Questions about 16" moped rims

[The Toecutter]

I'm seeking to upgrade my electric velomobile to light-duty DOT rims. I want to go 16" for all three wheels, including for my 3T Leafbike 1500W hub motor going in the rear. I am going to experiment with Mitas MC2 16x2.25" moped tires.

Does that mean I need a 2.25" wide moped rim? Considering that the tire size range a bicycle rim width of about 1" can fit would include a 2.25" width moped tire, that 2.25" moped rim seems awfully wide.

Bicycle rim width vs compatible tire size chart:

https://i.stack.imgur.com/S0Tib.jpg

I've spent a few hours searching and could not find a straight answer to this question.

I want to size the rim so that if the Mitas MC2 16x2.25" has too high of a rolling resistance coefficient to pedal efficiently with the motor shut off, that I can still go back to normal 20" Schwalbe ebike tires like the Marathon Plus or Marathon Greenguard using the same rims. But I definitely want sturdier rims for the speeds I'm going to soon be capable of reaching. My trike can currently reach 45 mph on flat ground and soon it will be capable of more than 70 mph.

 

[Chalo]

Motorcycle rim width is always inside the channel. Tires are typically 1.25 to 2X as wide as the rim width. The only rim width that makes sense for 2.25" tires is 1.5", unless it's possible to find an even narrower rim than that.

https://www.blogotive.com/wp-content/uploads/2017/07/Motorcycle-Wheel-Rim-Width-for-Tires-Size.pdf

 

[The Toecutter]

Thank you for your answer on this. All of my searching never led to a chart like what you posted, but that is exactly what I was looking for.

It's time to order some 1.5" wide DOT moto rims, the lightest I can find, and in a 32 spoke pattern if such a thing is made. I have a wheel build stand on the way and in my possession are two new KMX hubs to lace the rims to with 32 spoke holes. Still having difficulty finding 16x1.5" moto rims for sale anywhere.

 

[Chalo]

I have a wheel build stand on the way and in my possession are two new KMX hubs to lace the rims to with 32 spoke holes.

Yeah, good luck with that. 36 and 40 spoke drilling are both way more common than 32 in motorcycle land. Maybe you can find someone who has blank rims and will do custom drilling.

 

[The Toecutter]

Also looking into dirt bike rims. They may not be DOT certified, but are generally as strong/durable as rims that are DOT certified.

I'm also going to have some custom Cotter pin axles made that fit through the KMX stock hubs and thread into the stock spindles, and I am also going to fabricate stronger spindles that fit the same mounting pattern and axles that came with the stock KMX. That should make it able to corner hard at highway speeds without an entire front wheel assembly coming apart while addressing the existing steering spindles which are a weak link in the current system.

Again, I much appreciate your help. Your advice over the years has easily saved me tens of hours of research in that time and helped me put together a working prototype that is reliable enough to use on a daily basis.

 

[The Toecutter]

It appears as if 16x1.6" is the most narrow I'm going to find anywhere for a 32 spoke hole configuration.

I'm going to do further research on the following reasonably priced option:

https://www.bikebandit.com/aftermar.../rims-spokes/excel-rear-rim-spoke-kit/p/16487

It may be a good match for my Leafbike 1500W 3T wind motor which will eventually have 8-10 kW dumped to it with 250A phase current. I need a rim and rear tire that can handle it. The Mitas MC2 is rated for 62 mph.

I should probably only do the rear wheel in this kind of rim to start. It will be hard finding 20" bicycle tires that will fit a rim that wide if for whatever reason I need to resort to that, so perhaps I may just use Schwalbe Marathon Plus 406-47 on some quality-built double wall bicycle rims up front. Even though the Schwalbe Marathon Plus bicycle tires are rated for 32 mph, Cedric Lynch has used them at 50-60 mph cruising speeds in his custom fared recumbent with success. This combo might be a good balance between weight and safety for my application. If I lose a front tire, I can keep control of the vehicle, but if I lose a rear tire, I'll have zero control, so if I'm going to be going 60+ mph, I definitely need a rear tire at minimum that is rated for the task. Ideally, all three tires would be rated for the task, but I really am looking for 16x1.4" DOT rims with a 32 spoke pattern to make that viable, and I can't find anything of that sort available.

 

[Chalo]

It may be a good match for my Leafbike 1500W 3T wind motor which will eventually have 8-10 kW dumped to it with 250A phase current.

Do you know what the saturation current is for that motor and winding? Because beyond that point there's only more heat, not more power output.

I sure would want more than a couple of 14mm axle studs flatted to 10mm (with one of them undermined for cable passage) to anchor that much power.

 

[spinningmagnets]

In a smaller diameter rim, it takes fewer amps to get the same acceleration as a larger diameter rim.

The 3T is a fast wind, which means the available stator-tooth space uses fewer turns of thicker wire.

The larger diameter coil-wire with less length will have lower resistance, resulting in fewer battery watts converted to waste-heat.

This is a rarely-seen set of features that I believe has a lot going for it.

 

[The Toecutter]

This is a rarely-seen set of features that I believe has a lot going for it.

It should have the same copper mass as the 6T winding and 11T windings. The 3T version should be able to handle roughly twice as much current as the 6T, and get roughly the same continuous torque as the 6T and 11T windings.