Slightly TLDR – but I thoroughly skimmed
@TheGoodMomentum the wheels are looking great! I think you’re on the right track so ill just float some ideas to brainstorm on.
- I would get a hurry up on doing some cold-weather testing on the urethane compounds and specifically the core. I was reminded of the cracked and failed o-ring that brought down the Shuttle Challenger (PS watch the show Away on Netflix if you like space). The impacts of riding and applying motor power to the core after sustained freezing temp exposure are both things I would suggest testing since the seasons are changing. Obviously if you have some good data on this already its probably fine. But urethanes can vary a lot. Same goes for the adhesives and such, cold and hot
I very much like the deep concave face with the fingers extending to the edge. Keep this - I do not believe that the wheel diameter should be tapered from outside to in. Its not only likely to wear down on the inner edge much faster but think about the motions the wheel will go through if the opposite wheel goes over a bump or into a hole independent of this one. A flat wheel has a core that’s much narrower. So the inner and outer edges are not as thick. This allows them to deform at the edges and maintain the surface contact across the width of the wheel. Because of this, you may need to play with the thickness between the road surface and where the spokes extending from the hub end.
- Surface contact is directly related to efficiency. Not much way around it. A domed shaped wheel just wastes weight in the interest of reducing the impact of efficiency. The cloud wheels do exactly this. Big part of the reason the Onsari rubber wheels are eating more efficiency than pneumatics 30mm bigger in diameter.
- PU sucks when interacting with water. I dont know the specs of the wheel sizes and such off hand. But lets say its a 65mm wide wheel and you’d like the contact patch to be 45-55mm. Make it flat, cut tread into it. This seems silly to even still be talking about. Wheels need some tread. Were not downhill longboarding on a 77* cali day where it hasn’t rained for 6 weeks. Definitely a win to add some tread rather than creating a convex contact patch.
- I honestly think you can move on from ABEC cores all together. Lots of us, myself included still have ABEC equipment. But designing around the kegel is much better
- the taller your diameter gets, the more grip they can sustain and the faster the turn - the more lateral forces on the bearing seat in the center of the wheel. An area that some how needs to not flex much while enduring all of the lateral forces with 125mm/2 of leverage on it.
Totally agree - however, Id argue that the cars that do not have alignment corrections are only that way because their suspension and steering geometry is perfect. Adding to that perfect geometry, the range of suspension travel those vehicles are designed for does not cause substantial enough deviations to alignment as the wheel travels through the range. Im sure there are examples I’m not considering, but just applying that logically. My mustang has camber for that purpose and its been adjusted for bump-steer because its geometry is anything but perfect.
As it applies to esk8:
For deep pushes into corners, the overwhelming majority of that force is lateral grip on the contact surface of the wheels. As the angle toward the ground at which the rider’s forces are being applied changes (lean), that will dictate how much lateral grip is applied to the wheels vs toward the ground. The fixed axle transfers that force to the wheels, but it provides almost no influence on the vector or magnitude of that force.
A fixed axle suffers from two major issues for esk8 IMO: Bind and contact consistency.
- Bind occurs when the force required to compress the bushing begins to exceed the forces keeping the opposite wheel down-- what you’re doing to compress the bushing on one side is essentially lifting the other. Lots of esk8 riders use very firm bushings that are really tight for high-speed stability. You’ll know this if you ever kick a board around and get a feel for how loose you can ride when you’re limited to one human power. Other than rider error with weight placement, this can make the outside wheel start to lift mid-turn – then its washout city for you. Wider hanger widths help here
- Contact consistency happens because bumps, stones and everything that changes the elevation between one wheel and the other instantly causes an interruption in contact. This is fixed by softer wheels that can deform across the surface to take on a shape that is not parallel to the axle.
Independent suspensions eliminate both of these.
Glad to see these doing well
my mistake… I’ll practice reading some more…