Crab Walk, Rear Steer, Four Lidars: The Chassis Tech China Is Shipping Now
A crab-walking concept and a four-lidar minivan with rear-wheel steering as standard: what we shot in Chengdu shows luxury chassis hardware becoming ordinary family-car equipment in China.
Walk the halls of the Chengdu Motor Show, which ran August 21–30, and the same story kept surfacing on different stands: rear axles that steer, a concept that drives sideways, and lidar counts that would flatter a robotaxi. In the United States, this is the stuff of $2,000-plus option boxes on a Porsche and party tricks on a six-figure Hummer. In China, it is turning into standard equipment on family haulers — and the pace of that shift is the real news out of Chengdu.
Two vehicles our photographers shot on the show floor frame it neatly: JAC's crab-walking DEFINE-X concept, and the refreshed Li Auto MEGA minivan, which went from show stand to showroom in under two weeks.
What rear-wheel steering actually does
The mechanics are straightforward. At parking speeds, the rear wheels turn opposite to the fronts. That shortens the effective wheelbase, so a long vehicle sweeps through a turn it would otherwise need three points to complete. Above roughly 35–40 mph, the logic flips: the rear wheels turn in phase with the fronts, the tail stops swinging, and lane changes feel planted.
Crab walk is the third trick. Turn all four wheels the same way at low speed and the vehicle moves diagonally without changing its heading — useful for sliding into a curbside gap or off an obstacle. GMC's CrabWalk on the Hummer EV works exactly this way, with rear wheels that pivot up to 10 degrees.
JAC DEFINE-X: the concept that keeps coming back
JAC's DEFINE-X is a six-seat SUV concept roughly 16.4 feet (5 m) long, and Chengdu was its third major outing after the 2025 Shanghai show and Beijing this spring. The chassis is the point: an ICDC all-domain by-wire system developed with Huawei technology, a claimed four-wheel vector response time under 100 milliseconds, and rear wheels that turn up to 12 degrees — what JAC calls the largest rear-steer angle in the industry. That is enough, on paper, for a full crab-walk mode into a parallel spot.
Two honest caveats. First, DEFINE-X is a prototype, not a production model: JAC has published no powertrain specs, no price, and no timeline for a road-going version. Second, the car on the Chengdu stand sat with its wheels pointed dead straight the whole time we were there — no crab-walk demo ran, so the 12-degree figure remains the company's claim, not something we watched happen.
Li Auto MEGA: the same idea, actually shipping
The refreshed MEGA our team photographed in Chengdu made the opposite move: on September 2 it went on sale in China as a single Mega Home trim at 509,800 yuan — about $75,160 — with deliveries starting the same week. Rear-wheel steering is not an option on it. Neither is steer-by-wire, the 800-volt active anti-roll system, the dual-chamber air springs, or the four lidar units, up from one on the outgoing car. All of it is standard.
The numbers land where the theory says they should. The rear wheels turn up to 7 degrees each way, which gives this 17.6-foot, 554-hp (413 kW) minivan a turning circle of about 36 feet — tighter than the four-wheel-steered Hummer EV pickup's 37.1 feet, on a vehicle designed around seven seats and a 108-kWh battery rated at 440 miles (710 km) on China's generous CLTC cycle.
What the same hardware costs in the US and Europe
Now the price list from the other side of the Pacific. Porsche charges $2,090 for rear-axle steering on a 911 Carrera S, and the system moves the Taycan's rear wheels by a maximum of 2.8 degrees. BMW's Integral Active Steering manages up to 3.5 degrees on the 7 Series and i7. Mercedes builds 10-degree hardware into every EQS, but in Germany the full angle has been sold as a 1,547-euro option on the S-Class or unlocked on the EQS by subscription at 489 euros a year; US cars get it standard. GMC reserves four-wheel steer and CrabWalk for select trims of a Hummer EV that starts near six figures. In my view, the Mercedes subscription is the most telling data point of all: the hardware is so cheap to install that it ships in every car, and the price you pay is purely for the software permission to use it.
Why China is making it cheap first
Three forces are compressing the price. Electric platforms make rear-steer and by-wire hardware easier to package and cheaper to integrate than on a combustion chassis. Suppliers — Huawei chief among them — now sell complete intelligent-chassis stacks to any automaker that signs, which is how a mid-tier brand like JAC ends up showing a 12-degree by-wire concept. And China's price war pushes flagship features downmarket within a model cycle or two, not a decade.
Chengdu offered the receipts. BYD's new Da Han flagship sedan pairs rear-wheel steering with dual-chamber air suspension at a starting price local outlets peg around the equivalent of $34,000. Xpeng's GX full-size SUV lists steer-by-wire and rear-wheel steering as standard. Chery is promoting a by-wire chassis capable of lateral crab motion for mainstream-segment cars, and the Dongfeng-Huawei Epicland X9, a full-size SUV with rear steer, began customer deliveries right at the show. My bet is that within two model cycles, rear-wheel steering on a Chinese family EV will be as unremarkable as a big touchscreen — and export markets will start asking Western brands why the same feature still costs extra.
What we still don't know
- Whether and when DEFINE-X becomes a production model — JAC has announced no timeline, specs, or price.
- Itemized option costs on most Chinese models: because rear steer typically ships bundled and standard, there is no clean per-feature price to compare with Western option lists.
- How the MEGA's 7-degree system behaves at the limit — we photographed the car on a stand, not on the road.
