Cars vs Bikes in corners

N

NateDogg

Guest
I was under the apparently mistaken impression that cars were faster than bikes through corners. I mean cars with aero download. From what I have been able to determine, a racing motorbike will pull about 1.5g in a corner, camber thrust being what it is. I don't think any cars can match that sort of lateral loading without aero download.

At the same time, when similar two wheel and four wheel vehicles lap the same circuit, the four wheeler has a lower laptime. The only example of this that I could come up with is 125cc shifter karts and 125cc bikes at the Daytona24 road course. The karts ran 2:02 and the bikes 2:12. But at the same time Ben Boss pole was 01:48.376 compared to Daytona 24's pole of the Justin Bell's Corvette 01:49.394. Makes you wonder which is faster and where.

In terms of speed, It seems like the cars should be faster because of bikes being aerodynamicly dirty, Power needed to overcome drag goes up with drag Cubed, so a drag-to-power ratio isn't very useful. You'd want a drag^3-to-power ratio to compare top speeds.

Without downforce, I don't think any cars could exceed 1.5g's without some sort of dynamic camber or weight-shifting mechanism. While the peak coefficient of friction for some tires exceeds 2.0, you'll never get that after the load transfer to the outside tires, because loads reduce the coefficient of friction significantly.

I will have to find it again, I do recall that F1 Racing magazine did a motoGP vs F1 car side by side at Silverstone. The lap times were within a couple of seconds of one another, but the split times told the story: the F1 car smoked the moto-GP bike in the corners.

Also, Last Summer Nicky Hayden and Michael Andretti swaped Rides with Hayden driving Andretti`s Lola Honda and Andretti riding Haydens HRC RC51 Superbike at Mid-Ohio. Motorcyclist had an Article about the swap and a data graph with the speeds of the Car and the SuperBike around each Corner and straightways at Mid-Ohio. The Lola- Honda was quicker in every Turn except one and was faster down the Straight at 186 mph compared to 179 for the Honda RC 51. The bike and Car were close in the slower corners but the car with its extra Downforce was much quicker in the faster corners. The Lola- Honda also had a big edge in Acceleration and Braking.

I'm going to need some data for tihs one.
 
I'm not sure about the lateral g numbers for autos.

I have seen reports from skidpads and such where street cars on street tires approach and occassionaly exceed 1.0.

I have have also read reports that some of the open wheelers in CART and IRL have reached very close to 4.0 g's.

I don't have any hard data at my fingertips but I have seen these numbers.
 
NateDogg:

I saw that Article in Motorcyclist. That was Interesting stuff! Hayden spun out in the car and Andretti did just fine on the bike! I guess Hayden is still young and crazy enough to drive over his head in that CART car!! Good Article and very interesting as well!

Motorcyclist is a good magazine!
 
FlyBoy, agreed, Motorcyclist is a awsome mag. Hayden is an animal...This is too much for this thread I will set up another. It was a cool article, always interesting to see drivers switch around.

HS, I have to seen those numbers, and without downforce bikes just can't keep up with that level of a car. 4g's is breathtaking, or mabey lack there of. Still would like to see how much time is lost in the corners of all types of speed. On the other hand, not many cars that are remotly stock can keep up with a bike. Thats just a base with what I came to. I try to track split times and top speeds of bikes vs cars. Such as....

During Catalunya Testing, Loris Capirossi on a Ducati was timed at 202.5 MPH on the front Straight. Compared to 198MPH of last years top F1 car. Even being aero dirty, having no downforce pays off a little.
 
Here is some data I have picked up. The Bike is a 500cc 2 stroke. Note that corrner speeds are close to todays 4-strokes. Interesting.

the corner speed of the F1 and GP500 in this year Suzuka race.All data are come from the telemetry of JV's car(BAR) and Okada's bike(Honda)
corner name------------F1----------500
First Curve-------------248km------160km
turn2(no name)-------150---------120
turn3--------------------205---------140
turn4--------------------175---------130
turn5--------------------178---------130
turn6--------------------138---------110
Dunlop Curve----------235---------150
Degner Curve1--------190---------138
Degner Curve2--------125---------108
Hairpin--------------------62----------58
Spoon Curve1----------177---------133
Spoon Curve2----------135---------117
130R---------------------270---------200
Casio Triangle-----------58-----------53
top speed---------------316---------304
horsepower(about)-------800----------190
weight(kg)--(include driver)--600------130(bike only)
fastest lap--------------1'39'189------2'08'474
 
recent issue of Road & Track Speed Magazine puts 589 hp Skyline GT-R against zx-10. Followed by a zx-6 motorcycle against 2005 Corvette (400 hp). Issue named Tuner Bike vs Tuner Car sept/oct 2005 issue. Both use pro racers. Cort Wagner takes the vette around Buttonwillow Raceway in 2 min 7 sec. Next goes Doug Chandler(not a slow ex racing magazine editor) who goes 1 min 57.76 seconds on lap one on the 636 cc Ninja. Quote: " Mabee this isn't going to be as close as we thought" one Speed editor mutters as Chandler goes even faster on lap 2. Chandler's fastest lap of 1 min. 56.50 seconds puts him more than 10 seconds quiker than the vette on the slow bike. Unquote. But Wagner does manage a 1 min. 58.82 on the 589 hp Skyline. Then the zx-10 is a " green bullet shooting through the hearts of the Speed stafers who wagered their checks on the Skyline". Chandler beats the Skyline by 5 sec and the vette by 15 with a 1 min. 53. But, this is a no down force bike against a little down force car. Indy a F1 cars have real down force and smoke their comprable gp 990 cc motorcycle counterparts.
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On comperable compound tires most of the time a car will always outhandle a bike. Even the best street bike cannot expect to handle with a NSX, or 350Z, but they will also out motor them easily as well. Top Gear did a test like this and while the car ate up the bike in braking and cornering it could not make up the acceleration.... Now start a car in front and the bike prolly couldent pass unless you had a heck of a straightaway...
 
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