Suspension setup/Tyres. What have you got?

[Whodeeny]

How does one figure out the minimum (or maximum) rim width allowable for a given tire size? I have 7.5" Sunburst wheels going on my ERA that is in production now and was wondering what my options are. My preference is to make all 4 tires the same size as I will also be caring a spare.

[cycleguy55]

Originally Posted by Whodeeny

How does one figure out the minimum (or maximum) rim width allowable for a given tire size? I have 7.5" Sunburst wheels going on my ERA that is in production now and was wondering what my options are. My preference is to make all 4 tires the same size as I will also be caring a spare.

Tire manufacturers provide charts that show minimum and maximum rim widths, plus they also usually show which width rim was used for measured specifications. Like this chart from Avon: CR6ZZ | Avon Motorsport

[strictlypersonl]

Originally Posted by cycleguy55

Tire manufacturers provide charts that show minimum and maximum rim widths, plus they also usually show which width rim was used for measured specifications. Like this chart from Avon: CR6ZZ | Avon Motorsport

tirerack.com has that information. Select a tire that you think might fit and look in the Specs tab. i.e.
https://www.tirerack.com/tires/tires...omCompare1=yes

[Dominik]

Front Tire Width: 235/60R15
Rear Tire Width: 275/60R15

Camber front: -0.5°
Camber rear: -0.75° (less camber in the rear than front would lead to oversteer)
Toe (in) front: 1,5mm per wheel (toe out leads to better turn-in into corners, but less straight line stability - enjoyable in the mountains)
Caster: 3° (not the most critical measurement. Make sure left and right are the same)

Toe (in) rear: 1,5mm per wheel (less powerful cars can use less because the rear deflects less). Never toe-out.

Front Spring Rate: 450 lbs/inch (ride comfort is defined by front spring rate)
Rear Spring Rate: 560 lbs/inch (this depends on your ratio) Too hard rear makes the car oversteeer

Car: RAM LR Roadsters (UK) with Jag XJ6 Suspension parts
Wheelbase: 90"
Weight (approx.): 2,000(!) lbs.

If you can, go on a track with a tyre pyrometer and measure temperatures after a few laps.

More: Tune to Win, pg 42 ff, C. Smith