GEBE Gearing Questions

Perhaps your calculations are off ? You would probably need to have the items in hand to do a proper calculation; just sayin'...
 
Hills are conquered via familiarity and technique.

When in 7th speed, the momentum has to get around 25 mph for your pedals to catch up to the motor and be able to assist.

Momentum also gets you up in the lower 40 mph range on the bottom of a steep grade, which is full throttle PLUS. In other words, you want to be full throttle at the bottom of the grade to climb up the other side easier.

If you were easing along at half throttle on level ground, then going downhill, you could stay half throttle. If you are going full throttle, then decending, might as well stay full.

There is an adjustment a rider goes through to get acquainted with the engine/clutch potentials, the engine "talks to you", telling you either ease off or give it more throttle on both descents and ascents.

That is also why you can't let too many strangers ride, they won't know how to communicate with the engine on uphill climbs.
 
This should be the definitive answer, straight from Julia at GEBE in response to an email I sent:

Actual ratios are dependant on a number of factors, including actual tire size, belt length and deflection. Basic ratios are 19:1 to 24.5:1 - the #12 gear offers ratio of 22.25:1
Your assumption is incorrect - 296 teeth wouldn't be the accurate count-IF teeth were all the way around the drive ring; two spaces w/o teeth is not same distance as portion with teeth.

By my calculations 22.25:1 gives a top speed of:
8000 revolutions/minute * 26/22.25 inches/revolution * pi * 60 minutes/hour / 63360 inches/mile = 27.86 mph which is in line with quoted speeds

Thanks Julia!
 
I am getting 34mph on the flat with the #13 gear which seems from tentative calculation to be about right... however I am using the HTD gears..

Jemma xx
 
No one has posted an answer to the original question:
"How many teeth are on the motor and wheel pulleys?"

GEBE does not state on their site how many teeth the drive ring has - only the number of teeth of the various pinion options.

Regarding the drive ring they only make the cryptic statement "...less resistance allows for 148 teeth in the belt track..." but they do not state how many teeth there are on the drive ring.

Crunching the numbers, there just have to be more than 148 teeth on the drive ring.

From the information that mppardee posted above, from a response from Julia at GEBE stating:
"the #12 gear offers ratio of 22.25:1"
(Despite this number having four significant digits, it can't be all that accurate. This would work out with the drive ring having 265 1/2 teeth, which isn't physically possible.)

So....

Is there anyone out there who knows this number for certain (or who has a GEBE kit and would be willing to count number of teeth that there are on the drive ring)?

A BIG "thanks in advance"!

***********************************


Edit:

A thought just occured to me...

Are there ANY TEETH AT ALL on the drive ring itself???

If not, can anyone confirm this for me?

Another "thanks in advance"!
 
Last edited:
Don't know how it works but it works great.
My GEBE Tanaka 32cc does 32MPH on my bike.
That's 1 MPH per CC
Ask yourself this. Do you really want to go over 32mph downhill or up hill for that matter?
The real factor is do you want Chain,belt or friction.. then go from there ...
I you want to go fast and freewheel down hill the only real option is the STATON chain drive with freewheel, and if you got the bucks get the nuvinchi hub with it..
You will be a speed demen!!!!
 
No one has posted an answer to the original question:
"How many teeth are on the motor and wheel pulleys?"

GEBE does not state on their site how many teeth the drive ring has - only the number of teeth of the various pinion options.

Regarding the drive ring they only make the cryptic statement "...less resistance allows for 148 teeth in the belt track..." but they do not state how many teeth there are on the drive ring.

Crunching the numbers, there just have to be more than 148 teeth on the drive ring.

From the information that mppardee posted above, from a response from Julia at GEBE stating:
"the #12 gear offers ratio of 22.25:1"
(Despite this number having four significant digits, it can't be all that accurate. This would work out with the drive ring having 265 1/2 teeth, which isn't physically possible.)

So....

Is there anyone out there who knows this number for certain (or who has a GEBE kit and would be willing to count number of teeth that there are on the drive ring)?

A BIG "thanks in advance"!

***********************************


Edit:

A thought just occured to me...

Are there ANY TEETH AT ALL on the drive ring itself???

If not, can anyone confirm this for me?

Another "thanks in advance"!

I have a new drive ring sitting by me. They are 74 teeth
WITH 7/32" SPACING
 
you are forgetting to consider the # of teeth that could / would occupy the "empty" area.

the 267T that ocscully gave is correct for working out the ratios using varying drive pulleys.

steve
 
Thanks all for your help on this.

From what I am able to piece together from the three pertinent replies, the GEBE drive ring has some teeth on it, but that it has blank areas between the teeth. Why they would choose make it like this is still a mystery to me though.

Most important to me is that it has an effective equivalent of 267 teeth. I don't plan on buying a GEBE kit, so at this time I won't try to figure out just why they designed the drive ring as they did. I only wanted to be able to figure their total reduction in consideration for my own design.
 
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