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1/26/2021
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Hi there,
I read somewhere that with the new SRAM T-Type Transmission, you shouldn't replace individual parts as they wear out. Instead, you should replace them all at once after a longer period of time, compared to the classical Eagle systems. I have around 1800 km on my transmission, and the chain has started to be very noisy, while the chainring doesn't look too good either (some teeth have become quite thin). Has anyone replaced just the chain (and maybe the chainring) on this system? Will it continue to work, or will the new chain cause problems with the not-so-new cassette?
I replaced my GX chain at 2k miles, XX cassette and chainring seemed fine and I've put 500 miles on since then
Keep up with your chain wear and use good lube and you should be able to replace multiple chains before you wear the cassette and chainrings enough to need replacement. General rule for 12 speed is you can go through 3 chains before cassette and chainrings.
If you run your chain too long, you increase wear on the cassette and chainring. Run that long enough and you wear enough into the cassette and chainring that they no longer mesh with a new chain.
Nothing about Transmission changes this wear cycle.
I have no clue what the answer is here, but @the_pufalot is referring to this guidance from SRAM
Flattop chains appear to have ridiculous durability if treated correctly, so it seems they are saying the chain puts more wear on the rings and cassettes and therefore replacing the chain at the normal .5% wear could make things shift worse because there could me a mismatch between chain and rings. More WTF on this story here: https://youtu.be/2FUQGWn-C9M?si=IjK8b6m300ZhrNCC
If this turns out to be true in practice I’m going to be pissed. Current rotating 2 waxed chains on transmission.
Actually I was referring to a reply on another forum, where a guy posted a statement from Sram regarding this:
Chain wear intervals for Transmission will be different than Eagle Drivetrain. It's generally expected that you would replace the chain a few times over the lifespan of a cassette with an Eagle Drivetrain, but with Transmission we expect that the chain and cassette will wear together and be replaced at the same time. This is due to the increased durability of T-Type chains.
As Zero friction pointed out in that video, claiming that changing chains at normal for 12 speed 0.5 wear creates more wear than delaying that change to 0.8 is contradictory to everything tested/known about how drivetrains wear. Worn chains cause increased wear on cassettes and chainrings.
SRAM chains have been the longest wearing options for a long time, so that slows down wear across all components but shouldn't change recommend wear limits.
Changing at 0.8 wear only makes sense if you are the company trying to sell more cassettes and chainrings.
Thought I might come back with an update. I replaced the chain as stated, with 1800km done, and the new one runs flawlesly. It also resolved my problem with the entire system being very loud, now it's dead silent again. 1800km is less than Sram stated for the lifespan of their T-Type chains, but I guess it's better than normal Eagle, taking into account that I used it a lot in horrible conditions (winter & muddy EDRs).
Which chain was it, GX or one of the fancier ones?
Yes, it was GX. Still not sure if the next option (X0) is worth it. It costs almost twice as much.
Same here but I'm trying one, curious to see how long it lasts...
On eagle there is a big difference in durability between XO and GX level chains. I believe it is primarily due to the hard chrome finish on the XO chains.
On Transmission only the XX chain gets hard chrome IIRC.
Yeah, you’re right and I typed too fast; I’m trying an XX chain, not X0
Coming back to this; got 1,800 miles (including 2 pretty wet/muddy NorCal winters) on my XX chain and it’s at 0.75 so I’m gonna replace it.
I’ve had to replace xo t type chainring and chain. Chainring had three teeth missing. Chain was getting floppy. Not sure kms on, but cassette seems to be holding up really well
I just replaced an X0 chain with 2,000+ miles on it that was failing wear test on a Park Tool CC4 (>1%). Laid out side by side with a brand new XX chain, it had developed about 1/2 a link of elongation from the worn rollers. It definitely was a bit abused over the last 2 winters, riding in really gritty slop. The GX cassette it spent most of its time on looks almost brand new. X0 cassette also is in great condition - most of the wear is just on the anodizing on the smaller gears from the chain flopping around while descending. My derailleur cage is pretty scarred and the lower jockey wheel was pretty stiff, so I replaced that at the same time. You can get the aluminum cage assembly with jockey wheels now for ~$25, less than the old price of just the jockey wheels, so it's a no brainer to replace the whole thing unless you've got a fancy XX SL carbon one.
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