Dremel: Sram Red Rear Derailleur ( w/o taking apart?)

Discuss light weight issues concerning road bikes & parts.
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rino
Posts: 13
Joined: Fri Jan 13, 2012 3:15 am

by rino

Borrowing a dremel tomorrow and I want to tear into a brand new sram red rear derailleur to remove the metal on the front plate ("Red" portion) as typically done.

Have you done it? Much risk of hitting the spring while doing it? Can the spring be easily removed and replaced without removing pins? I was figuring on putting something between the spring and metal to be removed, a sort of buffer for when the dremel punches thru.

Not so interested in removing pins.

Please advise me guys...thx

jahknob
Posts: 113
Joined: Tue Sep 07, 2004 1:27 pm
Location: London, UK

by jahknob

Hi,

Be very careful. It is easy to break the spring and you'll have a job finding a replacement. It is possible to remove just one pin from the derailleur and open the whole thing up so that you won't have to take that risk.

A local engineer did it for me, having first tried without opening it up - he accidentally cut through the spring (he thought it was steel and would rebuff the cutting tool, but being Ti, it wasn't what he expected). He wasn't using a dremel.

I think that the ability to control the dremel tool at close quarters may be crucial, as there are quite a few people who have done similar work on their Red RDs without a spring problem. In the end, I sourced a replacement spring and he opened up the RD, installed it and closed it up again...

Good luck with your modifications!

j.

by Weenie


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stella-azzurra
Posts: 5072
Joined: Mon Jan 23, 2006 6:35 am
Location: New York

by stella-azzurra

A dremel with telescoping wand extension would be better but still possible for your hand to move and cut something you don't want.
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

rino
Posts: 13
Joined: Fri Jan 13, 2012 3:15 am

by rino

stella-azzurra wrote:A dremel with telescoping wand extension would be better but still possible for your hand to move and cut something you don't want.


picture of this telescoping wand?

artray
Posts: 1365
Joined: Fri Oct 07, 2011 2:08 pm

by artray

I put mine in a vice and made a hole in the middle and worked out from there. I used a very small bit to allow for any control errors. It is not to hard. If your not confident, you could practise on a bit of scrap first .
Good luck to you Sir :thumbup:

BmanX
Posts: 3844
Joined: Thu Nov 10, 2005 5:31 pm

by BmanX

I would be more interested in seeing what bits everyone is using to do the work with. I have a dremel (every weight weenie should) but I need some better bits to do the work that I would like to do. Something that removes a good amount of material but of course in a controlled manner.
BIG DADDY B FLOW
AERO & LIGHT is RIGHT

Cervelo SLC 5960g/13.13 lbs

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stella-azzurra
Posts: 5072
Joined: Mon Jan 23, 2006 6:35 am
Location: New York

by stella-azzurra

rino wrote:
stella-azzurra wrote:A dremel with telescoping wand extension would be better but still possible for your hand to move and cut something you don't want.


picture of this telescoping wand?


It's actually called a flexible shaft. It will attach to your dremel. With the correct bit it will give you more hand control.

Wear safety glasses!! :)

Image
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

rino
Posts: 13
Joined: Fri Jan 13, 2012 3:15 am

by rino

Stock Red Derailleur 145.0 g
Weight after dremeling & rothshek pulleys 127.8 g

17.2g drop

I did some hacking to the barrell adjuster but i think i'll return it to how it was (mooch one from a dead rd). I'll gain some reversing that. The insert piece was different than i expected and it's not as solid as i want.

Will probably replace some of the bolts with Ti but likely leave the limit screws stock. I'll replace the back stop screw with nylon later...
Attachments
127.8.jpg

fallen86
Posts: 45
Joined: Thu Aug 18, 2011 11:12 am

by fallen86

I made a wedge tool like the one below to pull one of the pins. Makes it way easier to dremel it once one pin is out.

http://lh6.ggpht.com/-8BQd19pBi6c/T3O8Z ... 25255D.jpg

BmanX
Posts: 3844
Joined: Thu Nov 10, 2005 5:31 pm

by BmanX

So what tips are you guys using on your dremels? I have a few tips but need to get some extra tips. I need one that removes a lot of material then some for doing more fine scupting and would like to know what you guys use.
BIG DADDY B FLOW
AERO & LIGHT is RIGHT

Cervelo SLC 5960g/13.13 lbs


by Weenie


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