Pedersen SE setup help?

Nate Knutson said:

I need to get a pair (front and rear) of Pedersen self-energizing
brakes set up correctly. I basically understand how they work, but
there's a few issues with their setup that I neeor d clarification on:

For the front brake, tightening the brake mounting bolt causes the
topcap it's sitting on top of to bottom out against the tip of the
cantilever stud, somewhat like a regular basic canti where the bolt
itself contacts the tip of the stud. I would guess that overtightening
the mounting bolt carries as much risk as usual of mushrooming the tip
of the cantilever stud. However, tightening the mounting bolt is also
the way that the brake's centering/spring tension adjustment is held in
place, like on cantis with integral pivots. Between the topcap and the
brake arm body, there's a spring that gets compressed when you tighten
the mounting bolt. The spring is the return spring for the brake arm,
but is it also there to add friction between the bolt threads and the
stud threads, or between the topcap and the bolt shoulder, or
something? Basically, how tight do you make the mounting bolt?

What parts of these brakes want lube? (Steep helical plastic threads
don't come up a lot in bikes).

Finally, I'm guessing that the spring tension can be set for individual
preference, but is there a correct range to start it at in order for
best feel and to avoid the brakes from failing due to not being able to
move inwards far enough, as I've realized is possible with these if set
up incorrectly?

Firstly, I've used them and I don't feel they have any advantage (and
many disadvantages) over a standard canti brake.

Leaving that aside, the top mounting bolt has to be tight enough, but
not too tight ;-) I did mushroom one of mine, at which point I threw
the whole lot away and bought Tektro Oryx, which use V-brake pads
instead of the annoying plain-post type.

Jobst will tell you they're probably unsafe because of the non-linear
response; in my experience the standard pad compound is so weak that
this compensates for any potential lock-up from the SE effect.

Zog The Undeniable said:

Nate Knutson said:

I need to get a pair (front and rear) of Pedersen self-energizing
brakes set up correctly. I basically understand how they work, but
there's a few issues with their setup that I neeor d clarification on:

For the front brake, tightening the brake mounting bolt causes the
topcap it's sitting on top of to bottom out against the tip of the
cantilever stud, somewhat like a regular basic canti where the bolt
itself contacts the tip of the stud. I would guess that overtightening
the mounting bolt carries as much risk as usual of mushrooming the tip
of the cantilever stud. However, tightening the mounting bolt is also
the way that the brake's centering/spring tension adjustment is held in
place, like on cantis with integral pivots. Between the topcap and the
brake arm body, there's a spring that gets compressed when you tighten
the mounting bolt. The spring is the return spring for the brake arm,
but is it also there to add friction between the bolt threads and the
stud threads, or between the topcap and the bolt shoulder, or
something? Basically, how tight do you make the mounting bolt?

What parts of these brakes want lube? (Steep helical plastic threads
don't come up a lot in bikes).

Finally, I'm guessing that the spring tension can be set for individual
preference, but is there a correct range to start it at in order for
best feel and to avoid the brakes from failing due to not being able to
move inwards far enough, as I've realized is possible with these if set
up incorrectly?

Firstly, I've used them and I don't feel they have any advantage (and
many disadvantages) over a standard canti brake.

Leaving that aside, the top mounting bolt has to be tight enough, but
not too tight ;-) I did mushroom one of mine, at which point I threw
the whole lot away and bought Tektro Oryx, which use V-brake pads
instead of the annoying plain-post type.

Jobst will tell you they're probably unsafe because of the non-linear
response; in my experience the standard pad compound is so weak that
this compensates for any potential lock-up from the SE effect.

Yeah, I know they're probably pretty bad overall (though not convinced
the design or at least the idea is 100% bad), but they're on a
customer's bike and they're not getting replaced, and I've been totally
unable to find an answer to these setup questions that I'm comfortable
sending out the door.