Qs 205 Mid drive/belt drive project & help

[orange streak]

I can't seem to find the information I am looking for to complete my project, so I need to seek out info in this thread.
I want to run a belt drive setup for my mid drive e-bike through a 5\8 jack shaft. I hope to modify the mounting kit to make it wider to accommodate a QS 205 Hub motor as my new mid drive motor in my urban commuter kit. Also make room for the belt. I primarily need held with getting the right parts & learning about what belt to use? In doing this I can free up my diskbrake mount so I can have my disk brake back & have brakes even with 21 inch mc wheel builds. At the same time I am debating on the use of a shifting five speed transmission with a internal geared hub with disc brake, preferably a nexus hub? Basically my options are a IGH with a 3 spline engagement teeth for the custom belt pulley or keep it reliable single speed & use a thread on freewheel with a broached keyway also on the Hub threads. In hopes to prevent thread stripping from motor torque. I am quite familiar with how much power can reliably be ran through a internally geared hub. Has anybody made a key way for thread on Freewheel? I will explain in further detail...

 

[orange streak]

My mid drive kit. Sticking with it. The current unmodified clearnce on the motor pulley side will only accomadate 3/4" width belt and that only if the pulley teeth are strattling the side plate. The other side shown with a 1" strap barley has clearance for a 25mm/ 1 inch wide belt.

 

[orange streak]

This is the type of cupped belt pulley sprockets I need, both for the motor side and the driven hub side. I can then use a reliable freewheel/sprocket mount freewheel to mount on the belt pulley. The freewheel & my hubs threads will be fabricated to have a key insert.


View attachment 2

 

[orange streak]

I need the correct type of belt pulleys to mount on my 5/8 keyed shaft. And what type of belt should I be using. I only have 5.25 inches from motor axle to jackshft. And I have 16 inches from the rear axle to the mid drive shaft on the right side. I'll be using roller tensioners off of the kit for the belts.

 

[orange streak]

Basically I cant make it much clearer, and its like this keyed sprocket mount but with 1" 3/8 internal threads and a freewheel mechanism mounted to the back hub. It should all mat e up just fine with some fiddling around

 

[MadRhino]

The one thing you don't say, is the purpose. I mean, from the pic I see that the bike has no suspension, so I presume it is not going to ride off road. On flat pavement, a QS 205 H50 can easily do 130 kmh mounted as a hub, and survive more power than most would want to ride. It can speed up a 10% hill at 90 kmh for many km before overheating. What is the purpose of mounting one as a mid drive ? Even if you fry one every year mounted as a hub, replacing it would still be cheaper and easier than building that mid drive and maintaining it.

Nevertheless, if you want to do it, you will have to make many of the parts yourself or order them from someone who has machining facilities. It is not standard, you are going into real building and fitting. Before you have a bike riding and reliable, there will be many problems to solve, mostly by try and error process. I know that some like building more than riding, that is one reason that I can see as a motivation to do it. Just curious to know yours. Good luck with your build.

 

[flat tire]

I don't understand why you'd mount one as a mid drive either. The motor is phenomenally heavy, not that well cooled and not really suitable for high speed with most controllers due to the terrifically high pole count so you won't get a great power density from it.

You're better off with a RC mid drive or one of the Cyclone motors. And like Rhino said, the bike needs to be up to the task: no suspension is at best a recipe to put unnecessary wear and tear on your butt, spine, and knees and make your ride and handling over rough surfaces suck.

 

[markz]

Yup too much work, if you want gigawatts of power then the Cyclone 7500W is your beast, but mounted on a bicycle I dunno about that part. Go with the Cyclone 4kw which is the 3kw motor with 65A controller, much easier and cheaper to do then custom.

 

[orange streak]

I've had the kit for a couple years and I know it so well that it wouldn't be much trouble to widen the mount. I love to build on my bike and it does stay on the road. I just want this badd a** motor in my bike and a belt drive setup so I can clean it up and get my disk brake side back. The chain line is awful on the left side and i want to just start over & do a left drive side to avoid to continue use of left drive chain and make it some what quiet running. Belt drive seems cool and I like the benefits that come with it. With batteries that weigh 92 pounds (7kwh of lithium ion cells) & hualing cargo I am getting 24wh per mile at standard 20mph ebike speed, actually 25mph and thats without even a freewheel on the wheel. Wheel turns the motor right now. It is my all road beast that I want to cruise at 45mph with out getting motor hot. I just need to know where to find the correct parts to do belt drive. Where do I start, what belt type should I use? 15mm or up to 25mm wide? I don't need other motor recommendations or criticized. I Apreciate your time for any valuable input.

 

[orange streak]

You all know you want to see it done and riding, so do I.
No response yet from lighting rods. I do like the composite plastic belt pulley, that save a little weight.

