Technical front & rear track proportion

is there a fixed formula to help determine the track relationship between front & rear axles? for example, if the rear track is 60", should the front track be equal? 1.1 greater? 1.1 narrower? or does it not matter as long as the Ackerman geometry is right?

thanks

 

Keep it as close to OEM as possible. Allow minor variation, wheel offset. No need to reinvent the wheel.

 

As with anything it depends on what you want to achieve. It's as much of a design decision as pegging tyre diameters, rake, etc.

 

In my world, the outside sidewalls of the chosen tires should be in line, front to rear as well as the engine cylinders but that's a whole other subject.

 

If it's fender less and viewing from the front, I like to see the front tires in a little more then the back...

 

It is not just about style. Difference in track width will affect the handling. If you are trying to add some oversteer, then wider track in front will help.

 

Surely the other way around? A wider rear track would load the outside rear more, inducing greater slip-angles relative to any given lateral acceleration - considerations of roll stiffness, roll centre heights, etc. being equal.

 

I have not seen a formula or a ratio ever written down anywhere. If one track width is wider than the other I usually prefer it to be the front especially on a short wheel base car. it makes for easier cruising down the road.

 

ALL of the "Factories" use the front "wider" for all cars I've ever heard of.

Also, if you look into most any respectable racing chassis design book, the front is suggested to be wider. 2 (or so) inches wider in the front.
Check ANY (well designed) three wheel vehicle. One with the "pair" of tires up front will ALWAYS out handle the one with the "pair" of tires in the back.

Mike

 

Front and rear tires tracking with one another

This is a interesting topic .I guess I never thought of the importance or actually even thought about it. Maybe thought it would( look better) if the front wheel were in a bit more than the rear. This is one of the many issues that I guess I have to consider with my A that I'm building almost from scratch. So many topics and so little time. I sure appreciate all your tips guys.Please ignor some of my dumb questions as time goes on Gene

 

Given that wheel 'track' is the centerline of the wheel and tire, side to side, the choice of wheels and tires can quickly affect the 'track' of either axle compared to the other. So, even if you do want the track equal, the axle width (wheel mounting surface to wheel mounting surface) may have to differ, depending on wheel choice, and the offset of that wheel. And if you want the track the same, it can be, even with wider rear tires and/or wheels, but the sidewalls won't line up even with the same track.

If, on the other hand, you want the outside sidewalls in line, them wheel track may have to differ if tires and/or wheels are not the same dimensions (size, width, offset).

Open wheel vehicles give more latitude than closed bodied cars, which accounts for the horrible rash of "tubbing" that occurred a few years ago because 'everybody" had to have huge rear tires, all other reasonable considerations be damned.

Ray

 

I like the same or slightly narrower up front. Cant stand seeing tires tucked under the fenders in the back and obviously too wide up front to be able to match.