Are as follows:

• Shifting is highly dependent on authentic Shimano SIS cables, third party cables like Jagwire (specified by many companies for OEM such as Cervelo) really don't work well. Replaced the Jagwire with Shimano on my Cervelo S2, the shifting went from mediocre to excellent instantly.

• Chain has been redesigned, they are back to a traditional pin design. The Chinese puzzle magic link arrangement seems flawed, it stretches out after 500-1000 miles and makes the drivetrain very noisy. I'm on my second 7900 chain, I'll be replacing it with a newer re-designed chain (back to the older linkage style) this weekend.

Many users complain about the noisy drivetrain on 7900: I suspect the chain re-design will resolve many of these issues. I find I have to keep the 7900 drivetrain much cleaner or it gets noisy much sooner than 7800. Again, could well be all related to the chain design, LBS already has the newer ones in stock. Shimano is giving them some mealy mouthed bull**** about why the did this, but I suspect my theory is correct, and my LBS agrees.

I'll report back soon. That's all very annoying, but I really do like the way it shifts, brakes, looks, etc. I get the feeling that chain is the problem. We'll find out soon enough.

RW please note. You are even more annoying, particularly when you're right. Of course if the new chain works better, 7900 may well turn out to be just dandy.

Stay tuned.

Why not just use a 7800 chain?

Would you buy 7900 again or go for 7800? Or maybe even a non-Shimano drivetrain?

fixed.

Lickton told me they discontinued the 7800 chain.

Just spoke to a Shimano rep. They discontinued the magic link because it was making drivetrains noisy, so I'm very hopeful that will be the resolution. Otherwise, very happy with 7900, the shifting, braking, overall feel is very good. Doesn't shift better than 7800, but braking is better, hoods feel better, it's lighter.

Yah but KMC didn't discontinue the 7800 chain.

If ordering on line how do you specify 7900 without quick link? Does Shimano have a different part number for this chain?

Regards, curtwally

Also I do have a new bike (Cervelo) and am quite interested in your comment about the shifting. How do I tell if I have Shimano cables (I did spec the DA7900 package so I thought I had 100% Shimano) or Jagwire?

Look at the cables, if they're Shimano they are gray and they say 'Shimano SIS' on them. Stock Cervelos have black Jagwire cables. Change them.

The 7900 chain with quick link has been discontinued, I'd pick up the telephone and TALK to a mail order place to make sure you get the newer one....

What is it about 7900 that requires Shimano cabling?

I just replaced my old Shimano cables with Jagwire and it works fine for my DA 7800 system.

Also, I got a 7801 chain from Jenson about 3 weeks ago. They are definitely not in great supply. I hadn't heard that they're being cancelled however.

It must be the sharper bends the cables make now that they run under the bar tape. 7800 is just not as demanding on the cable performance.

Hidden cables do cause more friction. Even though Campy has had hidden cables since the early 90's, the 2009 ultrashift levers require new low friction cable housing, at least for the right side/RD.

Jagwire housing did not work for me (with Campy 11). I've got some black Shimano SIS housing to try, but won't have a need for new housing until next year.

I always thought the 7900 chain came with both joining pin and the quick link, so the user could choose how to join it.

Campy only has a joining pin for 11 speed, but at least it works. No noise and no problems on any of my bikes.

The DA quick link was very convenient and seemed to be a clever design. But I just put a new DA 7900 chain on a about a month ago (this chain maybe has less than 1,000 miles on it) and the drivetrain started making noises recently. I'm pretty confident that the link starts making noise in the gears the instant the chain stretches out a bit, and then it drives you crazy. As I mentioned, the Shimano rep did admit on the phone that the discontinued it because it was making the 7900 drivetrains noisy.

I also noted that lubing the chain before each ride quieted things down, but only for about 20 minutes, and then the clicking would start all over again. The BB was just repacked, the pedals just cleaned, regreased, re-installed, the drivetrain is very clean and lubed, i.e., I'm 90% confident this is the problem. The chain was silent for the first few weeks, started getting noisy in the last 10 days or so.

BUMP

Any updates/new insights on 7900 chain noise? I have the exact same problem as patentcad. I replace my chain every 1000 miles. Stays quiet for about 300, then the buzz starts again. Last replacement in October, so probably got the newest chain type. Help!

7900 runs like a clock since I installed the SIS cables and the new chain, now I have a couple of thousand miles on this setup without any problems. Now it's great.

I have to say that the 7900 crankset is one of the best things on the new DA. Not only is it aesthetically pleasing and functionally solid, the stopper plate design is very simple yet effective and no special tools other than a Park BBT-9 and simple torque wrench (or hex wrench) are needed to install it (unlike "other" brands).

Does anyone else think that the new cable pull ratio on DA, coupled with the internal routing, is the real cause for the less than stellar shifting problems?

Maybe Shimano will tweak the cable pull ratio, call it DA 7900 SL, and charge and extra arm for it...

Shimano users who want a masterlink should try the current wipperman connex link or KMC missing link. Either should fit a Shimano chain. A SRAM 10 powerloc will not fit properly.

Internal cable routing can definitely cause problems. The new Campy ultrashift also has that problem. Cable housing friction is critical.

Is their really a different RD actutation ratio? Others report that you can use older shifters with the new RD.

the cable actuation for 7900 is different on the front shifter and front derailleur. rear shifter/derailleur actuation has not changed from 7800.

Do you have to clean the underside of the brakelevers too in order to keep it up to par with your 7800? I rode 7900 for a while on a club bike (I was the second to use it) and the brakes seemed gritty. I was told that it was like that because they were dirty. I never cleaned them to find out.

7900 quick link was more than noisy, it was actually causing the chain to sit on top of the cassette rather than dropping into the teeth. pretty considerable cockup of an otherwise nice piece of equipment. That said I bought about 10 KMC quick links at Interbike for $2 a pop so I won't be having any of those issues if/when the new bike appears...

Unfortunate. And this is why most of the Cervelo Team riders used 7800 levers this year. I had a quick look through the new Ride magazine, and the only Cervelo rider using 7900 levers was Haussler

Like I said, since going over to the SIS housing/new chain, 7900 is fine. Why Shimano ever went with that stupid magic link chain that really didn't work is just baffling. Why they had that stupid six month long vaporware introduction of the product is similarly baffling. Shimano is baffling.

maybe wouldn't have had those problems if it was a Campagnolo gruppo, just say'n

I took out a 2nd mortgage to do improvements to my house, I'm not doing it for my racing bike.

actually, the real reason Cervelo went back to 7800 was that the team was having front shifting problems because they use Rotor chainrings. the front derailleur has to sit much higher over these chainrings and the wider 7900 fd cage, combined with the higher fd placement, made chain dropping more of an issue. round chainrings would eliminate that. but then again, Rotor pays the Cervelo team money and Shimano doesn't...