High torque, low speed hub motor for 6x6 ATV with trailer

[ah2025]

Hi,

I'm working on a vehicle project. A low weight composite monocoque with a six wheel configuration, and either 4 or 6 driven wheels, all independently mounted with no through-axles. It's an all terrain vehicle, and needs to be able to tow some weight too.

Given the design, 4 or 6 hub motors on torsion axles would be the simplest solution, but rather like others, I cannot for the life of me find high torque (60-150nm) hub motors wound in a high torque and low speed setting. Let alone IP67/8 ones, as we'd ideally want amphibious capability.

Can anyone help source? If not, we're llkely to have to end up with internally mounted belt drive motors, a constant velocity joint, and then custom torsion axles outside the monocoque, with the ability for the CVJ to drive the hub through the inner side of the torsion axle arm.

Thank you!

 

[SlowCo]

What wheel and tire size are you going to use with the hub motors?
You could use wheel barrow double geared hub motors but getting them "amphibious-rated" wil be very hard.
Or get really large car gearless hub motors but that gets very expensive really quick: Car hub motor

 

[amberwolf]

If you need amphibiousness, you're probably going to have to go with inboard motors. I haven't seen anything that's going to truly be submersibly waterproof in a purchaseable hubmotor. It could be done, but OTS parts don't appear to exist for this.

Hubmotors are likely to make it heavier than a non-in-wheel motor, and require a more capable battery and more powerful controllers, since it'll take higher currents to do the same thing you could do with a lower current higher RPM smaller motor that runs power thru a reduction as it transfers to the wheels.


You might talk to QSMotor though, in case they can make you a custom version of something they already have--they also do custom windings.

 

[Hillhater]

…, I cannot for the life of me find high torque (60-150nm) hub motors wound in a high torque and low speed setting.

To be clear, what rpm range and wheel size are you intending to use ?

 

[ah2025]

What wheel and tire size are you going to use with the hub motors?
You could use wheel barrow double geared hub motors but getting them "amphibious-rated" wil be very hard.
Or get really large car gearless hub motors but that gets very expensive really quick: Car hub motor

Thanks. Yes, I've found a fair few hub motors with good specs (a few hundred dollars per motor is fine) but they would need to be IP67/8 and with all steel parts 316 stainless, which doesn't seem to exist.

I think we need a lot more torque than a wheel barrow motor can manage.

 

[ah2025]

If you need amphibiousness, you're probably going to have to go with inboard motors. I haven't seen anything that's going to truly be submersibly waterproof in a purchaseable hubmotor. It could be done, but OTS parts don't appear to exist for this.

Hubmotors are likely to make it heavier than a non-in-wheel motor, and require a more capable battery and more powerful controllers, since it'll take higher currents to do the same thing you could do with a lower current higher RPM smaller motor that runs power thru a reduction as it transfers to the wheels.


You might talk to QSMotor though, in case they can make you a custom version of something they already have--they also do custom windings.

I'm starting to have that sinking feeling that to get the speed/torque balance needed, and the water rated parts, it's going to be a custom build.

I hadn't considered the hub motor weight as such a factor. You're right that a 25kg motor will have all sorts of consequences to the rest of the assembly.

I've seen QSMotor thanks, and will get in touch. It may be that they can solve all the problems in a oner, at a price!

 

[ah2025]

To be clear, what rpm range and wheel size are you intending to use ?

Very large wheels (airless, composite type, sort of like tweels) c. 48". 100rpm should be the max.

 

[dwkdnvr]

New here and maybe not of much help, but I've been looking at high-torque options for a garden tractor/utility platform. UUmotor has a new option that looks pretty good (for my purposes) here: 2025 new 1:10 high gear ratio 200N.m 16 inch tractor tire hub motor . 120RPM, 200Nm, and in 'tractor wheel' form factor they claim up to 500kg of load bearing capacity. They also have a variant without the integrated wheel - just a 4x100mm hub and a single-sided 25mm support (250-350kg load capacity for the single-sided version).

Maybe not viable for you though, since it's unlikely to be sealed.

I'm also getting the impression that uumotor isn't a particularly respected brand, although I don't know how they compare to other manufacturers. They *do* provide full performance curves rather than just marketing numbers, but I have no idea how reliable they are.

I'd been heading down the path of using a BLDC driving one or two garden tractor transaxles (peerless 820), but the 'engineering' to get both the torque I'm looking for and load-bearing capacity per axle is proving to be a bit messy. Just going with 4 of the uumotor units would potentially be a sacrifice on torque output (which realistically I may not be able to use anyway), but would dramatically simplify the build.

