# Tyre sizes



## Smileygtr (Apr 8, 2017)

Would runnin 285.35.20 front and rear do any damage ??


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## borat52 (Jan 29, 2006)

No, its a tried and tested set up, same size front and rear = happy drivetrain.


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## Smileygtr (Apr 8, 2017)

Just with standard sizes suppose to be 255.40.20 and 285.35.20 i thought the rollin circumference might damage the box or something?


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## Teaboy (Apr 24, 2016)

Smileygtr said:


> Just with standard sizes suppose to be 255.40.20 and 285.35.20 i thought the rollin circumference might damage the box or something?


The wheel speed front and rear is 1:1 so running exactly the same size front and rear will keep the ETS happy. It's technically a better match than the stock set up as far as the drive train is concerned but from a handling point of view in some options is a step backwards.


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## Smileygtr (Apr 8, 2017)

Excuse me for being thick but why is it a step backwards?? Would of thought it should be better with more grip on the front??

Open to explanations lol


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## Teaboy (Apr 24, 2016)

Smileygtr said:


> Excuse me for being thick but why is it a step backwards?? Would of thought it should be better with more grip on the front??
> 
> Open to explanations lol


It is argued that the added grip at the front helps combat the GTR's tendancy to push wide / under steer at the limit of grip but the knock on effect is that the rear can break away first and can catch you out. Nissan went for a staggered set up for a reason.


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## Smileygtr (Apr 8, 2017)

What is the best combination to go for??


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## Teaboy (Apr 24, 2016)

Very subjective and you will get a lot of different opinions.
Why do you want to go wider on the fronts?


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## Smileygtr (Apr 8, 2017)

Tyres are already on pal.. just wanted to know all is ok


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## borat52 (Jan 29, 2006)

There was a minor 'craze' for the square set up at one point in time. I guess people were trying all sorts of different things to see if they could find any improvements or to be more cynical tuners might have been courting free publicity and trying to sell alloys and tyres ahead of their competitors.

Probably a pinch of both.

Either way the square set up seems to have fallen out of mainstream favour.

After having 305/30/20 rear 275/35/20 front I'm doing back to the 285/255 set up as:
1. It keeps the diffs happy
2. the speedo over reads with the 305's as the diameter is smaller than stock

The 305/275 set up does seem to induce more noise from the drivetrain in my opinion which cannot be good.


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## Teaboy (Apr 24, 2016)

Smileygtr said:


> Tyres are already on pal.. just wanted to know all is ok


Drive it and make your own mind up. You may well find it's better for you and if not go back to a staggered set up on your next tyre change. Your drive train will be fine.


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## Trevgtr (Dec 24, 2012)

Smileygtr said:


> Just with standard sizes suppose to be 255.40.20 and 285.35.20 i thought the rollin circumference might damage the box or something?


The 40 and 35 represent a percentage of the width, 40% of 255 and 35% of 285, so not spot on but close. Same tyres front and rear will obviously be spot on, so better than stock.

But wider isn't necessarily better or gripier.


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## Smileygtr (Apr 8, 2017)

Tyres are already on the car as i have only just bought it.. just wanted to make sure its ok to run this combination with no drivetrain issues or diff issues etc.. will change to factory setup if they are?


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## Papa Smurf (Sep 25, 2008)

Wrong
Standard set up is 255/35 R20 front and 285/30 R20 rear
In my opinion a square set up really doesn't work as it gives too much front grip and throws the entire balance of the car out.

Best offset is 265/35 R20 front and 305/30 rear and that keeps the rolling circumference within 0.7% and will give you better handling IMHO




Smileygtr said:


> Just with standard sizes suppose to be 255.40.20 and 285.35.20 i thought the rollin circumference might damage the box or something?


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## Teaboy (Apr 24, 2016)

nurburgringgtr said:


> Wrong
> Standard set up is 255/35 R20 front and 285/30 R20 rear


Check again.


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## Trevgtr (Dec 24, 2012)

Smiley is correct with regard to standard sizes though, 40 profile front, 35 rear.


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## Papa Smurf (Sep 25, 2008)

My apologies, you are correct. I spend so much time talking tyres and sizes that I forgot the OEM's were 40 and 35 profile.

Still hate square set up!


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## Mr.B (Feb 18, 2016)

Don't want to hijack the thread but I noticed the LM20 is running 285/345 Michelin Cup2's. Has anyone tried this and is it worth the wheel size increase?


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## Stealth69 (Jan 6, 2005)

I have that size on mine but I have after market wheels, no bad effects thus far as it's only .7% difference


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## Mr.B (Feb 18, 2016)

Does this set up give noticeably more grip?


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## Stealth69 (Jan 6, 2005)

Not really no lol the size increase was for aesthetic reasons.


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## Teaboy (Apr 24, 2016)

Stealth69 said:


> I have that size on mine but I have after market wheels, no bad effects thus far as it's only .7% difference


335 rear and it's a perfect match. As you say though a wider set up doesn't automatically mean more grip. 1 of the absolute best road handeling GTRs i have driven was on OE size and spec Bridgestone's with a few choice suspension mods and the right geometry.


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## Stealth69 (Jan 6, 2005)

Teaboy said:


> 335 rear and it's a perfect match. As you say though a wider set up doesn't automatically mean more grip. 1 of the absolute best road handeling GTRs i have driven was on OE size and spec Bridgestone's with a few choice suspension mods and the right geometry.


335 would probably be perfect but I'm not sure how they'd look on the 12" wide wheels  

To be fair not a lot is going to increase the grip for 620+ft/lbs on road tyres


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