rollsteer/stagger

[ZERO25]

Anyone know a mathematical formula for finding the correct stagger correlating with the steer angle of the rearend?

[MasterSbilt_Racer]

Anyone know a mathematical formula for finding the correct stagger correlating with the steer angle of the rearend?

Can't be done. Angle = turn forever.

[ZERO25]

Can't be done. Angle = turn forever.

Surely in this age of technology,some engineer somewhere has attempted to calculate this!

[MasterSbilt_Racer]

Surely in this age of technology,some engineer somewhere has attempted to calculate this!

All it does is dog walk the car. Now days, the car mostly staying hiked. If it don't set down, it's always skewed the same amount, so it isn't steering.

[ZERO25]

I would find it hard to believe, back when the Cup cars were doing it, that some of the engineers hadn't researched the idea.

[CageFaraday]

...rabbit trail...

[Matt49]

The direction the axle is pointing relative to the car doesn't change the amount of stagger required to get a solid axle to roll through a corner.

[dirtrace09]

But the stagger does change the amount of input needed from the front to control where the car wants to go due to the direction in which the axle is pointing.

[hotshoe65s]

You can indeed calculate the turn radius with a given amount of rear steer. You can also calculate the turn radius with a given amount of stagger.
It is not a 1:1 relationship and there are no optimal ratios. Of course they do not act independent of each other, but there is also no magic answer. The optimal rear steer and stagger depend on track conditions, vehicle setup, and driving technique.
If you want a way to determine your turn radius or understand any characteristics on your car I have built a dirt late model/modified simulation program that has that calculation included in it. I am working with a few guys to work the bugs out of it. I would sell it to a select few people as beta testers if interested.

[fastford]

a lot of thought has changed with the amount of dynamic roll steer these cars have today , we are on 1/2 and sometimes less stagger than we were 10 years ago.....

[Matt49]

I also think it's just important to keep in mind that stagger and rear steer accomplish two completely different things. Stagger is helping the rear of the car make a turn radius around the corner without scrubbing the tires. Rear steer is helping the entire car (not rear end only) make it around the corner without laterally sliding the rear end.

[Kromulous]

Question: are you guys a set the stagger and forget it, or adjust it to get the car to do whatever better?

I always considered setting it per the track, and keep it consistent, but over the years have wondered.

Also It seems a certain amount of tire scrub is needed to make more traction via less or more stagger. It seems like the modern way is to run a lot less stagger, and more rear steer like Fastford said but why is the question? trying to create more tire scrub against the track?

Example would be to have enough rear steer and stagger to make the car go around a corner with the least amount of scrub etc, the most efficient. Then take out / add stagger out to add or subtract some tire scrub. I know there will be considerable tire scrub from the effects of cornering to begin with, side load etc.

[ZERO25]

You can indeed calculate the turn radius with a given amount of rear steer. You can also calculate the turn radius with a given amount of stagger.
It is not a 1:1 relationship and there are no optimal ratios. Of course they do not act independent of each other, but there is also no magic answer. The optimal rear steer and stagger depend on track conditions, vehicle setup, and driving technique.
If you want a way to determine your turn radius or understand any characteristics on your car I have built a dirt late model/modified simulation program that has that calculation included in it. I am working with a few guys to work the bugs out of it. I would sell it to a select few people as beta testers if interested.

CP Furney years ago published a table for determing stagger based on banking angle and rear track width. He also believed you had to add a certain % to that based on certain track conditions and reduction of tire circumference due to weight transfer.

[hucktyson]

I think any scientific calculation of what is required is thrown out the window by the track not being perfectly smooth and the track not having even consistent traction from top to bottom and the cars sliding and wheel spinning. This is not asphalt. According to all of you Kevin rumley is the smartest guy on the entire planet and snort is the best driver and the have the best funded operation .... Only the last of which do I consider true but point being there are plenty of races where he is not a factor , if the “ smartest guy on planet earth “ is unable to harness the power of these scientific calculations to produce consistently dominate results you have to conclude it’s not possible

[Jking24]

I think huck hit the nail on the head. People forget rumley was a racer long before he was a engineer. No denying the data helps but we're all still racing on a ever changing surface with mother nature fighting us every step of the way. That's what makes this sport better than all the rest the challenge!