Another tyre thread...

As you know I will have to have 8.5" wheels at all four corners. I want larger tyres in the rear, but it has to be legal. Ive been informed that 265 wont fit but if you did get it on its an illegal fitment, and the 255 isnt legal either. So my option is to have 245 S03 all the way around or to buy another type of tyre which comes in 255 here in Au like Pirelli as I would want the most grip in the rear to make up for smaller contact patch. I realise that this wouldnt be perfect but it would have to be better than 245 S03 all the way around.

Anyone know how bad it is to do this?

The tyre shops seem to freely recommend this sort of thing.

 

Goodyear Eagle F1 GS-D3 comes in 255/35-18. I don't see why it would be illigal to import it it with different profile. Also this tyre is quiet cheap and it gets rave reviews every where.

 

Its not the profile but the whole tyre, its just not designed for our market and might not pass some strange Au regulation. If someone can state with 100% certainty then I may import it.

It needs to be 255X35-40X19 and I need the Ultimate performance tyre, i.e the best, to make up for the loss of 20mm of tyre and 1" of rim.

Anyone used these? They are designed to be used as a rear wheel tire.

Pirelli PZero ASIMMETRICO™

The p zero system concept:
- P zero direzionale front, p zero asimmetrico rear
- P zero asimmetrico all round

255/40 ZR19TL 96Y

 

I've been considering that tire, except there's one problem that I see with them. You can't rotate them. By the way, like Peter/Nathen has said above. The only markings on my tires (the stock shitzillas as they are called around here) are DOT approved (or something along those lines), there are no australian markings on the tyres. That is why I'm going to import my tires from usa since then I can be sure that they are DOT approved.

 

AFAIK tyre sizes aren't regulated at all except for circumference which is only to do with maintaining speedo accuracy.

The 255/40-18 and 255/35-18 both list an 8.5" wheel as being the minimum size so you should be OK.

 

Even though different brands/tyres might have the same markings (ie. 245/45/18), that does not mean that they all have the same width 'contact path'.

Example 1: On the S2000 the OME S02s are 225/50/16 in size and their contact path is 222mm. The OME RE040 on my Zed are 245/45/18 and the contact patch is 220mm. So the S2000 tyre looks wider and also has a wider 'contact path' than the RE040 on the Zed.

Example 2: As mentioned before, The 245/45/18 RE040 have 220mm contact patch. On my other set of wheels I also have 245/45/18 tyres, but these are RE055 (R-spec tyres). Their contact patch is 240mm. That is 2cm wider contact path even though it's still the same spec tyre.

The 1st number in the tyre specifications (ie. 245/45/18) is the width of the tyre at the widest point. That could be at the contact path, could be at the rim, or could be somewhere in between. So, if you want wide tyres, and have to get 245s, then just take a ruller with you to the tyre shop, and measure it yourself ... find the widest one to your liking.

Therefore, it's possible to get a 245 wide tyre that has a wider 'contact patch' than on 265. Are you confused yet? ;-)

ps. The 'contact patc'h width I'm quoting are not fvrom the specs, but directly from the tyres as I measured them myself. With the S2000 you had to do that if you wanted to retain the same width contact path with new tyres as the OME tyres have an un-usually wide contact path.

 

Originally posted by DavidM
Even though different brands/tyres might have the same markings (ie. 245/45/18), that does not mean that they all have the same width 'contact path'.

Hectic, I have to find these tyres and measure them. Realistically I cant see this happening. So is it safe to assume that the very best tyres have the largest possible contact patch for their width reading. Have you measured any Pirellis?

 

Originally posted by nuff
I've been considering that tire, except there's one problem that I see with them. You can't rotate them.

This was a problem I thought of when I first saw them last year, and with the amount of camber I have in the rear I think swaping them could be compulsory. Though im not 100% sure if I need to worry too much or not but they would be expensive.

 

So is it safe to assume that the very best tyres have the largest possible contact patch for their width reading.

No, not at all. Not only doesn't it have much to do with the 'quality', but you can also find that the same tyre/brand will have inconsistant width conact-patch in different sizes.

For instance when I had the S02s on the S2000, we also had ther S02s on the HSV. S2000 has 225/50/16, and the HSV has 235/40/18. The 235/40/18s has a contact patch about 1cm thinner than on the S2000.

Have you measured any Pirellis?

I only measured them in the 235/40/18 size, and they were only marginaly wider than the S02s in the same size ... thre was no more than 5mm in between them from what I can remember.

 

Cool thanks. They dont make S02 in 19" so they arent an option.

