Of the various kinds of unicycle hubs that are now available I like the KH 8 spline the best. The way the cranks attach with a pinch bolt makes a lot of sense to me.
For a long time I’ve had an idea for an 8 splined KH style hub that I wanted to build. I’m finally caught up enough with all the things in my life besides unicycles that I had a chance to work on two of them this weekend.
This design isn’t original - it’s similar to the Muniac’s “Drastic Lightfoot” hub in that aluminum flanges press on to the axle. In this design, the flanges press on to the axle over top of the same 8 splines that the cranks attach to. I machined the splines in the axle long enough to make it happen. This results in the bearings riding on the splines as well but I don’t think it’s a problem. I should also say that I remember Kris Holm describing a hub similar to this.
Like they say: “a picture is worth 1000 words” so I’ve created a gallery and taken photos of the hubs in various stages of construction. The gallery is located here:
Some time ago I bought several “drive side” Shimano bike cranks - cheap. Today I converted a couple of them to 8 spline just as a test … I don’t think they’ll work very well since there’s not enough material for a proper pinch bolt but I wanted to try my 8 spline broach to see how well it works. My plan is to convert a set of Kooka cranks to the pinch 8 spline style. Also, I’ve ordered a pair of actual KH cranks to try with the hub.
I don’t have a picture yet but this evening I laced up one of the hubs with an Alex DX32 rim. Looks pretty good but I’ve had things that look good fail miserably!
This looks intriguing! It would appear to be quite a solid connection to the wheel once laced up. I too like the pinch-bolt style of crank. How about titanium? Good work, and good luck with development! Dan
I have one of the new hubs assembled and swapped out with my current hub/crank setup. For over a year my MUni setup has been a home made Profile type 48 spline hub with 170mm GT branded Profile cranks. This setup has been just fine with the exception of some slight looseness in one crank if I don’t tighten the retaining bolts before riding. A problem not unlike other Profile hubs seem to have. The first thing I noticed about the new hub and cranks was the lighter weight … probably due to the aluminum Shimano cranks more than anything.
This evening I did several 1 foot drops plus a couple 2 footers and nothing broke! Everything seems solid - even the lame Shimano cranks so I’ll just ride it now and see what happens.
The flanges on this new hub are removable but I’m sure it would require a press since I pressed them on using Loctite. I didn’t intend on them coming off again but maybe that’s not a bad idea? I definately plan on making a hub with a disc brake mount as Ken suggested. I think it will be a wide one for a Coker. A titanium axle is a definite possibility too.
Like GB said, the flanges are square - not tappered in. I don’t know if that’s an issue or not but I’ve noticed that all my aluminum bike hubs are square too. The spokes seem to just wear into the aluminum where they contact the outer diameter of the flange. Oddly enough, the scalloping on the outside diameter of these flanges improve the way the spokes lay (see a photo I just added to the gallery) against them. I wish I could say that the scallops are a design feature but in reality they were put there just to be different. But I’ll take an “accidental” design feature any day!
Nice! I like the way it looks laced up. Those scallops are brilliant.
Did you weigh the hub before putting the cranks on and building the wheel? It certainly has less material than the KH or Profile because the aluminum hub body is trimmed down to a minimum so the weight should be less.
I weighed the bare hub at 404 grams … or .89 pounds. That’s not including bearings or retaining bolts.
A new set of KH cranks came in the mail today. I was relieved to find that the KH cranks fit on the hub perfectly. The hub and nice new shiny black KH cranks look good together. The cranks are the old style with “nubs” - but not for long.
My next task (after de-nubbing the KH cranks) is modifying a pair of Kooka cranks to the 8 spline setup.
If you ever need someone to test out the other hub, gimme a set of cranks, and lace it up. I will be more than happy to abuse the hell out of them. Im a REALLY sketchy rider, and I would really put those things to the test. Im not saying this so much as an offhand comment, but more of a concrete offer. and if they hold up after awhile, I would gladly pay ALOT for them. but seriously, I will test the hub for you. you need someone who lands like an elephant, not a smooth rider who lands everything perfect.