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Avid Speed Dial 7 set up

13K views 5 replies 5 participants last post by  dumper 
#1 ·
I think I have the BB7 calipers adjusted properly. But the levers not so much. I've dialed em both all the way each way and it doesn't make anything feel any different. What am I doing wrong?
 
#2 ·
The speed dial on the SD 7 levers isn't going to change the way the brakes feel when applied. That's not what they do. What the dials do is change (within the adjustment range) the amount of cable the lever pulls. This allows you to fine tune exactly where in the lever pull the pads make contact with the rotor. To see what the dial actually does pull the lever with one finger lightly until the pads make contact, then turn the dial. As you turn the dial clockwise it should move the lever blade further from the bar, counter clockwise should move the lever blade closer. This adjustment in conjunction with the coarser pad adjustment on the caliper allows you to get pad contact at the exact point in the lever pull that you want.

The dial doesn't make the lever feel different in a tactile sense. Regardless of the dial position the lever will still require the same amount of force to move it, etc. It simply fine tunes where in the lever pull the pads make contact with the rotor.

Good Dirt
 
#3 ·
Slight difference of opinion from that of Squash. The speed dial knob alters both the amount of cable pull AND the amount of mechanical advantage exerted on the brake cable...

When the knob is adjusted fully clockwise (i.e. the cable holder is furthest from the pivot), the lever then pulls the most cable and has the least mechanical advantage; this is most similar to typical V-brake levers.

When the knob is adjusted fully counter-clockwise (i.e. the cable holder is closest to the pivot), the lever then pulls the least cable and has the most mechanical advantage; this is most similar to older style cantilever brakes' levers.

By turning the speed dial knob, you can effectively alter the point where the pad contacts the rotor AND how hard the pads will press against the rotor for a given amount of lever pressure. However, I generally use the 2 red knobs on the BB7 caliper to adjust the pad contact point.

In terms of brake feel, when the knob is fully clockwise (least mechanical advantage), the lever should feel firm once the pads contact the rotor; when the knob is fully counter-clockwise (the most mechanical advantage), the lever will feel pretty mushy and vague at the trade off of more power (more on-off feel as opposed to finely modulated power).

If you're not able to feel a difference, I'm guessing that the cables and housing are to blame. Any compression in the housing or stretch in the cable will take away from the effectiveness and directness of mechanical brakes be they disc or V-brake or cantilever brakes. Consider getting a new set of cables/housings and make sure the ends of the housings are cut squarely so they sit flush against the ferrules or housing stops. Hopefully this will make your brake setup the best they can be.
 
#4 ·
Maybe I just can't feel the difference yet. The cables and wires are both new as well. Did a complete brake overhaul when I put the BB7 on. So I'd need the knob fully clockwise to have more "modulation"? That's what I was looking for anyway. As opposed to the normal "on/off" of most mech brakes.
 
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