LTWOO RX hydro sets

[jcr]

I have the GRT also. It seems to index okay on stand and work okay for a ride but then just becomes a bit crap. Exactly same with sensah stuff in the past. Id install an inline barrell adjuster so you can make slight tweaks on the road.

Do you find the quality of the cable to be on the low end? I find that high end cables doesn't seem to stretch as much.... my Sensah seems to "stretch" and the inline helps

[00Garza]

Do you find the quality of the cable to be on the low end? I find that high end cables doesn't seem to stretch as much.... my Sensah seems to "stretch" and the inline helps

I’ve been wondering this as well. I get the mech dialed in and a few rides later its off. Not terribly, but noticeably. Contemplating upgrading to some jag wire cable. Surely a better cable will help with shifting.

[jonathanf2]

I have the GRT also. It seems to index okay on stand and work okay for a ride but then just becomes a bit crap. Exactly same with sensah stuff in the past. Id install an inline barrell adjuster so you can make slight tweaks on the road.

If you're doing gravel with the GRT, the same happens with my GRX 812 RD as well. I think just riding on the rough stuff shakes up the RD a bit. Not terribly misaligned, but I do have to check it after a ride.

[jcr]

I’ve been wondering this as well. I get the mech dialed in and a few rides later its off. Not terribly, but noticeably. Contemplating upgrading to some jag wire cable. Surely a better cable will help with shifting.

Yes, every few rides there is a slight noticeable change, still useable but just very slight adjustment. I will be swapping for better cables at the end of the year. 

[abedfo]

Do you find the quality of the cable to be on the low end? I find that high end cables doesn't seem to stretch as much.... my Sensah seems to "stretch" and the inline helps

I am using the cables that come with it. So maybe a good shimano or jagwire set would help ! I'll get in the stand and have another faff with it.

[frnchy]

I just received my GRT 12 speed groupset (aluminum version) and wanted to share some stuff I noticed that I haven't seen on this thread or other posts/videos before.

• The derailleur pulleys are different sizes: 12 teeth on the guide pulley and 14 teeth on the tension pulley. They also run on sealed bearings and spin freely which is nice - one thing that really irks me about 105 is that Shimano uses pulleys with only bushings and they always seem to gum up.
• The thumb shifter is matte plastic rather than glossy, and it doesn't have any branding on it. I like this - it's grippier than a glossy coating.
• Both right and left brifters have retention clips for the hydraulic lines that prevent them from swiveling outwards. The clips are retained by two 2 mm screws in the rear of the body; when they're unscrewed the clip can be popped out and the lines can swivel outwards for easier installation if the hydraulic lines foul on the bars. But if the lines don't foul, I'd actually keep the clips in because they retain the nut so you only need one wrench to install the hydraulic line instead of two. This seems to be different than previous versions, or maybe just the carbon version? See Trace Velo's video here: https://youtu.be/NKNcKwiH6v0?t=928 where the nut seems to be held captive by the shape of the brifter's body rather than a separate retention system.
  
  
  
  
• The shift lever has a 1.5 mm grub screw at its base which adjusts the shift paddle position independent of the brake lever. There's a ridiculous range of adjustment, way more than would ever be realistically used, but hey it's there anyway.
  
  
  
  
• I screwed in the free stroke grub screw to see if I could replicate the rattling issue, and I wasn't able to, but maybe this will be an issue when the brakes are all set up.

I'm putting this groupset on my new commuter bike build which should be done in a few days (I still need to build the wheels...) - I'll see how it functions, if there's any break-in, etc, but my first impressions out of the box are good.

[00Garza]

Yeah, definitely looks updated from my GR9 set.

I thought the rattling was from the washer in the piston. I hear it in mine on the bumpy sections I ride. 

[tsneidin]

I’ve been wondering this as well. I get the mech dialed in and a few rides later its off. Not terribly, but noticeably. Contemplating upgrading to some jag wire cable. Surely a better cable will help with shifting.

