6700 vs 7900

[Onno]

I bought a sweet Parlee Z5 a few months ago, which I love. It came with Ultegra 6700 components. The one thing I'm not crazy about on the bike is the shifting and drivetrain noise. I'm used to Dura Ace 7700 (9 speed), which is pretty silky and quiet. The 6700 has shorter shifts, but it is also, to my mind, less precise. No matter how I adjust the rear derailleur, it seems noisy in the 4 big cogs. I've put on a new chain, and done lots of tuning off and on the bike.

Is it worth upgrading to 7900 shifters? Will this make any difference? Does the shifting on 7900 feel any different from 6700? Or is the problem likely to lie with cables, perhaps? I can't afford upgrading to 11 speed, which just requires too many new bits and pieces.

Thanks.

[thirdgenbird]

I am a campy guy so this is hearsay, but it remember people saying that 6700 was smoother than 7900 when it came out. Apparently they made some sort of an adjustment after 7900 complaints.

I would wait and go to 6800 or even 5800. I've seen people get by with their old cranks so if you wanted to keep it cheap:
5800 shifters
5800 derailleurs
5800 cassette minus one cog (to fit on current wheel)
5800 chain

I'm guessing you end up with 10sod that shifts better front and rear. I would probably just play it safe and do the whole group and drop the cog if wheels are an issue. 5800 is pretty cheap.

[dave thompson]

The big difference between 6700 and 7900 is the front shifting. The rear shifting is pretty much the same. IMO a 7900 rear der wouldn't give you the results you're looking for.

What chain are you running? I've found that different brands of chain can make a significant difference in drive train noise. My fave is KMC brand for 10-speed bikes, plus their quick-link makes removing/reinstalling the chain so much easier.

[Onno]

I'm using an Ultegra 6700 chain.

[AngryScientist]

is this new gear? generally speaking shimano bikes are usually pretty quiet in the rear.

the bulk of good shifting comes from cassette design. well designed ramps in the cassette account for the silky smooth transition between cogs. in this matter shimano cassettes are WAY nicer than sram, at least at the lower end, in my experience. also, is the RD worn, lots of play in the pulleys?

i would look towards a new cassette in the rear before you change anything else if chasing smoother shifting.

[oldpotatoe]

I'm using an Ultegra 6700 chain.

Get some slick stainless inner wire, 5(not4)mm der housing and metal ferrules. Route the der housing behind vs in front f the handlebars. 6700 and 7900 are essentially an identical design except for materials.

BTW- 10s spaced chainrings and 11s front shifter and der 'may' see some front der/chain rub at highest and lowest gear.

[dave thompson]

Is the chain installed in the correct manner? 6700 chains are directional and can make some noise if not installed with the stamped writing on the chain showing on the outside.

[Onno]

Thanks, all. I bought the bike used, and it looks to me to have been lightly used. I haven't really inspected the rear cassette yet. I'll check that next.

[Onno]

Did not know about a chain being directional either! I'll check that too.

[red7]

The advice here is sound. It's worth your while to see if you can your 6700 group to work for you because its potential is awesome. Save your cash for something else.

[thirdgenbird]

Verifying chain direction and replacing with new slick cables is a great idea.

[classtimesailer]

I have 7900 and would not buy it again. Go 11 speed and get it over with. I had 6700 before the 7900. They both work fine but cannot compare to my 7700 with DT shifters. If I was buying new, it would be 6800.
Btw, 6700 chains are crap. Get dura ace chains.

[texbike]

My fave is KMC brand for 10-speed bikes, plus their quick-link makes removing/reinstalling the chain so much easier.

Is the chain installed in the correct manner? 6700 chains are directional and can make some noise if not installed with the stamped writing on the chain showing on the outside.

I was running a SRAM 1091 and replaced it with a KMC 10 speed chain. It was astounding how much quieter the drivetrain was after the switch. I'm not sure if you would see as much difference moving from a Shimano chain, but it may be worth a try. What brand cassette is on the bike?

Texbike

[Black Dog]

Have you checked the rear deraillure hanger alignment?

[oldpotatoe]

I have 7900 and would not buy it again. Go 11 speed and get it over with. I had 6700 before the 7900. They both work fine but cannot compare to my 7700 with DT shifters. If I was buying new, it would be 6800.
Btw, 6700 chains are crap. Get dura ace chains.

Same chain w/o plating..5700 chains are the best value..least expensive compatible cogset and chain...just not shiny.

The guy would need a new rear wheel, BTW. Putting 10 of 11 cogs onto a 10s FH body will work but after removing some interior cog, it 'may' not shift well.

Another good call right above..der hanger alignment.

[mktng]

6700 is slow. I have no issues with my 7900 set up. It's not noisy neither.

However...

If I had a choice. I'd stick with 7800 forever Hahaha

[Onno]

So how do you check derailleur hanger alignment, without one of those fancy tools?

[mktng]

I'd take it into a shop. Get them to checkout your hanger as well. Slight misalignment of the Rd hanger can cause a lot of noise and lousy shifting. Once that's all good. Tune her up. I generally eye ball the Rd.... You can usually tell if your Rd is a bit wonky.

[Bob Ross]

No experience with 7900, but I've been riding a 6700-equipped bike for 4 years and never experienced any noise or lack of precision such as the OP describes.