 

[amberwolf]

Looks potentially interesting, but they're still using the terrible-idea flatted axle for torque transfer, when there are well-tested better ways to do this nowadays. They wouldn't even have to engineer anything, just copy one of the known-working integrated torque arm types. :lol:

High torque setups especially used in a high load / stress usage really should be using a "normal" axle that is under far less stress, and not transferring torque thru flats into the part of the frame that's meant to hold up the vehcile from the motor, but rather to some dedicated part of the frame that can easily handle that torque, using an integrated arm that transfers from some larger diameter portion of the motor axle (like the Grin All Axle, or the GMAC, the Heinzmann, etc).


The "gearbox" double planetary reduction seems interesting, not sure how well it works but gives me an idea I will have to let percolate within my brain (about using two planetarys in series from two different hubmotors as a reduction for a different motor). I've attached images of the planetary setup and other stuff off that uumotor page below, for reference.

 

[dwkdnvr]

Fair point on the axle - it does seem a bit undersized for something that is targeted at a reasonably heavy-duty application. At least it's double-sided, I guess.

But - the planetary gear is interesting. I looked into various gear reduction strategies as alternatives to a full transaxle, and they all seem to be rather expensive for anything that can handle any reasonable torque. Getting a decent looking 10:1 planetary reducer and a motor and a hub/wheel for the price is pretty remarkable considering that a standalone reducer seems to run close to that much.

I'd be tempted to order a single unit for use in my prototype/eval platform but it seems that we in the US will have to let the shipping-from-China situation play out for a bit. gives me time to continue looking for other options, I guess.

 

[amberwolf]

ATM you couldn't even get the package if you did order it, until they lift the hold on USPS processing anything from China. (unless maybe other carriers work around that, but I suspect they'll be coerced to join in).

 

[Chalo]

Leaf Bike will do custom motor windings at no extra charge. Their celebrated 1500 watt rated motor can be nicely packed with copper at 11 or 13 turns, which in either case is really slow at high and efficient torque. Because they are willing to customize, I wouldn't be surprised if they would furnish single sided stub axle hubs of you asked for them. They also make higher power hubs with wider stators, and if you need more power than 1500W continuous per wheel, that might be a good way to go.

 

[Chalo]

48V 52V 2000W single side shaft hub motor

Convert your original wheelchair, tricycle to be electric with leaf 48V 52V 2000W single side shaft hub motor.

www.leafbike.com

If you know what RPM and voltage you're looking for, they can wind motors to match the criteria.

 

[dwkdnvr]

ATM you couldn't even get the package if you did order it, until they lift the hold on USPS processing anything from China. (unless maybe other carriers work around that, but I suspect they'll be coerced to join in).

Well, crap - I'm dumber than I thought. Placed an order for some Spintend VESC controllers over the weekend and somehow neglected to register that they're shipped from China. Into limbo I go, I guess.

 

[ah2025]

New here and maybe not of much help, but I've been looking at high-torque options for a garden tractor/utility platform. UUmotor has a new option that looks pretty good (for my purposes) here: 2025 new 1:10 high gear ratio 200N.m 16 inch tractor tire hub motor . 120RPM, 200Nm, and in 'tractor wheel' form factor they claim up to 500kg of load bearing capacity. They also have a variant without the integrated wheel - just a 4x100mm hub and a single-sided 25mm support (250-350kg load capacity for the single-sided version).

Maybe not viable for you though, since it's unlikely to be sealed.

I'm also getting the impression that uumotor isn't a particularly respected brand, although I don't know how they compare to other manufacturers. They *do* provide full performance curves rather than just marketing numbers, but I have no idea how reliable they are.

I'd been heading down the path of using a BLDC driving one or two garden tractor transaxles (peerless 820), but the 'engineering' to get both the torque I'm looking for and load-bearing capacity per axle is proving to be a bit messy. Just going with 4 of the uumotor units would potentially be a sacrifice on torque output (which realistically I may not be able to use anyway), but would dramatically simplify the build.

Of substantial help, thank you. It's rare to find a product where they will state the load bearing capacity i.e. the actual mass of vehicle a hub motor can bear on its shaft. Most only talk about the ability in hauling loads.

It does appear I'm destined toward a custom build and wiring. Especially given the need for IP67.

I'm also considering a much more simple system for an internal motor, belt/chain drive and a CVJ running through a sealed gland.

 

[Chalo]

they're still using the terrible-idea flatted axle for torque transfer, when there are well-tested better ways to do this nowadays. They wouldn't even have to engineer anything, just copy one of the known-working integrated torque arm types. :lol: