I'm just a fan, not a racer, and certainly not a NASCAR fan, but I watch the roadcourse races and root for "our" guys (Boris Said, Scott Pruett, etc.).

It seems like there was an epidemic of "wheel hop" in braking zones. Is it the solid axles and balloon-like tires? I can't say I've ever heard of this before (on braking, that is). The announcers frequently said, "There it is. You can see the hopping that led to the spin." I never saw any hopping.

Overall, I like the look of the "car-of-tomorrow." It's a more modern looking thing, and doesn't have that bizarre, distorted look that the previous stock cars had taken on. I couldn't tell how quick they ran because they almost never mentioned nor displayed lap times. It was all about average MPH. It's good racing, with plenty of passing. There were a LOT of pits and a variety of pit strategies, so it was pretty hard to tell during the race who was REALLY leading. A guy would go from 4th to 25th, and it was impossible to know when or why.

but my guess is from the guys engine braking with the revs to high rather than heel/toe and using the brakes to slow the car.

I had heard an interview with Dale Jr. saying he feels he popped his motor in the race from too much "engine braking" in practice.

This is all speculative. I could be WAY off on my assesment.

or too much rear bias causing the backs to lock up. Since all the weight is on the front (espeically at Watkins T1), locking the backs just bounces the car and..voila, pirouette.

If you haven't deleted it, watch the Tony Stewart spin again, especially when they show the bumper cam, you can see the rear end start chattering before it swaps ends on him.

I watch the roadcourses as well, I just wish NASCAR would be more like Aussie V8s...*sigh*

I don't really know the physics of it, but threshold braking really exacerbates the effects of any imperfections in the track. Turn one in particular has a pretty bumpy braking zone, and you can definitely get wheel hop there. Same with the braking zone for turn one at lime rock...

Mike you are spot one with this assessment. None of the road racers seem to experience wheel hop to any extent. Why, they use the brakes instead of motor.

Wheel hop can occur on a rear wheel drive street car, regardless of rear suspension type, just by using too much engine when braking. Solid rear axles just seem to make the problem more apparent.