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Discussion Starter #1
Heya folks,

I just secured (at least I think I have!) a set of Michelin Pilotsport S2 tyres for my rears.

Those of you who saw my car, would have seen that my fronts are totally past their use by date and the rears are new. So I am going to put the rears on the front and the Pilotsports on the back. That's the plan anyway!

The tyre is 265/35R18. To my understanding these WILL fit the Rays rears (8.5") wheel. If anyone thinks otherwise... can you please chime in!

The reason I am getting them is mainly cause I am a cheap *******! :) They are $819.95rrp per tyre. I am getting 2 for $400.
 

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nice that's a bargain. where you get them from? Ebay :D lol

I think should be ok. Just double check if your rear tyres is 245?

cheers
 

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The tyre is 265/35R18. To my understanding these WILL fit the Rays rears (8.5") wheel. If anyone thinks otherwise... can you please chime in!

As I mentioned previously, the only issue I see is that the height of your tyre/wheel will no longer match the OME one ... which means that your speedo will be off and also the back of your car will sit lower (and the 245/45/18s will actually lift the front). Your front will be lifted by 9mm, and your back will be dropped by 1.75cm. So you're altering the stance of your car ... not sure what difference it'll make, but it's something that you should know. I'm guessing that in migth increase understeer.

Also the 265/35/18 will make your speedo off by 5%. So your speedo will show 5% more speed than you're actually doing. That is on top of the factory speedo-error ... which is not much bellow 100kph, but starts adding up over that. So when your speedo will be showing 100kph, you'll be really doing 'only' 94kph. And when it'll be showing 200kph, you'll be doing about 185kph (not 100% sure about the speedo error here).

Still, the tyres should fit and if you're OK with these two 'issues' then I see no problems.
 

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I was wondering if you could fit 265 45 18 on the stock touring rims which are only 8 inches wide?! does any know if this has been done or if even possible??
 

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Discussion Starter #6
This is a more temporariry measure until I get my stuff sorted with R spec and 2nd set of wheels.

I realise that it's not the "ideal" solution, but it's the best I can come up with at the moment.

The exact changes are
FRONT:
Specification Sidewall Radius Diameter Circumference Revs/km Difference
225/45-18 101mm 330mm 660mm 2073mm 483 0.0%
245/45-18 110mm 339mm 678mm 2129mm 470 2.7%
REAR
Specification Sidewall Radius Diameter Circumference Revs/km Difference
245/45-18 110mm 339mm 678mm 2129mm 470 0.0%
265/35-18 93mm 321mm 643mm 2019mm 495 -5.2%


Oh and re speedo error - when I was driving down from Sydney, I went past one of those radar thingys that shows you your speed. I had 110 on the digital speedo and had 110 on the radar thingy. So looks like 0% speedo error to start with :)
 

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Iggy - that's an absolute bargain and hard to pass up.

BTW the 265/35 would be illegal in NSW because the rolling diameter is more than 15mm outside of OEM specs. Not sure if Vic has the same rules though.
 

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[/quote]
Not possible AFAIK. As Mr Rizk said, minimum width for a 256 tyre is 9".
I believe the maximum recommended tyre size for an 8" wide wheel is 255 and this would have a little tyre bulge over the rim.
 

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Iggy:

The max and for safety reason.... you can go for 255 instead of 265... 255 will give you a huge wall already... and I was using 255 with the Rays wheel before my nismo wheels.... they look great actually! When you go to most of the tyre shop, they will honsetly not recommand you to put 265 on the 8.5J wheels.... only when you go up to 9J, then you will be more suitable for the 265...

I tried 255, and they both worked and looked great!

cheers,

richie
 

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Discussion Starter #10
Thanks for the replies and recommendations guys. I took good note of all advice and I still went ahead with it for 2 reasons:
1. **** good price
2. I BADLY need front tyres, and have no $$$ at the moment to buy new

But here is the update so far:
The tyres turned out NOT to be PilotSports. The guy was selling 2 fronts (PilotSports) and 2 rears and I got the rears, which turned out to be Pirelli PZero Rosso, which is still good and I am happy with that. I cannot wait to wear them in a bit more so that they get more grip.

