,
Increasing the scrub radius too much can cause wheel fight and twichyness under braking, especially on split friction surfaces and more sensitivity to bump steer. An extreme amount of scrub will result in an overall loss of traction as turning the wheel will add a sideways sliding component to steering which will reduce traction.
 |
| Mike Essa’s 2010 car shown here at Ken Block’s Gymkhana had a huge amount of scrub in its front suspension geometry by design. It severely hampered its handling in both drift and grip events like this. His new car was designed to have correct geometry in the front from a clean sheet of paper and it handles much better. |
It’s best to try and not deviate too much from the amount of scrub engineered into the car from the factory. To minimize the change in scrub radius it’s important to try to increase wheel width to the inside of the car as well as the outside by closely paying attention to the wheel offset, thus going wider while keeping the scrub radius the same. HellaFlush fanatics need to consider this.
 |
| You can have a Hellaflush car and still be functional. Dai Yoshihara’s Team Falken S13 is pretty low and pretty flush. This is all OK because the highly adjustable suspension can be made to work like this and the nature of the setup allows it. We run a lot of KPA and positive caster so we have a good scrub radius even with a lot of offset. We also correct the roll center and bumpsteer to be correct with the car low. We also still have a lot of wheel travel. This is more like Hellafunctional. I guess I use Dai’s car a lot as an example because I work on it quite a bit and know its setup inside out. |
KPA affects scrub radius, more KPA reduces the amount of scrub radius so sometimes this is a good way to decrease scrub due to offset changes. Generally if you have a race car with adjustable KPA you usually set the car up with a couple of degrees less KPA than positive caster so you end up with a good but not excessive amount of negative camber gain with turn in. This way you might be able to get away with less static negative camber. In some cases you may want the KPA to equal the caster. KPA affects the scrub radius so sometimes you end up balancing caster, KPA and scrub to get the car to handle in a desirable way.
 |
| Stance is Everything yo! Dai’s car is as Hard As F__k and so is the stunna flossing the carbon fiber credit card. Tiite! Who says I hate Hellaflush? If it doesn’t affect performance it looks badass! |
 |
| More proof that MotoIQ does not hate Hellaflush! |
