Wheels and the effects of smaller backspacing?

[andyw]

We’re thinking about these wheels but would like a little more depth on the fronts.

162575

Specifically, we're thinking of reducing the backspacing from 5” to 3.5”. Are there any concerns other than pushing the wheels out from the body 1.5" on either side... like negative impacts on handling or steering, other concerns we should be aware of?

Pictured:
•Rear 20”x11” w/6” backspace/0 offset (pictured)
•Front 17”x8” w/5” backspace/0 offset (pictured)

But on the front, we want 9” width with the backspacing reduced to 3.5”.

Thoughts?

[RoadRacer]

Two concerns are will the wheel hit anything - bodywork, suspension, chassis - and the geometry changes. But I've never seen posted what the perfect wheel offset is and even FFR's cars have used wheels with different offsets.

Read about scrub radius here: https://www.suspensiondesigner.com/kpi-kingpin-angle-scrub-radius-wheel-centre-offset/

The short version though, is that you'll probably not notice. Camber, caster, toe will make more difference to your handling. I added an inch spacer to my wheels to improve my geometry, but couldn't feel it. You can read about my calculations starting at post 484 (https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=460710&viewfull=1#post460710) and read #488.