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__Tango
15 January 2012, 1741
So, in reading the specs on the new Zeros (http://www.elmoto.net/showthread.php/1960-2012-Zeros-are-arriving-at-dealerships?p=24849#post24849), i was thinking about belt drives. With the small tooth pitch of the belt (8mm or close to 5/16") vs. a chain (example 520 chain is 5/8" or almost just under 16mm pitch), one might think it'd be easier to get drive ratios that are better suited vs. a chain.

Is this true?

Also, how feasible is a belt drive for DIY folks like (some of) us?

podolefsky
15 January 2012, 1754
I looked into this a lot and there are a few problems. Main one is finding rear sprockets large enough for ratios greater than 3:1 or so. They're out there, but they're expensive and usually made of cast iron (heavy).

You can find aluminum Harley sprockets, but they're for a larger pitch, so still not big enough to get a good ratio.

I think Ripperton ran a belt drive, but it was custom made and a pretty low ratio for racing (IIRC).

I'm guessing Zero is making their own (or has a custom supplier). Would be nice if they sold them.

__Tango
15 January 2012, 1808
I see. I looked at the specs of the Gates belt (the one that the zeros use), and i can't tell what the large sprocket is. I wonder how hard it'd be to CNC manufacture one out of Aluminum?

TonyHelms
15 January 2012, 1812
I have done a lot of research on this too, and it is possible. But would end up costing a LOT more then doing say a number 40 pitch chain. I think the biggest advantage would be the noise reduction! i hate that all I hear is my chain, I wish it were more like a Tesla where all you hear is the motor and gears wind up (sounds like a jet engine)

Richard230
15 January 2012, 1909
I see. I looked at the specs of the Gates belt (the one that the zeros use), and i can't tell what the large sprocket is. I wonder how hard it'd be to CNC manufacture one out of Aluminum?

From the specs, it appears that Zero is using a 28 tooth front cogwheel and a 132 tooth rear cogwheel on the S model and a 25 tooth front sprocket on the DS model (if that was your question). I also find it interesting that Zero offers a chain-drive version for the DS (according to the manual), presumably for those owners who want to ride the bike off-road.

ZoomSmith
15 January 2012, 2001
one might think it'd be easier to get drive ratios that are better suited vs. a chain.

There are several design limitations for belt drives. The biggest factor is the minimum sprocket (bend radius) size. Small sprockets bend the belt too much and reduces the life-cycle of the belt. There are also torque and RPM limitations to work around.

The Gates Poly Chain GT Carbon Design Manual is a great reference: Polychain Design Guide (http://www.gates.com/catalogs/file_display.cfm?file=Poly_Chain_GT_Carbon_Design_ Manual.pdf&thisPath=gates\catalogs&requesting=ptcatalog&location_id=524)

I like the Zero belt drive, but would have opted for the next size wider on the belt.

__Tango
15 January 2012, 2057
Ripperton was interested for the weight savings as well.


Does Gates (or any other belt company) give out the specs of the tooth profile so you could cut your own sprockets? a sheet of 12"x12" aluminum (6061 or 7075) in say 5x8" is well under $20. Given some time on a CNC mill and with the proper profile, you could probably cut it to the proper shape.

As far as the minimum sprocket, that makes sense, though i thought that the smaller pitch would give you more of an ability to get a good drive ratio. For some reason, in my pea brain, i have this feeling that it'd be easier to cut a rear sprocket for a belt than for a chain. I have no emperical evidence nor experience to support that gut feeling though...

podolefsky
15 January 2012, 2138
I think Gates has CAD models on their website. I'd love to see someone cut one of these on a CNC...seems like a really big job.

One idea I had was to get a cast iron gear (which you can sometimes find on e-bay cheap), cut most of it out and replace with an aluminum hub.

But if you don't have a frame set up for belt, you have to take the swingarm off to change it. I finally decided it was to big a PITA and just went with a chain, especially since I'm still messing with gear ratios. You pretty much have to have your gears nails down if you invest in a belt drive.

