Please advise me on a homemade motorcycle

[Hummina Shadeeba]

Going with (2) 21mm carbon polychain belts. In the guide you do all the math to figure how much torque the belt will see..then they say throw that number out the window and consider if it’ll be used in an abusive way such as on a motorcycle as apposed to on a conveyer belt and assume double the load.

I’m going to remove the shrink wrap from the cells and dip them in epoxy. I think the wrappers are the weakest link in the potted battery/motor mount. Do u think the bare steel cells will be a boon or hinderance to the strength? I plan to vacuum in chopped glass too

If need be I can glue a key to the frame and cut a keyway in the part

These leopard motors are pretty crappy with a huge air gap n thin magnets.

 

[Hummina Shadeeba]

im far from done. pulleys, especially a custom made one to mount to this adaptable freewheel i have with 4 bolt holes, that i then will mount to the uber rare, no longer made i think, dual drive hub from profile racing...is expensive. all n all a pulley set up is likely to cost maybe 8x more than a chain set-up. but im still in it.

for the motor i got doing 5hp and 7000rpm going through two belts and a jackshaft with two 3.1:1 reductions to the rear 24” wheel a 8mm pitch 12mm wide belt is more than adequate. so 12mm and add some flanges and its 21mm wide and 450-500$..just for that one custom pulley. so looking to china. the two smaller 22-24 tooth would be like 70$ each and the bigger 70 tooth are like 150$ minimum. thats before gettting the "bushings" that mount them, unless you want to mess with set screws or pins and that trouble. in hindsight i wouldnt have gone into this if i knew it was going to be possibly 1000$ just for the drive system. but china seems to do "gt" compatible pulleys (higher torque) so who knows and will find out tonight the overall china pulley cost. ill add it in this post and not add any more to this thread till something monumental happens.

i have spent a lot of time figuring how to pot the cells and what to pot them in that can also be used as a motor mount. it need be both flexible enough to not crack from the cell's slight expansion yet not so flexible as to bend from the torque of the motor so settled on a 95duro pu that i'll strategically add carbon to.

the plan is to pot just the battery and mounting bolts. ill pot them when i have a completed aluminum motor mount plate that i will bolt it to, and when its here i'll use the aluminum plate to orient the mounting bolts as the resin sets.

if it spins on the downtube i can add a keyway or simply pour some resin down the crack.

and a pic of a bike frame you could add a belt without needing to have a breakable frame. was thinking be nice to do that and run a bearing inside a bearing, internal and external bearings in the bottom bracket shell, so could run the motor jackshaft through it and also have cranks and pedals...and maybe somehow add a rachet to pedal..so only need one belt going to rear wheel. maybe one day
https://imgur.com/a/ZyT1Fvg


I’m still going to strip the wraps off all the cells and dip them in epoxy. Otherwise the steel cell, which I think could be a functional constructive part is a weakness


24” wheels. Suspension fork for 26” wheels. Super long seatpost.

 

[marka-ee]

It perplexes me why you'd use a 160kV motor to run a bike at 400-500 wheel RPM. The extreme amount of reduction required seems needlessly complicated and lossy, especially if it's belts.

Reminds me of the trend a few years back on this forum where the idea was to use a high rpm motor with a belt reduction, in a mid motor mount. The demo videos sound always reminded me of a dentist office, the noise was obnoxious .

Potting the battery ? You know sometimes a cell goes bad and needs to be swapped.

 

[Hummina Shadeeba]

I haven’t come across a thread or a bike with belts yet although I haven’t looked. Were the loud ones back then running a sine or foc program? I assumed it wouldn’t sound bad.
A main motive for doing it is I figure it’ll be more efficient than pretty much any other drive out there utilizing speed to gain power as apposed to relying on motor torque and subsequent high copper losses. And will have the motor’s exposed coils cooling in the wind. Belts last. Will look cool. Can get more power to weight or volume.

