On my Nightrider frame I did a bit of measuring and found that my BB5 sticks too far into the spokes in order to work with a 180mm rotor. From my best guess I would say that a 210mm rotor would be needed to give the right clearance to the driver side of the BB5.
So, does anyone know of a caliper that has a lower profile on the piston side than a BB5?
For reference the BB5 is about 42mm’s from the center of the caliper slot to the outside of the piston driver, and about 32mm’s from the center of the post mount holes to the outside of the piston driver.
If I could find something with about 5mm’s less it would give the spokes a bit of breathing room.
with the size of the BB5, I think you may also have to worry about hitting the crank too. I like the idea of a mech brake so you can run a shift lever drag brake. This is a great question. Hmmm… and running them on the right side means that the lever is in toward the spokes.
It looks like there is plenty of clearance on the crank arm side, but not on the wheel side.
Once I get a system up and running I want to have a shift lever for drag, and an inline cyclocross type lever for intermittent braking. That way I will be able to get the best of both world so to speak. I also like the simplicity of a cable system.
My plan is to have the cable housing stop at the fork crown, and to send the bare cable down to the caliper from there. This would fore go the barrel adjuster on the caliper. It would make a clean line with less housing to add friction to the system. If it ends up working I may just cut the barrel adjuster arm off of the caliper altogether to make it cleaner and lighter.
42mm od bearings are common to ISIS, and 40od bearings are common to square taper. How do we get square taper to be as predictable at crank spacing as ISIS, convert the bearings to accept the ISIS and maintain the 40mm od!
BB5/BB7 Forget it, but that’s not the end of the story
So, after working with the bb5 for a while trying to figure out how to get it to work with a rotor smaller than 200-210, I gave up. This caliper won’t work.
A friend gave me an old mechanical caliper with no name that was a little narrower, but not enough. The upside is that when I took the dust cap off on the driver side there was about 3mm’s of material there that was serving only to hold the dust cap on. So, I took out my grinder, and now I’ve got room to spare. I went ahead and sawed the barrel adjuster arm off of the caliper as well. I think I’ll be able to run the bare cable inside the frame up to a barrel adjuster mounted to one of my maggy bosses. It should make for a very clean cable routing.
Unfortunately I have no idea what kind of brake this is. It has pads that look like Hayes, but I couldn’t find a Hayes mechanical caliper that uses these pads. I’m sure there are other calipers that either work, or could be made to work. If anyone has any idea what this one is let me know.
Sorry for the lousy webcam picture, but hopefully it’s enough to make an ID.
I think that one is made in China. We’re looking to another fabricator to get us a quote. We did finally hear back from the initial guy, but since we started looking at other places, we should get those quotes as well. It won’t be long before we see production, and Hopefully not too long we’ll see Jtrops slick set up. I am excited to see a shift lever drag brake!
Well we’re going to make them for 42mm bearing isis because the spacing with crank spacers is consistent, and we haven’t tested a bolt on with square taper yet. We will be prioritizing KH because you can’t just weld on a mount, and weld on mounts will be available for nimbus and nightrider. but if the demand is there at the price point for the quantities we can afford, we’ll make them for Nimbus Isis and then start experimenting with square taper. We need them to be consistent, work well, and sell well before we can afford to experiment. However if you can get bearings that allow you to use ISIS in a 40mm frame, then you get 2 upgrades!
I’m running square taper with 40mm bearings and shims on a Nightrider frame with 42mm bearing holders. I understand that ISIS makes the spacing more predictable, and that there are a lot of ISIS uni’s out there right now. Those two factors make your decision to support ISIS first very reasonable.
I went with square taper for my uni because I honestly believe that splined cranks are super overkill for a road going machine. I like the fact that there are many cranks available for square taper, many cheap or free. So, at least for me, moving to ISIS wouldn’t be an upgrade. I will probably go for a weld on mount after all.
As for the mount, I think if you weld it on with the intention of putting two or three washers between the adapter and the mount that would be the place to adjust for the inward creep of the square taper cranks. As long as you move the washers from the inside to the outside of the welded mount you wouldn’t need shorter bolts as you adjusted for the creep. This might also have the benefit of placing the bracket a bit more centered on the tube rather than outboard towards the rotor.
Exactly, and agreed. The rotor is also spaced on the crank for creep, you can pull spacers from in between rotor and crank and shift them to the outside of the crank as it creeps in. So, you can space both the caliper and the rotor! the issue is that sometimes the cranks go on so deeply, that the chain ring nuts scrub the frame, and spacing the rotor can pull the chain ring nuts away from the frame. the cranks that were meant for 113, and 107mm chain lines keep the spider further away from the frame than those for 117mm bb’s for instance, and the crank can be spaced further with a crank spacer, and that modified square taper design the cranks went on further as well. square taper is cool and really won’t creep too much even with wear. the Schlumpf ISIS without crank spacers is the difficult hub with creep.
Could you rhyme off the available lengths again? Are you only offering the production sizes - 160-180mm? Nothing in there is useful to me, although neither is their previous shortest, 135mm. I guess I’ll be drilling either way so I might buy from you, depending on how that affects shipping cost.
I know you don’t plan on offering dual-hole right away, but if you were, that’s where I’d be at.
Hmmmmmm that’s right. I probably won’t get cranks from you if I can’t get 150’s. I found a source for other sizes of Sinz cranks at $50 a pop. If I can’t get 150’s from you, I will probably get them there.
This is CrazyChrisVT back again under a different name. Hey, I’ve been following this disc thread with keen interest. I haven’t been uni’ing very much, but have been biking alot, sorry to say. That includes insane downhill biking.
Anyway I can provide caliper measurements… I have here right now, and I’ll list just the brake/rotor combinations. Let me know if you want some measurements.
I’ll cut to the chase and say right now the Hayes So1e offers the “skinniest” caliper, of what I have.
Avid BB5 (mech) - 185 rotors.
Avid Juicy 5 (hydros) - 203mm rotors (on a hoggish Norco Shore Two!).
Hayes So1e (hydros) - 185mm rotors (a TERRIBLE brake but prolly more than enough for Uni).
Avid BB7 (mech) - 203mm rotors.
And I’ll chime in on the mech vs hydro debate. Both are very powerful. Mechs tend to be more “grabby” than hydros. Hydros tend to have better modulation (ie, when I go down Sugarbush on the Norco, I ride the brake the entire way and the Juicy 5’s are lovin’ it.)
The Hayes So1e brakes are probably more than enough for Uni, but they did fail at Sugarbush, sending my son on a nasty brakeless ride for a bit.
Also BB5s need to be adjusted all the time, but then again on a Uni they probably wouldn’t need very much attention.
I can provide measurements and photos if anybody is interested.
