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Lost my limit screw! Shimano R8000 front mech - where to find?

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Lost my limit screw! Shimano R8000 front mech - where to find?

Old 05-27-19, 03:33 PM
  #1  
johngwheeler
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Lost my limit screw! Shimano R8000 front mech - where to find?

I was adjusting one of the limit screw on my front derailleur (Ultegra R8000), and obviously slackened it too much, because it has fallen out.

Does anyone know:

a) Whether I can buy these as spare parts from Shimano? or
b) What the screw size & thread is so I find a 3rd party replacement?

I think the derailleur is already pretty close to the chain (which is why I turned the screw out so far), so it doesn't fall off in normal use, although shifting has become less precise.

Thanks!

John
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Old 05-27-19, 04:14 PM
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sch
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Well there is this: https://si.shimano.com/pdfs/ev/EV-FD-R8000-4282B.pdf Doesn't give sizes but the allen head is 2mm and it looks
like a standard set screw, not a special, perhaps 6-8mm long.

Then this on p12 indicates the allen size: https://si.shimano.com/pdfs/dm/DM-RAFD001-04-ENG.pdf

And here: https://www.engineersedge.com/iso_set_screw.htm shows set screws M4 have allen heads 2mm in size. So look for
a M4 set screws in that length and see if they work. stainless if available and use threadlock.

Last edited by sch; 05-27-19 at 04:23 PM.
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Old 05-27-19, 04:51 PM
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If you were closer, i'd just give you one..... but bloody hell you are almost half a world away
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Old 05-27-19, 07:19 PM
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You might consider using longer, M4 hex socket screws instead of setscrews, if there is room. 2mm hex keys are pretty small and the socket head takes a larger, more rugged 3mm key.
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Old 05-27-19, 07:31 PM
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johngwheeler
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Thanks for the replies. Rather maddeningly, none of the Shimano tech docs / exploded diagrams give the actual size. On some older groupsets, I've read that the rear limit screws were M4 and the front ones M3. I haven't removed the remaining screw yet to measure it, but it looks more like M3 than M4 to my eye. The screw head requires a 2mm Allen key.

Hopefully is a standard metric thread and not something weird.

I'll also get some "breakable" thread-lock liquid to prevent re-occurrence. TBH, I think my derailleur position may be a bit off, because I could only just avoid chain rub, even with the limit screw almost all the way out (now "completely the way out" :-) ). But it was a bit of a chore getting the derailleur position and cable tension right - most likely my lack of experience in doing this task!
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Old 05-27-19, 07:33 PM
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Originally Posted by JoeTBM View Post
If you were closer, i'd just give you one..... but bloody hell you are almost half a world away
Thanks :-) I fear the postage costs would exceed the cost of the screw several-fold.
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Old 05-27-19, 07:53 PM
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Just check with your local bike shop. Their used junk bin probably has one they will give you for free.
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Old 05-28-19, 07:30 AM
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Virtually all derailleur limit bolts I have encountered are 3mm x 0.5mm thread. If your LBS has a derelict derailleur box, you could salvage a suitable replacement from that.

Last edited by JohnDThompson; 05-28-19 at 04:20 PM.
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Old 05-29-19, 09:26 AM
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There was a thread recently about a stripped FD limit screw in the body of the Di2 FD, and it was M4.
M3 does seem more likely but the specified use of 2mm allen wrench makes M3 unlikely, not impossible
but unlikely. Also the close placement of the limit screws in the R7000 mitigates against using a screw
with a head so a SHCS is not a good idea and a phillips head only marginally better. If hardware stores in
Canada are like better ones in US they may have set screws in M3 and M4 for cheap but only a limited
selection of lengths. That is where I would start. Another (poor) option would be, once the thread size is ascertained
and if set screws are not easily found would be to get a long enough screw, cut the head off and slot the end
with a dremel for a blade screwdriver. This would require at least an 8.8 or better 12.9 rated metallurgy in the
screw.

Last edited by sch; 05-29-19 at 09:34 AM.
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Old 05-29-19, 02:41 PM
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Regarding part "a" of the original poster's question: From the EV diagram posted earlier, the Shimano part number is either Y5ZS98030 or Y5ZS98070. Just plug those numbers into Google and off you go.

The former (Adjust Bolts and Plate, A-type) are listed from one or two vendors on eBay and Amazon for <$10. Google doesn't turn up much for the B-type (second part #), so hopefully that's not the one you need. Anyone know what the difference is?

https://www.ebay.com/itm/Genuine-Shimano-FD-R9100-Front-Derailleur-Stroke-Adjusting-Screws-Bolts-Plate/222608184246

The downside is that a lot of these sellers ship from Japan, Taiwan, etc, so it could take weeks to reach you, depending on location.

Last edited by Metaluna; 05-29-19 at 02:44 PM.
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Old 05-29-19, 07:31 PM
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I just took the limit screws out a of older Shimano FDs and RDs. Both FD and RD screws were common M4x0.7 mm threads, the FD bolt was 10 mm long and the RD bolt 15 mm long although longer bolts would work for either. These had a cross/slot style heads but an Allen head would probably be an improvement.
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Old 05-30-19, 12:34 PM
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Just to add another wrinkle, standard socket head cap screws that fit a 2mm hex tool are listed in severalreference as M2.5 (x0.45mm pitch). Given that the R8000 may be a newer version and may have a slightly smaller screw, this may be a candidate.
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Old 05-22-21, 10:21 PM
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Originally Posted by johngwheeler View Post
I was adjusting one of the limit screw on my front derailleur (Ultegra R8000), and obviously slackened it too much, because it has fallen out.

Does anyone know:

a) Whether I can buy these as spare parts from Shimano? or
b) What the screw size & thread is so I find a 3rd party replacement?

I think the derailleur is already pretty close to the chain (which is why I turned the screw out so far), so it doesn't fall off in normal use, although shifting has become less precise.

Thanks!

John
Did you find the correct bolt size? Iím in the same problem as you were! Iím trying to find it, in AliExpress I saw several bolts but I donít have the correct size. Help! Thanks
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Old 08-02-21, 04:36 PM
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For the benefit of those seeking this information in the future the set screw is M4x.70mm by 8.5mm long. A 10mm long M4x.70mm stainless set screw from my local hardware store worked just fine.
Brent
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