As far as treads go, the sky's the limit. Treads bolt directly onto the outer rim piece by piece, and there are a bunch of options to choose from, including a range of pre-molded road retread options by companies such as Michelin that bolt on in sections, or a plethora of heavy-duty industrial options that use polyurethane, urethane or steel pieces in a range of different configurations for serious off-road grab.
Take the mammoth Caterpillar 797F Mining Truck (pictured above), which stands more than 25 ft (7.6 m) tall and weighs in at 1,375,000 lb (623,700 kg). Each of the big Cat's six monstrous 59/80R63 tires stands over 13 ft (4 m) tall, weighs about 12,000 lb (5,440 kg) and costs somewhere in the range of US$38,000 each.

An important consideration when dealing with e-tron is the aforementioned weight. Though smaller than the SQ7 TDI sold in Europe with its heavy V8 TDI engine, the e-tron is still some 400 lbs. heavier. If you go with a wheel that’s not weight rated for your car, you could find yourself easily bending your wheels or even worse. We did our best to find out what we could about the weight rating of the SQ7 wheel and came away confident enough to give it a try. Even still, it is heavier than stock and boasts a wider contact patch, which meant our electric range would suffer.
Just purchased a 2nd Traxion for my wife; after she borrowed mine she had to have one. This one arrived in perfect condition via UPS. Had to fine tune the brakes and shifters but that is easy. The people here having pedal/crank problems are causing the problem themselves by installing them dry and severly over tightening them. Put a little grease on the threads and take them down to just beyond finger tight. They are threaded opposite of the crank rotation and will not back out, and if you ever need to replace them they'll come out easily without seizing or galling. Great bike for the money!