ZoomSmith
15 January 2012, 2151
Given some time on a CNC mill and with the proper profile, you could probably cut it to the proper shape.
I don't think Gates publishes that profile geometry (still looking), but their authorized partners have access to it.


i have this feeling that it'd be easier to cut a rear sprocket for a belt than for a chain. I have no emperical evidence nor experience to support that gut feeling though...
Given the number of teeth required is higher for synchronous drives and the material you are cutting is thicker (2x-3x), I'd have a hard time backing that theory.

Really not trying to discourage you from attempting it. I'm sure it can be done, but the effort ($$) will be significant.

podolefsky
15 January 2012, 2219
I think you can find the profiles here (http://www.gates.com/designview/index.cfm?location_id=866) (but not positive).

but like ZoomSmith said, this would be a huge undertaking. Poly chain profile isn't a simple profile.

I'd LOVE to be wrong about this. If anyone can find someone that will do custom belt drive sprockets for similar prices (even 2-3X) that of chain, I'd be very interested.

helco
15 January 2012, 2231
im gearing my ICE harley for acceleration so small drive , big final drive ,13/14 front 72 rear , thats about as big a standard rear as you can buy . as to machining your own , i have my own cnc machine shop and as a project it would be fine to machine but as a cost exercise the time it would take would be prohibative , and then you get into custum belt lengths and they become difficult to sorce and very expensive .
good old fashion chain is just easier to manage and getting custum sizes is a lot easier .
I started looking at custum belts and drives and soon put it to one side as something that you need deep pockets for .
And belt alinment is an art all in it self if you are to get the best out of your expensive drive.

helco
16 January 2012, 1919
just worked on a suzuki s40 looks like one of the larger final belt drives and there are some on e-bay for $25 might be worth a look ,if the ratio works for you ..........................?

podolefsky
16 January 2012, 2008
i looked those up, i think they're 68 tooth? you'd need a 13-14 tooth front for 5:1. i don't think that's an option, unfortunately.

same with harley sprockets, they go up to about 72 tooth.

i think that's why Zeroo is using 8mm pitch, so they can actually get the ratio needed.

__Tango
16 January 2012, 2133
i looked those up, i think they're 68 tooth? you'd need a 13-14 tooth front for 5:1. i don't think that's an option, unfortunately.

same with harley sprockets, they go up to about 72 tooth.

i think that's why Zeroo is using 8mm pitch, so they can actually get the ratio needed.

Hence part of my original post about using belts to get a better gear ratio.

Though, i had forgotten about the whole "remove the swingarm to get at the belt" thing. That seems yucky. :)

helco
16 January 2012, 2208
the remove the swing thing has always been there ,but kind of ignored cos at the milage you would do ,not a 100mile a day commute , the belt would last forever if set up true and square, think the biggest harley stock ive found is 76 so at 4-1 thats 19 not bad and at 5-1 thats 15 , which if memory serves is one of there standard sizes , i got a link i can send you for belt length and tooth count if you like , but a big harley dealer like J&P has it in there on line catalog , with a belt calculater in it, you might even try looking at some of the beull stuff they got a little more odd sizes , look at the v-rod too , the thing to do is find a stock or near stock set up and then redrill the drives to match your rear wheel pattern , i can help if you got no-one near bye that can , it costs the same to mail it down the street as to mail to the islands if you use USPS , just let me know if i can help........................

podolefsky
16 January 2012, 2213
really? you can get a 15 tooth front pulley?

if that's right, I'd definitely be interested.

helco
16 January 2012, 2232
ok let me look it up tomorrow when i get back to my shop ,i will look at the off the shelf sizes ,most of which you can get used off e-bay for a quarter of the cost and i will post you something .....................

podolefsky
16 January 2012, 2337
Sweet, thanks.

teddillard
17 January 2012, 0319
A motorcycle with a belt drive is a Crime Against Nature. :D

Aside from my usual kneejerk fundamentalist position on motorcycle design, I've been looking into the belts too, just for the joke of having a bike that goes wicked fast almost silently, but, the gear ratio issue is what's put me off.