I just installed the GRT and had poor shifting, hard shifting and inconsistent indexing. I have the carbon version of the GRT 1x12 and initially there was so much resistance when shifting the rear that I thought the shifter would break. I found the problem, the hardened steel cable guide that the cable travels thru on the rear derailleur is not beveled/radius-ed like they are on my Shimano derailleurs. As delivered the cable has to ride over a hardened steel 90 degree sharp edge. I took my dremel tool with a diamond bit and added a radius and now my shifting is more consistent and easier. I no longer feel like the shift paddle is going to break. I really can't believe that this is designed so poorly. The picture below shows the problem area after I gound down the sharp edge, I didn't grab a before picture.

[jonathanf2]

I just installed the GRT and had poor shifting, hard shifting and inconsistent indexing. I have the carbon version of the GRT 1x12 and initially there was so much resistance when shifting the rear that I thought the shifter would break. I found the problem, the hardened steel cable guide that the cable travels thru on the rear derailleur is not beveled/radius-ed like they are on my Shimano derailleurs. As delivered the cable has to ride over a hardened steel 90 degree sharp edge. I took my dremel tool with a diamond bit and added a radius and now my shifting is more consistent and easier. I no longer feel like the shift paddle is going to break. I really can't believe that this is designed so poorly. The picture below shows the problem area after I gound down the sharp edge, I didn't grab a before picture.

You'll get the same issues on some Shimano rear derailleurs. My trick is to use a short piece of plastic guide tube in that section of the derailleur. The cable tension keeps the plastic in place. My GRX 812 RD came with a guide tube pre-installed, while my 105 R7000 RD didn't come with it. I believe RISK also sells cable end caps with the plastic pre-installed as well.

[TidyDinosaur]

Like these?
https://a.aliexpress.com/_mrP8OQm

[00Garza]

Helpful info. I'll check out my derailleur later to see what mine looks like.

[coffeebreak]

R7000 105 RD is particularly prone to this problem, ride it long enough and cable will cut thru the material and eventually fail. The routing is truly bad on that one.

[jonathanf2]

Like these?
https://a.aliexpress.com/_mrP8OQm

That or 1-2 cm of plastic guide tube does the trick.

[dsveddy]

I've done a teardown of my broken LTWOO brifter to see what's inside. I have the part-1 video up right now on youtube. Interesting finds include that the hydraulic reservoir is a modular part that pops right out.

(What's inside a L-TWOO hydraulic lever? Teardown & anatomy of a failure)


I'm currently putting together a video demoing the rebuild and analyzing/explaining the shift mechanism (hopefully dropping this week), but the short of it is that the shift mechanism is pretty much identical in design to Campy Ultrashift (diagram attached). This is a bad thing IMO. Fundamentally, this is a friction shifter. To hold the cable in place, it uses a friction plate with indexing indents pushed up against the de-tensioning ratchet by a couple of spring washers. You adjust the friction with the screw in the back of the shifter. Shifting feels tough because you have to overcome the friction plate in addition to everything else. I also think it's not suitable for off-road use, where a bump can increase the tension on the cable and spontaneously advance the index, causing a mis-shift

[jonathanf2]

I've done a teardown of my broken LTWOO brifter to see what's inside. I have the part-1 video up right now on youtube. Interesting finds include that the hydraulic reservoir is a modular part that pops right out.

(What's inside a L-TWOO hydraulic lever? Teardown & anatomy of a failure)


I'm currently putting together a video demoing the rebuild and analyzing/explaining the shift mechanism (hopefully dropping this week), but the short of it is that the shift mechanism is pretty much identical in design to Campy Ultrashift (diagram attached). This is a bad thing IMO. Fundamentally, this is a friction shifter. To hold the cable in place, it uses a friction plate with indexing indents pushed up against the de-tensioning ratchet by a couple of spring washers. You adjust the friction with the screw in the back of the shifter. Shifting feels tough because you have to overcome the friction plate in addition to everything else. I also think it's not suitable for off-road use, where a bump can increase the tension on the cable and spontaneously advance the index, causing a mis-shift

Yikes, makes me not want to try their ERX groupset. The LTwoo all-mechanical shifters seem to have better design logic and the ability to replace the hoods, though at the expense of not being able to shift in the drops. Honestly I think Sensah has the better shifters of the two Chinese groupset companies, though it seems they're having trouble getting their hydraulic shifters out to market.