Welcome to Velo Vision magazine, covering specialised bikes, cycling as transport and human power. It's a quarterly dose of cycle inspiration.
The current issue is Issue 16. The next issue is out early March 2005.
Subscribe now!
NEW! Discussion forum
- Magazine:
- Information:
- Subscriptions:
- Free small ads
Search news story archive:
|
Schlumpf gear-change unicycle hub prototype revealed
He's hoping to have it in production this summer...
News just in from Florian Schlumpf, the Swiss manufacturer of the Mountain-Drive and Speed-Drive bottom bracket gearbox transmissions:
***
Last Saturday night, I rode the first meters on the Schlumpf unicycle with integrated Speed-drive! And yesterday, I got your article about Greg's unicycle!
So I can't wait any longer to show you a first picture of the product:
This isn't the finished article, of course, as I have to work on the same issue as pointed out by Greg: minimal backlash.
The completely new designed shifting part should provide zero backlash - the only backlash remaining is from the gears...
Hope to start production in late summer.
***
Readers of Velo Vision 13 will have seen the article about how unicyclists (Greg Harper and UniFrank) have been making DIY hubs for a while, with the object being to increase speeds without excessive wheel size. But the Schlumpf device will be the first to allow gear changes as you ride along.
This development won't be of much use, unfortunately, to anyone interested in making a 'direct drive' or HUB bike (again, see the magazine for background) unless you fancy riding it fixed gear! Unicyclists, of course, don't use a freewheel.
No word on prices as yet, nor on a name for the hub.
Posted on 18 March 2004
Your comments ...| From: Dan Wilson ([email protected]) on 18 March 2004 |
| Nice hub! what kind of gearing are you thinking? would you be able to make one with a gear reduction for hill climbing, one to one, and a gear increase for higher speeds, and will it be strong enough for MUni? Or would it only have two speeds and if so is the gear reduction an option? Thanks, Dan |
| From: Peter Eland ([email protected]) on 18 March 2004 |
Hi Dan,
I think Florian (the maker) will be reading this, and he can say for sure, but to try to answer a few myself:
- I expect the gear ratio will be 1:1 and 1:1.65, so direct drive and gear-up by 65%. That's the ratio of the standard (bicycle) Speed-Drive unit on which this hub is apparently based.
- The gears are shifted by tapping that button on the crank axle end with your heel - so there's just two possibel positions: protruding on the left or protruding on the right. So I very much doubt there's any chance of more than two speeds.
- I'd guess it would be designed to be strong enough for Muni (mountain unicycle) use: Florian's bicycle products are very well-engineered and reliable.
- Don't know about a gear-down version: most demand is likely to be for gear-up, and it might not be commercially viable.
Hope that helps. |
| From: florian schlumpf ([email protected]) on 18 March 2004 |
Dan,
the gear ratio will be around 1:1.5
As Peter mentioned, there won't be a large market for a gear reduction. At the moment, we will bring the speed increasing system to the market, and then let's see how interest for a lower version is....
Florian Schlumpf |
| From: John Long ([email protected]) on 18 March 2004 |
For God's sake make one for the Coker. If we could increase the gear ration by 50%, 30 MPH on a unicycle would be a reality. Scary to think of such a thing, but I'd sure like to try.
JL |
| From: Bernard Weir ([email protected]) on 21 March 2004 |
Paradigm shift!
If Florian can put out a High-Speed (1:2.5)unicycle hub cheap enough and light enough, I can foresee a whole new kids' cycle sport built around lowracer delta trikes on asphalt/concrete "tracks". BMX dirt tracks are getting built out, but there's lots of shopping centre car parks out there, and council cones ...
Imagine a 20" front wheel shifting up to 50" down the straight, brake, slide the corner, back to 20" for the accelerate out ...
And no derailleurs to jam!
And no greasy chain to jam in the spokes!
High speed, please, Florian - I might just buy two!
{owner of HSD-Rohloff minibike conversion} |
| From: Ralf Grosser ([email protected]) on 21 March 2004 |
THis could also change the sport of pennyfathing racing as wee know it.
This is could be the best thing to happen since the Krypto gear. |
| From: Mark Stonich ([email protected]) on 22 March 2004 |
I believe I know how to design a part that could be added to a Sturmey Archer AW 3 speed hub that would eliminate the play that you get when converting an AW to a 2 speed fixed gear.
I don't have time to pursue this right now. But, judging from the responses I got when I mentioned it online, I believe that if the Schlumpf BB gear were available as a fixed gear, with a 25% reduction, it would sell quite well here in the states. Providing that there wasn't any perceptable play.
Visit http://www.fixedgeargallery.com/ to get a taste of the depth of fixie mania here in the USA.
|
| From: Antony (at pedalcars dot info) on 23 March 2004 |
> there's lots of shopping centre car parks out there
Yes - if you don't mind doing your racing on Sunday nights, and fending off the local boy racer moro... sorry, I mean, "car conversion specialists" in their Vauxhall Novas with bits of plastic falling off!
Speaking from substantial experience of racing on car parks, you need an office / industrial car park that's not used at weekends; you also need to know someone in a significant position within said office who can get you permission without asking many (or any!) other people. |
| From: Mark ([email protected]) on 23 March 2004 |
| re Mark Stonich's comments on fixed gear usage - this idea has been floating around on both the cyclingplus and fixed gear lists for a while also. It was concluded that the current mountain/speed drives wouldn't cope with fixed gear (ie backpedaling) usage. Presumably this unicycle type will? |
| From: Florian ([email protected]) on 24 March 2004 |
| Yes, our new unicycle gearing system is designed for full load in both directions. |
| From: Ken Looi ([email protected]) on 06 April 2004 |
Can't wait till the production version comes out! I'm a unicyclists from Welington, New Zealand. Just recently rode across Cambodia and Vietnam on a unicycle- this will make it so much easier to travel with (can use a smaller wheel), and also a lot faster and adaptable to your terrain. And if it was strong enough would be great for MTB races as well (we've done heaps of these on unicycles recently). I'll be doing a 24hr race solo again, as well as a few century rides- this will be perfect!
Look forward to seeing the production hub. |
| From: ron mccurdy ([email protected]) on 25 April 2004 |
| we make trikes for special needs. Many clients cannot ride freewheel and so have been stuck with single choice gearing. This would make available a trike which could handle hills much better |
|