I have a lot of fun messing with ratios- always did, especially with trail bikes. I don't actually see myself settling on a final ratio- in fact, the more I go down this road, the more I'm even feeling like I'm not even going to be settling on a final motor. I can literally switch motors out in 10 minutes, along with the drive ratio...

__Tango
17 January 2012, 0741
You know Ted, for most folks, what you said probably isn't their main concern, however for a group like us, that's definitely a consideration. I imagine having the ability to muck with the drive config without having to remove the swingarm may be desirable.

Then again having the silent factor would be neat too. :)

Richard230
17 January 2012, 0851
I guess if anyone wants to really use a belt on their el moto and couldn't find a ratio low enough, you could always cobble together a secondary drive like all IC motorcycles have to reduce the rpms between the motor output shaft and the drive sprocket. You could use gears, a chain or another belt to reduce the ratio to where you wanted it. Of course you would gain some weight, loose useful space and reduce the efficiency of the drive system, so sticking with a chain is probably the lesser of two evils, especially considering the cost and effort to accomplish that solution.

I too was thinking about the issue of having to remove the swing arm when replacing a belt and then I realized that doing so would be the perfect time to grease the swing arm bearings and that is always a good thing to do as they tend to be neglected by most owners.

Which brings up one other observation that I have about the 2012 Zero's owners manual. It doesn't tell you how to remove and reinstall the front and rear wheels. I have read a whole lot of motorcycle owners manuals over the years and I think this is the first one that omitted that task.

Allen_okc
17 January 2012, 1013
personally i like the chain drive - its the only noise the bike makes...

podolefsky
17 January 2012, 1141
personally i like the chain drive - its the only noise the bike makes...

true - it is what makes people turn and look as i'm riding down the street.

that sound is pretty unique to elmotos...kind of like the iconic sound of a harley. wouldn't be the same without it.

StanSimmons
17 January 2012, 1518
I'm looking at the Goodyear PD belt system for my Honda ST1100 shaft drive conversion.

I want nothin' but tire and wind noise when I'm riding... I am adding a REALLY loud Stebel Nautilus horn to wake up the cagers, and I'm toying with adding a noise making system that will have several different sounds available, including the factory ST1100 sound, perhaps a Harley sound (to mess with the "loud pipes" guys), a diesel truck sound and definitely the Jetsons car sound. :)

Richard230
17 January 2012, 1525
I'm looking at the Goodyear PD belt system for my Honda ST1100 shaft drive conversion.

I want nothin' but tire and wind noise when I'm riding... I am adding a REALLY loud Stebel Nautilus horn to wake up the cagers, and I'm toying with adding a noise making system that will have several different sounds available, including the factory ST1100 sound, perhaps a Harley sound (to mess with the "loud pipes" guys), a diesel truck sound and definitely the Jetsons car sound. :)

I thought they used to make "horns" with various odd noises some years ago. They were popular in cars for a while during the 1970's, I think.

Those loud horns are great for waking up auto drivers, but might give the occasional random pedestrian in the vicinity a heart attack, though.

helco
17 January 2012, 1705
ok humble pie time ......stock rear pulley 66-72 and stock fronts 29-32 ( 27 and 28 market ) ,the 15 tooth i was thinkin is only 1/2 " wide and would be about as much use as a chocolate fire guard ! sorry to led you down a path , thats why i said about checkin me parts catalog something sounded to good , and normally if it sounds to good to be true it normally aint !!!!!!!!! :(

podolefsky
17 January 2012, 1728
No worries...already talked myself out of it anyway :)

Allen_okc
18 January 2012, 0620
I am adding a REALLY loud Stebel Nautilus horn to wake up the cagers, and I'm toying with adding a noise making system that will have several different sounds available, including the factory ST1100 sound, perhaps a Harley sound (to mess with the "loud pipes" guys), a diesel truck sound and definitely the Jetsons car sound. :)

i was looking at the sound generators myself - i was in favor of sounds that would freak the public out with something like train noise, jet airliner, steam locomotive or even chitty chitty bang bang - just a thought...