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Wheelie Bad Ideas: Do go-kart wheels work on a BMW Z4?
We're testing some of the most adventurous tyre modifications possible - but will they be genius, or really wheelie bad ideas?
Words by: Andrew Woodhouse
Published on 15 December 2025 | 0 min read
We're testing the limits of what's possible with a modification by trying the zaniest tyre options on a BMW Z4. From go-karts to train tracks, let's see how it goes!
Episode One: Can a BMW Z4 run on train wheels?
Have you ever wondered what would happen if a sports car left the open road and ventured onto railway lines? In the first episode of our new YouTube series, Rory takes a BMW Z4, equips it with bespoke train wheels, and puts it to the test.
You’ll get a front-row seat for the full transformation: swapping rubber tyres for steel wheels, tweaking the suspension, and experimenting with traction and braking on the rails. With Top Gear engineer Peter Ross on board, we explore whether a car designed for smooth tarmac can handle such unconventional terrain. The episode covers every step, from modifying Audi-derived train wheels to adapting the BMW so they fit the track gauge, and even adding ballast and a parachute to improve performance. Stand by for surprises, hands-on engineering, and unexpected outcomes as we push what’s possible with a car you could pick up from Autotrader. Whether you’re fascinated by innovative engineering or simply want to see a sports car take on the British rail network, this first episode offers something a bit different. So, if you want to see a sports car behave in a way it was never designed to behave, or you just want to know what happens when curiosity meets engineering, this is the one. Found on Autotrader. Tested in the strangest way possible! Watch the full episode now and stay tuned for episode two.
You’ll get a front-row seat for the full transformation: swapping rubber tyres for steel wheels, tweaking the suspension, and experimenting with traction and braking on the rails. With Top Gear engineer Peter Ross on board, we explore whether a car designed for smooth tarmac can handle such unconventional terrain. The episode covers every step, from modifying Audi-derived train wheels to adapting the BMW so they fit the track gauge, and even adding ballast and a parachute to improve performance. Stand by for surprises, hands-on engineering, and unexpected outcomes as we push what’s possible with a car you could pick up from Autotrader. Whether you’re fascinated by innovative engineering or simply want to see a sports car take on the British rail network, this first episode offers something a bit different. So, if you want to see a sports car behave in a way it was never designed to behave, or you just want to know what happens when curiosity meets engineering, this is the one. Found on Autotrader. Tested in the strangest way possible! Watch the full episode now and stay tuned for episode two.
Episode Two: We put go-kart wheels on a BMW Z4
In this video, Rory Reid dives into an unusual challenge: can small wheels actually outperform big ones?
To find out, he fits the smallest wheels possible onto a BMW Z4, using trailer-sized rims and custom adapters so they’ll clear the brakes. The transformed Z4 instantly grabs attention, looking a bit like a toy car escaped onto the road. The showdown gets even more interesting as Rory pits his tiny-wheeled Z4 against a Lamborghini Urus sporting enormous 22-inch wheels. On the test track, the Urus’s speed and comfort shine, thanks to its impressive size and ground clearance. Yet the tables turn when it’s time for some driving fun. On a wet handling pad, the Z4’s petite wheels let it slide and drift effortlessly, serving up a go-kart feel that brings an undeniable grin/ The verdict? You’ll have to watch to find out. Episode two is live now.
To find out, he fits the smallest wheels possible onto a BMW Z4, using trailer-sized rims and custom adapters so they’ll clear the brakes. The transformed Z4 instantly grabs attention, looking a bit like a toy car escaped onto the road. The showdown gets even more interesting as Rory pits his tiny-wheeled Z4 against a Lamborghini Urus sporting enormous 22-inch wheels. On the test track, the Urus’s speed and comfort shine, thanks to its impressive size and ground clearance. Yet the tables turn when it’s time for some driving fun. On a wet handling pad, the Z4’s petite wheels let it slide and drift effortlessly, serving up a go-kart feel that brings an undeniable grin/ The verdict? You’ll have to watch to find out. Episode two is live now.