Potted batteries are pretty common. I think me damaging them if not potted is a more likely problem

Getting closer

Getting the gear reduction is more complicated but not too problematic so far and I enjoy the challenge. Don’t know why you’d say lossy. (Noisy?). Surely more efficient than the Mac hub I had with plastic planetary gears and 5:1. I’ve even read belts can be more efficient than chains when under heavy load.

 

[Balmorhea]

Belts are inefficient compared to sprockets for the same reasons that tires on pavement are inefficient compared to steel wheels on steel rails. There’s nothing magic about them; they’re just rubber. Rubber has hysteresis and scrub to a different order of magnitude than steel.

 

[Hummina Shadeeba]

Not necessarily:
https://www.cyclingabout.com/belt-drivetrain-efficiency-lab-testing/


Belts aren’t just rubber

 

[Balmorhea]

Not necessarily:
https://www.cyclingabout.com/belt-drivetrain-efficiency-lab-testing/


Belts aren’t just rubber

Those folks weren’t testing the increased friction in other parts due to high belt tension. You don’t have to work with belts much to feel firsthand how much drag they add to the system. I am willing to believe they’re less awful at high pedal power, but I’m not willing to ride at high power all the time.

Drive belts have been around the entire time that bikes have been around, and yet they still aren’t widely adopted. Why do you think that is?

Sometimes it seems like e-bike enthusiasts are systematically dragging up all the dumb ideas that have been tried for bikes and rejected time and again over the last 150 years, just because they don’t have to suffer to provide the extra power that those dumb ideas cost.

 

[Hummina Shadeeba]

Not necessarily:
https://www.cyclingabout.com/belt-drivetrain-efficiency-lab-testing/


Belts aren’t just rubber

Drive belts have been around the entire time that bikes have been around, and yet they still aren’t widely adopted. Why do you think that is?

a belt from 120 years ago was probably leather. Not widely adopted today for many reasons but efficiency doesn’t seem to be one. if you want gears on the other hand The internal hubs that go with them aren’t as efficient and are more expensive than derailleurs and chains but a lot of people have been going that way and a lot of manufacturers make that. On a single speed a belt rocks and has many advantages.

If you have a link to a dumb dual belt w a jack shaft drive bring it. Don’t just call it dumb show it.

 

[markz]

Drive belts have been around the entire time that bikes have been around, and yet they still aren’t widely adopted. Why do you think that is?

I will stick with 7 and 8 speed gear train with chains and 26" until I am forced to change due to availability in store. But they wont be going anywhere, 26" aint absolete and aint antique.

 

[Hummina Shadeeba]

Sometimes it seems like e-bike enthusiasts are systematically dragging up all the dumb ideas that have been tried for bikes and rejected time and again over the last 150 years, just because they don’t have to suffer to provide the extra power that those dumb ideas cost.

Have you heard of the sur Ron? Has jackshaft and one belt stock and you can add another as an option. Is that bike a dumb idea?

 

[Balmorhea]

Sometimes it seems like e-bike enthusiasts are systematically dragging up all the dumb ideas that have been tried for bikes and rejected time and again over the last 150 years, just because they don’t have to suffer to provide the extra power that those dumb ideas cost.

Have you heard of the sur Ron? Has jackshaft and one belt stock and you can add another as an option. Is that bike a dumb idea?

Well, since you ask, yes. Harley Davidsons have used toothed belts for ages now, and they're dumb too.

If you don't think Sur-Ron is a dumb bike, you should try doing a five mile commute on one with the battery unplugged.

 

[serious_sam]

If you don't think Sur-Ron is a dumb bike, you should try doing a five mile commute on one with the battery unplugged.

Using that logic, you should try a five mile commute in a Tesla with the battery unplugged. Or a five mile commute in a gasser with the fuel turned off.

 

[Balmorhea]

If you don't think Sur-Ron is a dumb bike, you should try doing a five mile commute on one with the battery unplugged.

