Kamil's '03 350Z Journal
 

Hey everyone,

I introduced myself late last year shortly after picking up a red '03 Z.

http://i186.photobucket.com/albums/x...psv9s4izca.jpg

I'm starting this thread to keep track of any modifications and/or repairs that will take place during it's life in my possession. As of right now, I'm really considering tracking the car so that's where most mods will stem from. So, on with the 1st mod: tires!

The PO sold the car to me with a set of amazing rims, the Enkei RPF1's. They're 18x9.5 but came wrapped with 225s on a 40 sidewall. I personally HATE the 'stanced' look and stretched tires. And since this setup would be useless on the track, I've decided that would be my 1st 'upgrade'. So, after some research I've decided on the Bridgestone Potenza S-04 Pole Positions. I bought them in the following size: 265/45R18

Can't wait to install these on the car sometime next week! Next purchase will most likely be suspension / brake related.

Here's a pic of the rim meat:

http://i186.photobucket.com/albums/x...psdmhpn4yf.jpg

nice pick up. What are the offset on those wheels? looks like a low offset rfp1 i haven't really seen much of on the Z. maybe spacers in the rear in the future? good set of wheels tho!

Kamil,

265/45s?? I'd be careful with that. That's way too tall of a tire.

225 45% 18 25.97 Stock Reference Size
245 45% 18 26.68 Stock Reference Size

265 45% 18 27.39 Delta is +1.42"/36mm Front and +.71"18mm Rear

This can possibly lead to issues with the car being squirrelly (not a word but describes it best :icon17:) and twitchy and not to mention the wheel speed errors (ECU expecting differential wheel speed F-to-R) leading to issues with VDC (if your car is so equipped) and possibly TCS if you have that instead.

If you have a base model (didn't look carefully), no issue.

9.5s (with that HIGH offset, not low - the rears are sunken pretty far) can take up to a 275, 285 tread width with little issue (on the wheel and clearance wise) but in doing so, you need to lower the aspect ratio. See below.

225 45% 18 25.97 Stock Reference Size
245 45% 18 26.68 Stock Reference Size

245 40% 18 25.72 Front-Alternate
255 35% 18 25.03
255 40% 18 26.03 Front-Alternate
255 45% 18 27.04
265 35% 18 25.30
265 40% 18 26.35
265 45% 18 27.39
275 35% 18 25.58
275 40% 18 26.66 Rear-Alternate
285 30% 18 24.73
285 35% 18 25.85
285 40% 18 26.98 Rear-Alternate

Just want to put this out there as advisement.

Beautiful car, BTW!

Mic

255/40 and 275/40 is what I run personally.

Those tires are gonna be too tall. I'd exchange them if you can for something more suitable for a Z, maybe like StuLax18's setup or even a 275/40 square.

Thank you for all the feedback guys, really appreciate it. I bought these from Tire Rack and they're not mounted up yet. Their site is listing a 45 side wall for the stock tire size which is what I went with. Are you saying their website is wrong? If so, I should have no issues returning them:

http://i186.photobucket.com/albums/x...psjkyarvy8.png

Yeah that is correct for stock tire size but the 45 is an aspect ratio of the width... So when you ordered 265 wider width tires you should have gotten a 40 series aspect ratio to make them not so tall... 265/45/18 is like an suv sized tire... If you can return them you should do so..

Also im guessing you have a base model z but if you dont you need some staggered tires...

At the top under tools use the tire and wheel calculator tp help you out. But I would just see if you. Could swap them for some 265/40/18...

In other words the 45 on a 225 tire is an inch and a half tall... The 45 on a 245 tire is 2 inches tall... The 45 on a 265 tire is 2 and a half inches tall... You get what im laying down?

Thats just an example not an exact measurement

Also the po sucked at wheel buying, should have gotten 18x9.5 +15 front and 18x10.5 +15 rears... Looks like you got 18x9.5 +35 (or similar to stock 30) that's why you probably could use some 20-30mm spacers.

I understand now. Thanks for clearing that up. I was wondering where Mic was pulling those numbers from but it makes complete sense now. I have the Touring model. And yes, the OP def sucked at wheel shopping (any idea which forums I should post those wheels up for sale on? lol). I'll call TR in the morning to see what I can do about returning these. I have a feeling I'll be eating a re-stocking fee.

Ooo if you have a touring edition doesnt your slip light go cray cray whenever you go out driving with all the same sized tires?

I would stick to the staggered set-up 245/40 front 275/40 rear.. But that might be a little wide for the 9.5 wheel. Best suggestion is to play with the calculator and see what will work best with your wheels... 265/40 rears and 235/40 fronts might work well.. Or a 245 square with 40 series front and 45 rear...

https://www.tacomaworld.com/tirecalc...0r18-265-45r18

Another cool tool

That's the thing, it does not go off at all. I've pushed the car aggresively through corners multiple times without setting it off. The system does work because it has went on before while driving through rain around a turn.

Personally, I hate the fact all 4 wheels are the same size. RWD cars belong with a staggered setup. If I could sell these rims, I'd get myself a 18x8 for the front and a 18x9.5/10 for the rear and then go with proper tires for those. God damn you PO...

You could dish out the $700 for 2 new rear 18x10.5 +15 and then run spacers in the front... Then run the 285 and 255 combo..


Your lucky you don't have problems with traction control mine sometimes goes wacky around turns... Its annoying.

Or you could sell the whole set and get a freshy set of 17s for a true track rig set-up... Those wheels look mint though I would have a hard time giving them up, but someone mighy give you some good money for them...

You could still run a staggered tire setup with the 9.5 tires. 255/40 and 275/40 will both fit on those wheels if new wheels aren't in the budget right now.

^^^ This.

Just to mention it again, there is something called the "1.2 Factor" which is a general guideline for proper performance tire-to-wheel sizing.

It says that the tread width can be up to 1.2x the size of the wheel before performance starts falling off due to sidewall slippage and tread squirm.

Example:

In this case, you have a 9.5 inch wheel (241mm). Applying the 1.2 Factor (241mm x 1.2 = 289mm) you can run up to a 285 tire on it safely.

Note: It is physically possible to run as much as 1.3 to 1.4x but performance is diminished.

And conversely there's another unwritten "law" that says you technically shouldn't go UNDER tire width/wheel width ratio of 0.9:1. But it's done all the time on stretched applications. You just have to find a tire installer who is willing to accept the liability.

If you are going to track the car, you probably want to buy Bridgestone RE11, R71R, Hankook RS3, Nitto Nt01, Z1 star spec, or anything in the same realm.

Square setup is very common track people use as well for Z

I think people touched on it, but I'm not sure anyone explained exactly how the tire size numbers work. A 275/45/18 tire would mean the tread width is 275 mm, the sidewall height is .45 x 275 mm, and it's for an 18" wheel. That's how you can compare different tread width tires but still get the same overall diameter and therefore they are compatible.

So like my 255/40 and 275/40 have 102 mm and 110 mm sidewall respectively. On the FX I have a 265/50 and 295/45 for a 132.5 mm and 132.75 mm sidewall. That's a good example of how you can have much different tire sizes but still be the same OD, which can be the goal. However, like you know the Z actually comes with a slightly larger rear tire stock.

Thanks, Stu, was going to do that review of the "how to determine the height" but decided to go back to bed instead. Hahahaha.

But ya, I have that tire info always handy in a spreadsheet for easy calculations when considering tires for anything, the most recent for my "non-Z33-Z", and whip it on out when people need the info here. Laff! :icon17:

Good Tire Brand, I like your choice of tire. I use only Bridgestone and Poles are great, but make sure they fit.... You have received some very good advice here.