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Discussion Starter · #1 ·
Ok so I'm getting some new wheels for my Gtr. Same size alloys all round with the same offset.
My question is could I run 265x35 tires on the front and 285x30 on the back? Will this massively affect the way a Gtr works or will it not be an issue.
 

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Rolling diameter needs to be the same and the car was designed with matching rubber on each axle.
 

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most big name tuners run a 265. you can clear all 4 and there are no rubbing issues. stay with a 35 side and you're golden.

edit* Re read your post. Are you running a staggered setup? if not, why different sized tires? if you run an 18X 9/9.5/10etc, then run a 35 sidewall. if you are replacing with the same spec wheels as stock, no need to change from the 245/45/17.
 

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Discussion Starter · #6 · (Edited)
Ok peeps, iv changed the tires. 2 were bald and had to be changed. Could not afford all 4 and 2 that were still on are good anyways. The ones that are older are seriously stretched so moving to 285's 2 at a time.
Alloys 18x11j et 0. 265x35 on the front and 285x30 on the back. They did not do 35 profile in a 285. The front 2 will be changed soon for 285's, when the tires are dead. But will it damage anything or just make the 4wd act a bit odd?
I did drive it tonight and noticed on very light throttle the 4wd gauge is reading about 10, were as normally it reads 0. Iv also shimmed the hicas last night to stop it moving and as expected the hicas light is on and the powersteering is slightly heavier. Will or can the hicas affect the 4wd?

Arches rolled and not a problem btw :)



Thanks guys :)
 

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Alloys 18x11j et 0. 265x35 on the front and 285x30 on the back. They did not do 35 profile in a 285. The front 2 will be changed soon for 285's, when the tires are dead. But will it damage anything or just make the 4wd act a bit odd?
But remeber, it's not about having the same number for sidewall. The number is a percentage of width so having a 285/35 is NOT going to be the same as a 265/35. Ironically, it may be that the difference in rolling radius is amall given that your intention is to run 265/35 and 285/30. There are a few rolling radius calculators on the net so find one and put the numbers in and see what it says....

EDIT:- Use this calculator HERE. Looking at it, you're sizes are 2% different in circumference which works out at about 7mm difference in RR......

I can't recall the allowable difference in rolling radius F/R but it aint a big number. The bigger the differential in RR, the more strain it puts on the transfer box....

With his knowledge of the GTR 4WD system I would be amazed if Andy (R32Combat) didn't know what the accepted differential in RR is.........


TT
 

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Discussion Starter · #10 ·
Ok so it's width not size in a round about way. Well iv not adjusted the tire pressures yet. I have sensors fitted. The backs are 6psi more than the front at the mo. Is it worth trying higher pressure front and lower back or the other way round to try and even it out? Or will this not make any impact?
 

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It's a calculation based on all tyre measurements - width x ratio x diameter.
The difference between 265/35 and 285/30 is something like 15mm/0.6" which is 2%. Also, the 285 tyre would be 24mm/1" smaller diameter than OE.
 

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Discussion Starter · #14 ·
Well just asked Scott at Abby. Yup your all correct :( and it the rolling radious thats the major issue but the width difference is not helping I guess. So my options are slowly drive the 15 miles home and either order 2x 285x30x18 tires or pull the front prop for the time being. Looks like Iv got an overweight Gts-t :rolleyes: :flame:

An to boot mytires have put the price back up. I paid £105 each and now its £137. Grrrrrr
 

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You need the same tire size for front and back, otherwise you will wear out your transfer box. It happened to me, stay safe use same tire size
 
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