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!
See how many cars you can race around the track before some awesome crashes happen! (Additional cars sold separately).

3: Down hill- I think this would be the least of your problems. not to mention if you're fine with the previous scenarios. " a box can slide with free fall"
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.