LTWOO ER9 & ERX - Electronic groepsets

[pavlo.k]

In spec batteries? What is that?

2 x 14500 800mAh, 3.7v, 2.96Wh

[Serge_K]

gents, is the piston dying on ER9 shifters a thing? I have the same problem on 2 bikes, and the bike shop looked at one and says the piston is dead.
I tried to bleed both rear brakes and am not really getting anywhere. i thought i was incompetent, and now the bike shop saying it's broken. the thing is i dont actually trust them to be competent either.
Rear derailleurs dying, been there, done that, i know it's a thing.
But dying hydraulic pistons in the right shifter?

[Rajmundx]

2 x 14500 800mAh, 3.7v, 2.96Wh

I used batteries that comes with groupset.
The seller said on auction that it was like you said: 14500: 800mAh, 3.7V, 2,96Wh.

[jonathanf2]

I used batteries that comes with groupset.
The seller said on auction that it was like you said: 14500: 800mAh, 3.7V, 2,96Wh.

You should be fine then. I think batteries need a bit of break-in period and they'll eventually settle in. I've never tried riding my LTwoo bikes until full drain, but on the plus side you could always carry a spare set of 14500 batteries if you're doing a long journey ride with no charging in-between.

[pavlo.k]

gents, is the piston dying on ER9 shifters a thing? I have the same problem on 2 bikes, and the bike shop looked at one and says the piston is dead.
I tried to bleed both rear brakes and am not really getting anywhere. i thought i was incompetent, and now the bike shop saying it's broken. the thing is i dont actually trust them to be competent either.
Rear derailleurs dying, been there, done that, i know it's a thing.
But dying hydraulic pistons in the right shifter?

in the lever, not in the caliper?
what are the symptoms?

[mashiro2004]

gents, is the piston dying on ER9 shifters a thing? I have the same problem on 2 bikes, and the bike shop looked at one and says the piston is dead.
I tried to bleed both rear brakes and am not really getting anywhere. i thought i was incompetent, and now the bike shop saying it's broken. the thing is i dont actually trust them to be competent either.
Rear derailleurs dying, been there, done that, i know it's a thing.
But dying hydraulic pistons in the right shifter?

Hi Serge_K, the pistons are the ones inside the calipers. The levers don’t have pistons; they have membranes that hold the mineral oil and allow it to be pushed into the hoses to close the calipers. Are these the parts the mechanic told you were faulty?
It also happens with Shimano that these membranes can fail, especially if you try to push the caliper pistons back in without opening the bleed screw on the lever to let the air escape.
The same thing happened to me when I was younger: I damaged the diaphragm of a brake lever on my scooter while retracting the piston to change the pads.

EDIT: I said something wrong at the beginning — there is a piston in the lever as well.

[Serge_K]

Hi Serge_K, the pistons are the ones inside the calipers. The levers don’t have pistons; they have membranes that hold the mineral oil and allow it to be pushed into the hoses to close the calipers. Are these the parts the mechanic told you were faulty?
It also happens with Shimano that these membranes can fail, especially if you try to push the caliper pistons back in without opening the bleed screw on the lever to let the air escape.
The same thing happened to me when I was younger: I damaged the diaphragm of a brake lever on my scooter while retracting the piston to change the pads.

in the lever, not in the caliper?
what are the symptoms?

thanks both. yes, i mean in the shifter. the bike shop is saying the caliper mechanism is broken, not the caliper.
Tbh, i might have been guilty of pushing back the caliper pistons without opening the circuit at the shifter. Not saying i did, but can't say that there's no way i'd ever do that.
So i guess my question should be: is the braking mechanism failing at shifter level a thing on the er9?

[mashiro2004]

“Up to now, only one user here on the forum has had an issue with the membrane, and he managed to get a replacement directly from LTWOO. It doesn’t seem to have happened to anyone else, and even reading around online it doesn’t appear to be a very common problem.
It was mainly with Shimano shifters that this issue occurred relatively often — so much so that Shimano eventually started selling the replacement part, whereas at the beginning I remember they would replace the entire lever for that problem

[pavlo.k]

“Up to now, only one user here on the forum has had an issue with the membrane, and he managed to get a replacement directly from LTWOO. It doesn’t seem to have happened to anyone else, and even reading around online it doesn’t appear to be a very common problem.
It was mainly with Shimano shifters that this issue occurred relatively often — so much so that Shimano eventually started selling the replacement part, whereas at the beginning I remember they would replace the entire lever for that problem

Something weird suddenly happened to my front brake. I rode a bike yesterday and everything worked perfectly fine and this morning my front brake does not work. Feels like there's barely any pressure in the system. It still moves the pistons when press on the lever but the lever goes all the way to the handlebar and there's barely any bite. I'll try to top up some fluid today but I can't see how something like this could have happened without something breaking on the inside. there are no leaks anywhere

Update: I bled it and it's rock solid again. Any idea what could have happened to the brake that could cause something like this? I built a bike about 3 months back but I only rode it for about 200km and it was perfectly fine until today

[jonathanf2]

Something weird suddenly happened to my front brake. I rode a bike yesterday and everything worked perfectly fine and this morning my front brake does not work. Feels like there's barely any pressure in the system. It still moves the pistons when press on the lever but the lever goes all the way to the handlebar and there's barely any bite. I'll try to top up some fluid today but I can't see how something like this could have happened without something breaking on the inside. there are no leaks anywhere

Update: I bled it and it's rock solid again. Any idea what could have happened to the brake that could cause something like this? I built a bike about 3 months back but I only rode it for about 200km and it was perfectly fine until today

Maybe there was a bolt or screw that was loose allowing air into hydraulic line? It's also possible the seals on the pistons could be compromised. I'd just make sure everything is properly fastened. Ride it for a few km, and see if the problem happens again. If it does, perhaps there's an issue with the shifters.

[pavlo.k]

Maybe there was a bolt or screw that was loose allowing air into hydraulic line? It's also possible the seals on the pistons could be compromised. I'd just make sure everything is properly fastened. Ride it for a few km, and see if the problem happens again. If it does, perhaps there's an issue with the shifters.

it stopped working after about 30 minutes,

Looks like I have a leak from the hose/lever connection which is totally my fault.

[Rajmundx]

Either everything went back to normal after the update, or the app is lying
Yesterday I had almost 100% battery and after more than 2 hours of riding it dropped by only about 3–5%, I think, so that’s interesting.

Another interesting thing was that right at the beginning Wahoo showed me a notification once saying that the batteries were low, but after that there were no further messages xD

[Serge_K]

“Up to now, only one user here on the forum has had an issue with the membrane, and he managed to get a replacement directly from LTWOO. It doesn’t seem to have happened to anyone else, and even reading around online it doesn’t appear to be a very common problem.
It was mainly with Shimano shifters that this issue occurred relatively often — so much so that Shimano eventually started selling the replacement part, whereas at the beginning I remember they would replace the entire lever for that problem

The bike shop replaced the shifter, problem is gone, so the problem wasn't with the caliper or hose. My friend trusts the shop, and i sold him the shifter, so they had little to gain from not simply bleeding the existing system properly. Did i damage things through my own incompetence? Could be. I have the same problem, and instead of wasting hours and hours again, i'm tempted to just replace the shifter to see what happens.
The shifters we're talking are v1, we bought the groups in the summer of when they first released the er9.
That's the problem with competence. When you're incompetent, it's not always evident that you're incompetent.

Also, PSA: Er9 RD (v1 or v2) is NOT compatible with v3 right shifter. The internet seems to be adamant that it is, yet i can confirm it isn't. my friend's new shifter wont pair to his old RD, and i was able to pair another v1 or v2 shifter in 2min. So v3 shifter does NOT talk to v1-v2 RD.

Last: as a post mortem analysis, is there a way to inspect the membrane to see if it's actually the problem?

[pavlo.k]

Either everything went back to normal after the update, or the app is lying
Yesterday I had almost 100% battery and after more than 2 hours of riding it dropped by only about 3–5%, I think, so that’s interesting.

Another interesting thing was that right at the beginning Wahoo showed me a notification once saying that the batteries were low, but after that there were no further messages xD

there's a bug in the firmware. It seems to send 0 battery level when the drivetrain wakes up.

[mashiro2004]

The bike shop replaced the shifter, problem is gone, so the problem wasn't with the caliper or hose. My friend trusts the shop, and i sold him the shifter, so they had little to gain from not simply bleeding the existing system properly. Did i damage things through my own incompetence? Could be. I have the same problem, and instead of wasting hours and hours again, i'm tempted to just replace the shifter to see what happens.
The shifters we're talking are v1, we bought the groups in the summer of when they first released the er9.
That's the problem with competence. When you're incompetent, it's not always evident that you're incompetent.

Also, PSA: Er9 RD (v1 or v2) is NOT compatible with v3 right shifter. The internet seems to be adamant that it is, yet i can confirm it isn't. my friend's new shifter wont pair to his old RD, and i was able to pair another v1 or v2 shifter in 2min. So v3 shifter does NOT talk to v1-v2 RD.

Last: as a post mortem analysis, is there a way to inspect the membrane to see if it's actually the problem?

Hi i found this video for shimano:
I personally have never done it and I would not be able to diagnose a faulty membrane from a healthy one.
But your problem is oil leak or blocked pump?