Here’s an update on the KH-Schlumpf hub.
The intent was to make a geared hub with ISIS spline that’s good for both on and offroad riding. Here are the some of goals we had for this hub:
-Standard 100 mm bearing spacing with flanges as widely spaced as possible,
-1:1 or 1.5:1 gear ratios
-ISIS spline axle and internals strong enough for offroad riding
-Snappier, easier shifting with improved round shifter button shape and a stronger shift rod and bash-resistant shifter system
-No requirement for a lever arm bolted to the saddle frame, replaced instead by a knurled 42 mm sleeve over the right bearing. The bearing clamp becomes the “lever arm” required for gearing- no need for bolt holes in the frame.
Removing the lever arm makes the hub fit in any existing KH frame sold since 2006. For earlier KH frames, the bearing housing lips must be ground down to 2 mm height for it it fit. This also allows the wheel to be flipped to allow the rider to choose their preferred direction of button movement for shifting.
I’ve been working on this for 2 years and have tested it on a KH24 and KH29, including North Shore trails with drops up to 2 m, XC trails and road riding. Attached is a photo of the result- the final production prototype built onto a KH29.
It’s an awesome ride. The gearing allows you the same riding you’d have on a regular uni, plus 36’er - like speeds once you hit easy trails or road sections. And you can almost keep up with the bikes on road commutes to the trailhead! Weight is 1420 g, heavier than the Moment hub but surprisingly not that noticable. There is slight back and forth looseness when you idle but you don’t notice it after you’ve ridden a few metres. With ankletop shoes, shifting is easy and instant once you’ve practiced a bit.
For road touring you get the speed of a large wheel with the hill climbing ability of a 29’er. Stability is slightly less than a 36’er. The 125/150 cranks seem ideal because 125 seems (to me) to be the ideal length for road riding.
Regarding limits to the use of this hub: It’s not possible to state limits on, say, drop height with this hub, due to differences in rider skill, weight, and style. With the level of testing it has had so far, I personally would use the geared hub for all kinds of offroad use, but I would stick with a regular splined hub for pure agressive technical riding.
We’re starting production but lead time on getting it to stores is still long (on the order of months). I’ll post further about availability and price once that’s worked out.
A geared KH24 will be at Fluck for anyone to try.