Wednesday, October 25, 2017

RE-Xtreme RC Drift Bible - Balance

Balance - Grip vs Over Steer and Under Steer or perhaps some of each.

Lets have a look at this picture.

Start at the same speed... Chase car dives in while the lead car holds a wider line.

Chassis tuning is a fine balance.  If this was your "judged corner" and you couldn't reach the RED out clip, your car was following the blue curve... What could you do? Hit reverse?? NO.

RWD relies heavily on balance.
4WD chassis front wheels are usually understeering through wheelspin overspeed anyway, so lets focus on RWD dynamics.

The blue car... has more grip on the front tyres. Simple. the front tyres travel a lesser distance and as speed reduces, the front grip drags the car into the apex.

This is the feeling of the modern D1 car. The front will never "push" it will roll at the tyre high grip fresh sticky radial limit and only the rear can oversteer by invoking massive power and higher speeds to follow crazy lines.

The red car... has less mechanical or tyre grip at the front wheels. The front tyres can scrub further at the same speed. therefore actually understeering or "pushing" away from the apex.

Neither is wrong... but sometimes you have to tune for both.

Add weight, change layout, change tyres, change chassis rake, change spring tension, change shock oil, there are too many variables here.

But if you can't run the wall, then the simple fact is ... change something to get the balance you need.

Front Grip bias promotes steering and turn in, but the rears have less grip and have to cope with more looseness. Spinning is often a result with even small changes in steering.

Front grip can add corner speed but smoothness and accuracy of steering become more important.
Many will turn up the gyro on a high front grip car, this can almost negate the need to steer or remove the ability to correct from a given line.

You simply can't deviate from the cars tuned line. 

building in some scrub can also help to be less dependant on line and be more flexible (especially in the chase position)

but if you choose the line and tuning like your friends do... of course that will bring the most reward.
in competition, you have to hit the judges marks, so tune for the track radius and speed.

But as always ... have fun!

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