Oh man. Noticed yesterday that the (L) limit screw on my rear derailleur is threaded and useless.

I think I can probably get it out but does anyone know if it’s possible to get replacements for these?

The rear derailleur is a Shimano Deore XT M772. I’ve found the Shimano technical document here:

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/RD/EV-RD-M772-2707F_v1_m56577569830706603.pdf

I don’t know if my rear derailleur has a long cage or super long cage but I don’t think this matters?

Anyway from looking at the above it seems I need a screw listed as M4 x 18.7 but after a bit of Googling it isn’t obvious if such an item can be readily procured from anywhere.

Does anyone have any ideas?

I’m going to try my LBS (where I bought the bike a few years ago) in case they happen to have some lying around but I’m worried if that doesn’t work I’m going to be um…screwed.

Surely I won’t have to buy a whole new derailleur just because of that sodding screw? I really can’t afford it at the minute 😕

Oh wait, a Google search for ‘Shimano Stroke Adjuster Screw M772’ reveals this:

http://www.sjscycles.co.uk/shimano-rd-m772-stroke-adjuster-screws-and-plate-prod32389/

I think these may be what I’m after if anybody can confirm? Has anyone used SJS Cycles before I wonder?

Thanks in advance if anybody can help..

In the absence of helpful responses, I’ll start with the obvious: you just need a screw that’s the right thread. Longer doesnt matter.

More of interest though, is why the screw is “threaded” – I guess you mean stripped? If the derailleur body is alu and the screw steel, you may have a different issue.

Yeah I think I mean stripped then (?)- basically the cross-hair on the head is mangled and so the driver is unable to rotate the screw.

I’m not sure why this has happened as I generally don’t touch the limit screws because I tend to take the bike into a LBS for a full service once or twice a year. I usually just tweak the tension from the barrel shifter when needed. I have only recently got it back from the LBS so I’ve no idea if/why it ended up stripped and why they haven’t at least mentioned it to me. Gears were indexed fine though. Anyway, I guess that’s another story.

Cheers for the advice- I did suspect that the length of the screw didn’t matter so it’s good to have that confirmed.

Is there any particular way to match a screw with the same thread? If they perfectly ‘mesh’ together (along the shaft) does this indicate they are the same thread or am I talking bollocks?

Patiently avoiding all temptation for innuendo here.

You’ve rounded the socket. It’s not stripped and it’s not threaded.

Any M4 screw will work, your lbs throws old mechs out all the time and will no doubt let you have one.

As science officer says: it sounds like the scre head rather than stripped or threaded. hich is goodnes for you.

No maybe you can tellme hy my PC suddenly refuses to type the letter otherise knon as double u?