hodie21

I have a dura-ace 7800 group that is 3 years old.

Having problems with smooth shifting on the FR Derailleur and a little less than perfect on the rear.

Just had it tuned up by my LBS mechanic who is really good. He said he had a really hard time getting the FR DR to shift correctly.

As in shifting fine on stand but throwing over when on the bike.

This is the reason I took it to them to tune on it. I could not figure it out and neither could he.

Having the itch to buy a SRAM Red group.

Also, how long should a set of chainrings last?

datlas 

I have a dura-ace 7400 drivetrain on my roadbike, it is 25 years old with at least 35,000 miles on it.

So a good drivetrain should last a LONG time.

Velo Dog

I don't think any of mine have that many miles, but certainly 10,000 is no challenge. I still have my old college Peugeot, ridden almost daily from 1970-74 and occasionally since then, and everything in the driveline is original except the chain and the rear der (broken in a crash). The 105 components on my Rambouillet probably have 12,000 to 15,000 miles, all original except for a precautionary chain replacement last year.
Front derailleurs really don't have to do much. I might be concerned about a shop that couldn't make mine work.

exhibitx

shouldn't the "really good" mechanic be able to tell you if your chainring(s), cassette and chain need to be replaced?

coffeecake

You should be getting a new chain regularly, in order to extend the life of your cassette and cogs.

mayukawa

The only things I have worn out on my 7800 is the chain and cassette. If I wear the items down until they're no longer usable, then (for me) it's ~8K miles for the chain and ~$10K miles for the cassette. The FD cage is about half-way worn through, so I guess I probably expect maybe 30K miles from it. Not sure about the chainrings, both still look pretty good. There seems to be very little wear on the pulley wheels on the RD. My previous crank (not 10 speed) lasted around 50K miles before the performance degraded, and became totally unusable at around 75K miles (chains will slip under power). My previous RD had the spring wore out (got too weak) before the pulley wheels, but I changed them out at 75K miles.

jdon

+1. I change my chain every 5000 miles or so and keep everything clean and lubed. Very little wear on the cassette and chainrings. I also replace all cables annually.

I hate drivetrain problems so do what I can to avoid them.

ericm979

I have DA 7800 on my #1 bike that is 3.5 years old. The RD is even older, it's a 7700 that I used for a couple years before I got the 7800 bike. It can handle the 12-30 cassette that I use for the Everest Challenge. I put about 6000-6500 miles a year on this bike. Everything works fine. I have replaced the crank once (to a lighter and cheaper crank, demoting the one that came on the bike to my #2 bike) and replaced the chainrings on that crank once.

I do replace the chain frequently, around 2500 miles or so, when the shifting starts going downhill. And the cables get replaced a lot- inners twice a year, outer housing once a year. Shimano 10sp cables wear out fast, and are the first thing to look at when you have shifting problems. You can inspect the inner cables inside the shifter, which is where they break, using a flashlight and looking through the insertion hole. If you see any fraying, replace. Replace if it's been more than 5000 miles or 1 year since they were replaced last.


If you maintain it, it'll last a long time.

kevin0cr1

I have 3k miles on my current bike. A shift cable broke last week so I took it to LBS to fix and asked the owner to check my chain while he was at it. He said the chain was badly stretched (I had been having some shifting issues) and needed to be replaced. He also said the cassette and chain wear together so I needed to replace the cassette. I had him do it, but it seems odd to me that you would have to replace a cassette every time you replace a chain. I'm wondering what others think about that.

Kai Winters

Until it or parts of it fail. It depends on the part, the care, how it is used, etc.
My old Ultegra shifters, rear shifter, began to fail in one gear after 5 years of very hard use. One of the detentes was wearing and needed a bit of extra trimming when shifting. It still worked but not perfectly. I replaced the drive train with Campy Carbon Record/Chorus and for the past 10 years has been flawless. The old Ultegra wound up on my cross bike and was used hard for the next 5 years before I sold the bike.

velocanuck

sounds like you are looking for a reason to justify SRAM red and the mechanic probably picked up on that.

