OB_Dirty Pete
Registered
Just came back from GT 1 and 2 races at Mosport.
I was talking with the Crew Chief of a Mazda team. He's a Brit who came to cars through bike racing, so he knows a lot about both.
We were talking about why bikes, even Superbikes, get around the course so poorly compared with even modest four cylinder "stock" bodied race cars. The answer is in the cornering of course, we all know that.
He says that it's because the best bikes can only generate about .7 G lateral. Which is about the same as a Buick loaded with church goers. A stock Vette will do .95 G and a Viper over 1 G. This guy's race car pulls 2 Gs. He says grand prix cars pull nearly 4 Gs sideways. I know that a grand prix tunnel boat pulls 4.5 Gs.
He says (and the physics guys among you are welcome to punch holes in his explanation if you can),that cars are able to pull 1 G+ not just because they have a better weight to contact patch size ratio, but because "they lay flat on the pavement."
With a car, you can just keep adding rubber width until the rubber's drag interferes with top speed or steering.
He says that for a bike to generate 1 G lateral, it would have to be able to lay flat on the pavement (remember the daredevil riders who rode around the inside of a huge barrel...parallel to the ground? They had to generate 1 lateral G minimum to do this.) But because a bike can only achieve a maximum level pavement lean angle (combined bike lean and rider hangoff) of about 70 degrees, it can only generate about 70% of one G. i.e. .7 G.
It follows, he says, that if you are leaned over 45 degrees, you are doing .45 lateral G.
This makes some sense to me at a gut level. Has anyone the mechanical/physics/chassis management knowledge to verify this man's explanation?
By the way, I was amazed that the Busa created more interest among the car racers in the pits than it's ever caused among a bunch of bike guys. They all knew exactly what it was and loved it!
[This message has been edited by Dirty Pete (edited 04 September 1999).]
I was talking with the Crew Chief of a Mazda team. He's a Brit who came to cars through bike racing, so he knows a lot about both.
We were talking about why bikes, even Superbikes, get around the course so poorly compared with even modest four cylinder "stock" bodied race cars. The answer is in the cornering of course, we all know that.
He says that it's because the best bikes can only generate about .7 G lateral. Which is about the same as a Buick loaded with church goers. A stock Vette will do .95 G and a Viper over 1 G. This guy's race car pulls 2 Gs. He says grand prix cars pull nearly 4 Gs sideways. I know that a grand prix tunnel boat pulls 4.5 Gs.
He says (and the physics guys among you are welcome to punch holes in his explanation if you can),that cars are able to pull 1 G+ not just because they have a better weight to contact patch size ratio, but because "they lay flat on the pavement."
With a car, you can just keep adding rubber width until the rubber's drag interferes with top speed or steering.
He says that for a bike to generate 1 G lateral, it would have to be able to lay flat on the pavement (remember the daredevil riders who rode around the inside of a huge barrel...parallel to the ground? They had to generate 1 lateral G minimum to do this.) But because a bike can only achieve a maximum level pavement lean angle (combined bike lean and rider hangoff) of about 70 degrees, it can only generate about 70% of one G. i.e. .7 G.
It follows, he says, that if you are leaned over 45 degrees, you are doing .45 lateral G.
This makes some sense to me at a gut level. Has anyone the mechanical/physics/chassis management knowledge to verify this man's explanation?
By the way, I was amazed that the Busa created more interest among the car racers in the pits than it's ever caused among a bunch of bike guys. They all knew exactly what it was and loved it!
[This message has been edited by Dirty Pete (edited 04 September 1999).]
