Staggered Wheel Sizes And The Attesa System

[nisskid]

ok, as im sure most of you know, and most likely have discussed before, the GTR runs staggered sized wheels and tyres front and back, now looking at previous models i have seen people mention that changing the track (offset) and wheel size (or more relavently tyre size) can mess with the ATTESA system. now im assuming its simply a matter of programming in staggered sizes into the ATTESA system, but what will this mean to aftermarket wheels etc, i mean with the older models it was simply a matter of just not staggering the sizes and offset, but how will they used aftermarket wheels with different sizes and offsets etc or will this ATTESA system really not give a shit about changing size and offset?

[Sydneykid]

ok, as im sure most of you know, and most likely have discussed before, the GTR runs staggered sized wheels and tyres front and back, now looking at previous models i have seen people mention that changing the track (offset) and wheel size (or more relavently tyre size) can mess with the ATTESA system. now im assuming its simply a matter of programming in staggered sizes into the ATTESA system, but what will this mean to aftermarket wheels etc, i mean with the older models it was simply a matter of just not staggering the sizes and offset, but how will they used aftermarket wheels with different sizes and offsets etc or will this ATTESA system really not give a shit about changing size and offset?

The only issue with R32/33/34 style ATTESA was rolling diameter, wheel offset, track and tyre width were all irrellevant. The R35 has similar requirements;

255/40ZRF20 fronts = 255 * 40% = 102

285/35ZRF20 rears = 285 * 35% = 100

A 2% difference is well within the ATTESA's ability to handle. Keep in mind that new tyres versus almost worn out tyres (of the same size) is more than 3%.

Cheers

Gary

[Adriano]

Gary, you forgot the wheels in your calculation,

255/40ZRF20 fronts =712mm

285/35ZRF20 rears =708mm

Difference is .56%

[blur]

Im sure when they calibrated the assetta ecu they designed it compensate for mismatched tyre size.

[VB-]

its that close it doesnt matter, driving around a corner would throw it out more than that when the backwheels take a more inside line of the corner (it makes sense in my head lol)

[supadan]

is thouse calculations still good for the r32 atezza system

[Sydneykid]

Gary, you forgot the wheels in your calculation,

255/40ZRF20 fronts =712mm

285/35ZRF20 rears =708mm

Difference is .56%

No I didn't, I am calculating the difference in tyre sidewall height.

You are calculating the difference in total wheel and tyre height.

We are both correct.

Cheers

Gary

[Sydneykid]

Im sure when they calibrated the assetta ecu they designed it compensate for mismatched tyre size.

There is effectively no difference in the tyre size (diameter), width is irrelevant to the ATTESA.

Cheers

Gary

[Sydneykid]

is thouse calculations still good for the r32 atezza system

As far as tyre diameter is concerned, R32/33/34 & 35 all have the same tolerances.

Cheers

Gary

[nisskid]

yep, the info i looked at when i created this thread was false, rolling diameter makes a lot more sense then width of track. can lock this thread now as its based around false info.

[mobilcepet]

Gary, you forgot the wheels in your calculation,

255/40ZRF20 fronts =712mm

285/35ZRF20 rears =708mm

Difference is .56%

How did you come up with the number??

[mobilcepet]

I'm now running 245/35 19F and 285/30 19R... Is that okay?

*Sorry, I was reffering to R34

Edited June 7, 2009 by mobilcepet

[LSX-438]

I'm now running 245/35 19F and 285/30 19R... Is that okay?

*Sorry, I was reffering to R34

Work out the tyre height thus:

TyreHeight = (Width * Profile% * 2) + WheelHeight[mm]

Therefore 245/35/19 =

245 * 0.35 * 2 + (19*25.4) = 654.1mm

And 285/30/19 =

285 * 0.30 * 2 + (19*25.4) = 653.6mm

Heights of these two tyres are within 0.07% which is well within tolerace.

[nisskid]

http://www.1010tires.com/TireSizeCalculator.asp