Geared 36

unisk8r · 2004-11-12, 05:18 AM

For the past 8 months one of my fabrication projects has been a geared 36". Today I finally completed the first version and took it for a short spin. The 150 cranks seem fine with the 1:1.5 ratio. I used a double 22/18 cog reduction, with a std. 3/32" chain. The hub is a PW track hub & cog. The jackshaft is a couple of track hubs cut & just the cog portions welded together. Adjustment via dropouts & std. chain tensioners. The basic frame was brazed up by Rick Hunter per my "V" design, and I welded on the jackshaft housing. The bars are another custom design of mine. All components are still unpainted, and will likely remain so until I'm satisfied with the workings.
Pete Perron

unisk8r · 2004-11-12, 05:20 AM

here's a closeup of the transmission. The hub rotates freely on the axle via 4 sealed bearings.

unisk8r · 2004-11-12, 05:20 AM

and from the front:

unisk8r · 2004-11-12, 05:23 AM

And for what it's worth, I'm calling this a Geared 36" (tho I do like the "Uber-36" moniker), 'cause the only Coker product here is the tire (not even the tube). I don't see why we keep referring to these as Cokers, some day there will be another tire choice anyway and no Coker products will be involved... Just my .02

TheObieOne3226 · 2004-11-12, 05:59 AM

Very very nice...How was the ride?

john_childs · 2004-11-12, 06:55 AM

You should paint it green. Green is the color of envy.

It will be interesting to find out if it rides better than the internally geared hubs like the Uni.5 and the Schlumpf hub. The jackshaft drive type of gearing definitely has potential. The other advantage with the jackshaft gearing is that you can gear it higher than you can with an internally geared hub.

Now we need some fast riders to come to Seattle and try to break the 1 hour distance record and the 100 mile speed record using your unicycle.

UniBrier · 2004-11-12, 07:05 AM

This may be the machine to conqor the Marymoore Velodrome. Maybe you've heard of the place.

2004-11-12, 07:08 AM

"unisk8r" <unisk8r@NoEmail.Message.Poster.at.Unicyclist.com> wrote in
message news:unisk8r.1flex5@NoEmail.Message.Poster.at.Unicyclist.com...
>
> And for what it's worth, I'm calling this a Geared 36", 'cause the only
> Coker product is the tire (not even the tube). I don't see why we keep
> referring to these as Cokers,

That seems very reasonable to me: to call that a coker would be very
misleading, or more probably an untruth. You might be tempted to conjure up
your own brand name, to be applied to the genre of all unis following the
pattern. A KH unicycle is merely a (good) modification of a standard
pattern, yours deserves a wider recognition, in the way that Blue Shift now
defines that particular geared unicycle . I think your gearing concept
would be a nice addition to a smaller wheeled machine, if it could be done.
It looks a mean machine and I like it, especially how, with the double
gearing, the pedal axis remains in line with the wheel centre. Nice simple
concept, not sure how difficult it was to fabricate. Look forward to
hearing some road reports.

Nao

daino149 · 2004-11-12, 07:17 AM

I love the design.

What I can't figure out is how the two cranks manage to stay in sync. Is there another gear system on the other side, or are the two cranks connected directly? Or is there something else I don't see?

Great job!
Daniel

john_childs · 2004-11-12, 07:38 AM

Quote:

Originally posted by daino149
I love the design.

What I can't figure out is how the two cranks manage to stay in sync. Is there another gear system on the other side, or are the two cranks connected directly? Or is there something else I don't see?

Great job!
Daniel

Pete is going to have to explain the details of the design.

The basic design is that the hub body is on bearings and rotates around the spindle. It is a one piece spindle and the cranks attach to the spindle. That keeps the cranks in line. The trick is that the hub body is on bearings and is able to rotate faster than the spindle.

2004-11-12, 07:48 AM

On Thu, 11 Nov 2004 23:18:53 -0600, "unisk8r" wrote:

>For the past 8 months one of my fabrication projects has been a geared
>36".

Great concept! I notice two chain tensioners. Can the tensions be
adjusted separately without the drive getting out of true? Maybe that
is not needed because both are 22/18.

You probably have to adjust chain tension to hit a compromise between
friction losses and backlash, maybe you can comment on that?

Klaas Bil - Newsgroup Addict
--
"Deflating pi does not reduce calories, it just concentrates them. - billham"

unisk8r · 2004-11-12, 05:43 PM

I used twin dropouts and chain tensioners ala giraffe. Only here there are 2 chains. In a perfect world, there would be no chainline issues. But here, even though I did my best to get the cog separation on the jackshaft equal to the separation between the hub and the crank cogs, it seems that so much tension is required to avoid crank play, that the stress results in a ever-so-slight bend of the jackshaft housing. Those that have peered down the chainline of a giraffe know what this means. You want it perfect. I think this arrangement is fine, and I suspect that the inferior chain has more to do with the necessary tension than the cogs. I've adjusted so much tension that there's friction at the wheel.

