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Professional Crastinator
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Discussion Starter · #1 ·
I'd like other people to try this out and report back.

I hear it said that you should use "incompressible housing". This goes against that. A LOT.

But this simple mod makes my BB7 mechanical caliper feel like a hydro - and this is the prototype, using a hand-wound spring and a threaded barrel adjuster.

A good spring + a smooth barrel will = "supermodulation"
I gotta get down to the lathe.

Note the relative motion between the caliper and the barrel adjuster supported by the spring. The barrel adjuster simply slides in the hole - it is not threaded in. You need to watch at high quality to see the details.

This is on a 185mm rotor.

NOTES:
- The barrel adjuster should be under an inch long. The threads make the action less smooth.
- The spring is 1/2" long free length, and requires about 4# to displace 3mm.
- When the spring compresses, the barrel should bottom out before the spring is completely squeezed to its solid length; maybe 3mm of movement.
- This modification does increase the lever pull distance by a tiny bit, so minimize any extra play.

If someone packages this and markets it, don't forget where it came from.


-F

PS - already posted in the brake forum
 

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Just buy a cheap set of hydraulic disc brakes from ebay or use the mechanical discs as is..

Your brakes maybe the only thing stopping you from crashing into a tree when you are bombing down a hill. Doesn't seem like a good idea to mess with the brake cable on a mountain bike.
 

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Professional Crastinator
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Discussion Starter · #4 ·
I guess you guys haven't tried something like Hope brakes. You get power, modulation, lever reach adjust, and bite point adjust. Those options are only available on BB7s with SD levers and expensive hydros. Add the modulation of Hope brakes to the BB7 (for a couple dollars) and I think you have something. If you are running 160mm rotors, the modulation is probably OK, but the power is lower than 185's. This mod could be used on 203mm rotors and they wouldn't be "grabby" or "digital" like most people describe them.

And altering the cable stop doesn't seem dangerous to me. One's choice of brake cable housing is just as risky (not very risky at all).

-F
 

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Air Pirate
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2,037 Posts
I don't know about the spring thing (I like the feel of my BB-7's as they are) but I do like the idea of some sort of adjuster for the 7's. I have never understood why SRAM/Avid chose to put an adjuster on the BB-5's and not on the 7's. I know the 7's have the dual pad adjustment dials, but I would like to have those for pad adjust and a caliper mounted adjuster for the cable adjustment.

I know most flat-bar brakes have cable adjusters and those are enough for the cable adjust with 7's, but I am running drop bars with v-brake/mech disc compatible drop levers, which do not come with cable adjusters. I tried adding a Mickey adjuster at the top-tube cable stop for the rear brake, but it didn't work that well and anyway could not be used if I do a planned switch to full-length housing for the rear brake. My current solution was to add some cross/interrupter levers and utilize the cable adjusters on those.
 

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Professional Crastinator
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Discussion Starter · #7 ·
I don't know about the spring thing (I like the feel of my BB-7's as they are) but I do like the idea of some sort of adjuster for the 7's....
Yeah, this is not an adjuster.

If you simply installed a barrel adjuster with lock nut in the cable stop you would have the adjustment you are talking about. All of the cable pull force would be hanging on the lock nut though. For aluminum, that might be too much stress. But if you used a steel barrel and lock nut you'd be OK.

-F
 

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there are no such things as "on - off" brakes. if i squeeze lightly, i stop slowly. if i squeeze hard, i stop quickly. that is called modulation. simply adjusting how hard you squeeze the lever is all the modulation you will ever need....
 
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