Open-Source Sports Electric Vehicle (OSSEV®)
Whilst a lot of sports cars use larger diameter wheels for aesthetic reasons, smaller wheels and tyres have many advantages. The main ones are less rotational inertia and less unsprung mass. It is a compromise between many factors though, including in ride and handling, aesthetics and the ability to convert the power & torque into forward motion.
For an EV the size of OSSEV®, we think a 15" wheel is the best option. This doesn't rule out slightly smaller or larger wheels though, assuming the fit over the brakes and clear the bodywork.
The Mazda MX-5 and the Eunos Roadster use wheels with 4 × 100mm PCD. This is different to the standard Ford pattern of 4 × 108mm PCD. With the MX-5e is makes sense to to stick to the Eunos hubs and the 4 × 100mm PCD. For the OSSEV®, the Ford layout is preferrable as it gives many more options for the hubs and uprights.
This 5-spoke Compomotive MO1571 design is lovely.
These Enkei PF05 alloys only come as a 16" rim. They come in silver, dark silve, gold and blue on special order.
Given enough interest and volume, a one-off design for this sports EV could be commissioned.
The use of a fairly standard wheel size will enable a wide choice of tyres. The fact that our sports EV is also quite light means we don't have to use tyres specifically designed for EVs either.
For the MX-5e we have fitted Yokohama Advan Neova AD08RS 205/50 R15 86V RPB TL tyres to 15" × 7" Rota Slipstream alloy wheels.
Mazda MX-5 wheel nuts are M12 x 1.5mm. The torque setting is usually 88 - 118Nm.
The car will be fitted with a Tyre Pressure Monitoring System (TPMS) with CAN Bus interface.
Unlike a lot of modern cars, the OSSEV® will have a space for a full-size spare. Fitment is optional though, allowing more luggage/storage space if required.