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SRAM dual pivot brake spring?
 

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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

6/11/17 7:50 PM

SRAM dual pivot brake spring?

My wife returned from a ride complaining that her front brake caliper was rubbing on the rim. When I had a look, it turns out that the spring that pushes the brake caliper arms back apart when the lever is released had broken just where it exits from where it is clamped at the brake bolt. Anyone know where I can obtain a replacement spring - I couldn't find anything available through Googling.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

6/12/17 11:29 AM

Check local shops

They may have a damaged or take-off brake with the spring. Also, download SRAMs parts catalog so you can get the exact part number. Searching for that may work better than a text description. If none of that works, contact SRAM directly. Come to think of it, you may want to try that first, as they may send you a replacement under warranty.

If the shape is similar enough to those of other brands, you may be able to customize one to fit. Re-bending a spring from a hardware store may be possible, as could bending one from scratch using spring steel wire from a hobby shop. Surely a handy guy like you has a wire bender in a drawer someplace. ;-)

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dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

6/12/17 1:37 PM

I think that these springs often give a shorter fatigue life when their chrome finish results in deeper, and more-localized pitting than if a more electrically-passive finish was used.

That said, the very short length of most of the current caliper springs (to save weight) means that a smaller amount of material (steel) is controlling the substantial force/distance "working" of the spring, so unless a very high-grade material and process can be used for a repair part it will be very difficult to make a suitable replacement.

I attempted to make a "softer" replacement for the too-stiff return spring that was on my Campagnolo Gran Turismo touring derailer, and found that a secondary hardening process would be needed to allow sufficient winding-up of the replacement spring without it unfortunately yielding it's tension. I chose instead to use longer shift levers with "retrofriction" or "ratcheting" action, levers I pirated from a stem-shifter assembly and mounted onto a downtube clamp.







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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

6/12/17 3:50 PM

I checked the SRAM spare parts catalogue, and the spring is not shown as a spare part. So I guess I either cannibalise a brake that is otherwise damaged or purchase a replacement caliper.

Edit: I also fired an email off to SRAM Australia, and received a reply asking that I take the brake to my LBS so that it could be returned to them. I'll see what happens...


Last edited by Nick Payne on 6/14/17 4:48 AM; edited 1 time in total

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

6/13/17 5:15 AM

Definitely contact SRAM first

I'll bet they'll help you out.

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