Enclosed Belt Drive for Trampa ATB and MBS Matrix II trucks (Gauging opinions)

[Creavenger]

Took me a while to write a thread but here we go, since a few months I am working on designing a ** drive system** and I would like to share the ideas and get some feedback for you guys.

In the end of 2019 I mainly researched gear drive systems. Unfortunately, I do not have the resources to make a reliable and MOSTLY affordable gear drive mainly due to manufacturing and material costs. For experience, I bought some geardrive parts from the kug3lis sale and designed the missing parts for it, just need to machine them somewhere in the future to use on a future build I will probabbly look at gear drives again when I have some more experience and connections.

However, my goal is still to develop my own drive as a spare time project and more of a personal endeavour to learn from. I am also getting into the CNC world, cant wait to machine some parts for this

Current concept

So recently I have been looking into an enclosed modular belt drive for mountainboard trucks. They are easy to maintain, quiet, foolproof and allow modular gearing. I’m aspiring to make a few sets of my own drives, which I want to use on a future beast I am planning to build.
Furthermore, I want to involve the community in this project, so some of the first sets would be for real world testing. After testing, feedback and making changes, I’m aspiring to make a small run (IF there is interest and I can keep it affordable and worthwile for everyone).

Before im diving further into CAD I want to know what gearing and motor you guys would choose for your builds using Trampa ATB spring or MBS matrix II trucks

I selected some different gearing options (added smaller pinions which could potentially be swapped in the future). Having enough torque is great and necessary IMO so I dont really want to go to a lower gearing. I also added 3 different motor kv’s and the corresponding approximate speed (loaded) when using a 12s battery. The differences between gearings are quite small but still noticable between low and high. The table gives a nice overview with some different motor options. Smaller ratio also means a little more ground clearance (up to about 8mm between lowest and highest). Of course smaller slave pulleys can always be added later on if the drive allows it.

What gearing would you use? (feel free to suggest gearing options aswell)

• 1:4.4
• 1:4.5
• 1:4.7
• 1:4.8

What motor?

• 130 - 150 kv (lower kv’s)
• 170 kv
• 190 kv
• 200 kv or higher

Here are some basic requirements I have set for the drive as of now
(firm means its a set requirement, variable can still change and wish is something that would be nice to have but not necessary).

Lets see the interest
I want to keep these drives affordable, wouldnt it be nice to have an affordable 4 wheel drive option for example?

What would you honestly pay for a good enclosed belt drive system (two enclosed drives incl. pulleys, idler and belts).

• € 100 - 150
• € 150 - 200
• € 200 - 250
• € 250 - 300
• € 300 - 350

Would want to test/buy an enclosed belt drive if you were in the market for a drive system?

• Yes!
• No!

I am not sure how fast this endavour will go and where It will end up but I have been very excited about this project and looking forward to continue it. I will use this thread for updates.

Thanks for reading through the thread and contributing to the polls if you did. Feel free to let me know what you think in the comments.

[xsynatic]

Nice written Post.

Your Polls are broken, try to change the “allowed groups” to the blank option again so we can vote.

I personally would like to test it, give feedback and all sorts of things, but currently don’t have set plans on buying one for myself. (Applies to drives systems in general, not just your project!)
Maybe in the future if i don’t like my belt drive anymore, who knows.

My current setup has 15/72 gearing with 190kv motors. I like how it is but Don’t have experience with different gearings. So either keep the gearing or experiment with something new, i’m open for changes.

[Creavenger]

Working now? And thanks for the feedback

[xsynatic]

Yup, now they work.

[Creavenger]

Bump, need some more data

[PixelatedPolyeurthan]

I think gearing it for higher kv motors are the way to go. From 190kv and up as the higher the kv, the more power the motors can handle. Others can further elaborate.

So you want to design something very much like @ janux enclosed belt drive?

[glyphiks]

I don’t think motors over 190kv have a real standing for mtbs. Not enough torque.

I think 1:5 ratio is a sweet spot for 2wd, speed freaks can go for 190kv (or higher if you hate torque) and the torque monsters can opt for lower kv motors.

[PixelatedPolyeurthan]

@glyphiks

Not enough torque.

I read quite the contrary, that higher kv can handle more A which in turn is more torque. I don’t understand the technical side of this but it what I have understood. Let me try and find the thread with that info

[PixelatedPolyeurthan]

@glyphiks like what is said in this topic
🔩 1:7 belt drive for mountainboard with badass torque

[glyphiks]

Thats an interesting read. But they are talking about pretty high ratios for 190kv and above.

[Creavenger]

@PixelatedPolyeurthan I’m also thinking to gear the standard setup for the higher kv’s (170 - 190 kv) as this is more common and gives more power. Its similar to the janux drives just for mountainboard trucks. Gonna play with the gearing a bit to see what gives the best form factor, since I want the drive to be compact.

I agree with @glyphiks, the higher gearing would give plenty of speed at 190 kv. Plus if more speed or torque is needed pulleys can always be swapped in a larger housing.

The drive by @Marsl187 looks very interesting, would improve ground clearance and provide a lot of torque, this would be very suitable for the mountainboarders in hilly area’s.

I am aiming to make the drive a hybrid so it can also be used for speedier builds. Additionally I aim making it as low profile as possible especially in width to hopefully allow 6396 motors. A 6396 190 kv motor would provide crazy torque and still enough speed.

[BillGordon]

@Andy87

[Andy87]

1:5 @ 170kV is good, wouldn’t go higher in kV for a mtb. Street/AT cruiser can go 190kV and down to 1:4.4 maybe. Below it would be too less torque for me, but that’s just my opinion. Kaly boards run 1:4 at 190kV if I’m not totally wrong and people are fine with it too. If you don’t run bindings too much torque isn’t good as well. So it really depends what people want to achieve with there setup.

[Creavenger]

Thanks for the feedback yeah it depends on personal preference. I will use these for a street setup, hopefully with 6396 motors. But I love torque so will probably choose towards 1:5

[Andy87]

A year and a half ago I thought 1:4 is totally enough with 170kV motors. My opinion changed over the last summer. I‘m riding 1:4.89 at 170kV and looking now for a gear drive that can give me even higher gearing .
The good thing on a belt drive is that you can cover a good range of gearing options.
Setting up the max gearing at 1:5 still gives people the option to gear down easy if they don’t need the torque.
Wouldn’t go smaller than 14t on the pinion thou. So maybe 70/14 equals 5/1 and 70/18 equals 3.89/1 for the people who just need speed.
Downside on the high torque belt drive is definitely the clearance with 8“ and it’s definitely nothing for people who want to go with 6-7“ wheels.

[Creavenger]

First concept renders (configured for trampa hanger). 15T pinion, 72T slave pulley, still looking into the idler setup (bearing sizes, mounting) and fasteners. The drive can also be used without an idler.

At the moment most of the design constraints are related to manufacturing, I dont have a cnc yet and I will have to go through a significant learning curve before being able to cnc complicated parts.
Next up parts will be optimised for 3D printing, after printing i’ll check the fit/dimensions and maybe mount the drive and do some rolling tests/low speed riding.

Need to source some HTD5M belts between 440 and 470 mm, If you are reading this and got any left over let me know.

[taz]

This looks very similar to the Trampa enclosed belt drive.
It is a solid solution but it has very high drag with the idler and I feel this will be the same.
So as someone that had an enclosed belt drive and has moved on to gear drive my opinion is that they are not worth the effort.

[Andy87]

Why so less enclosed chain drives out there?
The french guys have some nice options there and drag should be less than belt + idlers.

[taz]

I think the case would make for not enough clearance on an enclosed chain drive but I could be wrong.

[Andy87]

Depends on the chain size. With 06b and 42teeth it’s already a very close call.
Case around wouldn’t help there yes.
Buuut 40t is good and why not double stage? Options are there
Don’t want to say a gear wouldn’t be more easy/light and cheap