Now I had a rather large drama today when I went to put the new tyres on. The problem is that one of the rears had a 3cm nail in it!!! F*CK I thought... just what I need. So realistically... I had 3 tyres that were unusable (ie the front 2 and one of the rears). the hole was about 1cm from the side wall... which sux, because that can really compromise the integrity of the tyre... especially because it's a cheaper tyre (IMHO). Anyway... the guys wanted me to get new tyres... but I just didn't have the mulla... so after some persuation they patched it up. However, I am not really a fan of patched up tyres and high performance driving!!! Just me I guess...... :)

So now I am driving with the old rears on teh front and the new rears ... well on the rear!

There are a few problems with my set up... the difference in circumference of the tyres differ so much that the computer thinks that the rears are in constant wheelspin... so teh VDC jhust kicks in as soon as you get over 20km/h. You CANNOT switch VDC off while the SLIP light is on! So I HAVE to switch it off when I start the car.
Another problem that I noticed driving home 2nite on teh Nepean... at around 80km/h the computer just goes bezerk and the SLIP, VDC OFF, ABS and HANDBRAKE lights come on and stay on. Cruise works fine... everything feels fine... just it goes nuts. SOOOOOO ..... I am in a bit of a pickle.

My best solution is to get the new wheels+tyres as soon as possible and just get by on what I have for now until I do... OR get another 2nd hand set of good tyres fro the front... something like a 225/40 which will match the rear (from memory).

So yeah... learning experience.
 

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Iggy:

Sorry to hear about that... but that's what DavidM has come up with in his post... the car's stance has been altered and that's also why the VDC kicks in since our "smart" (rather annoying) computer thinks that the rear wheels aren't spinning correctly compare to the front wheels...

Thanks for sharing your experiences with us mate!

Cheers and good luck!

richie

ps. You can go try 255 width for the rear wheels in the future, they were great when I tried it last time! no vdc problem and it helped turning in quite well!

I think I went for 255/40/18..... profile is exactly the same, but just 10mm wider than the stock tyres!
 

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I think I went for 255/40/18..... profile is exactly the same, but just 10mm wider than the stock tyres!

245/45/18 have a sidewall that is 110.25mm tall, and the 255/40/18 have a sidewall that is 102.00mm tall. So there is a difference of 8.25mm.

So there will be a 2.5% difference in diameter/circumference.
 

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Discussion Starter #13
This is starting to really piss me off... ABS seems to kick in just before total stop from time to time... no reason (ie no traction problems), but I feel the drumming in the pedal. Argh! This setup sux!

Well I found some 2nd hand tyres this morning for sale, which could solve my problems. They ar 245/35R18 which is at least the same profile as my rears, which should stop the comptuer going bokers... I hope... any thoughts?
 

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I am not too sure if going for profile 35 will solve your problem though... Nismo had tough time testing the tyre combination for their wheels on 350Z too... at first, the wheels (with tyres) were only available for those cars without VDC... so I think you gotta make sure that everything will work before you spend more money...

cheers,

richie
 

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This is starting to really piss me off... ABS seems to kick in just before total stop from time to time... no reason (ie no traction problems), but I feel the drumming in the pedal.

Is that even when you have the VDC off? If so, is it when you're going straight, or only when you braking and turning? If it's when going straight, and with VDC off then I don't really know why the ABS would be cutting in ... afterall, it should cut in when it senses 'lock', and not slip. And I would think that it would do each wheel independently.

I can only picture the VDC doing what you're saying when you have some lock on the car while braking.

They ar 245/35R18

I have 245/40/18 all around as my track setup. On the track that setup does not cause any problems with the VDC switched off and certainly no weird/early ABS. They do provoke the 'dormant' features a bit more though.

On the road I have not had any problems even with the VDC on, but then again I have not pushed the car with the R-spec tyres on and usualy drive quiete sudetadly.

One would think that going keeping the same width/profile on your car (even if it's different from mine) would procuce the same results. But I'm only quessing at that.
 

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Discussion Starter #16
Actually I think it's VDC not ABS kicking in... I think the computer thinks it's getting some major wheel spin due to difference in circumfrence and goes apeshit :) Ah well... It's a 2nd hand set for around $130 per tyre so I am happy to give it a go and see what happens. BEsides, I am going to get the same VDC kill switch as David in the next few weeks.
 

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Discussion Starter #18
[/quote]
Thanks for that. It IS a good calc :)

Why does it say this tho:
"When changing tire sizes, we recommend staying within 3% of the diameter of the original tire. Any more than this and you face the risk of brake failure."
 

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David, did you get the VDC kill switch installed? How did the install go? Is it working as advertised?
 
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