0-60 drops a half-second
In April and July I reported on a radical new wheel-motor system from Orbis Wheels that completely eliminates the center hub structure of the wheel and instead uses a small, high-speed electric motor to power the rim via a ring gear and pinion drive. At the time, the startup company’s functional proof-of-concept test vehicle was an electric minibike, but because dorky minibikes don’t stop much traffic—even on the Society of Automotive Engineers show floor—the company also mocked its idea up on the rear axle of a traffic-arresting winged and spoilered Championship White Civic Type R. “Made’ja look!”
The whole point of this crazy wheel-reinvention is to eliminate the unsprung weight that has prevented widespread adoption of in-wheel or hub-mounted motors to date (Ferdinand Porsche first proposed the idea in 1897). That SAE-show prototype’s corners still weighed some 20 pounds (9 kg) more than the Honda parts, but a summer spent beavering away on computers and CNC milling machines has managed to completely erase the unsprung weight penalty. Yes, the entire metal and machinery clockworks you see framed within the new wheel rim weighs precisely as much as the Honda-spec tire, wheel, brake system, hub, and knuckle that left the Swindon factory. And none of the weight loss came from using costly or exotic materials.
The wheel and the brake system save most of the weight. By moving the point at which the brake clamps way out to the wheel rim, the mechanical advantage increases enough to drastically reduce the braking force required along with the amount of heat the brakes generate. That allows the weight of the new steel rotor to drop from 12 pounds (5 kg) to just over 2, while the tiny six-piston caliper cribbed from a Buell motorcycle weighs a similar 2-plus pounds (900-plus-g), down from the Honda’s 12-plus pounds (5-plus kg) (and that Buell chomper is too strong, so it’ll soon be replaced by a 1-pound (454-g) Brembo two-piston bike caliper). Eliminating the wheel spoke and hub structure that formerly transmitted the massive cornering and braking forces between the road and the suspension drops the wheel mass from 29 pounds (13 kg) to 13 pounds (6 kg)—that’s carbon-fiber wheel mass achieved with aluminum. The billet-machined aluminum knuckle/upright shaves a half-pound off Honda’s cast original and bolts right up to all the original suspension mounting points, preserving factory geometry.
The new wheel bolts on and off about as easily as the factory one. Simply remove the wheel cover (the team has 3D-printed a black cover that mimics the look of the front factory wheel and spins with the wheel, but the final design will require a stationary cover that helps keep dirt and debris out of the wheel and features air ducting). Next, pull a retaining pin that allows the caliper to swing downward and inward off the rotor, undo three “lug nuts” that hold the outer wheel-retention roller carrier, and the rim pops right off. (A matching set of three fixed, tapered Delrin rollers contact the inside of the rim so that the lower two inner and outer rollers carry the car’s weight and the upper ones keep the wheel from tilting while cornering.) The electric motor’s pinion easily engages with the ring gear on the wheel with no need to carefully align anything.
These two permanent-magnet AC electric motors, borrowed directly from a Zero S ZF13.0 electric motorcycle, add about 50 hp and 70 lb-ft of torque to each rear wheel. They spin the wheel rims via a fixed 6.2:1 gear ratio. They’re powered by Zero Motorcycle batteries with a total pack capacity of 13.3 kW-hrs. Removing the back seat and cargo area floor and mounting these batteries and the controller that makes it all work adds about 180 pounds (82 kg) to the curb weight of the original Civic Type R.
Orbis cofounder Marcus Hays has brought that same white SAE-show CTR to the Hyundai Motor Group California Proving Ground for us to sample on the eve of our 2019 Car of the Year evaluation days. This is also a proof-of-concept prototype, and as such it’s undergone no vehicle integration work, so the electric axle is controlled via a thumb throttle from a Jet Ski that’s mounted to the shifter. It works just like a nitrous-shot button. And the noise coming from the dozen rollers on those wheels is nearly deafening, despite evidence of aftermarket sound-deadening materials slathering the cargo area.
But what fun! Flick that thumb-switch, and a great whirring noise attends a firm shove in the back as 100 extra horses nicely fill in the torque interruption of the manual shifts. We played around with the car (and used up maybe 6 percent of the battery pack), then passed the wheel to chief tester Chris Walton, who just took “ownership” of our very own Civic Type R long-term test car. Having very recently mastered the somewhat tricky launch of a car that doesn’t let you free-rev the engine to desired level for launch, Chris does a couple of unboosted runs to establish a baseline for the Orbis car with all its extra battery weight. Oh, and it’s also carrying the extra weight of a ride-along mechanic who knows how to instantly shut everything off should something go “poof.” Also note that because the rear motors cannot yet be declutched, when they’re free-wheeling—as during this baseline run—they’re regenerating electricity and adding drag.
Chris’ baseline comes in at 6.3 seconds to 60 mph—considerably off the pace of four stock test samples that range from 5.0 to 5.8 seconds. The trackside crowd erupts when Chris makes his first e-Assisted run, which is visibly and audibly quicker, louder, and more exciting. Within two more runs he’s shaved 1.7 seconds off the baseline, outrunning our quickest CTR by 0.4 second—impressive, given our car’s 342 pounds (155 kg) of added burden. A bit of quickie math to predict the performance without our 154-pound (70-kg) passenger suggests we’d have run a 4.4-second time, or 0.6 seconds quicker than our best stock CTR.
A quick look at the graphs of each run clearly shows how the e-motors keep the car accelerating during shifts, which on Chris’s baseline run consumed 0.25 second on the 1-2 upshift at 27 mph (43 km/h) and 0.20 second on the 2-3 upshift at 58 mph (93 km/h). It’s easy to imagine a production-optimized battery and controller further reducing the onboard mass and improving those times by another few tenths—presuming the sound deadening required to mask the roller noise doesn’t add all that mass back.
Chris’ original runs are aborted just above 60 mph out of fear that with the 6.2:1 gearing we might overspeed the unpowered e-motors and demagnetize them. Orbis’ next engineering challenge is to employ clutches to disconnect the motors at higher speeds. Hays mentions that an all-electric AWD Lotus 7 kit car the company is converting will employ two different gear ratios—2.2:1 in front and 6.2:1 (clutched) in the rear. Such a setup would provide strong rear-biased acceleration feel and all-wheel-drive traction from rest, stronger front regenerative braking from all speeds, two separate peak-efficiency speeds, and with those rear motors disconnected, improved cruising range and efficiency.
With a great 0–60 time in the bag, Hays gives the go-ahead to attempt a quarter-mile run. Chris sets out to establish a baseline, but his first run is aborted toward the end by a “poof” and some smoke. When the e-motors are not being powered, they regenerate energy, and the rate of regen delivered by that 306-hp Honda mill at 80-plus mph (129-plus-km/h) was more than any Zero bike was ever expected to see. The team discovers a blown fuse, and without a handy replacement, our test session is ended.
We’re confident Orbis can easily overcome these electrical obstacles. We’re less optimistic about the long-term durability of those rollers running on the wheel rim. The rims got very hot during our few short runs, and there was no debris to contend with. Can Orbis design shields and covers that keep debris out? How much debris can they tolerate? And can the unholy racket these roller rims make be reduced or sufficiently masked? Watch this space for answers, and look for the Orbis Civic at this year’s SEMA show.