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Duk
Verde
Verde
Posts: 532
Joined: Sun Aug 19, 2007 9:15 pm
Location: South Australia

Increasing Track Width

Post by Duk »

If I add spacers to between my wheels and the hubs, do I really increase the track width?
It sounds stupid I know, but if the distance of the upper and lower balljoints from the upper and lower chassis pivot points hasn't increased, is the track width really any different?
Another example would be adding spacers/changing offset of the wheels shouldn't change the actual wheel rate if the spring rates remain the same. Or so is my thinking :wall:

Some reasoning behing my thinking is that, with my Pace Engineering knuckle risers, my car now has sufficient negative camber gain on bump to allow an increase of front wheel track of about 20mm per side without hitting anything it shouldn't.
Do I simply add wheel spacers or do I go to all the effort of making/have made for me custom suspension arms???
To me, longer suspension arms is the technically correct way to do it, but obviously expensive and with potential legal issues when used on the road.
Wheel spacers could achieve the same visual result but only (IMO) by changing the scrub radius of the (front) wheels.

"Kvestions, kvestions............." :mrgreen:
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GTV27
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Posts: 296
Joined: Mon Apr 09, 2007 12:20 am
Location: Brisbane, Australia

Re: Increasing Track Width

Post by GTV27 »

A good question.

Track width is centre of wheel to centre of wheel, so by reducing the offset (eg by adding spacers) you are moving out the wheel (including the centre point) and thereby increasing the leverage effect on your springs via a longer effective 'lever arm' between the point of load (the centre of the tyre, for all practical intent) and the pivot on the body thereby reducing the wheel rate for a given spring rate (but by stuff all, so that's not a biggie in the scheme of things).

However, as you correctly surmise, your scrub radius goes to hell in a handbasket and steering weight and feels gets spooky as all hell. The 45mm offset wheels orginally fitted to the GTV6 give the best weight and feel (IMHO anyway).

Going to 30mm offset wheels (like used on TS or 3.0 75s) gives more track, but weights up the wheel (they had PS, so no drama) and dulls the feel (which I believe that many blame the PS for). I've not tried an offset less than 30mm, but expect that it would get worse from there. I use 35mm offset 7.5inch wheels for a compromise between extra track and retaining nice steering.

For a race car, the extra track may be worth the steering issues. For a road or rally car, I'd have some doubts (allthough, it would look fat).
Jason
1983 GTV6 2.8 litre
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