Hi,

I was hoping someone can validate my math for calculating increased track width (assuming 0 degrees of camber)? I'm not sure if i should be adding or subtracting the offset from the centre figure. Subtracting feels right as my point of reference is the ground and not the hub.

Standard OEM AP2 Wheel Front = 7" = 17.78cm
17.78cm/2 = 8.89cm = Center of Rim
8.89cm-0.55 = 8.34cm = new center with offset

RPF1 9" +45 = 9" = 22.86cm
22.86cm/2 = 11.43cm = Center of Rim
11.43cm-0.45 = 10.98cm = new center with offset

track increase on 1 side = 10.98-8.34 = 2.64cm
Total track increase = 2.64cmx2 = 5.28cm = 2.07"

Thanks

 

Depends on what your trying to achieve by calculating this. Some measurements discount the wheel all together and look purely at the hub as the point of reference. Some in the wheel center line such as your case, and in my reference point for the sake of handling/suspension tuning and scrub radius, the outer edge of the wheel to account for total new track width.

 

Hey,

Thanks for the prompt reply.

My goal is to check if i need to move up a class in a super sprint series. My car is basically stock except for a set of PSS9s and wheel / tyre (255) combo.

These are the regulations for the the class i want to stay in.

I'm pretty sure i break 8.1 but 6.4 is the one i was confirming.

Suspension
6.1 The type of shock absorber is free but not their number or mounting points.
6.2 The rate and length of springs is free and adjustable spring platforms are permitted.
6.3 Sway bars may be added, replaced or deleted.
6.4 It is permitted to adjust the wheel alignment in accordance with the manufacturer’s recommendations and/or normal wheel alignment principles, except that the original dimensions must be respected as to - 21 - SSP 03 2016 Technical Regulations Version completed at 7:29 AM on 7/5/16 wheelbase and a maximum increase in track of 25mm (1”) is permitted for camber adjustment only.
6.5 Camber adjustment kits are permitted.
6.6 Plain bushings may be replaced by those of a different material provided that original dimensions are retained.

Wheels and Tyres
8.1 Wheels can be altered, in both diameter and width, by up to one inch in width and two inches in diameter over manufacturer’s original specifications, provided that the tyres do not extend beyond the outer edge of the coachwork (including wheel arch flares) when viewed vertically from above.