3.8:1 geared direct drive wonderhub

So this hub is effectively twice the gain of a Schlumpf?

Good luck getting this thing rolling, then I wish your great luck with your landing when you try stopping :astonished:

You need the longest cranks possible, 175-180.

on the other hand, bring on the G12s

It’s something like 2.4 Schlumpfs (if that’s a unit of measure) with no shifting but on a 20" wheel. I have your 125mm and 150mm cranks I can try with it. I’m hoping I don’t have to go larger than that. It will definitely be a challenge to get it going on flat ground and riding it up any kind of incline but should be feasible on a slight decline. I’ll probably need to practice a skate-style start for flat ground.

Would love to have this disc brake setup on my Schlumpf.

It depends on how you define the unit “Schlumpf” but I would argue it’s more than 2.4.
The Schlumpf gear ratio is about 1.55. To be precise it’s 17/11.
If you would drive the pedals (in high gear) through a second Schlumpf, you’d increase the total ratio to 17/11 squared, that’s about 2.39.
Now if you drive the pedals of that second Schlumpf through a third Schlumpf, the total ratio would be (17/11)^3 or 3.69. If you will, that’s three Schlumpfs in series. Waaalrus’s ratio of 3.8 is even a little bit more than that. I’d say it’s about 3.07 Schlumpfs.

I figure it will be difficult to ride, and even more difficult to get started, even on a 20 inch wheel. The virtual wheel diameter is almost 80 inch! Curious to read a ride report.

Just add one… I did.


150s on a 20 is getting into pedal strike territory but could be manageable.

On the other hand your gain ratio with a 3.8 gear and 150s on a 20 would be 6.43:1, getting into the “Danger Will Robinson! Danger” territory on my gain ratio chart, comparable to using 70mm cranks on a 36, but without the big wheel stability but a much smaller distance to fall. I would suggest rollerblading safety gear since it is likely to be similar kinds of falls.

I find that cranks larger than 114mm throw off my balance. This is tolerable on my 36" freewheel unicycle because it affords me time to recover from imbalances. I’m not sure how it will work with a high-geared 20". Pedal strikes shouldn’t be a concern even with longer cranks because I’m not planning to take it mountain unicycling and I have my pedals level when I turn.

I have six sets of elbow pads and six sets of knee pads (three include shin protection - this is not including a couple shin-only pads). I got these elbow and knee pads specifically for my 36" freewheel riding, downhill speed runs, and (possible in the future) skatepark riding:


I figured these would be best on drag falls which might move other pads I have. They are not perfect because they didn’t work great with a recent fall:

After that I had a I had a great idea to wear a particular set of elbow pads under a compression shirt on my trail rides. They have great protection and are comfortable but too easily moved and slipped down (before).

Thanks for the suggestion!

Sorry, I wasn’t very clear. I was referring to the inboard disc brake setup which the Trike hub has. I am already running the setup with outside disc and spirits.

Getting close to pre-order. Sturmey-Archer hub.

if its a sturmey made hub, isn’t there a possibility that they might consider making a reasonably geared 3 speed uni hub or at least a reduced version of this, perhaps a 2:1.

It’s still a freewheel hub. Aside from a few people pushing the limits of unicycles it’s not really a big market. Still, I wonder if the axle from this hub is at all compatible with the internals from another hub. I doubt it, but hmm…

The only thing as far as i understand that would make a geared up single speed hub freewheel is the pawls. As there are no alternate gears, the pawls could be replaced with solid pieces which cannot disengage.

Even if that was to happen there are 3 problems

1: Backlash - this isn’t a schlumpf and has not been designed in such a way that going backwards was even intended (although the internals are likely to be as strong backwards as forwards). The tolerances don’t need to be tight because the hub is built to freewheel.

2: One (high) gear isn’t always good - Humi rexes are a nightmare to get going and dont have the rollover ability or stability that a larger wheel provides. They are only 1.5, if you went to 2+ you would end up with an uncontrollable dose of ‘danger will robinson’ meets ‘pedal strike much’ on any of the reasonable (small) wheel sizes. Put this thing on a 36er and it will feel like you have a 20kg wheel.

3 Strength - I don’t know exactly what stresses drift trikes take but I doubt they hop or ride roots and rocks. The 6 bolt connection to the frame looks great for lateral strength but a small drop could shear the bolts. On a trike, the riders weight is distributed more over the back wheels than the front whereas all of a unicyclists weight goes through the axle. Perhaps a lightweight rider who rides road only might be ok.

Edit: by comparing the size of the bolts to the size of the axle, it looks like it uses M5 or 6 bolts. M5 is a saddle bolt, M6 is a seatpost or frame bolt. I wouldn’t trust 6 of either of them sideways to survive any drop without shearing. Yes there is a support built into the hub body but that would not help much.

Sunrace (sturmey) by making these have shown that they are interested in making bits for fringe sports. Drift trikes may be riding a bit of a popularity wave atm but the market for the hubs may well be as small as the geared uni market.

I dunno about you guys, but I reckon I would be way more interested in a geared unicycle if I could afford it. Not saying anything bad towards the guy who makes Schlumpf’s, I know he’s a one-man show, but adding £900 to the price of a unicycle to go a little faster is unfeasable for a lot of people. I’d be willing to bet the market for a geared uni hub is far greater than what you see at the moment because the price is so prohibitive :smiley:

These are available for pre-order now for £295, paypal sales@jrdrifttrikes.com. I just put in my pre-order.

Wow, a whole front end with a wheel for only 295GBP, i feel I’m going to be able to afford a geared hub pretty soon :smiley:

Finally got this delivered and built it into a unicycle. I still need to adjust the brake. The rotor is a custom 225mm Hope and the largest cranks I can put on are 125mm. I didn’t get much time to practice with it yet, maybe 20-25 minutes in which time I was able to do about a half revolution. I’m guessing it will me take a few weeks to be able to ride this on flat ground.

Amazing! Looking forward to videos!


What is the wheelsize, 20 inch? That would be 76 virtual inches. You would have about the same leverage as with 59 mm cranks on a 36 inch. This must be difficult to ride indeed. And the wheel looks so innocent.