Cycling UK Forum

I was out cycling with my mid week cycling club buddies recently when a colleague complained his chain kept falling off the lowest gear into the spokes. As he didn't appear to be technically minded I offered to give his rear derailleur low gear limit screw a tweak. Not having ever worked on a Shimano 105 rear derailleur before I was surprised to find the the only tool I needed was a 2mm allen key!! As no one in the group appeared to be carrying such a small key we had to leave the job for later. Does anyone know why on earth the Shimano 105 is so designed when a simple crosshead/phillps screw would have done the job? I suspect that if in fact I was carrying a 2mm key, it would have easily rounded out when I would have tried to loosen the crud encrusted screw.

Screws are so old fashioned!
Allen keys are where it's at!
Next it will be torq fitting!!

cricklewood_graeme wrote: ↑6 Apr 2022, 11:50am … Does anyone know why on earth the Shimano 105 is so designed when a simple crosshead/phillps screw would have done the job? I suspect that if in fact I was carrying a 2mm key, it would have easily rounded out when I would have tried to loosen the crud encrusted screw.

It’s progress, you old fuddy duddy

Get with the programme…

viewtopic.php?p=1677847&hilit=Vessel+JIS#p1677847

Aren't they M4 bolts requiring a 3 mm key?
https://dassets.shimano.com/content/dam ... -4339A.pdf

Thanks

Jonathan

Jdsk wrote: ↑6 Apr 2022, 1:07pmAren't they M4 bolts requiring a 3 mm key?
https://dassets.shimano.com/content/dam ... -4339A.pdf

No, both the Ultegra R8000 and XTR M9000 rear derailleurs I have need a 2mm allen key to adjust the limit screws and B screw.

NickJP wrote: ↑7 Apr 2022, 12:18am

Jdsk wrote: ↑6 Apr 2022, 1:07pmAren't they M4 bolts requiring a 3 mm key?
https://dassets.shimano.com/content/dam ... -4339A.pdf

No, both the Ultegra R8000 and XTR M9000 rear derailleurs I have need a 2mm allen key to adjust the limit screws and B screw.

I'm not an expert on these things and I find the families confusing but are those "105"?

Thanks

Jonathan

Jdsk wrote: ↑7 Apr 2022, 7:55am

NickJP wrote: ↑7 Apr 2022, 12:18am

Jdsk wrote: ↑6 Apr 2022, 1:07pmAren't they M4 bolts requiring a 3 mm key?
https://dassets.shimano.com/content/dam ... -4339A.pdf

No, both the Ultegra R8000 and XTR M9000 rear derailleurs I have need a 2mm allen key to adjust the limit screws and B screw.

I'm not an expert on these things and I find the families confusing but are those "105"?

Thanks

Jonathan

I suspect you know full well they aren’t even as you ask. The mistake you are making is a M4 set screw can come with a 2mm Allen key head.

Paulatic wrote: ↑7 Apr 2022, 8:38am The mistake you are making is a M4 set screw can come with a 2mm Allen key head.

Thanks.

Is that the case on the RD-R7000? (I can't find the version of the instructions that shows the tools.)

Jonathan

Found it... it's the "Dealer's Manual" for
DURA-ACE RD-R9100
ULTEGRA RD-R8000
105 RD-R7000
https://si.shimano.com/pdfs/dm/DM-RARD001-04-ENG.pdf


Jonathan

I have had a couple of Shimano gears where the limit screws seem to be made of Swiss Cheese (and Allen heads) . Replaced with Stainless cross head.

Barrowman wrote: ↑7 Apr 2022, 9:21am I have had a couple of Shimano gears where the limit screws seem to be made of Swiss Cheese (and Allen heads). Replaced with Stainless cross head.

You're not alone, some discussion in the thread linked above:
viewtopic.php?p=1677847&hilit=Vessel+JIS#p1677847

which includes where JIS screwdrivers fit into this.

Jonathan