Shimano GRX 1x Shifter Issue

After completing the Festive 500 I decided to give the bike a bit of TLC. So yesterday I took the wheels off and gave everything a scrub. When I put the wheels back on, the Shimano GRX ST-RX810-R dual control lever wouldn’t shift back up the cassette to an easier gear. It was getting dark, so it went into the shed till this afternoon, when I could get another look at it.

Same thing today, the shifter does nothing. The small lever to go down to a harder gear goes all the way out, but has no resistance, while the shifter to go up the cassette, to an easier gear, doesn’t budge. I took the bar tape off, removed the the gear cable, but even with that removed, the shifter wont budge. I made sure the cable outers was seated correctly and that the gear cable was in nice and tight, but no amount of forcing would make the lever budge.

Anyone come across anything like this before with a Shimano dual control lever? Any ideas what I need to do to get it working again…?

GUESS:

The gear cable-end has come adrift inside its slot in the lever. Either take off the hood and have a look or put some traction on the cable while fiddling the levers and see if that pulls it back in

??

Did both of those things, didn’t make any difference. It feels like the lever is being stopped from moving by an obstruction in the mechanism.

I seem to remember on some shifters that some part of the mechanism swings out with the lever and can foul on either the rubber hood or even bar tape if you’ve really gone for tight wrapping round below the lever. Maybe have a grope round below the levers & see ?

After that I’ve got nuthin

I know from changing the cable on 105 levers than even the tiniest bit of frayed wire that’s fallen into the mechanism can stop it working properly. I ended up having to remove the panel under the lever to get everything clear.

As above with the 105 cable. Mine was fine, suddenly went iffy then snapped 10 mins later approx 10mm from the end of the cable. Worth taking the cable out just in case yours is about to do the same (also a massive ball ache trying to remove a tiny bit of cable like that!)

I’ve taken it to the LBS, so should find out in a couple of days if it’s fixed or 🤬. Bit pissed off, as it meant I could get out for another 100 miler before starting back at work next week. I shall drown my sorrows in beer…

So no idea what was “wrong” with my dual control lever, as chap in the shop got it working after replacing the inner gear cable. He did say that they’ve had issues with the Shimano cables with that fancy coating on it before, still doesn’t explain why it just stopped working after a wheel change though. Doesn’t fill me with confidence for the future…

The wheel change will have had nothing to do with it bar moving the mech before and after. If changing the cable fixed it then that likely where the fault was (as suggested a few times above). Worth being able to do that yourself as you wouldn’t have missed any riding (and you could end up needing to do it yourself when you’re also into bike packing!)

@mashr the lever wouldn’t move with the cable in, or out, as I had the cable out as one of the first things I did. Also, I built the bike from components, so it’s not like I don’t have any idea where the clue tree is. Given how much they charged, they had to do more fiddling than just fitting a new cable.

@k1100t I have the same issue you described – lever just won’t budge. It feels locked solid. Cable end seems to be located properly within shifter. Moving the lever (or trying to) does not add tension to the derailleur cable. Seems to indicate an issue within the shifter itself. I wish the LBS had told you what the issue was!

It turns out that the cable had in fact somehow come out of the puller within the lever. Because it had popped back it looked like it was seated properly. No idea how this happened – cable seems to glide nicely…