View Full Version : PING Harper: Could you Blueshift a MUni?

Memphis Mud
August 23rd 03, 12:33 PM
Dear Mr. Harper,

Another thread is polling for the optimum uni. I love my 24" MUni for
what it can do. I love my 29r for what it can do. I love riding Cokers
(tho I don't own one) for what they can do. I love my 20.

It occurs to me that since (I think) you can gear a 24" all the way up
to a 48" uni, that your system would lead us to the all time ultimate

My math skills don't compare well to yours, but it seems that if you
could gear a 24 to a 36 then couldn't you also gear a 24 to a 20? Would
this hub withstand the rigors of MUni?

Can you imagine a crosscountry race where you could easily ride up steep
hills, and then, with a simple switchover, cruise at 18 to 25 mph along
the gravel roads...

Please tell me I'm not just dreaming.

Thanks. Tom.

Memphis Mud - Student of GrandMaster 2T

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August 23rd 03, 10:45 PM
I want one!


If life had a meaning, would you want to know it?

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August 23rd 03, 11:43 PM
Yes yes! Me too chap!

XWonka - Ed, Edd, & Eddy Watcher

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August 24th 03, 03:12 AM
I will be interested to see Harper's reply. I'm not great rider, but my
one attempt on BlueShift would tell me it wouldn't work well for a muni.
You don't have that 1:1, direct drive control, which to me would be
pretty critical for working obstacles, etc.

"Specialization is for insects..." Robert A. Heinlien

"Yeah, and for unicycles too....." Nurse Trixie

tomblackwood - Registered Nurtz

My other brake is my face!

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August 24th 03, 08:54 AM
tomblackwood wrote:
> * I'm not great rider, but my one attempt on BlueShift would tell me
> it wouldn't work well for a muni. *

Tom, I think that Greg keeps short cranks on his Blue Shift, making it
harder to ride than normal. With longer cranks it would be easier. This
is according to John Childs, and since both of these guys are away on
some fantasy ride on Vancouver Island, we might as well spread as many
lies as possible while.

In 1:1 mode, it should be fine for Muni, at least for a little guy like
me. Greg is a beast, maybe he will have a problem. Plus he jumps on to
and off of anything that he sees.

The other mode is 1.5:1, so a 24 becomes a 36. Problem is the cranks
don't get any longer. Or is that the advantage? So if you had 6" cranks,
when you go to 1.5 mode that would be like having 4" cranks.

Personally, I want to put one of these on a 20" as well as a 29".

It feels really weird to ride it at first, then when you switch back to
a regular uni, that feels weird.

Greg: please hurry!

iunicycle - Old back, new cricks
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Memphis Mud
August 25th 03, 01:20 PM
nbrazzi wrote:
> *...but it seems like it would be impractical for Muni, where the
> whole point is to negotiate constantly changing ride conditions. *

One racecourse we have here is 1 or 2 miles of challenging MUni followed
by 3 miles of rather easy singletrack and gravel road. On my 29r with
125s, I screamed through the latter but the former is impossible. On the
24 MUni with 170s, I feel like a bulldozer. The technical stuff is fun
and doable but gnats pass me by on the latter parts.

I wouldn't want to make that kind of switch for just a small portion,
but for a mile or more, I think it would be worth it. Besides, Phase II
will be easier to shift without tools. Have faith.

> *...Also keep in mind that the Uni.5 is designed for gearing up the
> hub and it sounds like your talking about gearing down the hub. The
> current design definitely doesn't support gearing down and I don't
> know if such a thing could be done. *

Ah, the mother of invention.

I tried the Blueshift once when it was loaned to Rhysling. I failed. It
had medium sized cranks. I think I could've ridden it with 170s. (and
quite a bit of practice). So gear it 1:1 for 24" MUni. Then shift to 48"
Monster. That might be negotiable with 170s...

It could change the face of Uni. Just like my Sears 3-speed with the
banana seat and sissybar did back in '68. (before that, I and my peers,
were limited to one lousy gear). My Schwinn 10-speed in '72 was another
quantum leap! My 21-gear mountain bike changed things again, opening up
still more new avenues.

Now I ride my single gear MUni...

What fascinations await in the future? Eh, Harper?

Memphis Mud - Student of GrandMaster 2T

Mantra: Avoid Hitting Tailbone...Avoid Hitting Tailbone...
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Klaas Bil
August 25th 03, 02:56 PM
Aaah! I've come up with exactly the same question during my
family/unicycling holiday to the Alps from which I returned this
weekend. Cranking up a loooooooong mountain trail turned out to be quite
a different cup of tea than cranking up those steep (really) but shrt
Dutch slopes. But since it looks like I may see Harper in person in a
month or two I had saved the question to discuss IRL. Interesting.

One point of doubt though on MM's original post. Whereas 48" is the
-theoretical- maximum (limit) to gear up a 24" wheel, this is not
practically possible afaik, at least not with a single stage gear
sun/planet gear system. But if the downgearing would work at all then to
go down from 24" to 16" with 7" cranks would be fine enough...

Klaas Bil

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August 25th 03, 04:51 PM
About a year ago, someone asked if it would be possible to gear a Coker
-down- from 36" to 24" in order to make a tractor that could crawl over
anything. I thought that was a cool idea...for someone else to do. I
think gearing down is not too complicated for a planetary gear system in
a unicycle hub but I can't remember. I also considered it before
thinking about two-speed systems so I don't know if it can be easily
shifted to 1:1 like the uni.5 hub can.

There are alot of parts in the drivetrain that would have to be made
bullet proof. There was alot of development time that went into the
Profile unicycle hub although the transition from their bicycle hub to a
unicycle hub/axle is quite simple. The number of parts in the Profile
hub is pretty small. In a geared hub there would be lots of gear teeth
and extra bearings to worry about.

Geared hubs for unicycles must handle large impulse torque changes and,
as such, are necessarily quite heavy already. Beefing them up to handle
MUni riding won't make them any lighter.

harper - Old dog, no tricks

-Greg Harper


"Are you OK???" - Just about anyone I've ever ridden with

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