Front/rear stagger

[dguy]

(split off from this thread so as not to pollute the diet )

By the way, in order to fix a lot of the handling characteristics of my Fiero (due to weight distribution) I have calculated the requirement for 245's on the rear while keeping the 205's on the front.

I'd be interested in seeing how you worked that out if you don't mind sharing.  I've heard of plenty of people's preference for a 10-20mm stagger, but this is the first for something as large as 40mm.

[aaron88]

The formula is actually very simple if you make sure a few things are the same front and rear.

The tread must be similar
The rubber compound must have the same modulus and thickness
The side walls must be similar stiffness front and rear (side wall as a percentage of the tire width usually compensates for this)
The tires must have the same speed rating

There are a few more but it’s not worth getting into because generally if you have the same make and model of tire front and rear and very importantly the have the same speed rating.  Then you can just make the tire width a direct percentage with the weight on the tire.  If both tires have the same weight per square inch of contact area then they will both have the same slip angle.

Eg. The weight distribution on my car is 46% front, 54% rear.
Therefore; 205mm front and 245mm rear, are the same distribution of tire width. 205 is 46% of (205 + 245).

It’s that simple for most applications.  Please note though, when using different series tires front and rear (ie. 45 series front 60 series rear) or different compounds of rubber (ie, different make or model of tire or speed rating), the process of calculating the sip angle is much more involved and will require some trial and error.

Does this help?


Aaron

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[dguy]

In other (very general) words, the idea is to balance front/rear grip to the weight distribution.  Gotcha....  thanks!