Wednesday, October 1, 2014

Race Car Service and Repair Bay Area - Chassis Adjustments - Zucchi Motorsports Sonoma - 707-334-3700

negative camberPositive camber


Camber is the inward or outward tilt of the wheel at the top of the tire. Negative camber is the tilt of the top of the tire towards the center of the vehicle.

Positive camber is the tilt of the top of the tire away from the center of the vehicle. Camber adjustments are utilized to help maintain the maximum grip allowable from the surface of the tire through the corners of the track. Proper camber adjustments are very critical for achieving maximum cornering speeds.

Proper camber adjustments are achieved by reading tire temperatures. Read the section on Tire Temperatures for the proper way to decipher what your tires/camber are telling you. In a WC car you are allowed camber adjustments on all 4 tires. In NASCAR Racing we are allowed a wide range of adjustment for the front tires. +5 is the most positive camber allowed, while -5 is the most negative camber allowed. In the rear we are only allowed adjustments of +1.8 through -1.8.


Contact Patch
When camber is set correctly it allows the entire surface of the tire to adhere to the track thus maximizing the use of the tire contact patch when taking a corner at high speed. On all tracks except road courses you'll want to run with negative camber on the right front & positive camber on the left front. Running camber as such will create part of the pull to left that will help the car get through the corner easier. The more excessive the cambers the greater the pull can be. Running excessive amounts of camber will cause premature tire wear due to the fact that the tires aren't running on the full contact patch of the racing tire.

camber

As a general rule, the flatter or slower the track the more camber you'll need on both front tires. More positive camber on the left front & more negative camber on the right front would be required at a track like Martinsville over a high speed high banked track like Talladega. Another factor in determining camber is body roll. The more the car "rolls" over through a corner the more negative camber you will need in the RF. Body roll is determined by how stiff your springs & or sway bars are. The stiffer the springs, the less body roll. The less body roll, the less amount of negative camber required in the RF.
Rear camber is not as critical as front camber due to the fact that the rear end is solid axle. The same theory holds true though as you might want negative camber on the RR & positive camber on the LR on an oval track. On a flatter track you may not need any camber in the rear. Stagger built into the Goodyear tires will naturally create some negative camber in the RR & positive in the LR as is.

When competing on a road course like Watkins Glen or Sears Point or any track where your making both left & right handed turns you'll need to "square" up your camber or make it equally negative on both sides.

When all is said & done, knowing how to read & understand tire temperatures will be the determining factor in how much camber to set in your wheels. In fact it's the only way to properly adjust for correct amounts of camber. Since you must constantly monitor tire temperatures you will always be readjusting camber (at least in the front). Just when you think you have your tire temperatures & camber perfect, you'll change a spring or tire psi to find more speed, or the weather will be different forcing you to make some adjustments elsewhere. All that hard work you spent on achieving those perfect temperatures will have to be thrown out the window & the whole process begins once again.

Keep in mind that adjusting one part of the car & not readjusting camber could be throwing off your original adjustment. Let's just say for example that you didn't take tire temperatures after changing the RF spring & running another 20 laps. Your times are slower after the spring change & you give up on that spring change because it made you slower. Maybe it wasn't the spring change that made you slower it was your camber being off that made you slower. Readjust the camber after running 20 laps with that spring change then decide if that was really the wrong way to go. Did you go faster after making the spring change? No. Did you go faster after making the spring change & camber change? Ah there ya go <g>. Take constant notes of each & every adjustment you make. If it doesn't work, you'll at least know how to set it back to where is was before you started.

Here is a synopsis of how camber effects the handling of the chassis:
• More negative RF camber allows the car to turn into a corner quicker & will loosen up the chassis.
• Less negative RF camber takes away some of the pull to the left. The car won't turn in as quick into a corner & will tend to tighten the chassis.
• More negative LF camber will reduce the pull to the left while tightening the chassis from the middle out.
• More positive LF camber will increase the pull to the left & allow the car to turn into a corner quicker loosening the chassis.
• More positive camber in the RR will loosen the car from the middle out.
• More negative camber in the LR will loosen the chassis entering a corner.

source: http://www.racelinecentral.com/RacingSetupGuide.html

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