I was just thinking about the different ways we have come up with to transfer power from the motor to the wheels, and I was thinking about how I really like hub motors, but it seems that no matter how well they’re made, the issue of either the PU not sticking to the hub, or the ride quality being not nearly as good because of much less PU between the hub and the road is always a problem. So I was looking at some of the pneumatic tires Trampa makes, and I was just wondering, why hasn’t anyone made a hub that fits inside a pneumatic tire? You wouldn’t lose any of the ride quality as the inner hubs/spokes/rims are easily large enough to allow for a hub motor designed to fit in there without compromising the hub motor either…
I dunno, has anyone tried anything like this? Seems like a good solution to the main problems I keep hearing about with hub motors.
Not to mention a hub motor that size would have huge mechanical advantage compared to our current motors so that mean way way more torque with out gears. That is a good idea let’s so if anyone is skilled enough to invent it. BTW I want those wheels for my build so bad.
In terms of width, I figure as long as it is mounted in the wheel and is flush on the outside, it would work just fine. Be kinda like a hybrid direct drive like Carvon… Half hub half Carvon style direct drive sticking inwards a bit.
Anyone know what the inner diameter of that wheel I posted is? If one was to make a hub motor specifically for that using those dimensions that could be a very powerful motor, it’d be similar to the bike wheel hub motors, and those really are quite powerful! Hmm I’m really liking this idea… Kinda wish I developed it first now though,… Oh well, free too all!
This definitely needs to be done. One of the biggest issues hub motors are subject to is vibration wearing the crap out of everything. Put a little cushion of air surrounding them and the problem would be greatly reduced. Only drawback is the drag and bad wear characteristics of rubber. Though if the trampa wheel was used as a platform, you could swap between rubber and urethane depending on conditions.
If I still worked at a machine shop, would be all over this.
Hey they got some great stuff they’re! This one in the description actually says it could be used as a skateboard wheel, along with scooter and bike wheel.
You would need a solid tire, which would be heavy and without the comfort of the inflated tires.
Your motor would weigh 2.5 KG instead of 700g and torque would be less than in a geared system with a light weight and small motor. If the torque would be equal, your efficiency would be low and heat would build up. Electric motors simply don’t want to produce high torque. They want to run relativity fast at relative low torque output.
Gearing is simple, efficient and the way forward.
If you look at the hub motors out there you will realize that they all face the same issues.
Mechanical strain on motor ( which is the last thing you want), poor efficiency, heavy, limited tire choice and ride comfort. Since a MTB wheel is bigger, the gearing is smaller relative to the wheel size. Some systems are already smaller in diameter than the wheel diameter. Why would you want to deal with the downsides of a hub motor?
The wheel is bigger, so can be the motor. But these bigger motors are expensive and probably need a rewind to get the right kv, much much work.
There is a 4wd hub motor mountainboard already on es forums, search 4 it.
Not true. If the wheel is bigger, you face negative wheel gearing. A hub motor is not 1:1. it is usually 0.8:1. On a pneumatic wheel the gearing is even worse. In consequence you need to compensate that. relative to the board, the motor can be bigger, but your wheel is also bigger! one RPM on the wheel will get you further than using a 90mm PU wheel. So you need more torque on the motor side and things will go in the wrong direction. A 1KW bike-hub motor weighs a lot! So would your hub motor. You don’t want such a chunky piece attached to your board.
The Chinese solid tire hub motors deliver 500W and torque is very limited. It would get you rolling on the flat, at the price of very low power and 4KG of extra weight and non inflated tires.
Compared to what? They produce more torque than gas engines at lower RPMs. Tesla has proven this repeatedly.
When using a small motor in a belt driven system, maybe i can see what you’re saying. When throwing a fuckload of iron and copper into the center of a pneumatic ring, I think you’ll be surprised.
The question is how fast can we get it without losing the desired amount of torque as we shift the KV up in order to find the sweet range.