Using that logic, you should try a five mile commute in a Tesla with the battery unplugged. Or a five mile commute in a gasser with the fuel turned off.

A Tesla kicks ass compared to a stinking gas car. But a Sur-Ron is super weak compared to a stinking gas motorcycle.

 

[Hummina Shadeeba]

Not necessarily:

https://www.google.com/amp/s/electrek.co/2020/02/11/watch-electric-sur-ron-race-a-6x-as-powerful-gas-dirt-bike-and-place-your-bets/amp/

The storm bee is coming!!


Power isn’t everything and neither is the ability to ride it home when out of power. maybe not breaking is everything. with talk of this being done long ago and a bad idea im hoping you post an example.





moving to this 130kv bigger motor and will be 9.4:1 overall gear ratio: 24:70 at the wheel and 24:78 coming off the motor. 78 tooth is 7 3/4" diameter. not very big

https://www.alibaba.com/product-detail/7kw-MP80100-sensored-RC-outrunner-brushless_60521839105.html




with 24" wheels and 50v top speed shows 49mph but i'll use a vesc which only does 95% duty cycle bringing it down to 45mph and then accounting for losses and this and that...will see and want 40mph top speed
http://advanced-ev.com/Calculators/TireSize/

locking bushings seem really nice making assembly much easier and more concentric and look cool. surprised i dont see them more often. hella expensive:
https://www.grainger.com/product/CLIMAX-METAL-PRODUCTS-Keyless-Locking-Assembly-38AT68

 

[markz]

If you don't think Sur-Ron is a dumb bike, you should try doing a five mile commute on one with the battery unplugged.

Using that logic, you should try a five mile commute in a Tesla with the battery unplugged. Or a five mile commute in a gasser with the fuel turned off.

A Tesla kicks ass compared to a stinking gas car. But a Sur-Ron is super weak compared to a stinking gas motorcycle.

Well I dont know about kicks ass. Yes, instant insane torque is stupid crazy from what Joe Rogan has said on his podcast many times.
We can skip over cost, because rich people dont care about cost.
Here comes the juicy part though, Rich Rebuilds. Try getting used parts for that Tesla, try getting Tesla to reactivate the Tesla once in a crash. Try getting a Tesla certified mechanic to fix your Tesla in a timely manner in your own city. Try driving 2000 miles without wasting who knows how many hours to recharge.

Sure there are many great things about a Tesla, I agree but there are also many downsides too. A Electric Vehicle isnt really comparable to a motorcycle in certain respects. I wouldnt want to ride a motorcycle on long trips and you wouldnt want to drive a Tesla offroad or through mud, rivers, in the bush like you would a motorcycle.

 

[Dauntless]

Here's a 12kw belt drive.

https://www.alibaba.com/product-detail/12000w-large-motorcycle-off-road-tires_62501191981.html

 

[markz]

Hopefully you can find the belt locally when it breaks, unlike a chain thats sold in every local bicycle shop.

 

[Hummina Shadeeba]

Here's a 12kw belt drive.

https://www.alibaba.com/product-detail/12000w-large-motorcycle-off-road-tires_62501191981.html

That looks nice but with the motor and swing arm not pivoting from the same point it looks like the belt would be constantly tightening and loosening.

With essentially no seatstays getting a large pulley to fit on the rear is easy with those bikes. I’m realizing I can’t fit bigger then a 34 tooth on the rear without the belt rubbing. I’m still making it with this little bmx frame anyway but the gear ratio is coming down and a giant pulley in the frame is necessary

Belts last a really long time in my experience. A friend sells track bikes he makes w belts and he literally welds the frame back together around the belt. He’ll have to weld it to replace the belt. He says he hasn’t had to replace a belt yet.

 

[markz]

Until they are broke and your f'd!

Belts last a really long time in my experience.

 

[Dauntless]

Until they are broke and your f'd!

Belts last a really long time in my experience.

He can carry spares.

