Is SRM affected by changing rolling radius?
 

Question to all those who changed the rolling radius of their z's tyres, did it affect your SRM operation? I'm pretty sure it'd be ok but would like to make sure.

thanks

i dont think it should, it bases its calculations on drivetrain speed and engine speed. if your wheels are slightly smaller or larger rolling diameter, then that will affect the speed of your drivetrain, and srm would still rev match to that speed. as far as i know, the only thing changing your rolling radius would change is the readout on your speedometer. since SRM doesn't care what the number on your speedometer reads, i don't think it will make a difference.

SRM is unaffected by any gearing change past the output shaft of the gearbox. You can change rear-end gears or tire diameters and it will still work.

VDC is affected by tire diameter change if the front and rear diameters (and hence revolution speed) are dissimilar by more than a certain margin.

Like others have said... NO, your all good.

Damn good point about the vdc... i didn't consider that...

As long as you are even front to rear I don't think it matters what size they are overall other than for speedometer error.

My speedo is off anyway, when i do 100kph the actual speed is 93. Increasing the RR will actually make it more accurate.

Comparing front to rear diameter ratios OEM=1.01 (Bridgestone 245/40 275/35)

I changed to 1.00 for daily driving. (Hankook V12 255/35 295/30)

My track set is .98 but still good. (Toyo R888 265/30 295/30)

No SRM or VDC issues.