Shimano RD-M550: Unknown adjustment screw ?

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Laowai_1
Posts: 21
Joined: 29 May 2018, 11:46am

Shimano RD-M550: Unknown adjustment screw ?

Postby Laowai_1 » 1 Jun 2018, 9:14pm

In my continuing efforts to better understand the bits on my bike (and why they really haven't worn out after 28+ years....) could you please look at the attached photo and tell me what is the purpose of the relatively large round-headed screw with a small index mark, which is normally hidden beneath the cable clamp bolt of my rear derailleur ?
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Shimano RD-M550 unknown adjustment screw

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gaz
Posts: 13777
Joined: 9 Mar 2007, 12:09pm
Location: Kent, car park of England

Re: Shimano RD-M550: Unknown adjustment screw ?

Postby gaz » 1 Jun 2018, 9:36pm


Laowai_1
Posts: 21
Joined: 29 May 2018, 11:46am

Re: Shimano RD-M550: Unknown adjustment screw ?

Postby Laowai_1 » 1 Jun 2018, 9:52pm

Got it, thanks.

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NATURAL ANKLING
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Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Shimano RD-M550: Unknown adjustment screw ?

Postby NATURAL ANKLING » 1 Jun 2018, 10:57pm

Hi,
Spring tension adjuster..................know cose I got one............... :)
If You Don't Try You Don't Do.....Don't Do You Don't Get...I'm Still Trying....Well Very..
You'll Find Me At The Top Of A Hill...............Somewhere...After Dark..

Brucey
Posts: 36104
Joined: 4 Jan 2012, 6:25pm

Re: Shimano RD-M550: Unknown adjustment screw ?

Postby Brucey » 1 Jun 2018, 11:41pm

I quite liked that as a scheme; if you ran with the low setting and the shifting went bad because the cables were starting to drag, you could have a 'get out of jail free' by moving to the other setting until you fixed the cables.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~