[CR]A little more about springs

(Example: Production Builders:LeJeune)

In-Reply-To: <MONKEYFOODaKELXGR0F00001502@monkeyfood.nt.phred.org>
From: "Dennis Young" <mail@woodworkingboy.com>
Date: Sat, 18 Feb 2006 10:37:33 +0900
To: classicrendezvous@bikelist.org
Subject: [CR]A little more about springs

Our bikes continue to age along with us. Bending springs arms is also a method used for trigger tension adjustment on guns, but currently new silicon alloy spring technology yields springs with easier compression, yet stronger force in the closed position. Competition high powered rifles utilize this to allow for a more sensitive trigger, but the gasses are allowed to dissipate more productively before breech exiting, thus more accuracy with a heavy bullet. Indy car valve springs also utilize this material. They claim no spring performance deterioration within the hostile high temp. environment over repeated use. The consequence for bikes would be lighter pull yet stronger braking, even on the planet Mercury.

Dennis Young Hotaka, Japan

> << I finally bent each side of the springs inward several mm using
> some twisting action with a pair of pliers, off the bike. I measured
> and reduced the static pre-load by about half.
> I was really surprised how much the power improved, especially from
> the hoods! It used to take much of my strength just getting the
> pads to
> the rim, but now a good pull (more like a twist) from the tops
> translates into stoppage and it's plenty of response for paceline
> work.
> I agree! Here's what I just wrote to Kyle Brooks (I should have hit
> "reply to all")
> "While the actual spring rate. i.e., strength of the "springiness",
> cannot be changed easily, the spring itself can be bent so as to exert
> less (or more) pressure on the brakes arms.
> This is not done with a punch or screwdriver (!) at the pivot (that is
> an old and sloppy way to center the brakes in the forks)
> There was a tool specifically for this which was a tube which slipped
> over the spring end, allowing additional leverage to bend the spring.
> The principle at work here is to bend the spring ends inward (toward
> each other) to reduce the pressure on arms.
> This is best accomplished by leaving the spring center in the channel
> in the brake pivot, but unclipping the ends from the grooved stubs on
> the back of the caliper arms. Once both sides are free, hold the
> calipers and grab to spring ends with needle nose pliers (or slide on
> that tube tool) and bend the spring inwartd toward the center of the
> fork.
> How much depends upon the effect you want, but it is prudent to go
> just
> a little at a time to prevent overdoing it... Reassemble the spring
> ends in thir respective arms and try the brake action by squeezing the
> brake lever to see if the effect is lighter."