Anyone got any thoughts or experiences with this? Brand new GX Transmission, ok yesterday (but difficult to say works better than the 11sp GX it replaced) but today is total shit.
Only issue yesterday was occasional not meshing with cog 3 - but that seems a known issue.
Today it will not even look at cogs 11 and 12 and is struggling to get to 1 and 2. It’s like suddenly the chain is too long. I’ve checked the chain length and the A-B position and all is current (and certainly hasn’t changed since yesterday). Tension lines (whatever they are called again) are lined up. No impacts on the mech at all yesterday. Just seems like it’s gone from fine heading to the car to a complete heap today.
Anyone seen anything like this?
Nope, mines still sweet 6-9 mths in with zero adjustments.
mine was built up by a pro. Just for the avoidance of doubt, I’m assuming this is DIY and you’re looking for advice on what to check? Otherwise I’d be telling you to go back to the mechanic obvs.
It sounds like something wasn't lined up / settled before the set up was done - whatever that was has now settled / moved and hence it's out of wack. Or something is loose that has now slipped.
I would suggest checking over that everything is tight and as it should be - also do things like slacken off the main mech bolt, seat the mech properly and re-torque, and then set up again as if it was from scratch. Include a check that the mech hanger is properly tight to the frame. Re-check chain length.
Basically - start install again from scratch, hopefully that will do it.
mine was built up by a pro. Just for the avoidance of doubt, I’m assuming this is DIY and you’re looking for advice on what to check? Otherwise I’d be telling you to go back to the mechanic obvs.
Not not DIY but the shop no longer exists. As I said though, rides in the street were bang on. First ride was fine (minus known issue). Nothing has changed between yesterday (fine) and today (crap) so it’s really odd
Assuming you've done the basics correctly, something has possibly shifted or cables stretched in so try setting up from scratch again i.e. release and reclamp the cable with the shifter in the correct gear and barrel adjuster somewhere in the middle etc.
Did you change the cranks and if so did you choose the right one i.e. boost or non boost? Is the chain brand new and is it a 12 speed one?
This confirms my biases that SRAM is dog****, but even by their standards, something is clearly amiss. Accidentally bent derailleur hanger? Cable slipped at pinch bolt or bedded into a ferrule?
To avoid further doubt, "Transission" = new style AXS. So no hanger, no cable, no b-tension screw, no hi/lo screws. If it was just that stuff it'd be sorted in minutes
Ah, my experience is with old school victorian GX. I should have noted the capital “T” in transmission. Thanks for clarifying. Only other thought I had is how fussy 12 speed is with hanger alignment, and how this would fit problems at the top and bottom gears of the cassette, but not fit if nothings changed. But I’ll leave it to people with actual experience now.
A mate has been having problems with one of his bikes with a transmission setup.
He has other bikes that also have transmission which are fine.
From what he said he has to keep re setting what is effectively the B tension adjustment. The thing where you slack off the axle/ mech and do whatever it is that sets it.
He's also had to replace the plastic insert which sits directly in the frame.
Maybe something to check.
Mine went to shit after the first ride, then once reset has been fine since.
The little plate that sits on the inside of the frame next to the mech has moved - check that's aligned properly.
And, make sure the frame insert isn't greased.
The SRAM app is good for getting the setup spot on. Especially the plastic guide for correct jockey wheel,placement to the cassette
The little plate that sits on the inside of the frame next to the mech has moved – check that’s aligned properly.
I was just think that was the one part you can’t just go over without taking things apart - glad you suggested it! Fingers crossed…
I'll stick to my mechanical setup I think
I’ve had that with both my bikes with Transmission fitted.
Loosen the rear axle and the derailleur bolt then re-torque as SRAM recommend.
I did that and they’ve both been absolutely faultless since then.
Send it to me and I’ll send a brand new mechanical X01 rear mech and shifter in return.
Not not DIY but the shop no longer exists.
Has another dealer picked up the brands warranty work? If so, I'd get them to fix it (assuming they are reasonably local...). If you f++k anything up, it's gonna be expensive to fix...
This confirms my biases that SRAM is dog****
I have no bias as I run both 12 speed Shimano and SRAM and I find both excellent and equally easy to set up.
Thanks @hungrymonkey! You win the day!
Very odd that a knurled part like that can move seemingly easily (had to hold it in position when putting the mech on) but an easy fix now I know what to look for. All is good in the world again… apart from maybe that 3rd cog… unless it’s just the first to show this problem 🤔
🙌
That mech bolt wants doing up pretty tight - 25Nm iirc?
Hopefully it'll be all good from now
35Nm! Luckily I’ve got a sizeable Park torque wrench these days, so can be confident of hitting that number with reasonable accuracy
My daughters sram gx has developed play and won't shift cleanly. I think its due to the immense power output of a 9 year old only riding in the dry.
Sram has good ideas but rubbish Engineering
Someone knocked your bike over that you don't know about? Bent mech hanger🤔
I've 12 speed GX on two bikes, on my hardtail it has been flawless for over 2 years. On my full sus, it occasionally needs to readjusted (every 6 months or so, but is still working after 6 years) as I find a gear or two not meshing properly. I reckon it's something to do with the suspension twisting a tiny bit which means the mech ends up twisting too, and undoing the 'b' screw, totally unproven 😬
Someone knocked your bike over that you don’t know about? Bent mech hanger🤔
Transmission doesn't use a mech hanger.
You can still bend the mech cage, maybe 🤔
AXS hacked by the Russians, to bring down the US bike economy.
Sram has good ideas but rubbish Engineering
You say that but despite my 90kg (with gear) I can't brake my GX and it's faultless.
But then again I can't break my SLX 12 either and the mech is supposed to be very fragile based on reports here so what's going on?
You say that but despite my 90kg (with gear) I can’t brake my GX and it’s faultless.
Apart from not being able to brake?
lol….
”check the cable hasn’t pulled through..”
”check the plastic jockey wheel aligned is correct’’”
I think this highlights why we all have opinions, but sometimes not the answers!
FWIW, I’ve got GX transmission on my bike and it’s literally 10 times better than all previous shift iterations I’ve used. Phenomenal, especially under load.
DrP
Sram have announced a firmware update allowing additional inboard micro adjustment. This looks like it might resolve my gear 3 issue:
