Hey Fellows,

I've finally managed to install my purchased ERX groupset.
I bled the brakes as described in the instructions. Everything's fine on the right brake lever. The left brake lever looks like it's leaking out from the upper locking bolt on lever. You can see the mineral oil seeping out.
Additionally, the pin/piston in the brake lever (I think it is called master cylinder) is making a smacking noise (this isn't the case with the right brake lever) - see video attached.
Do you guys have any similar experience and/or way of explaining how, or if it's even possible to repair it?

If it is not repairable, are the shiftet / levers of the ERX interchangeable with ER9 or ER7 versions and where to get this as separate spare parts?


Thanks for your help in advance.

1. Loose the chain
2. Disassemble the RD and move ot away from the bike (do not forget to unplug power connection)
3. Unscrew the small philipps-head screw on the bottom of the RD (the screw sits approximately at the depth of the groove of the mounting bolt of the RD cage) until it no longer loosens. Press the RD cage towards the RD and pull the srcrew out (if you do not hold the RD cage the spring pumps out the cage and you cannot reconstruct the position of the spring - inside the RD and on which of the three holes the spring was on the RD cage). How do I know? I didn't hold the cage when I removed the screw.

So if there are people here who can remember the original position of the spring inside the RD and in which hole the spring was positioned on the RD cage side... PLS let me know :-)

So if there are people here who can remember the original position of the spring inside the RD and in which hole the spring was positioned on the RD cage side... PLS let me know :-)

1. Loose the chain
2. Disassemble the RD and move ot away from the bike (do not forget to unplug power connection)
3. Unscrew the small philipps-head screw on the bottom of the RD (the screw sits approximately at the depth of the groove of the mounting bolt of the RD cage) until it no longer loosens. Press the RD cage towards the RD and pull the srcrew out (if you do not hold the RD cage the spring pumps out the cage and you cannot reconstruct the position of the spring - inside the RD and on which of the three holes the spring was on the RD cage). How do I know? I didn't hold the cage when I removed the screw.

So if there are people here who can remember the original position of the spring inside the RD and in which hole the spring was positioned on the RD cage side... PLS let me know :-)

Do you guys know if the master cylinders (of the levers, not the calipers) of the brake levers are interchangeable so I can swap e.g. left with right one?

Do you think the cylinders of ER9, ER7 or other ltwoo hydraulic brakes are compatible to the ERX ones?


Since I got no advancing reply (for my problem described here) from ltwoo support and different AE shop I am thinking to buy a spare brake lever and only switching the master cylinder...

Hey fellows,

Read through the thread but still confused on swapping RD pulleys. Can some pls sum up the right setting for me?

- Stock config is upper pulley 11 teeth and lower pulley with narrow/wide 12t teeth.
- In which order I need to replace the pulleys? Stock upper with Shimano lower (with longer teeth, but no wide/narrow) and vice versa, or only the lower stock pulley with 11t Shimano lower pulley?

Thx guys for your help!

Thx for your reply.

Regarding to your link the attached pic should be the Ultegra pulleys from the AE shop. Could you (or someone else) explain to me the narrow-wide teeth profile, as I do not see any differences on the wheels. My understanding is that narrow-wide means an alternating teeth width and not longer/short teeth or gaps between teeths, is this correct?

EDIT: Could 11t narrow-wide pulleys exists at all due to the even tooth count?

Another thing I do not understand is why changing the lower (tension) pulley has effect on better performance with larger cassettes (>32t)?
My original lower pulley (12t) has a diameter of 51/52mm the lower ultegra one (11t) is 45/46mm...So how does this bring the RD's cage closer to the cassette?

Maybe someone can push me in the right direction here :-)

Thx :-)

That's what I said :-) It only makes sense for this case. If you setup your bike build for the first time you do not need to change wheels as you can adapt chain length right from the start fitting your setup. I only want to avoid misunderstanding that someone thinks swaping of pulley wheels in general is performance boost :-)