Camber changes due to smaller wheel/tyre combo

[Tones]

I was running a smaller wheel/tyre combo on the weekend at Eastern Creek. The current road tyres are 205/55-15 but the semis are 195/50-15. According to http://www.bigcustomwheels.com/info_specs.jsp calculator the overall diameter is 30mm less and speedo will read 5% faster than the actual speed.

Would running the smaller diameter wheel/tyre combo change the way the weight loads up the suspension and change the camber?

[ed]

camber is a mechanical property of the suspension components, and rim/tyres wont change this. this goes for both dynamic and static camber

caster though will be reduced a tiny amount, and may turn-in a tiny bit different

[takai]

Withdrawn. Being doped up on meds doesnt make takai a good thinker.

[ed]

how so? 4321

[takai]

Point taken. I withdraw the previous statement, being doped up on promethazine hydrochloride 50mg doesnt produce solid thinking. The car will be a poofteenth lower, but the strut angle doesnt change.

[Tones]

I assumed the unladden suspension angles would be the same ie when car is jacked up and the smaller OD wheel is on. So I was just wondering about when the car was back on the ground. Would the weight of the car would lower it further than the 15mm lowering (due to the smaller OD wheel)?

[takai]

Nope, because the sprung weight doesnt change with wheel size. Your loaded and unloaded camber will be the same. You will just be approximately ((15*2.5)+0.55*205)-((15*2.5)+0.5*195) lower.

[jezza323]

if the wheel offset is different it may also change your track, but no, camber will definately remain the same

[Tones]

I'm using the same wheels so offset is the same. Anyway, this is good news as I was afraid that I'd need a new wheel alignment for the smaller OD semis.

[jezza323]

what brand semi's are you using? and how do you find them?

[Tones]

They are 2nd-hand Dunlop D01J. I haven't used other semi's but compared to my Toyo T1R road tyres on the track, they are much much stickier on the corners. The limit of traction is so high that it'll take some time to find the new limits without coming off the track.