[QUOTE=rob.northcott;1337067]
Q should always be the distance between the pedals, but as the length of the axle is pretty constant on unicycles the main thing affecting the Q is the shape of the cranks. So people tend to refer to straight cranks as “having no Q factor” and offset cranks as “having more Q factor”, which is not really correct terminology, but people know what it means.
The bottom bracket axle on a bike is usually quite a bit narrower than a unicycle axle, and bike cranks have to angle outwards to clear the chain stays of the frame. So using bike cranks on a unicycle will result in a wider stance (higher Q) than the same cranks on a bike. Unicycle cranks tend to be straighter on average than bike ones for this reason.
Rob, thanks for the detail, and you’ve got me intrigued to find out the Q Factor for a few different applications. Whether our crank choice changes Q variance from hub to hub? Or if we took the standard crank Q for the Original equipment and compared it against the current 20.4 measurement?
OKay Lunicycle, good idea. We’ll get a full dressed weight for the complete uni, keeping in mind that will include Mount, Rotor, cranks and handle. I have a KH29 with a Magura as well, and we’ll report the Weigh IN amounts
Yah it looks like it should work with most calipers. It just seemed like you were limiting what calipers you could use in the description.
I think I would suggest the opposite approach. Space the disk away from the crank and have the caliper in a fairly fixed position. This would help with people like me who like experimenting with different setups and constantly changing things around. If you space the disk the built in adjustment in the calipers could take care of the small variance you would have left.
All the ISIS hubs (except the Nimbus Super-wide) are specked to the same axle dimensions. The Koxx hubs tend to be on the larger side for their tolerances and the cranks might sit a bit further outboard on them.
Some old square taper hubs are funny widths but pertnear everything is being made with 100mm bearing spacing now.
Your cranks do look kind of wide but you still need to clear the brake calibre.
Murphy’s law is that any exposed edge like the disc (doesn’t even need to be sharp or sticking out too far, got the scars…) is going to end up making contact with your body during a crash. Sorry, not a fan of the outboard disc for MUni for that reason alone.
I agree also re too prone to damaging the disc.
HS33’s do a good job on both counts - no risk of injuring rider during UPD, and unlikely to get damaged during UPD.
Not really odd just my POV
Perhaps I wasn’t clear enough - jump on a 24", go down a trail, apply the brake. jump on a 36’er, do the same. The braking experience is not the same due I would guess to a lot of factors including a perception of how granular braking and riding control is, based on the distance the wheel covers relative to crank etc.
For sure the outboard disc looks to be an effective/cheap way to retrofit disc brakes to uni’s and it’ll be interesting to hear what guys have to say when they use it, but tbh they don’t appeal to me much as they are for MUni, especially when the hs33’s are already doing the job.
I know what you mean - that’s one of the main reasons I’ve not tried any sort of extended handle yet (well, that and I can’t be arsed to build one!)
That’s why I said it was odd - not trying to argue, I just meant that in theory a rim brake shouldn’t really be affected by wheel size, so it’s interesting that practical experience says otherwise. I suppose it’s because of the difference in gearing and the feel of the ride. I’ve got HS33s on my 26x3 and 29er, and they feel pretty similar, but then there’s not very much difference in size. Like I said, my coker’s got a very different brake setup, so I can’t really compare it directly (it really needs a lever that pulls less cable).
Hmmm… I haven’t thought of removing my HS33 from my muni to install a disk yet, but it’s going on the Nightrider as soon as I get some Sinz 125s and a mount made! Big wheel, small cranks = need for precise braking… when it’s time to test durability I can set up the Muni and hit Middlesex fellsway or Lynn Woods, and Jeff can take it to Highlands… all granite meat griders to see how it lives up to a beating.
I have to disagree about Maguras not getting damaged in UPDs. At last California MUni Weekend there were at least four Magura failures, and probably fewer than 20 people were using them. They fail all the time. Now, mostly what fails is the hydraulics, but that’s why you shouldn’t be running hydraulics. We run hydraulics on MUnis because V-brakes won’t fit over 3" tires; a disk brake solves that issue.
I would be concerned about achilles slicing, though. I have definitely gotten my foot caught between the crank and the wheel.
I don’t want to speak for other off road UNI-er’s but I always wear at least neoprene shin pads for Urban rides and KH Leg Armour for aggressive Muni. I would not suggest an aggressive off road ride with our disc without lower leg protection. In fact, I’ll have it in the disclaimer for purchase.
Thanks for the back up Tholub, and we’re looking toward a CA Big wheel rider to use this on the downhill descents and see the smooth consistent modulation with this set up. I have used Magura exclusively on 3 uni’s prior, and am convinced the upgrade is significant.
We have identified out test bed group, and will be making arrangements with these uni forum members to test out the disc brake system soon. Hoping to have product out to them with 2 weeks, understanding that it’s still winter, and snow rides sometimes are reserved for the heartiest of souls.
We’ll be able to report back our findings and next steps as we move through this process. A lot of riders have inquired about timelines for production, and we’re hopeful for a May end of Month to take orders. If we have any updates, we’ll be sure to keep the fourm informed.
Thanks for all of the interest in participating in the demo!
Thanx for pointing this out… the Schlumpf is what I was hoping to use with this system. looks like the c-clip would be hit by a crank stop… this will be trial and error with that hub. Hmmm…
How are you planning on selling this? Will you have options for just the rotor/mount, rotor with crankset, crankset and caliper?
Another thing I was wondering is whether or not you could make a mount for the Nightrider that would bolt on to the gusset? It seems like you could drill one more hole and use the existing hole to get a fairly secure connection. I have a friend who is a wizard with a torch, and so welding won’t be a problem, but it would be nice to be able to mount without welding.
The machinist gets back on the 15th, and we’ll be discussing clamp on mounts, But I am not sure if that’s the way to go given forces involved… have to test it out. I will also be fabricating a mount for the nightrider soon.
I would like to sell the rotor and mount as a stand alone, and also bundled with a sinz crank of the size and spindle type of your choice. Jeff and his web team are diligently getting the site updated for ecommerse and it looks like we may be kinda ready for orders end of May.
We have a few guys selected for testing out the disk, and if all goes well maybe we can get some manufacturers’ interest, so the mounts will already be on frames in the future! We’ll see!
The exposure in this forum has put the project in front of a lot of eyes, and some real industry leaders with lots of insight. This is gaining legs very rapidly.
I agree with jtrops. If we could drill and bolt to add the brake mount it would be a much simpler job than welding. For example, I would not the to strip the frame and then repaint it.
I’m pretty excited about it. I was coming up with my own plans for building something similar, but at this point I’m waiting for theirs. It is a slick way of handling it, and if the Sinz cranks can handle multiple pedal mounts that would be even better.
Looks like we have a design for a universal bolt on mount for Steel and Aluminum rigs, even the nimbus Nightrider frames! I have no idea how long for production…
Already have mine, Discs modulate better than rim brakes, are mechanically better for the spokes, they utilize all spokes equal torque on braking. Definately superior to a Magura rim brake, Good job!
One suggestion on geared hubs. If you brake through(attached to crank) the gearing, it puts alot of stress on the gears,you would be using the gears to take up all the braking weight. If you brake at the hub it stops the wheel no gearing involved, and at the price of a geared hub, more undue stress through the gearing could have expensive/catastrophic results.
