Belt Drive Meditations

I'm writing the email right now and will report back with my findings. What aspect of my terrain should I concern myself with when choosing a 13 or 14 tooth driver?

Thanks for your continued help. You've been more than generous.

The smaller the driver that you use the greater your reduction and there for the lower final gear you will have, meaning better hill climbing lower top speed. The bigger driver will add top end but you will have to pedal more to get the bike going and to climb hills. The GEBE Site indicates a 10% change for each tooth added or subtracted. Read the information on the drivers at the link above, its all explained there. Ask GEBE for a recommendation based on the motor you plan to use.

Okay, ocscully, here's the information I was able to gather from Golden Eagle.

"Hi Jon,
Thanks for the details, don't know that we'd ever be on the same page, but I hear where you're coming from:)!! Eagles are bicycle Assist units, you intend to build that motorcycle, yourself - please, just wear your helmet (thanks).

Yes, the 4n1 key is included with order of the ring

The gears are 5/16" - 24 thread pattern, to fit drive shaft of our clutch housing/bell assembly.

I've heard the Honda 50 is available in either a wet or dry clutch, (supposedly one fits, the other doesn't) several customers have purchased kits, intending to mount the 50, but cannot recall further calls or orders - leads me to believe it didn't work out so well.

Bolt hole pattern on our 76/78mm clutch housing is:
1) measure bolt holes - diagonally, left top to bottom right=3 7/8 "
2) measure bolt holes - top left to top right=2 3/4"
3) measure from outside edge of clutch shoe, straight across drum to opposite, outside edge of clutch shoe.=3"

There are parts houses where you can buy gears of different bore and timing belts of different pitch and length and, sorry, I don't have the specifics, nor am I at liberty to disclose.

Best of luck on your 'labor of love' and you're sure in the right place (at MBc) to get help working thru the rough spots.

Best Regards,

I'm still in the process of dissecting it all.

Basically they are telling you that they have no intention of helping you determine weather or not their parts will work with what you are trying to do. So we may have to rely on members of mbc to get the information. I sent an e-mail to the folks at Max Torque earlier today asking about their HTD Clutches and got a very helpful reply from the owner of the company. Their instock 5mm pitch HTD clutch is a 23t which is to large for what you are trying to accomplish. As I said before you need either a 13 or 14. The owner of Max Torque's son is the owner of Pfeifer Industries and the smallest 5mm driver they offer is 14t I believe. I'm going to try and contact the folks at Max Torque tomorrow by phone and talk with them about a clutch for my project. Judging from the e-mail I recieved from them today they have experience customizing clutches specifically for the Honda GXH50. I'll forward the e-mail to you if you wish and also ask them if they could build a clutch for you with a driver supplied from GEBE. If you decide to continue to persue this type of drive train you may just have to make the decision to jump in and solve the problems as the show up. But I'm sure that in can be made to work. Despite the secracy GEBE is showing about their parts there isn't any thing out of the norm for them. Still I think the main hurdle for you is going to be price. Its been my experience when you start on a project like this where you are mixing and trying to match various parts it can get expensive very quickly, and alway in the back of your mind is I can just get a build kit from for $200.00 and be done with it. But if you get alot of satisfaction out of putting together something out of the ordinary, then the price becomes less of hurdle.

I could just build a kit from bicycle-engines, but where's the fun in that? I'm going to email Pfeifer tomorrow regarding a clutch and some pricing info.
I could just build a kit from bicycle-engines, but where's the fun in that? I'm going to email Pfeifer tomorrow regarding a clutch and some pricing info.

The man you want to contact is, I'll be calling him tomorrow as well.

I just did a search on the GEBE belt and sure enough the information is right here on mbc. The GEBE belt is a 5mm pitch, 9mm wide, and 1635mm length.

The GEBE rear drive ring has a dia. at the belt surface of 133cm. and an approx. number of teeth/grooves of 266? approx./estimated due to the way the GEBE ring is made with sections of teeth/grooves every 90 degrees around the dia. and sections where there are no teeth/grooves.

Based on the info. GEBE sent you I'm assuming the drivers they sell have a bore of 5/16 in.

I just did some quick math and the 13 will give you 20.4:1 reduction, the 14t will give you 19:1 and a 15t would give you 17.7:1

The 133cm measure ment above was taken from another post on this board and does not seem to be accuarte. That means the ring is 50 some inches in dia.

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I haven't gotten any recent emails. Any luck, ocscully?

I had a good conversation with Jim Donavan the owner of Max Torque on Friday, and we talked about a HTD Clutch for the system for my project. We talked briefly about wat the smallest driver he could attach to one of his clutches and still work with the 5/8in. dia of the Honda Engine and he said he would get back to me with an e-mail with the answer as well as the name of who at Pfeifer Industries I should contact about some other parts I'm considering. But so far I've not heard anything from him either? I have done some checking at the Pfeifer Industries web site and in their tech section they list the various dia. of the drivers and pulleys they sell and I'm beginning to think that You won't be able to get a small enough driver on the clutch to go direct to the GEBE Drive Ring? So that puts you back into the world of a Jackshaft to get the reduction you will need. The jackshaft opes up many possabilities, but also added expense. One idea would be to locate the jackshaft such that you could use all GEBE parts including their belt. Or bite the expense bullet and build a system like I'm envisioning for my project.

If I don't hear back from Jim buy tomorrow at lunch I'll call him again to see if he has any updates for me.

Hm, that's what I was afraid of. Well, I'm not going to give up until I know for sure. I might make a phone call tomorrow as well. I appreciate the update.
Well, I just got an email from Jim as well. He said his smallest inhouse clutch was 17 tooth. I inquired about the possibility of slaving one of the GEBE gears to his clutch, it's my last hope on the belt drive front at this point.

We'll see what happens.