As for the ride, I will confirm Harper's and Childs' assessment that it is less forgiving. I think that because your inputs are magnified at the wheel due to the gearing, that you have a smaller "sweet spot" of controllability. Crank length is definitely much less of an issue. I think it will just take practice to "get the feel" of it. But it's definitely smoother overall than a direct drive, and the lower cadence was a big motivator for me; I still don't spin well!

I'll report more later after I become more familiar with its potential...

unisk8r · 2004-11-12, 05:47 PM

Daino, John is correct. The cranks are attached via std. square tapers to the 180mm axle (spindle), which is otherwise a smooth and solid stainless steel rod. The Phil Wood company kindly (but for a price) made the longer-than-normal axle for me. The hub rotates faster than the axle due to the gearing.
Pete

steveyo · 2004-11-13, 12:28 AM

I may have missed this, but how does one shift from one cog to the other, or rather shift the driveshaft's connection from one cog to the other?

unisk8r · 2004-11-13, 01:14 AM

Stevyo, no shifting...think 1 wheel track bike. The jackshaft is a solid piece that connects the 2 top cogs as one. Drive pressure goes from the crank up to the jackshaft, then back down to the hub.

I rode it again briefly today, and it seems to magnify any input. You step on the pedal and it accelerates. You backpressure the pedals and it slows down, alot more than direct drive. I also notice that the side-to-side effect of pedal pressure is pronounced, not too bad, but maybe that's more to do with the 9" spread of the pedals. That's not much more than a wide-hub direct drive, but there's definite Q-factor. As I pedalled smoother it was minimized. And starts are a bitch, I'm learning all over again!

Bottom line is that with less room for pilot error, I'm still working my way up to go fast. I'm doing about 15 (only on the flats so far) with much less pedal effort, but more balancing effort.

2004-11-12, 05:18 AM	#1
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	Geared 36 For the past 8 months one of my fabrication projects has been a geared 36". Today I finally completed the first version and took it for a short spin. The 150 cranks seem fine with the 1:1.5 ratio. I used a double 22/18 cog reduction, with a std. 3/32" chain. The hub is a PW track hub & cog. The jackshaft is a couple of track hubs cut & just the cog portions welded together. Adjustment via dropouts & std. chain tensioners. The basic frame was brazed up by Rick Hunter per my "V" design, and I welded on the jackshaft housing. The bars are another custom design of mine. All components are still unpainted, and will likely remain so until I'm satisfied with the workings. Pete Perron Attached Images

2004-11-12, 05:20 AM	#2
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	here's a closeup of the transmission. The hub rotates freely on the axle via 4 sealed bearings. Attached Images Last edited by unisk8r; 2004-11-12 at 05:26 AM.

2004-11-12, 05:20 AM	#3
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	and from the front: Attached Images

2004-11-12, 05:23 AM	#4
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	And for what it's worth, I'm calling this a Geared 36" (tho I do like the "Uber-36" moniker), 'cause the only Coker product here is the tire (not even the tube). I don't see why we keep referring to these as Cokers, some day there will be another tire choice anyway and no Coker products will be involved... Just my .02 Last edited by unisk8r; 2004-11-12 at 05:30 AM.

2004-11-12, 05:59 AM	#5
TheObieOne3226 ***** Member Join Date: Nov 2003 Location: Philadelphia Age: 24 Posts: 3,441	Very very nice...How was the ride? __________________ SWAT Gallery SWAT webpage Arrow Racing Sixsixone "Obie is definately a trend setter, I got in to unicycling because of him, and came here because of him" - KJ-52 "try not to annoy the great Obie, for he is better than us." - Murde Mental Disclaimer: The above message was not intended to offend anyone. If you are offended I can take no responsibility for my actions because I don't feel like it. Also you are reading an internet newsgroup where not everyone will share your same views and beliefs, be able to take criticism and post/read threads at your own risk.

2004-11-12, 06:55 AM	#6
john_childs Guinness Mojo Join Date: Oct 2001 Location: Portland, Oregon USA Posts: 12,380	You should paint it green. Green is the color of envy. It will be interesting to find out if it rides better than the internally geared hubs like the Uni.5 and the Schlumpf hub. The jackshaft drive type of gearing definitely has potential. The other advantage with the jackshaft gearing is that you can gear it higher than you can with an internally geared hub. Now we need some fast riders to come to Seattle and try to break the 1 hour distance record and the 100 mile speed record using your unicycle. __________________ john_childs (att) hotmail (dott) com Team Never Wash Your Muni My Gallery :: Unicycling Bookmark List :: World Clock

2004-11-12, 07:05 AM	#7
UniBrier Time To Ride Join Date: Aug 2002 Location: Brier, WA USA Age: 50 Posts: 4,171	This may be the machine to conqor the Marymoore Velodrome. Maybe you've heard of the place. __________________ Steve Hop Drop & Roll “If something is too hard to do, then it's not worth doing. You just stick that guitar in the closet next to your shortwave radio, your karate outfit and your unicycle and we'll go inside and watch TV.” – Homer

