kingpin angle, scrub radius

[Bugpac]

from what i have read in rortys tech site, have perfect kingpin angle with zero scrub radius is maybe not such a great idea.

http://www.rorty-design.com/content/tech.htm

i was under the impression that it was best to have the kingpin meet the center of the tire maybe it is not.

[Gene]

This is interesting. I read Rorty's article and saw that he is talking about positive scrub in the 10 to 35 mm range. Here's what that means to most of us:

10 millimeter = 0.393 700 787 inch
35 millimeter = 1.377 952 756 inch

We're talking about very small numbers here. Plus most of us are on sand so it might be hard to tell the difference without going from a car with zero to a car with some positive scrub.

I can tell you this: mine had negative scrub - maybe 5 inches and it absolutely was the car from he*l to steer because it pushed right as it turned left and left as it turned right. Chain drive enhanced lousy steering.

Maybe positive scrub would benefit in a chain-driven car.
Gene

[yoshi]

Scrub radius is just that, the tire scrubs across the ground. Positive and negative scrub has it's perks but if you don't have power steering you want as little resistance possible. That's why Gene had to go to the gym everynight, just so he's in shape to turn his steering wheel every other weekend. If you don't have power steering,....zero srub all the way......IMO

[KWiKSand]

You know, I was just thinking... we have had two blasters over the years, and on both of them the front tires/rims were mounted backwards, effectively increasing the positive scrub on them. Nearly every blaster I have seen on the dunes with stock wheels is like this too. Neither kid said anything about it being harder to turn. Sometimes I think in the Sand a lot of this just doesn't matter as much.

[Bugpac]

i had a raptor with zero offset front smoothies and it turned way difrrent "stiffer". but were talking like having a 1" or +/-

[yoshi]

A blaster has a relativley small wheelbase. I noticed a difference in turning when I flipped my 400 ex rims around for the sand. The wider stance corners better, but is noticably harder to turn. Not that big of a deal but on a rail with a big stance it could make a huge difference with the kingpin being off. Just ask Gene, he'll tell you first hand what it feels like and wether or not it's noticable, lol....