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PostPosted: Thu Mar 01, 2012 9:11 am 
King of the DuckBoard
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Suntour Self Energising Rear Brake

Pederson Design did they really self energize? How?


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PostPosted: Thu Mar 01, 2012 10:24 am 
Gold Trader / MacRetro rider
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they had a cam in them that moved the brake arm toward the rim in an
"in and forward " type motion so the pad rubbing the rim pulled it in tighter

same effect can be simulated by fitting 10mm bore canti's to an 8mm brake post ,wont have the modulation but feels similar

these were not recomended for the front as they could be a bit severe


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PostPosted: Fri Mar 02, 2012 10:51 am 
Old School Grand Master
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Imagine granny getting her tit caught in the mangle.
It's the same principle.


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PostPosted: Fri Mar 02, 2012 11:02 am 
King of the DuckBoard
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suburbanreuben wrote:
Imagine granny getting her tit caught in the mangle.
It's the same principle.



Not an image i needed :lol: :lol:


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PostPosted: Thu Mar 08, 2012 9:59 pm 
Dirt Disciple

Joined: Tue Jan 06, 2009 9:44 pm
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Location: bristol
The simplest explanation, if you consider the left rear brake, is this :

Imagine the existing brake pivot is replaced by a very coarse bolt with a standard right hand thread.

The LH brake arm no longer has a smooth bearing surface to fit on a standard brake pivot. Instead it has a matching very coarse internal thread.
In effect the brake arm has become a 'nut' that is screwed onto the
threaded brake pivot.

In operation, as the brake arm moves toward the rim, it also moves forward
in the same direction as the rim. The effect of the brake pad rubbing on the
rim also encourages the brake arm to move even further towards the rim.

This is known as a 'self servo' effect, and has to be very carefully designed
to avoid grabbing. The pitch of the 'thread' is one of the critical factors,
along with selection of appropriate brake pad materials.

There is an internal spring,as with conventional cantilevers, returning the
brake arm to its resting position. The pitch of the ' thread' is so coarse that
the brake arm moves forward more than it moves in.

Pedersen offered the design in both front and rear versions to Suntour,
who manufactured the rear version only under license. The front version
was considered too dangerous, as any distortion/buckling of the rim
could bring the brake pad accidentally into contact with the rim, actuating the self servo effect with potentially damaging results.

If you do choose to run the front version, use generous clearances between
brake pad and rim.


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PostPosted: Fri Mar 09, 2012 11:26 am 
Devout Dirtbag
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I had a full set of Scott SE brakes...
The biggest problem was the threads were made of composite and failed pretty easily. That and the inital set up being a PITA...

Had no problems with the front being grabby or severe.

Went back to Ritchey logic canti's and Winwood polymer blocks in the interests of reliability...


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PostPosted: Fri Mar 09, 2012 2:58 pm 
Dirt Disciple

Joined: Sun Sep 11, 2011 7:24 am
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Quote = 'So how did Pederson Self Energizing brake work?'



Answer = They Didn't


Lol


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PostPosted: Fri Mar 09, 2012 3:05 pm 
Special Retro Guru
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Easton22 wrote:
Quote = 'So how did Pederson Self Energizing brake work?'



Answer = They Didn't


Lol

Snappy comeback.

Presumably you have loads of experience of using them, then?


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PostPosted: Fri Mar 09, 2012 3:51 pm 
Old School Grand Master
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Neil wrote:
Easton22 wrote:
Quote = 'So how did Pederson Self Energizing brake work?'



Answer = They Didn't


Lol

Snappy comeback.

Presumably you have loads of experience of using them, then?


Doesn't need to - the fact that we do not see any of these type of brakes on mountain bikes confirms the above.


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PostPosted: Fri Mar 09, 2012 3:53 pm 
Special Retro Guru
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02gf74 wrote:
Neil wrote:
Easton22 wrote:
Quote = 'So how did Pederson Self Energizing brake work?'



Answer = They Didn't


Lol

Snappy comeback.

Presumably you have loads of experience of using them, then?

Doesn't need to - the fact that we do not see any of these type of brakes on mountain bikes confirms the above.

Eh?

I've seen several on here.

And I've got a few sets (rear only) myself.


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