For anyone with a Mountain Board, or even a board with large, or pneumatic tires:
What pulleys are you using for your build, and did you make them or buy them? If purchased, from where? If made, got a link?
What gear ratio are you using on what size wheels?
What motors are you running or have had success/failure with?
What motor mounts are you using, and are they made or bought?
Are you running chains or belts, and how are they holding up?
What kind of riding/abuse do you inflict on your setup?
I recently picked up a used mountain board with 8" tires, and Iām trying to figure out what my options are for sourcing and custom mounting a drive/pulley system. Iām not sure what premade products or open source designs are available for pulleys/mounts or what gear ratio to shoot for, or even what motor/mounting solution to go with, so I was hoping to gather some information for myself, and anyone else who might find themselves in similar situation.
For anyone interested, my deck is made by āHylineā, and has 250mm āEarthboardā trucks that look like they would be compatible with a Paris style motor mount/clamp. Iām thinking of using dual TorqueBoards v.4 mounts, which will hopefully be long enough to accomodate whatever pulleys I need. Iām also thinking of going belt drive, dual 9mm or 12mm, with dual Torqueboards 6355 motors, but I donāt know if that setup is strong enough for light duty trail riding, which is about as crazy as I plan on getting at this point. Any help or feedback is greatly appreciated.
Iām trying out XL plastic 9mm pulleys, a 78 tooth and a 16 tooth for my 8 inch wheels. I have no idea yet if it will work, but itās starting to look promising. Itās a pain getting relatively cheap big pulleys, and I failed to find any above roughly 48t using the standard HTD that everyone seems to use.
Will let you know how it goes, should be riding in the next couple of days.
A helpful tip to finding very large pulleys is using this creator and having someone 3D Print you one.
All kinds of presets and belt types are supported. I can be tough to figure out how it works, but it isnāt very hard.
If you need someone to 3D Print something for you, I can do it. I have made some pulleys for quite a few people now and as far as I know, atleast from those I have heard back from, they work great. Motor pulleyās are a no-go though.
Here is just one example of how big these pulleys can be made.
I would encourage people to start designing things in cad relating to esk8ās or atleast using STL sources such as thingiverse and having more parts of their builds be 3d Printed. It saves a lot of money and boosts the publicity esk8 building gets when it is seen on websites like those.
I was aiming for a low enough top speed with 8 inch wheels, to maximize torque, I donāt intend to go super fast so was aiming around the 30kph max speed mark at 8S. This is what I came up with, and why I went 78t:
Let us know how it goes. Are those purchased, or 3d printed parts? Iām curious to find out how or if the plastic and 3d printed pulleys will hold up.
@Genex Thanks for the links. Iāll check those out.
They have 13 / 80 sprocketsā¦ so that would give you 1:6+ ratioā¦ would have to figure out how to mount the sprocket though.
You can check chain sprockets, too, although Im not so confident / knowing in theseā¦
As I am from EU, this site does not offer much to me unfortunately (shipping), so if you find someone who has ordered there and can confirm the goods are ok, that would be cool, probably would have ordered a few bits if I were in USAā¦
Other than that - Check ebay
It is possible to order small belt pulleys from china and also beltsā¦ with sprockets it is harder, so that scooter page might come helpfulā¦ you can even go for 20teeth motor pulleyā¦ Just check your wheel diameter and make sure that 80teeth sprocket is not bigger than your wheelā¦ as it is quite largeā¦
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A while ago for myself I found a 65t belt cog on ebay (from usa)ā¦ not sure if the deal is still available, I think the guy had limited quantity of themā¦
As for the chains - Iāve seen (on endless sphere) someone who just took a regular bicycle sprocket and chain and mounted it on his mountainboardā¦ worked quite ok for him!
Iāve got an extensive collection of pictures of different mounts / boards/ builds and sprockets, if you are interestedā¦ I could try to send some of these pictures to youā¦
We are working on a gear box without belt or chains, extensive testing goes on right now. If everything goes well weāll make it available for everyone. We had to go through some iterations the last months, but right now it works quite well.
Thatā's cool! Even better would be some āāgearingāā ā¦ not sure how practical that isā¦ but I once started a discussion related to this thingā¦ one gearing for starting up / off road ā¦ and one for top speed / flatsā¦
Well, itās one gearing and it fits all. It goes 51,4km/h with 10s at the moment, for me thatās fast enough for an eMTB, but if required, it could also go faster with 12s :-). And it takes definitely any hill as long as I am managing to stay on it, which is not always easy (cross country).
Would be great if there was a way to install / design a clutch and make it possible to use at least 2 different gearsā¦ ā¦ anywaysā¦ congrats for the speed record ā¦ I wonder what motor are you guys using and what gear ratio it hasā¦ I assume it could be around 200kv motor and 1:4 ratio?
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Could update this topic for future readers as Iāve collected some background info from ES forum about mountainboard gearing ratios and performance ā¦ althoughā¦ will probably do it sometime laterā¦
@Okami thanks for the info. And imo, anything related to the drivetrain is on topic, including @elkickās gearboxes.
Feel free to add anything you want to this thread that might be useful or interesting. The purpose of this thread was to try and gather info about mountain board mechanical options in one place, so go nuts!
Integrating a clutch would be nice, but a huge challenge. On the other hand I donāt think itās really necessary seeing the power those two motors develop with the gear box. Since drag is reduced significantly that helps too.
Sensored motors, KV is correct, gearing is 1:5,x, 8" tires, we are testing different setups currently. Our aim is to have the setups tested in every thinkable situation to mitigate risks of failures and to ensure reliability. We are also trying to avoid any need to adjust or service the gear system. Which is another challenge. But riding those boards for testing is already compensating all those efforts!
The belt is exceptionally long to try to get more teeth engaging on the motor pulley. That means the motor mount has to be stronger, as any flex becomes more noticable. That is still perhaps a concern in my build. I really wanted 12 or 15 wide belts/pulleys, so I might go down the 3D printing path if this doesnāt work out. At least with mountainboard trucks they are nice and wide to fit wider pulleys.
Iām looking for a wheel pulley 72 tooth, for a 15mm wide belt 5mm HTD. It needs a hole in the center with a 40mm diameter. The wheel Iām mounting it to has 4 bolts 2.5 inches across from each other. This pulley can be plastic or metal. Are you still willing to 3D print this sort of thing or know someone that might?