AngryScientist 

lots of people think their local bike mechanic is "awesome". if he cant make 3 year old DA stuff work perfect, he's much less than "awesome". i do all of my own bike work, but if i did use a mechanic and he told me " i had a hard time with..." anything - that would be the last time he saw me. bikes are very simple machines, someone getting paid to work on them should be dumbfounded by anything.

in other words - if you want sram red go for it, but know that your DA set-up is probably fine. lots of opinions on the forums, but DA and Sram Red are round about equal on performance, so you wont be gaining much.

p.s. - if you do get red, dont let your current "awesome" mechanic set it up.

gsteinb

it depends on how worn they are. one of the advantages of regularly replacing your chain is you extend the life of your cassette.

kevin0cr1

Thanks. I realize that I should have mentioned in my post that the cassette and chain were both 105 and were both brand new 3000 miles ago. Should a 105 cassette really go bad after 3000 miles if it's kept fairly clean and well lubricated?

Daytrip

My LBS said the same thing: Replace both at 2,000 miles or when the chain is stretched. I checked here, and the consensus seemed to be that if you replace the chain every 2,000 miles or so (again, when it is stretched 1/16th of an inch), then you should get more than 6,000 miles out of the cassette with multiple chains.

One thing to remember is that those chain-wear gauges don't work very well. Or, to put it another way, they work to the LBS and Shimano's advantage. Use a steel ruler instead.

Secondly, what gsteinb said.

Psimet2001 

I didn't read all of the responses but they probably said the same thing. Barring unforseen circumstances your DA 7800 should be fine for many more years to come.

First - new cables, housings and chain.

If that doesn't work then pin it down to exactly what component is failing or causing the problem. If you ran your chain too long then you might be needing new cassette and or chainrings. You would most likely notice skipping though instead of "imperfect shifting".

Also....times when I have had OK shifting in the stand but not while riding it has been the following:

Cables - friction - put a drop of oil on the cable carrier under the bottom bracket
Worn out derailler.

only about 3 times in 20 years has it been the shifters.

Even then 7800 is one of the best groups of all time IMHO. Get replacement parts and keep riding it.

garysol1 

40,000 miles on my 2005 DA7800 group. While I do swap chains at around 3,000 miles
my cassetes are rarely ever replaced. I do replace all cables
at least once a year and usually more often than that. My bike still shifts and
stops as good as new.

twilkins9076

In a word...NO. If you never cleaned and lubed your chain, it's possible that it might have worn enough to damage the cassette as well, but with cleaning and lube mine have all lasted at least that long if not longer.

Jaeger

Mine is Campagnolo Nuovo record and it's 25 years old as well. I'm not sure how many miles the chainrings and freewheel have on them but I'm sure they have at least 20,000 miles as well.

As long as you don't run a worn chain far too long the rest of the drivetrain should last a long, long time.

kevin0cr1

Thank you for the responses regarding the need for cassette replacement. I think I'll be more careful about measuring my chain to prevent premature wear of the cassette. Maybe the LBS was erring on the side that would bring it more revenue, but I had been thinking for a while about getting a smaller cassette and this gave me a good opportunity to do so.

DannoXYZ 

My 1991 Dura-Ace 8-spd drivetrain has about 60,000 miles on it and going strong. Mileage spread out between 4 different sets of wheels. I regularly clean and oil my chain every 500 miles or so. I get about 4-6k miles out of a chain. Cassette replaced every 10-15k miles or so. Although I did have an aluminium freewheel on the race-wheels that only lasted about 6,000 miles.

Randochap

Depends totally on maintenance and the kind of weather you ride in.

tkehler

When the itch increases, you must buy the SRAM Red group. Don't let that itch go to waste now, d'you hear?

Grumpy McTrumpy

this.


I had a chain stretch by more than .25 with less than 1000 miles on the cross bike due to conditions and corrosion. It nearly ruined the drivetrain but I managed to catch it before it did too much damage.

StanSeven

I get about 2500 miles on a chain and change the cassette with the third chain.