Would you get the S03 255X40X19 from the US or get a 255 Pirelli to make up for the size downgrade? The Zed does have alot of tiresmoking torque, and once I start modding it i'll need the most possibe traction in the rear?

Do you know the weight saving for the HT exhaust, I did a search and the weight I found didnt seem to match what I had heard it was?

 

Murray - I don't believe that the width of the tyres is the problem. You just need to ensure that the rolling diameter of your new tyres is not greater than or less than 15mm from the OEM diameter. So you can go to as large a wheel / tyre combo as you like, but then you just have to lower the profile to maintain an appropriate diameter.

I suggest that you first pick tyres that impress you for their characteristics (ie max dry grip, handling etc). Then get your tyre calculator out (I use this one at www.tyresave.co.uk/tyresize.html) and makes sure that your new tyre diameter is within spec.

 

Thanks KY350,
But I might not have been clear, NRMA has stated that you cannot run a wheel wider than 8.5" on the 350z otherwise the whole cars insurance is void. I have 9.5" wide Volks with 275 rubber already but I can't use them.

So now with the info provided by zuff & Peter about being able to import tyres legally, and the knowledge that 255 is the biggest on a 8.5" rim, im trying to decide whether I should stay with S03s in the rear, so I have the same type of tyres on all four, or get some Pirellis to make up for the reduction in grip that will take place when moving to a 255 from a 275 tyre.

I hope that makes more sense, sorry.

 

Cool thanks. They dont make S02 in 19" so they arent an option.

I don't think that they make the S02s anymore ... from what I gather, what is around are the 'left overs'.

Would you get the S03 255X40X19 from the US or get a 255 Pirelli to make up for the size downgrade? The Zed does have alot of tiresmoking torque, and once I start modding it i'll need the most possibe traction in the rear?

Are you still using 19" wheels? As far as which tyre, I'm not sure which one is better for you ... me, I'd probably just find and get something localy as it seems like a lot of effort to import the tyres. There has to be something here that suits your needs ... there's a lot of good tyres around.

On a side-note, the grip level is not directly related to a tyre width. To take it to an extreme, I'm very sure that a 205 R-spec rubber will offer more grip than even a 265 street-tyre. Same thing applies with 'good' and 'not so good' street tyres. I'm sure that 'good' 205 tyre will have more grip than any width retread. That is due to the rubber compound.

 

Originally posted by DavidM
Are you still using 19" wheels? As far as which tyre, I'm not sure which one is better for you ... me, I'd probably just find and get something localy as it seems like a lot of effort to import the tyres. There has to be something here that suits your needs ... there's a lot of good tyres around.

Im only getting x2 new rear wheels and tyres, and as the front are 19" I wont be getting anything with a smaller diameter in the rear.

me, I'd probably just find and get something localy as it seems like a lot of effort to import the tyres. There has to be something here that suits your needs ... there's a lot of good tyres around.

If you were to ignore the importing factor in the equation, which of these two setups would you run? I cant change the fronts yet as they are near brand new. Keep in mind that this is a downgrade for me and I dont want to notice the loss of traction, so mantaining the most possible grip is the ultimate factor here.

Setup 1:

Front: 8.5" Wheels with Bridgestone S03 245X35X19
Rear: 8.5" Wheels with Bridgestone S03 255X40X19

or

Setup 2:

Front: 8.5" Wheels with Bridgestone S03 245X35X19
Rear: 8.5" Wheels with Pirelli's Best 255X40X19

The setup would only have to stay like this for the life of the tyres, then I can upgrade them all to Pirellis or something better.

On a side-note, the grip level is not directly related to a tyre width. To take it to an extreme, I'm very sure that a 205 R-spec rubber will offer more grip than even a 265 street-tyre. Same thing applies with 'good' and 'not so good' street tyres. I'm sure that 'good' 205 tyre will have more grip than any width retread. That is due to the rubber compound.

I know this, but it will be directly related to the width if I stay with the same type of tyre, e.g. If im on a 275 S03 then downgrade to a 255 S03, the level of grip should decrease equal to the loss of tyre.

 

I would go S03 all round, like david says, they loose grip after certain number of kms. If you have Pirelli's in the back, lets say after 9000km your cars handling might be very unpredictible. And it might have a lot of understeer.

 

Sorry nuff I couldnt find where David said that about the S03s.

 

He said it some place, I can't remember where, but I see that you remember that David has mentioned it

 

LOL, He said this about the Azenis RT215:

"I could only match the S02 lap-times with the RT215s. Also they became really slippery once they had around 9,000km on them."

 

Murray, you are correct. I'm getting confused, there are way too many tire threads this week

 

Agreed