Here are some part numbers for the 8x30mm timing belt I am using. This is probably a bit of an over kill for my bike. 62375K72 Chain Sprocket 6497K219 Motor Sprocket 38t, not listed currently on catalog page 6497K224 Shaft Sprocket 64t, not listed currently on catalog page 6086K117 Quick disconnect bushing for 1.25" shaft for chain sprocket
You will need to select a bushing to match the shaft and sprocket. I went around several times before I got it right. I agree with Damon that you should not be seeing the brush heating as bad as you are. Something else is going on. A 24V motor would have to have pretty high currents to move a BMW around with direct drive. You probably need to run the motor at pretty high RPMs and have at least 6:1 ratio. On Mon, Nov 3, 2008 at 5:37 AM, SteveS <[EMAIL PROTECTED]> wrote: > Which belt drive parts did you use? I was looking at McMaster last night, > but the belt drive parts don't have any specs. > > I was running 36V on mine. That shouldn't matter though at low speed, right? > I imagine there it's all about the controller. I'm using an Alltrax 4845 > which should be good for 400A (short term). > > Maybe I should put the thing back together and take some real data. > > - SteveS > > Mark Eidson wrote: >> >> I have a 4.74:1 total drive ration between the motor and wheel and top >> out at 52MPH at about 3000rpm with a 72V pack. >> http://www.evalbum.com/preview.php?vid=1231 >> My motor is a 6.7" with 8 brushes. My belt drive components are from >> McMaster-Carr. >> http://www.mcmaster.com/ >> I really designed my drive ratio for 96 volts but only put in >> 72.......to save weight and cost. 52MPH is fine for me. Acceleration >> is very good. No overheating even in AZ when it is 120F. >> >> >> On Sun, Nov 2, 2008 at 7:20 PM, SteveS <[EMAIL PROTECTED]> wrote: >> >>> >>> Like starting to smoke hot (don't tell Jim!). Right from the brushes - >>> actually one set I think. Could be they aren't set yet as the motor had >>> just >>> been rebuilt. All the brush holders were fairly hot to the touch. The >>> motor >>> housing was cool. I should have run the brushes in with no load. >>> >>> I didn't measure amps - left my Palm with the Alltrax software at work, >>> but >>> I bet I was pulling over 300 motor amps. >>> >>> I know riding around slow in the yard on grass (the bike) is probably >>> worse >>> case, but I really would like a bit more low end. My problem is I have to >>> climb a gravel driveway when I get home, so I need decent low speed power >>> at >>> a lower SOC on the battery. >>> >>> I know you run a lower ratio too Damon, though I think my rear tire is >>> bigger - 19". I calculated I get 2.33 MPH/100 RPM. That gives me 63MPH at >>> 2700 RPM, so I really can afford a higher gear ratio, as I really don't >>> need >>> to go over 50 or 55. The bike seems to roll easily. I did some pull tests >>> with a spring scale on a flat concrete floor and it pulled easily (I >>> forget >>> the value...). >>> >>> In any case, I already tore it down and started planning out how to run a >>> chain reduction to the drive shaft. Actually I think it'll be a better >>> setup >>> physically. Just have a bit of chain noise. BTW is there a source for >>> drive >>> belts? I would think that would be quieter. Since it's before the final >>> 3.36:1 ratio it doesn't have to as beefy as a final drive belt would be - >>> more like a primary belt (if anyone uses them there). I don't know much >>> about chain and belt drives having owned shaft drives for so long now. >>> >>> Anyway, I was grinning a bit! >>> >>> - SteveS >>> >>> damon henry wrote: >>> >>>> >>>> I would not give up on the shaft drive just yet. What do you define as >>>> hot? It's likely that the insulation in your motor is rated up to 180 >>>> deg >>>> Celsius. Try measuring the brushes with a temperature probe after you >>>> heat >>>> things up. How many amps were you pushing through the motor? More amps >>>> will >>>> give you better acceleration (and make things heat up even quicker). And >>>> finally, what speeds will you be doing most of your riding at, what kind >>>> of >>>> RPMs will your motor usually be turning, and how often will you be >>>> riding up >>>> hill? Lugging the motor at low speed around home will heat things up >>>> because >>>> there is no air flow being generated by the internal fan in the motor. >>>> Pulling the same amps to maintain a higher speed, the motor will run >>>> cooler >>>> because of the higher RPMs. >>>> >>>> I have been running my motorcycle for years with a chain and a 14 tooth >>>> (now 13) front sprocket and a 41 tooth rear. That overall ratio sounds >>>> to me >>>> like it is close to what your shaft drive setup provides... unless I am >>>> reading your ratio backwards. >>>> >>>> Having said all that, I can ride my motorcycle around all day long at >>>> low >>>> speed without any heating issues at all. The times that my motor has >>>> been >>>> the hottest has been in the snow when I have used it to drag the kids >>>> around >>>> the cul-de-sac on a sled at very lows speeds. That's easily remedied by >>>> a >>>> well placed armful of snow, but the extra drag of towing the kids really >>>> heats things up. How well does your motorcycle roll? >>>> >>>> damon >>>> >>>> >>>> >>>> >>>> ------------------------------------------------------------------------ >>>> >>>> >>>>> >>>>> Date: Sun, 2 Nov 2008 08:26:43 -0500 >>>>> From: [EMAIL PROTECTED] >>>>> To: listserv@electricmotorcycles.net >>>>> Subject: [ElectricMotorcycles] BMW update >>>>> >>>>> Another milestone (of sorts) in my BMW motorcycle conversion journey. I >>>>> had played around with an Elec-Trak motor direct to the shaft drive, >>>>> which proved woefully inadequate. From taking with several people it >>>>> seemed that I really needed to go to a higher gear ratio (the >>>>> 'built-in' >>>>> ratio is 3.3:1); or, possibly, a bigger motor. Jim Husted found a nice >>>>> 7", 8-brush, motor for me. I thought I'd try it direct just to see, >>>>> which I did yesterday. It did pull away (slowly) from a stop and >>>>> actually had ok acceleration, but the brushes got hot from my low speed >>>>> driving around the yard. >>>>> >>>>> So I guess I'm finally convinced I need to add a gear reduction. I had >>>>> hoped to use a planetary gearset, but really couldn't find anything >>>>> appropriate, so it looks like chain and sprockets. Now I have my winter >>>>> project. >>>>> >>>>> Too bad, as the direct drive was absolutely quite; really sweet. >>>>> >>>>> - SteveS >>>>> >>>>> >>>> >>>> ------------------------------------------------------------------------ >>>> When your life is on the go—take your life with you. Try Windows >>>> Mobile(R) >>>> today <http://clk.atdmt.com/MRT/go/115298558/direct/01/> >>>> ------------------------------------------------------------------------ >>>> >>>> >>>> No virus found in this incoming message. >>>> Checked by AVG - http://www.avg.com Version: 8.0.175 / Virus Database: >>>> 270.8.5/1762 - Release Date: 11/2/2008 9:51 AM >>>> >>>> >>>> >>> >>> >>> >>> ------------------------------------------------------------------------ >>> >>> >>> No virus found in this incoming message. >>> Checked by AVG - http://www.avg.com Version: 8.0.175 / Virus Database: >>> 270.8.5/1764 - Release Date: 11/3/2008 7:46 AM >>> >>> > > > >