 

[orange streak]

Nobody has altered freewheel threads with keyway? (Recomendations for a belt type to a guy who knows nothing about belts?) What pulley teeth gives me a gear ratio to get at least 40mph? How do I get the the right length of belt to fit my already given measures. Good place to get key shaft mounted pulleys? Hope for some advice, just seem to be in a hurry.

 

[tigcross]

Hi there,

I do have some experience with belt drives, my 2nd bike used a Eteck motor, Sevcon controller and a belt drive to a 20" wheel. The setup worked very well accept for belt skipping under heavy re-gen. if you're planning on including a freewheel in your system that won't be a problem for you.

I built my large diameter pulley out of skin-plywood, carbon fiber, epoxy and a couple of old disk break rotors. At the time there were no plastic pulleys available in the size I needed.
the building process was to lay up my disk break rotors between layers of 1/8 birch ply, epoxy and carbon cloth. I built up a roughly round disk that was 1" thick. I then mounted the disk onto an unlaced hub and chucked it into a large lathe to bring it down to perfectly round, at the circumference I needed for the number of teeth I intended to use. The final step as to take it off of the hub, lay it flat and then pour epoxy teeth into the gaps created by wrapping a precisely cut belt around the disk. It turned out to be very strong and I never had a problem with that part of the bike. I you need a really large pulley this might be a viable option for you to consider. In the end I decided that I wanted the simplicity and reduced maintenance of a hub motor.

I know that you're pretty committed to the belt drive, but I wonder if you've considered putting that perfectly good hub motor into a wheel instead? The benefits:
-regenerative breaking, a real plus for cargo hauling
-quiet, and no chain/belt-line hassles
-all of that space that is taken up with the mid drive would be freed up for batteries
-if you lace it into a moped rim you can use a huge tire and get some rear cushion

 

[flat tire]

Look at an industrial supply like Granger or Mcmaster. They'll have the kind of things you need or close enough to be modified.

Also consider taking the bike to a machine shop. The people who work there will probably think your bike is interesting and they can offer better advice and maybe do the work for you.

 

[MadRhino]

100 lbs of batteries and hauling cargo on long distances, are good reasons to build a custom stoke monkey. Making it a belt drive is another challenge. I would use motorcycle belt drive components, to have a perfect match between the belt and pulleys and tensioner, then adapting the bike to it. Check Buell belt drive components.

 

[orange streak]

I know that you're pretty committed to the belt drive, but I wonder if you've considered putting that perfectly good hub motor into a wheel instead? The benefits:
-regenerative breaking, a real plus for cargo hauling
-quiet, and no chain/belt-line hassles
-all of that space that is taken up with the mid drive would be freed up for batteries
-if you lace it into a moped rim you can use a huge tire and get some rear cushion

I like rolling effeciency so much, I like the freewheel method to reduce motor drag and weight in the wheel. I admit I have a 21 inch gold mc rim waiting to be in use for the rear, & fitting it with a 2.75 inch wide tire if I don't restrict my needed room for a belt line, tough call.

No more batteries on this build this won't be my 300 mile range ebike cruiser build. I seem to find a pot hole and destroy a wheel and don't want to re-lace a motor in a wheel.

 

[orange streak]

100 lbs of batteries and hauling cargo on long distances, are good reasons to build a custom stoke monkey. Making it a belt drive is another challenge. I would use motorcycle belt drive components, to have a perfect match between the belt and pulleys and tensioner, then adapting the bike to it. Check Buell belt drive components.

Thanks for a heads up. The only requirement is those cupped belt sprockets to save on width space when mounting and weight. Still seeing what's capable with this freewheel or lock it in place if necessary with a keyway if possible.

 

[orange streak]

Looks to me as though I should make room for 20 mm wide belts to get it to fit good It will be made precise and I like high quality parts.

 

[orange streak]

Ok I learned from a friend I should use gt2 belts. Also after some measurements and research, you most likely can not put a 3/16 key shaft in a freewheel, there is not enough metal left to have proper use, & it get to close to the inner workings. Just out of curiosity and for the sake of over engineering. I did figure out a alternative method for high powered junkies. Take a thick coupling of proper diameter size with a threading of 1.375. X 24tpi on the inside & screw it on to the hub. Drill four precision holes and thread in recessed allen head grub bolts so they are flush or don't stick up. Now you can see to add your machined keyway slot. Next slide on a keyed freewheeling clutch with mounting plate for sprocket. Pretty neat idea I came up with. Or just mount a shaft with mounting plate to dual disk brake hub and slide on a freewheel or roller clutch.

 

[atarijedi]

100 lbs of batteries and hauling cargo on long distances, are good reasons to build a custom stoke monkey. Making it a belt drive is another challenge. I would use motorcycle belt drive components, to have a perfect match between the belt and pulleys and tensioner, then adapting the bike to it. Check Buell belt drive components.

Zero Motorcycle is another option for drive components.