 

[goatman]

Going with (2) 21mm carbon polychain belts. In the guide you do all the math to figure how much torque the belt will see..then they say throw that number out the window and consider if it’ll be used in an abusive way such as on a motorcycle as apposed to on a conveyer belt and assume double the load.

I’m going to remove the shrink wrap from the cells and dip them in epoxy. I think the wrappers are the weakest link in the potted battery/motor mount. Do u think the bare steel cells will be a boon or hinderance to the strength? I plan to vacuum in chopped glass too

If need be I can glue a key to the frame and cut a keyway in the part

These leopard motors are pretty crappy with a huge air gap n thin magnets.

would vacuuming in carbon fiber instead of chopped glass help with cooling?

 

[Hummina Shadeeba]

Could short through carbon fiber. I’ll be using carbon laying it down first, then fiberglass, then the cells thatve been stripped of their wrap n dunked in epoxy, then I’ll pour the mass of the resin. A hard water clear polyurethane. Tell me if u think I’m wrong but the wrap likely ruins the cell’s ability to be a structural benefit.

Finding a place that can make custom pulleys in India was key for getting a pulley that will go on the wheel And have three transtorque locking bushing in the mail (although I’ve since found a place in India that makes a clone for much cheaper).

And after going through the calculations a 12mm wide 8mm pitch GT belt is good enough for me and still way beyond what is needed at this torque n speed.

I’m getting closer. Pulleys almost finalized. Then finish the big plate that will both be motor mount and bolt to the battery. That plate will be used in the potting of the battery to orient the bolts while resin sets. Then pop it out of the mold n ready to assemble.

 

[Dauntless]

would vacuuming in carbon fiber instead of chopped glass help with cooling?

Absolutely not. I know you're thinking of experiments with better thermal conductivity from special carbon fibers, but your average carbon fiber is more of an insulator from heat. It would trap it, not conduct it.

Additional problems to that approach:

Conductivity would require a continuous length of carbon fiber. He's talking about loose chop strand mat mixed in. It doesn't matter that copper conducts electricity better than aluminum if there's a break in it.

Fiberglas is better as a reinforcement in his approach because the individual wicks will flex instead of breaking. You mix in carbon fiber rods and they will break, reducing the reinforcing qualities. You're likely to wind up with mostly granules like sand, which have compressive strength but that's about it. And it needs to be mostly sand/aggregate to get that. You can compare that to making sugar cubes with string or the like in them. They won't just break up with the string or even just sewing thread holding pieces together. That is what the chop strand mat is doing for you when you mix it in your epoxy, which has no strength in thickness.

At about the boiling point of water, there can be issues with continuous exposure to heat with common carbon fiber, THE EPOXY YOU CHOOSE, the actual structure created, miscellaneous things. People think carbon fiber is automatically stronger, automatically durable, automatically better. It only works that way with proper handling. Fiberglas is far more forgiving of your limited knowledge.

 

[Hummina Shadeeba]

I’ll be laying fabric first. Carbon for its rigidity around the through-hole for the jackshaft but mostly will be glass fabric for its durability and flex as the potting will be essentially turned into a big clamp bolted around the downtube to the aluminum plate. Then the mass of unfilled resin after the cells. Epoxy is too rigid and brittle for potting it seems with the slight expansion of cells and will use 95a polyurethane. Maybe not ideal for the mechanical needs of the jackshaft support but the softer pu was recommended by expert at bjb enterprises for potting cells. The expert being @pylonflier who is a member here. You can see him, Troy, in most of their videos

 

[Hummina Shadeeba]

probable will produce eddy and hysteresis in the close batteries. None of u wrote that. could enclose motor in a shield. Which sucks and rather just have a thick backed steel behind the magnets. and now i want to quick find an 70mm about diameter stator by 80 long. How close is too close to 26650 cells? I intended the motor to be as close as possible to save space and it will go 6500rpm

And will have to see and easy test to set up