"linear"... interesting choice of words, since I believe Shimano called their brakes "SLR" for "Shimano Linear Response". Makes no sense to me, but who am I to question the marketing guys??

My recollection of Shimano's SLR brakes when they came out is that they made a number of improvements. The ones that I recall are:
1. added ball bearing pivots to the calipers
2. added sliding plastic bits on the caliper springs to reduce friction from the spring sliding against the stop on the caliper arms
3. used teflon lined cable housing (still a relatively new thing)
4. added the springs in the brake levers. The springs helped return the levers to the "closed" position (i.e. the non-activated position). This meant that the brake caliper springs didn't have to provide all of the force needed to return the levers to the closed position, so the caliper springs were made weaker. This reduced the tension on the cable, which reduced the cable friction, which reduced the overall force required to activate the brakes.

I'm still using the Shimano Ultegra single pivot brakes that I bought in 1989, which was the first Shimano SLR brake that I used. They are still a great brake requiring much less effort than my vintage Campy Record sidepulls or Weinmann centerpulls. I've never used dual pivot brakes, so can't make any comparisons to them.

Going back to the Campy sidepulls... I used some advice from others and added a bit of teflon sleeving to the caliper springs of my Campy Record brakes. Like the Shimano SLR single pivots, this reduces the friction that normally occurs when the spring slides against the stop on the caliper arms. I got the sleeving from McMaster-Carr, but some folks use teflon lining scavenged from cable housing.


Steve in Peoria