Looking for a Source for Toothed Belt Drive Pulleys

[Silvaire]

Are there any inventors/modifiers that know of a good source to buy STOCK toothed pulleys from? (Stock belts seem to be widely available, but not stock pulleys.)

I can find suppliers that will custom make pulleys for you, but like any custom machined component I am sure the cost is understandably quite dear. If you have found someone who offers stock pulleys I'd like to know.

From looking at various sites, there seems to be a bewildering number of different drive systems used - even of those of nearly the same size. It seems that standardization has been slow to come about in this field.

My project likely will use something around a 5M or 8M pitch by 15mm width for the first reduction from the engine. I plan to use about a 20mm to 25mm diameter steel pulley on the clutch. The driven pulley will be around 75mm to 100mm and aluminum. Hopefully these sizes are conservative for use on a Subaru EH035.

(Note: I DO know that building your own design ALWAYS costs more than buying a kit! But nothing available has everything I'm looking for, I have some ideas. The fun for me is in designing and building something just because I think I can do it - and I'd like to think there is a possibility that it just might be the next "better mousetrap"...)

 

[sjacome]

hope it can help u!

here's a link obtained somewhere in this huge forum

http://www.wmberg.com/

 

[ocscully]

Try Pfeifer Industries in Naperville Ill. They have a really good supply of all things Metric Timing Belt http://pfeiferindustries.com/ I bought several pulleys from them last spring and they are a great company to do business with. They have alot of experience in the go-kart industry as well as alot of experience doing custom one-off prototyping. Check out their site and then contact either Jim or Brian via e-mail or phone they are very helpfull and willing to share information and ideas. If they don't have what you need already in stock they can make it for you.

Here is a link to a thread on a long term project of mine that uses metric timing belts. Although its a frame mount using the Honda GXH50 the photos might help http://www.motoredbikes.com/showthread.php?t=7580&page=3&highlight=giantstone

ocscully

 

[Happy Valley]

Mention Robin 35's and innovating a belt drive for it and I'm all ears. What have you got so far, let's discuss.

 

[Silvaire]

Right now I'm at the "dreaming and drawing" stage. The Subaru EH035 appeals to me because of its small physical size and its high quality. Many people are using it with good success. I've owned a number of pieces of yard equipment that use "micro" 4-stroke engines, including a Ryobi weed eater and a Honda tiller with a GX31 engine. The GX31 is a nice engine, but it is bulkier than the Subaru, and now that it has been replaced by the GX35 it seems to have little support. The Ryobi works fine in a weed eater, but it has low power output is very cheaply made (not that it was ever a contender for a motororized bike engine). These are the only engines I have had actual experience with. Other than the line of Honda engines and the Subarus, there really aren't any other well made micro 4 strokes, - and for me it must be a 4 stroke. The GX50 seems unnecessarily large and heavy for a bike that will be pedaled as well as powered. Thus, I have chosen to work with the Subaru.

I have in mind building a drive system that will allow the bicycle can be ridden with minimal drag when not using the engine. Such a concept may not be in the general consensus of those of this forum, but to me, if a bicycle with a motor mounted on it cannot be ridden efficiently when you are not using the motor, then what do you really have? (NO, I'm NOT going to answer that one!)

Were it not for wanting minimal drag when not motoring, I'd strongly consider just buying a GEBE kit. I have studied the GEBE and am quite impressed with it. I think their snap on drive ring with its self centering properties that can be installed by one with limited mechanical skills is a real stoke of genius. I did get a chuckle reading a post where someone was disappointed by the small number of parts in the GEBE kit -as if they weren't getting their moneys worth! Isn't simplicity a hallmark of good design?

Anyway, my comments aren't about the GEBE system - except to say that it provides the level of drive train efficiency that I want to have in my own system. The Subaru seems to work fine for them, so I expect the Subaru to be quite adequate power-wise for any efficiently designed drive system. My goals aren't to go fast, but to have a smooth, quiet, reliable, rider friendly bike that can be efficiently pedaled when not motoring.

I don't expect that I will have any hardware assembled for a matter of weeks - or maybe months. Right now I'm researching parts and ideas and making drawings. I will indeed post reports of my progress when I have something to show that others might find interesting.

 

[ocscully]

Here are a couple of links too some items that may help you accomplish your goal. First is the Grubee HD Hub with a lefthand threaded flanged freewheel for the driven sprocket. http://www.bicycle-engines.com/freewheel-sprocket-axle-wbrake-p-297.html
You could mount your final driven pully to this flanged freewheel to get the pedaling quality you are looking for. The Hub as speced by grubee is spaced for a SS freewheel on the pedal drive side but the axle can be flipped 180 degrees and a few spacers added and you can mount a multi-speed freewheel if you so desire.

The Second Item is the Jackshaft setup sold by MaxTorque. http://www.maxtorque.com/html/jackshaft.html The rectangular steel Tube that forms the base could be the the top of your rack.

Just soom ideas to consider during your brain-storming/design process.

ocscully

 

[Happy Valley]

Good enough. Seems well thought out and sounds like a winner.

I don't think the worthiness of R/S EHO35's will be too hard to find around here- lol http://i404.photobucket.com/albums/pp123/dback19/035.jpg
-at least for those who have tried a bunch of different engines. I'm using them and others....and for my taste they are just right, smooth, enough power and most important to me....quiet. Of course I'm all about MABs, motor assisted bicycles that maintain all of the functionality of the pre-motorized bike 100%.

As well, I've long been thinking of utilizing a belt drive. Gebe has been a major contributor in this regard with many satisfied customers. My interest lies in a bit different track, I want a rack mounted system that does not drive off the spokes. This would be most likely off the hub but even possibly off the rim, if that could be engineered.

BTW, it occurs to me you didn't state where you plan to mount the engine, frame or rack?

 

[Silvaire]

My thought at this time is to mount the engine as tightly and cleanly as possible behind and below the seat. The term of choice for an engine mounted anywhere near this location seems to be generally known as a "rack mount". (To me, the term "rack mount" implies a somewhat crude looking engine mount made using several long straight members and that somewhat resembles a conventional rear bicycle rack intended for carrying small cargo.)

I don't want to change the terminology of the art, so I guess I could consider that my plan is to have a rack mounted engine. Rigidly mounting an engine requires a minimum of 3 contact points with the frame (considering that these points are compression/tension loaded only). Even fewer points can be used if any of the points can absorb torsional and/or bending loads as well. I have no problem using the solutions that others have used and refined over time, but sometimes designing with a clean sheet of paper can generate some possibilities that others have not considered. I'd like to come up with an engine mount that is more compact and simpler in appearance than what I have seen so far.

 

[mabman]

You mean like this? Not the greatest picture but the motor is placed where you want it. The typical rack mount is usually located more over the center of the axle.

If you keep the overall weight of your system as low as possible and use a good bike for your base and keep drag to a minimum with your drive train I think you will be surprised at how well the bike still pedals as a bike. One thing for sure is to make sure you have the gearing to be able to maintain cadence while the motor is assisting. If your engine/drive is capable of 30 mph then you need to have a gear that you can pedal at that speed at your optimal cadence in other words? Most here don't want to pedal, but if you do it is quite fun and you get better gas mileage also and can maintain higher speed on uphills, false flats and against headwinds.

 

[Happy Valley]

Well gee, thanks for taking the time to explain all that setting me straight
and forgiving the inaccuracies of language in using the loosely vernacular "frame mount" or "rack mount" in the interest of discussion......here on a discussion forum.