No suspension other than perhaps some flexing plastic. Activity geared for the young.

We used to slide down an ash or clinker faced very high hill on car hoods liberated from the auto wrecker next door to the hill. That hill was steep.

Fastest I think though was the time we constructed a box on a pair of 1920 Olympic type skies. We used this one on snow of course. I cut an old guys grass and he gave them to me. They were far longer than todays skis.

Or maybe the time we went down a hill and passed a car in our home made jeep gravity car with four aboard. We were doing fine until we lost a front wheel. I was driving and managed to stay on. One guy lost a tooth in the episode. I was the only one that remained aboard until it stopped. Probably because of my white knuckles type of grip on the steering wheel. There is something to be said for brakes.

Also with the ski unit we eventually hit a solid object that broke the tips and put Us through the 2X4 front members of the box. I guess as we were so young in those days that period was the start of me building things.