Cheap Ass 6x2 Pneumatic Belt Setup. 3D printed Pulley/ Vex Versa Pulley. Thingiverse link in post #534

Decided to document this setup in its own thread to showcasing the performance and invite discussions. It was also brought to my attention that I was spamming the no words thread. I agree, it would be best to wait until the project is done and reserve the incremental updates to this thread.

What is needed(3D printed Pulley + 3D printed pulley adapter)

  1. Tire with hub from aliexpress. $69 for a set of 4 (shipping included) https://www.aliexpress.com/item/free-shipping-6X2-tyre-6-Inch-Scooter-Tire-Inner-Tube-Set-Electric-Scooter-Wheel-Chair/32840489792.html
  2. Three M6 Bolt, 45mm length $7 for 25pcs https://www.mcmaster.com/#91292a143/=1e8wvz4
  3. 3D printed pulley adapter https://drive.google.com/drive/folders/14AF8h_PFzBTdH6JRkKynJ70I3WzezC0N
  4. 3D printed pulley(Any teeth count from 42 to 60) https://drive.google.com/drive/folders/14AF8h_PFzBTdH6JRkKynJ70I3WzezC0N
  5. Trucks $65 should have 8mm shaft with 35mm free length. TB218 will work. products/torqueboards-218mm-trucks

What is needed(Vex Robotics Pulley + 3D printed pulley adapter) 2. Three M6 Bolt, 25mm length 3. 3D printed Versa pulley adapter https://drive.google.com/drive/folders/14AF8h_PFzBTdH6JRkKynJ70I3WzezC0N 4. Vex robotics versa pulley(42T or 60T, 18mm) $5.99 https://www.vexrobotics.com/vexpro/motion/belts-and-pulleys/htdversapulley.html 6. three qty of locknut(8-32) $6 for pack of 50

7. 3 qty of bolt(8-32) 1-1/4" . you’ll have to grind it a tiny bit $6 for 50 pcs

Pics: MVIMG_20180818_223405 MVIMG_20180818_233203 fb85e18431863a4b842d622e24e7bf74900ff36d_1_443x500 d6144d2a08db3348291e757f3f79d255f965d984_1_483x500 MVIMG_20180821_004435 MVIMG_20180821_004516 Tire above has been pressurized to 60psi.

Now I wait for 2 weeks to receive the other 3 wheels so that I can test it on a board. I don’t have long axle trucks to properly test the wobble, but I did spin it on a normal truck and didn’t notice any wobbling. Can’t say anything about balance. How do you guys test for that?

Any comments?

EDIT1: Modified the part to save plastic image 3Dprinted_pulley_assembly MVIMG_20180918_121535 MVIMG_20180921_180021

36 Likes

you can eliminate wobble by using some tire pearls - I did that to mine and had no issues with wobble afterwards even on 3D printed hubs.

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I’m highly interested to see how these turn out

My experience has been mostly positive with these hubs and tires. I took a slightly different approach to the wheel pulley. I utilized the 3 hub bolts to attach a 3D printed adapter that fits the profile of VEX Robotics versa pulleys. The pulley presses onto the spokes of the adapter and then (3) 8-32 bolts hold the pulley in place.

I’m running enertion motor mounts with 15T motor pulley and 345-5M-15 belts. The wheels run quite true, I’ve had them up to 35 mph no problem on 12s5p/FOCBOX.

And yes you need TB 218 trucks.

20180821_204102

20180821_204220

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That is really good to hear. I am looking forward to riding mine. I really like your idea too. My current design is very strong but likely over-engineered(And hence higher cost to 3D print). I want this to be a super inexpensive setup for people to get into pneumatics.

I might try out your setup too on a second board that I’ll helping my friend build. This way I can compare them both.

BTW, around how many miles have you gotten on those wheels(+pulley)?

I’m currently testing something similar (inexpensive tire option with 3D printed hubs). Below I’ve posted my current 3D model as well as the tires I’m planning to use. Parts have been 3D printed, I have the tire from amazon, and the bolts to screw them together come in Thursday.

Main reason I’m testing these tires is they’re super inexpensive (they were on sale for $5 each at the time I purchased them). They are from amazon which means they are super accessible and quick to receive, and they’re semi pneumatic (no airing them up) which is technically less maintenance at the expense of customization.

I’ll post the 3D models over here as well at the end of the week assuming they work well after I’ve tested them.

https://www.amazon.com/gp/product/B000N6BR3A/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

3 Likes

Design looks nice, but I don’t think these tires are mean for anything serious. From amazon: “These tires are ideal for hand trucks, lawnmowers, utility carts, and other lawn and garden equipment”. So basically not meant for speed. But be safe when testing them.

The 6x2 tires are however proven to be reliable around here. You could get them from https://psychotiller.com or if you don’t mind waiting for 2-3 weeks from here:

Apparently there is a discount of 15% in 6 days.

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I’ll definitely check these out if mine don’t end up working out :smile: I’ll let ya know how it goes

Looks so close, you could even remove the belts and have gear drive :slight_smile:

you mean like this (5:1 inner gear drive with helical gears for 5065 motors to stay as close as possible to the truck) image :wink:

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Straight cut gears will be noisier but you won’t have the axial load you will get with helical

https://khkgears.net/new/gear_knowledge/gear_technical_reference/gear_forces.html

https://www.youtube.com/watch?reload=9&v=PANVccyJuFI

3 Likes

Sure but who cares about axial load when you have a factory made grub screw hole in the motor shaft? As I said this is for 5065 motors that also have the added benefit of having a cut shaft (=perfect for experimenting with 3D printed gears) plus grub screw. You can even buy them with a thread on the motor shaft - axial loads should thus not be an issue.

Looks like 6-shooters LOL :joy:

A bit confused. Where is the grub screw located? The axial load will get transferred to the bearing which are built to work mostly with radial load. I think that’s what he’s talking about. Am I missing something?

You can probably go with double helical gear which 3D printing won’t care about. As for the drive double helical gear, one can even get it printed in metal(SS) if machined part is expensive.

@Maxid i too use DYNA beads in all my 3d printed rims and motorcycle tires… i have NEVER had issues w/ buying my tires online and mounting them at home using those beads

As long as the motor has a thrust bearing to compensate, no issue.

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We should ask @Nowind if he upgrades his motors or how he deals with the axial load in his helical gear drive. From what I see I think he does not upgrade anything and the normal bearings are ok with being used like that.

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For me all this Motors used in esk8 applications comes from RC Modell Flight… they have had do deal with axial load since day one IMO

There are small changes which helps the motors with the Helicals, but nothing special.

Cheers

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@MoeStooge, your thoughts on Axial load using helical gears?

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Good point - I didn’t even think of the propellers these motors were initially used to drive.