Hub Motor & Urethane Riding Qualities

So you’re saying the Evolve GT 97mm wheels are made by you? If so, I just got a boost of confidence!

Im enjoying the conversation about wheel size, thickness of urethane and hubmotors. I agree that handling is very important for safety but also for riding comfort and fun. In another thread I mentioned I used a Boosted Board for a couple of days, and although it doesnt have amazing speed, acceleration and range compared to my DIY, it definitely was just as much fun to ride, simply because it handles so well and carves so nicely.

@ChrisChaput you mention that if you would ever develop hub motors, you’d go for a very large diameter wheel to have enough thane thickness to get the right handling. I personally have concerns this could negatively affect handling by increasing the ride height unless you compensate with a drop down deck. Wheel bite and weight are also increased. What do you think about that?

I mentioned one way that I would approach the challenges regarding hub motors. Here’s how I’m looking at our current situation. “Our” meaning the electric skateboard building community. And I’m not going to speak on behalf of the guys oversees who are just trying to make a buck by selling some piece of junk that looks decent enough but falls apart or dies in a week or two. They build boards to make money. I want to make boards for skaters who can tell the difference between acceptable and exceptional.

To get a decent urethane-to-hub ratio you’re going to have to one of two things, or a little of both. Increase the height of the wheel, decrease the size of the hub/motor, or both. Because of my (negative) experiences with metal cored wheels delaminating on the first run (Labeda 90mm Streetluge Wheels), I always want to make sure that my thane is securely fastened to a structural component such as a hub or a sleeve that provides a good chemical bond. A good PU material like Estaloc works great but I still use a mechanical lock as a fail-safe. If 2mm is the minimum wall thickness for the sleeve, you’d have to add 4mm to the hub motor diameter. If you used a 5065 motor then you’d be looking at a 54mm minimum hub diameter and a wheel that’s at least 65mm wide, more if you want your axle-nut to be recessed.

That’s a pretty small motor and yet it’s a pretty big hub. It’s 9mm bigger diameter than the Flywheel hub so to get the same urethane depth you’d need a wheel that was 9mm taller. The 90mm wheel goes 99mm. But if you look at the fact that the 45mm hub is half of the 90mm wheel, then a 54mm hub would need a 108mm wheel to be half.

So that’s just the math behind urethane depth, but are the current 5065 motors good enough to power your board with 99mm to 108mm wheels? If not, then what can we do?

  1. Find a way to make small motors powerful enough
  2. Put bigger hub motors into bigger wheels
  3. Put bigger hub motors into the same sized wheels

I don’t have as much confidence in making huge technological gains in “small motor” power. It will happen, I just don’t know when and by how much. I know a bit about making nice big wheels, and I don’t like not having enough urethane. What makes sense is to get the best small motor that you can find and make the wheel with the most urethane that you can handle.

You can drop decks, drop trucks through the deck, and use rocker to lower your ride height. Big wheels are tricky. Wheel bite is a bitch. But I’ll do whatever I can NOT to go back to steel wheels.


We don’t make the Evolve GT wheels (83mm, 97mm), but Evolve may be releasing some genuine ABEC 11 SuperFly’s in different sizes and/or colors.

I’m pretty sure that Jeramiah likes black for Ollin so maybe you should tell him that you think that would be sick …:wink:

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gotcha, well hopefully the thane on these are close to the quality of yours!

Mr. Chaput’s inspiration and dedication changed the face of skateboarding I know that it also changed the face of electric skateboards. Stoked on it all!


Concrete Wave in the house!!! Nice to see you here Michael.


nice to be here…the water is fine…just gotta be careful not to get my skate wet!


Hey Chris, could you explain a bit more about this… What is Rit? Sorry if it’s a stupid question, but I would like to have a try


Thanks …

Ask the risk of sounding like a teacher here, “There are no stupid questions”. And I just assumed that people would know what Rit is. My bad.

Rit is the brand name of a dye that is perhaps used mostly for fabrics but is also really good at coloring a lot of other objects. Their FAQ’s on their website is

I used Rit Dye to turn some green No SkoolZ into amber colored “BertZ” that were used in the Lords of Dogtown movie (I played skater Russ Howell). I think that you boil water in a big pot (vat), add the dye, stir, and soak your wheels overnight. I’m sure that there will be some guys on here with more experience who can tell you of their results. Certainly turning light colors into darker colors would be easier than dark into light, but it doesn’t appear to harm the wheels in any way so check it out. (Just now realizing someone had also answered the question … Doh!)


@ChrisChaput big thumbs up!! loved your input here, ride quality and carving grip were my biggest arguments against using hubs and Im glad to hear a professional talk about his development experience on urethane thickness & cores.

I have tested a lot of wheels and I completely share your view - the thicker the urethane ring, the more comfortable and grippy the ride, most noticeable on rough ground. sadly, for me, at around 90mm wheel size, boards start to look way too tanky and loose a lot of their natural beauty. :sunglasses:

when do we get back our 90mm 75A flywheels?!! :smile:


I really don’t think hub motors are for me. I live in Sweden and the roads here are far from perfect. I think the roads are killing hub motors so I need belt driven.

I killed one of my hub motors in like 10 battery cycles in Norway :smiley: They take some beating!

@ChrisChaput I got to try the Carvon V3’s with your 90mm Flywheels yesterday, super smooth! I cant wait for mine to arrive. I wanna take 4 of your soon to released 107mm flywheels and use them on a 4wd V3 build.

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But the sad thing is …it seems that you can’t put 107mm on v3 - they are too wide.

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@ChrisChaput : Whatever your motor diameter is, a bigger urethane sleeve will always impact your gearing (e.g. 0.7:1 instead of 0.9:1), putting even more strain on your system and making it more inefficient. You would need to make your motor produce more torque for compensation and we know that there is a square relation between torque and efficiency. Your motor would produce more heat than you could ever dissipate. Heat = inefficiency. In consequence a skateboard hub motor always wants the thinnest urethane ring possible, no matter of motor size. Adding more urethane is the last thing you want to do, if you don’t want a steep drop in performance. In consequence the hub motor urethane tire will never perform as good as a proper urethane wheel, especially on rough roads this is a big issue. Hubs are made for relatively smooth roads. The reason why hubs on bikes work, is the weight of the motor. Big and heavy stator with lots of copper in it + a lot of poles. Have you ever lifted a 1000W bike hub motor? Same output power as a small 500gr outrunner but 5KG in weight. Unfortunately we can’t squeeze such a heavy motor into a skateboard wheel, nor would we like to carry it. There is no solution for thick urethane on hubs.


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What would the recommended urethane thickness be for hub motors? I am thinking about building some and am going to use either 16mm of urethane or 13mm of urethane around the motor. Which is more suited?