Alan:
I do not doubt for one moment of your unhappy experience with a TLS brake. I have read several of your posts telling of difficulties controlling the braking effect of the TLS. With each reading, I have reflected on my personal experience with my TLS. I think it time to say something.
My TLS is well behaved, giving me braking power proportional to applied lever effort. There were two or three times I had adrenaline pumping situations where I grabbed all the brake I could ... I had no brake shoe grab, lockup, or self augmenting action during those panic stops. Moreover, I do not believe a disc would stop me any shorter from any legal highway speed (one time stop).
So why the difference between your experience and mine?
Possibly:
1) design difference between one brake plate and another, especially in the cam profile. IMO, this is not likely to be much of a factor.
2) there exists a critical coefficient of friction between brake shoe material and drum lining material that creates the self augmenting feedback that leads to grabbing and un-controllability. IMO, too "sticky" a brake shoe material could account for this effect.
My "gut" recommendation to anyone having grabbing with a TLS is to try a "harder" shoe material.
FWIW, my TLS is pictured below. I think it is a Dunstall. I installed it in the late 60's .... my memory does not stretch that far back to be sure what it is.
[ATTACH=full]5673[/ATTACH]
Slick
