Should I replace chain only or cassette & chain (Ultegra)

I have a full ultegra 6800 groupset on my summer, best weather bike which I have ran for four years now. It has only been used in dry conditions and cleaned/lubed very regularly and is still running and shifting nicely. I have got the bike out and checked the chain and it’s still not at the 0.75 level yet which I have read is the better time to replace to keep optimal performance and possibly keep the existing cassette and just replace the chain.I estimate the bike to have done around 3000 miles so I guess based on that whilst the chain hasn’t reached the stretch level should I replace the chain right away and still be able to keep the cassette or would it make sense to replace both the chain and cassette now?

I’m in the leave it all until its all knackered and replace all at once camp. With that type of use I’d pretty much expect it to last the lifetime of the bike.

If you really want to change it, try the chain on its own. If it skips, (most likely in the small sprockets) change the cassette too, or just put the old chain back on and revert to my first suggestion.

At 0.75 I would say you are at the correct point of changing the chain only. On my gravel bike where I get through chains every couple of months due to our sandy Dorset conditions, I’ve gone past 1.0 and still saved the cassette/chainring.
My policy now is to buy the cheapest chain I can (Sram PC1130) and change more often.
I’ve been told that 12 speed drive chains should have chains changed at 0.5. I can’t comment from personal experience though.

If that cassette is on its first chain and it’s not stretched excessively yet I’d just try a new chain and see if it meshes ok. I’d have thought it would be ok.

I usually get 3 to 4 chains per cassette. Chains changed at .75 and new cassette when a fresh chain skips.

See what shifts are like just changing chain, if not great, either change cassette or try bedding new chain for a few hours on a single sprocket (so effectively 2×1 gearing) before testing shift smoothness again.

I usually get 3 to 4 chains per cassette. Chains changed at .75 and new cassette when a fresh chain skips.

Why not put one of the first chains back on? They’ve only had 0.25 stretch. Plenty of life left in them.

Use 2 or 3 chains and just keep swopping them until its fubard or you want a new drive train.

Sometimes I move my drive train to the winter bike.

Ultegra chain rings must be made of gold they are so expensive!

You’re supposed to swap 11sp chains at .5 not .75 – though I’m not religiously strict myself. Anyway, I’d swap chain only and see how it goes with the cassette.

Ultegra chain rings must be made of gold they are so expensive!

I sell the cranks and buy a new chainset, much more economical that way. Someone even gave me £10 for a big ring which I’d specified was too worn to hold the chain.

Thanks for the thoughts and suggestions. As it isn’t at 0.75 yet I will put a new chain on before any more miles on that bike. My chain tool only tests for 0.75 and 1.00 so I can’t be more specific on stretch just that isn’t dropping into the 0.75 just yet. Good point made about the 0.5 being the optimum time for 11spd. I do think the ultegra cassette looks very well built and finished compared to lesser ranges. I have got some 105 stuff on a winter bike and must say the finish does look much better on the ultegra. The thing is the winter bike is used in terrible conditions in comparison to the summer bike drive train wise so cannot really be compared like for like. Ultegra cassettes are not cheap, though if they are lasting like this one seems to be so far they are worth the money. Well 3000 odd miles on a chain and not big stretch is good I thought, but bike and conditions, rider, chainrings varies, this was all on a brand new bike.

I forgot to change my chain for once (run 2 cassettes/different wheels, so cassette usually gets less wear).
When I changed it, shifting was fine, riding on the flat was fine, just powering uphill caused chain to jump in a few cogs. So I’d say that’s what you need to test.

0.75% – change chain and it’ll probably be fine.

I’m in the leave it all until its all knackered and replace all at once camp. With that type of use I’d pretty much expect it to last the lifetime of the bike.

There’s a couple of big disadvantages to this approach. If you stuff a chain mid-ride then you won’t be able to get a replacement to fit and you’ll be faced with an immediate, expensive bill. If you are in the middle on a multi-day ride, or need the bike quickly, this might be a challenge as you’d need to source chainrings, cassette and chain all together which may prove expensive. It also doesn’t work well if you swap wheels / cassette ratios for different events.

Also, my experience is that people that follow this approach suffer a lot more issues with mechanical failures, specifically snapped chains, due to running the drivetrain all of the way to the end of its life.

Depending on the bike and mileage, even following this route I would still expect to get more than one groupset in the life of the frameset. For an MTB, my XTR grouppo was properly dead at 3,000 miles (it had 3 chains in that time), but the bike is back to new with a nice 12 speed XT setup. For winter road riding, it’s amazing how much stuff wears when used in crappy, salty conditions. I’d expect to get through 2-3 chains in a year and would probably need a full drivetrain refresh in the same time period if just using a single chain. Summer bikes last forever.

Yes, i know what you mean about the summer bikes lasting forever. The fact the chain has not reached the stretch point us somewhat puzzling though compared to on my mtb where it did within 500miles. I know its very different situations but I would have thought the stretch side of things would happen through use still regardless of conditions though the quality of chain and groupset varies and the weight of bike and wattage running through to make it move all is different too. I don’t really want to but another chain measure tool, most only do 0.75 or 1.00, tho saying that if the optimum time to change is 0.5 for 11spd I should probably look to get one to know when that is 🙂

I’ve got a Park CC-2 which I picked up cheap some time ago. Good thing.

If you have a steel ruler, you can measure just as accurately, but it needs a bit more maths to work out the stretch percentage. Effectively, 12 links should be exactly 12 inches measured pin centre to pin centre. If yours is more than this, a bit of maths will tell you the percentage that it’s stretched, but 1/16″ is about 0.5% and a good threshold for replacing modern chains.

That cc-2 looks a great piece of kit. I would settle for a standard drop in currently that measures for 0.5. Yes I have seen the guides about measuring manually, with a few calculations. I’ll see if I can source one 🙂 as then I can stay on point with replacements, I’m fine on my mtb and winter bike as they are 8&9 speed.