dj55b

iTrader: (2)

Here you go ... pulled it out of a magazine and thought was a nice little piece

elwood

iTrader: (1)

The last line, last column should read "Rear Sway Bar", and I think the tire pressure recommendations are backwards, too.

Kentetsu

Yeah, last line should be rear swaybar. They are correct on the tire pressure recommendations though...

The only problem with charts like this is that everyone is starting from a different set of settings. So, if your car is really fudged up to begin with, these recommendations might not apply. It would probably be more effective if they gave you a baseline to start with. 40 psi tire pressure, -3 degrees camber, etc...

Also, adjustable shocks are another quick and easy way to fine tune your handling. Those settings would be a stiffer setting on the front shocks to reduce oversteer, etc. But then the only problem with that is if you go too soft on the front shock settings, instead of increasing oversteer you start increasing understeer. Its really tough to lay out a standard "one size fits all" type of chart like that. But it is still useful as a guide for beginners....

dj55b

iTrader: (2)

ya sorry last line is suppose to say Rear sway bar ... sorry guys ... my fault

As far as the overall chart ... i personally didn't know you could change the oversteer understeer of a car by changing toe and camber ... good to know on the shocks too there kentetsu

t_g_farrell

iTrader: (1)

The tire pressures are backwards. I always have run 3# less pressure in the rear to reduce oversteer. Always have since I first autocrossed the car.

If you decrease pressure your going to slightly increase the tire patch and weight distribution, so lower air in the front will tend to give you more oversteer, not less.

Kentetsu

I've got to disagree with you there T G. But again, it all depends on your starting points. If you're running very high pressures to begin with, then you could very well end up getting increased grip from a lower psi. Everything is relative.

Take a look at this guide. It covers a bit more information, but not a whole lot on tire pressure effects.

http://www.wtrscca.org/tech.htm

Here's some info from Khumo that I just found:
SCCA/NASA Racing
Race Schedule Race Results Competition Tires Year In Review Contingency Form Tire Setup

Recommendations
The following recommendations are provided to help you get the performance out of your new Kuhmo V700 tires as safety as possible. However, auto racing and racing-like activities may be dangerous, and may result in property damage, personal injury, or death. Always approach the performance limits of your car and its tires with appropriate caution.

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Tire Mounting
While mounting and balancing V700 tires on your wheels should be left to a professional with the proper equipment, there are several factors that you should confirm with your installer before he mounts your tires. The V700 tires features an asymmetric tread designs and "SIDE FACING OUTWARDS" and "SIDE FACING INWARDS" messages are branded on their sidewalls. New tires should always be installed accordingly. However, while V700 tires continue to be branded with right ("R") or left ("L") side of vehicle markings and rotation arrows which originated with KUMHO's desire to reduce stress on the tire's tread splices, KUMHO has since developed tread splices that make following the side of vehicle markings and directional arrows unnecessary. Today, there is only one part number for each size tire and experience has shown that V700 tires can be installed on either side of the car, run at any wheel position, and are not required to be run directionally. Because a tire mounting lubricant should be used when installing V700's, it is best to mount your tires far ahead of their use in competition to minimize possible tire slippage on the wheel which might affect balance. Slippage can be confirmed by running a chalk line vertically across the wheel flange onto the tire sidewall. If the line doesn't remain lined up after competition use, some slippage has occurred and wheel balance should be rechecked.

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Tire Break In
The V700 does require break in. New tires will be slippery for their first laps, and will begin to feel better as they get scuffed in and build up heat. We recommend that drivers heat cycle their tires before using them in competition. Heat cycling helps you get the most consistent performance and tread life out of your tires. It is the process of gently bringing the tires up to temperature for a short duration and letting them cool. Ideally, you should break in your tires, remove them from your vehicle, and set them aside for more than 24 hours before your track sessions and races. Often this requires running a practice session on new tires to prepare them for a future race, while you use tires prepared previously for the current race. The Tire Rack offers an automated heat cycling service which can complete this process before your tires are delivered to you.

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Tire Pressures
The V700 will work well on most cars with inflation pressures between 35 and 40 psi ("cold" inflation pressures for autocross use and "hot" inflation pressures for racing use). Cars that are light, well balanced and relatively easy on tires will find slightly lower pressures may work for them, while heavy, high horsepower cars that are generally harder on tires may find that they need slightly higher inflation pressures. Generally adding air pressure in small increments (2 psi) to the tires on the end of the car that looses traction first works best. For example, if a car is understeering, add pressure to the front tires. If the car is oversteering, add pressure to the rear tires.

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Alignment Settings
Your vehicle's alignment settings can influence the performance of your tires and often can be adjusted to maximize their capabilities. Like most tires, the V700 features a symmetric internal construction and will require negative camber to achieve its full potential. If camber is adjustable, most cars will perform best when camber is adjusted into the -2° to -3° range. Caster settings can enhance straight line stability and cornering traction, and if adjustable, should be set at the maximum positive value for the vehicle. Toe settings may be adjusted to enhance steering response and corner turn in.

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Rain Conditions
Because wet track conditions are frequently different and always changing, you need to use your best judgment when selecting tires for driving in the rain. For damp conditions where standing water is not present and water evacuation is not required, shaved or worn V700 tires can be used. Standing water should be avoided whenever possible and V700 tires with nearly new tread depths should be used if any standing water is present. However like all tires, the V700 will be forced to hydroplane when their tread design's ability to remove water is exceeded by the vehicle's speed and/or the water's depth. Most cars should begin by using cold inflation pressures for wet track conditions that are 5 to 8 psi below the cold inflation pressures they use in their tires for a dry track.

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Tire Shaving
The Ecsta V700 and Victoracer are molded with 6/32â?? of tread. At this depth, both tires will provide excellent wet track handling and traction. However, using a full tread tire on a dry track will cause the tire to over heat. This will cause the tire to chunk or peel apart, ultimately causing tire failure. This is especially the case with the Ecsta V700, as the compound is softer than the Victoracer. We recommend shaving both tires to at least 4/32â?? of tread for dry track use. This will not only extend the life of your tire, but will produce faster dry track times. The Tire Rack and Vilven Tire both offer a shaving service that can complete this process before your tires are delivered to you.

68GT500

The guide is fine - as a rule of thumb.

And that is all its supposed to be.

Most experts will find that for their specific setup- especially at the extremes - it will be in error.

Those tables are not intended for the experts..