Ultegra Cassette durability.
 

I have a road bike with an Ultegra 9 speed groupo. It has about 2000 km on it. I recently took it in to a lbs for a tuneup as it was not shifting crisply.

The owner took out a Park chain tool and told me it measure ".75" and the chain needed to be replaced. I expected as much.

But then I was informed the cassette need to be replaced as well. That didn't seem right to me. I asked for the chain to be replaced but decided to delay the replacement of the cassette.

I clean the chain and lube it religiously. I'm shocked the cassette could need replacement. Has anyone worn out an Ultegra 9 speed cassettes that quick?

Cheers,

R.

Smart decision, you can always replace the cassette later if necessary.

The wear rate of cassettes is almost entirely determined by the condition of the chain. As the chain "stretches" the pitch no longer matches the sprockets and it begins to wear them at an accelerated rate. That's why it's important to replace chains before this happens. There's no magic wear point, but experience dictates that those replacing chains at roughly 1/2% (1/16"/12") stretch enjoy good cassette life, and those who wait until 1% do very poorly, and have a good chance of needing a new cassette with the first chain replacement.

At .75% chain stretch, and especially when determined by a chain checker which tends to read high, I'd expect the cassette to be OK, though it could be toast, especially if you did most your riding on the same sprocket.

In any case I never replace a cassette until I've determined that it won't run acceptably with the replacement chain. That's the acid test. If the old cassette runs with the new chain, it's fine. If not, it isn't, and you'll have to replace it after all. Note: the greatest cassette wear will be on the smaller sprockets that you use the most so it may run better in some gears than others. It's up to you to decide what you'll accept as OK, unless it skips.

BTW- there's never any harm to the new chain caused by running it on an old cassette. Chains wear on their own schedule regardless of the condition of the sprockets they're running on. In the chain drive industry they say "chains wear sprockets, but sprockets don't wear chains.

It should definitely last longer than that if that's the real mileage. Since you replaced the chain does it shift better now?

That's a big Amen. I have a chain checker made by Rohloff and use it for a quick check. As the chain wears I then measure it with a ruler. It's the only accurate way to measure for chain life. I replace at the 1/16" over 12 inch mark.
You are going to need a measuring tape in English rather than metric. Chains are still made with a 1/2" pitch. I think 12 and 1/16" is 30.65 cm.
2000k is too short a life for a 9 speed chain if properly maintained. Friends who ride with me and remove the chains for cleaning routinely get over 6000 miles (9500K) from a chain and at least twice that for a cassette.
The shop is covering their butts. That makes at least three that I have heard that reccomends a new cassette with a new chain.

Thanks gentlemen.

I'm currently waiting to get my bike back and see if the old cassette is still good. I typically use the same sprockets and so I might need a new cassette. The chain was maintained the entire time - in fact I'm known to be fairly anal about making sure it is clean and lubed. But being just north of 200 lbs and riding on average above 30 km/h I suppose it is possible that the chain and a few sprockets have expired.

Looking forward to getting my bike back to see. I think I'll order a chain checker while I'm waiting. Sounds like a good investment.

Thanks for the advice!

R.

Ultegra cassettes use steel sprockets, so I would expect that at only 2000km your cassette should be fine.

Also, as FBinNY pointed out, most chain checkers tend to read a bit high, you really need to confirm by measuring the stretch over 12" (24 links).

2000km would be a very short chain life. Learn to use a precision scale to check actual elongation. That Park tool will show a Shimano chain to be .25% elongated when new, so the actual elongation was .5% at most and perhaps as little as .25%. You may have used the chain half as long as you could have.

Cleaned how? I trust you're not using solvent on it...

No solvent. I use a in situ chain cleaner and biofriendly chain cleaning detergent from MEC.

I lube it after with a Finish Line Teflon based aerosol.

Buy a 12" stainless steel machinist ruler to measure the distance between the pins on the chain. You should see 12.000" with a new chain. Replace the chain when you see more than 12.060".

A quality cassette can last 15-20K miles if kept clean and lubed.

Call it bio-friendly hand soap, it's still a solvent. You're washing lube out of the rollers and crud in. It also keeps the aerosol from penetrating. No wonder, then, that your chains wear so quickly.

If a chain looks cruddy, wipe it down with a rag and add a little more lube. (The aerosol may be okay for this top-up; I prefer a dry lube.) If you really must deep-clean it, remove from bike and soak in a solvent - a real solvent, not the tree-hugger stuff - agitating occasionally to flush the rollers, then air dry completely before adding a liquid lube. (IMO the aerosol is too lightweight for a primary lubricant.)

But consider leaving the chain on forever without washing. The only time I deep-clean my chains is when the wear indicates time for a change and I move it to the "use with a worn cassette" shelf. I'm heavier than you, generally ride Ultegra 9-speed, and my chains last at least twice as long.

New chain worked like a charm .. the gearing works as good as new.

Makes sense DMF. I've switched to Progold and got a bag of shop rags. I have an SRAM powerlink chain so I can detach and keep the cassettes and cranks clean too.

I hope this one lasts a bit longer.

Cheers