dan Le foot]

I have a few 12-27 cassettes that I have been hoarding. I will be using this with a compact crankset. I find it to be perfect for my needs.

Steve

PS: I HAVE read the installation manual! I still NEED help! :confused:
Hey Steve.
The Shimano instructions for me are always a bit confusing. You think someone from Japan wrote them. :crap:
When I get stuck (which is often) I put it away and simply sleep on it. Amazing how the right answwer comes to me in the morning. If that fails I go to the Zinn and Park "how to" books. If that fails, I ask the forumites here for help on a specfic issue.
Have fun.
Sunny in San Diego this morning. Need a ride.
Out
Dan

[11.4]

Serious question so some reasonable answers:

1. Cable routing in the STI levers is almost completely new. You have to remove the little cosmetic cap on the 7900 levers like you did on the 7700's. Tiny screw and small plate -- don't lose them and be sure they go back on straight. The cable routings are straightforward but you have to figure them out. The shifter cable goes in from the side and the Shimano instructions have very small and badly drawn illustrations -- you have to hunt for it and fit it in correctly.
2. Clamping the STI levers is sensitive -- it's a titanium clamp and the clamp mechanism is relocated to accommodate the internal cable routing. It is fine when fastened but I've seen a lot of people overtightening it.
3. The front derailleur has two steps on the lower ring, one on the top. If you are used to a trim on the big ring and don't read the instructions, you'll be frustrated. Adjustment is a bit more precise than with 7800 -- you don't have a lot of range to play with. And the front shift is a lot more powerful -- if you are using any chainring except 7900 you'll find the shifter can easily flex the big ring under load and make shifting funky or cause overshifts. This is not a problem but requires you get it adjusted right.
4. Rear shifter is same as before, perhaps easier.
5. Brakes are same as before. Brake pads do seem to wear faster than 7800 so plan on spares. However, they are absolutely superb on all rims I've used them on.
6. The chain now comes with a pin like before. If you like it, fine. I am running one of the KMC high end chains (the gold one) and it works superbly. I'd use the Dura Ace chain til it wears out, then go with KMC. The KMC is quieter and if there's even a small bur on the Dura Ace pin, it catches on things and you have to file it down.
7. Cables are a bit better than on the 7800 series -- better housings. Mine have consistently come with a few fewer ferrules and stuff so be sure you have extras. Don't know if I was short-changed but it was annoying to have to find others in the middle of a build.

That's about it. It goes together very smoothly. The only shifting problems are when it isn't adjusted correctly and adjustment does need to be spot-on. Then it's entirely better than 7800. On the stand you may not notice much difference but under load it shifts much better and especially with a KMC chain is quieter and smoother. And the brakes are so much better they are almost scary -- don't be a reflex grabber on turns or hills, or you just skid. The STI levers are a bit more exposed to dirt so plan on being careful of them with a spray can of triflow.

[SoCalSteve]

Serious question so some reasonable answers:

1. Cable routing in the STI levers is almost completely new. You have to remove the little cosmetic cap on the 7900 levers like you did on the 7700's. Tiny screw and small plate -- don't lose them and be sure they go back on straight. The cable routings are straightforward but you have to figure them out. The shifter cable goes in from the side and the Shimano instructions have very small and badly drawn illustrations -- you have to hunt for it and fit it in correctly.
2. Clamping the STI levers is sensitive -- it's a titanium clamp and the clamp mechanism is relocated to accommodate the internal cable routing. It is fine when fastened but I've seen a lot of people overtightening it.
3. The front derailleur has two steps on the lower ring, one on the top. If you are used to a trim on the big ring and don't read the instructions, you'll be frustrated. Adjustment is a bit more precise than with 7800 -- you don't have a lot of range to play with. And the front shift is a lot more powerful -- if you are using any chainring except 7900 you'll find the shifter can easily flex the big ring under load and make shifting funky or cause overshifts. This is not a problem but requires you get it adjusted right.
4. Rear shifter is same as before, perhaps easier.
5. Brakes are same as before. Brake pads do seem to wear faster than 7800 so plan on spares. However, they are absolutely superb on all rims I've used them on.
6. The chain now comes with a pin like before. If you like it, fine. I am running one of the KMC high end chains (the gold one) and it works superbly. I'd use the Dura Ace chain til it wears out, then go with KMC. The KMC is quieter and if there's even a small bur on the Dura Ace pin, it catches on things and you have to file it down.
7. Cables are a bit better than on the 7800 series -- better housings. Mine have consistently come with a few fewer ferrules and stuff so be sure you have extras. Don't know if I was short-changed but it was annoying to have to find others in the middle of a build.

That's about it. It goes together very smoothly. The only shifting problems are when it isn't adjusted correctly and adjustment does need to be spot-on. Then it's entirely better than 7800. On the stand you may not notice much difference but under load it shifts much better and especially with a KMC chain is quieter and smoother. And the brakes are so much better they are almost scary -- don't be a reflex grabber on turns or hills, or you just skid. The STI levers are a bit more exposed to dirt so plan on being careful of them with a spray can of triflow.

Thank you so much for the great information! Truly appreciated!

2 quick questions:

1.) The shifter cables, do they go in on the side or the bottom? Picture shows the bottom...

2.) Do you think those stock pads are OK to use with carbon rims? (exclusively).

Again, thank you so much!

Steve

[Johnnyg]

You will need special pads for carbon rims. You can adjust the shift leaver reach for smaller hands with a small screw in the front of the shifter under the hood. Good luch. JohnnyG

[c-record]

The new chain is DIRECTIONAL. Meaning the lettering should face the outside edge of the bike not the center. Check that for sure or it won't be 100%

[11.4]

Thank you so much for the great information! Truly appreciated!

2 quick questions:

1.) The shifter cables, do they go in on the side or the bottom? Picture shows the bottom...

2.) Do you think those stock pads are OK to use with carbon rims? (exclusively).

Again, thank you so much!

Steve

The holes are in the sides of the levers. They are hard to find until you know where to look and you have to roll up the hoods to find them. The cables go in at a sharp angle which prevents the cables from going in unless you point them correctly. And there are a couple other holes on the sides of the levers that look like possibilities -- you can see the cable track inside the hole, which gives it away.

I wouldn't use the stock pads with carbon rims on a regular basis. I've used them for a couple rides with Edge carbon rims and found they work fine, but they do wear extremely fast then -- as in, a couple rides. I'd use the Swiss yellow ones.

[SoCalSteve]

To re-hash an old thread...

I just installed the cables on my 7900 shifters and it was so easy!!!

Cant wait to get the rest of the bike built (rebuilding my Ottrott).

Pictures and a follow up...to follow.