2004-11-12, 07:08 AM	#8
Naomi Newsgroup User Posts: n/a	Re: Geared 36 "unisk8r" <unisk8r@NoEmail.Message.Poster.at.Unicyclist.com> wrote in message news:unisk8r.1flex5@NoEmail.Message.Poster.at.Unicyclist.com... > > And for what it's worth, I'm calling this a Geared 36", 'cause the only > Coker product is the tire (not even the tube). I don't see why we keep > referring to these as Cokers, That seems very reasonable to me: to call that a coker would be very misleading, or more probably an untruth. You might be tempted to conjure up your own brand name, to be applied to the genre of all unis following the pattern. A KH unicycle is merely a (good) modification of a standard pattern, yours deserves a wider recognition, in the way that Blue Shift now defines that particular geared unicycle . I think your gearing concept would be a nice addition to a smaller wheeled machine, if it could be done. It looks a mean machine and I like it, especially how, with the double gearing, the pedal axis remains in line with the wheel centre. Nice simple concept, not sure how difficult it was to fabricate. Look forward to hearing some road reports. Nao

2004-11-12, 07:17 AM	#9
daino149 On Vacation - till i find a job Join Date: May 2002 Location: San Jose, CA Age: 28 Posts: 2,012	I love the design. What I can't figure out is how the two cranks manage to stay in sync. Is there another gear system on the other side, or are the two cranks connected directly? Or is there something else I don't see? Great job! Daniel __________________ OPPORTUNITYISNOWHERE

2004-11-12, 07:48 AM	#11
Klaas Bil Newsgroup User Posts: n/a	Re: Geared 36 On Thu, 11 Nov 2004 23:18:53 -0600, "unisk8r" wrote: >For the past 8 months one of my fabrication projects has been a geared >36". Great concept! I notice two chain tensioners. Can the tensions be adjusted separately without the drive getting out of true? Maybe that is not needed because both are 22/18. You probably have to adjust chain tension to hit a compromise between friction losses and backlash, maybe you can comment on that? Klaas Bil - Newsgroup Addict -- "Deflating pi does not reduce calories, it just concentrates them. - billham"

2004-11-12, 05:43 PM	#12
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	I used twin dropouts and chain tensioners ala giraffe. Only here there are 2 chains. In a perfect world, there would be no chainline issues. But here, even though I did my best to get the cog separation on the jackshaft equal to the separation between the hub and the crank cogs, it seems that so much tension is required to avoid crank play, that the stress results in a ever-so-slight bend of the jackshaft housing. Those that have peered down the chainline of a giraffe know what this means. You want it perfect. I think this arrangement is fine, and I suspect that the inferior chain has more to do with the necessary tension than the cogs. I've adjusted so much tension that there's friction at the wheel. As for the ride, I will confirm Harper's and Childs' assessment that it is less forgiving. I think that because your inputs are magnified at the wheel due to the gearing, that you have a smaller "sweet spot" of controllability. Crank length is definitely much less of an issue. I think it will just take practice to "get the feel" of it. But it's definitely smoother overall than a direct drive, and the lower cadence was a big motivator for me; I still don't spin well! I'll report more later after I become more familiar with its potential...

2004-11-12, 05:47 PM	#13
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	Daino, John is correct. The cranks are attached via std. square tapers to the 180mm axle (spindle), which is otherwise a smooth and solid stainless steel rod. The Phil Wood company kindly (but for a price) made the longer-than-normal axle for me. The hub rotates faster than the axle due to the gearing. Pete

2004-11-13, 12:28 AM	#14
steveyo Don't feed the machine. Join Date: Jul 2004 Location: Albany NY, US Age: 47 Posts: 2,989	I may have missed this, but how does one shift from one cog to the other, or rather shift the driveshaft's connection from one cog to the other? __________________ steveyo ...like having your own personal rollercoaster... - a few uni race write-ups - muni and kokopelli uni t-shirts, mugs and stickers

2004-11-13, 01:14 AM	#15
unisk8r One Wheel Wander Join Date: Nov 2003 Location: Redmond, WA Posts: 768	Stevyo, no shifting...think 1 wheel track bike. The jackshaft is a solid piece that connects the 2 top cogs as one. Drive pressure goes from the crank up to the jackshaft, then back down to the hub. I rode it again briefly today, and it seems to magnify any input. You step on the pedal and it accelerates. You backpressure the pedals and it slows down, alot more than direct drive. I also notice that the side-to-side effect of pedal pressure is pronounced, not too bad, but maybe that's more to do with the 9" spread of the pedals. That's not much more than a wide-hub direct drive, but there's definite Q-factor. As I pedalled smoother it was minimized. And starts are a bitch, I'm learning all over again! Bottom line is that with less room for pilot error, I'm still working my way up to go fast. I'm doing about 15 (only on the flats so far) with much less pedal effort, but more balancing effort. Last edited by unisk8r; 2004-11-13 at 01:18 AM.

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