Theory thread

[Austin34471]

Was reading the bump steer guage post, and had a related question

Dou you set toe with the rf on the bumpstop? And lf on tether?

Do you race with the car there or at ride height?

[95shaw]

Do you race with the car there or at ride height?

So, can we say the need to check bump steer is effectively eliminated, as long as toe is optimized, on the bump, and near tether?

Maybe offer some insight on benefits of bump steer guage with this setup.

[billetbirdcage]

Lets say a few thing for the sake of discussion:

So if you set toe at .5" out statically like most measure it, then it is what it is at the dymanic. Lets say that this is at the ideal toe out of .75" (making up a number). Does it really matter whether which way you measure it, it's still at the ideal .75" toe out.

How much toe out is perfect? lets just say it's .75". What is or how much does the toe change when you steer? Is it still .75"? How much Ackerman the car has will effect how much this changes.

No matter how you measure it, it's a reference point. Sure knowing the dynamic toe out can be useful if you going to alter stuff to have a different toe's between static and dynamic and anything in between that the car see's. However if your just adjusting the toe without altering anything else that changes the toe curve or Akerman then you can just adjust the toe what ever amount you want from either state and see if it helps the car. But doing it from static is a hell of a lot easier.

Using my first paragraph dimensions which are the exact same thing just measured different ways and both will measure the same in the other state, so what did you gain by making it harder to measure by going to the dynamic state after you did it once just to know that number?

.5" out static wheels straight
.75" out dynamic wheels straight

if you alter either states measurement a 1/4" more out you still end up with this:

.75 static
1.0" dynamic

[Austin34471]

Lets say a few thing for the sake of discussion:

So if you set toe at .5" out statically like most measure it, then it is what it is at the dymanic. Lets say that this is at the ideal toe out of .75" (making up a number). Does it really matter whether which way you measure it, it's still at the ideal .75" toe out.

How much toe out is perfect? lets just say it's .75". What is or how much does the toe change when you steer? Is it still .75"? How much Ackerman the car has will effect how much this changes.

No matter how you measure it, it's a reference point. Sure knowing the dynamic toe out can be useful if you going to alter stuff to have a different toe's between static and dynamic and anything in between that the car see's. However if your just adjusting the toe without altering anything else that changes the toe curve or Akerman then you can just adjust the toe what ever amount you want from either state and see if it helps the car. But doing it from static is a hell of a lot easier.

Using my first paragraph dimensions which are the exact same thing just measured different ways and both will measure the same in the other state, so what did you gain by making it harder to measure by going to the dynamic state after you did it once just to know that number?

.5" out static wheels straight
.75" out dynamic wheels straight

if you alter either states measurement a 1/4" more out you still end up with this:

.75 static
1.0" dynamic

Agreed. As long as you know both static and dynamic at some point for reference. Another fun thing to think about is.. put say 700# on the RF wheel and turn it 20deg. Put say 200# on the LF and turn it 20 deg. (Weights replicating how much weight is on each corner on corner entry). Where are both of the contact patches actually pointed? 🤔 Some road course cars run anti Ackerman because the outside tires contact patch turns at such a delayed rate compared to the inside/less weighted tire.. and their tires are much less floppy than ours

[95shaw]

Agree with both above posts.

My point was , as long as the ideal toe is achieved dynamically, bump steer becomes largely irrelevant.
Provided the front suspension stays on the bump and tether.