Riceboy369

Hey all ... I plan on getting DTM Kreuz 10 rims soon .. w/ Toyo T1-S tires to go with it ... But im just confused as to what sizes to get !! ... (I've checked the forums on what other ppl did, but would like to know the pro's and con's of their decision).

Anyway ... I drive a Blue 350Z Touring 6 Spd .. and decided to stay with the 18's ... But i'm not sure which ones to get.!. .. Well, obviously the rear wheels will be a big bigger in width (right? haha i dunno ... i just see everyone getting bigger rims on the rear than the front) .. Is 18x8 on front and 18x9 on back a good choice? Any recommendations?

Quesiton: What exactly is the different between having 18x8 and 18x9? Pro' and con's?

Moving on ....

For some reason, im just biased with toyo tires .. no idea why, but thats what ill be looking at .... and it appears that the Toyo T1-S is one of the best choices from their selection ... But i am confused on what the tire size should be to match the rim size...
I know the stock tire spec is - Front: 225/45-18 , Rear: 245/45-18 ... Should i go with the same tire specs or change them?

Lastly, the tire pressure monitor should be able to work with the new rims right?


Thanks to anyone who is kind enough to help me ! Your aid is greatly appreciated

ranger5oh

If you go with 8" width front, and 9" width rear, you should run 245/40F and 275/40R for the correct size. You wont F up your VDC or TCS this way.

You need a larger rear rim to run the correct stagger. You can put wider tires on a wider rim, that is why everyone does that.

Audito350Z

iTrader: (1)

The Z has wider tires on the rear, so it may have a wider rear wheel. The Track model has 18x8 front and 18x8.5 rear with the staggered tire sizes. The Touring has 18x8 all around, but has the staggered tire sizes... rear wider than the front. This is typical in some rear wheel drive cars. For instance, the Porsche 911 with 18" wheels has 18x8 with 225/45-18 front and 18x10 with 285/35-18 rear.

another option to the one ranger5oh offers:

Front: 18x8 wheel with 28 offset, 245/40-18 tire
Rear: 18x10 wheel with 30 offset, 274/40-18 tire

The tire pressure monitor may not work with the DTM wheels. They are not a universal fitment, so you will just have to try them and see.

Cheers,

PeteH

Riceboy369

Well, Ive decided to go with the 18x8 on front and 18x9 on the rear ... now all i gotta figure out is the tire sizes ...... hmmm...

Well, what is the difference between putting 225/45/18 and 245/45/18 in the front? I know that the #'s 225 and 245 are the width of the tire ... but how does that affect the car? (Probably a stupid question? I dunno) ... and why aspect ratio 45? ..

Does these spec's affect the treadwear of the tire? For example .. does 225/45/18 have less tread wear than 245/45/18 ??

Thx .... Once i get set on the tire issue, ill be getting new rims ! ..

D'oh

Usually you want to start with the tire and work backwards.

So, on the Z it is important to match the overall diameter of the stock tires so you don't get VDC problems. If you go check out a tire calculator, you will see that the stock tires are:

225/45-18 = 26.0" diameter front
245/45-18 = 26.7" diameter rear

So, you want to match those sizes, and increase width a bit to improve traction (hopefully) or make the car look cool or whatever. You also don't want to go too wide in front or the power steering may start to feel funny and you don't want to go too wide in back or the car may understeer too much.

So, IMO a good front tire is:
245/40-18 = 25.7" (similar to 26.0" of stock tire)
255/40-18 = 26.0" (same as stock)

And a good rear would be in the 245-265 range:
245/45-18 = 26.7" (stock size)
255/45-18 = 27.0" (a little bigger than stock)
265/40-18 = 26.3" (smaller than stock, maybe good with 245 fronts)
275/40-18 = 26.7" (same as stock, maybe good with 255 fronts)

I think your 8" front and 9" rear wheels would work with any combination of those tires (you might want to stup up .5" in front and back for the larger tire combos), but I would personally run either:
1. 245/40-18 front with a stock rear or a 255/45-18 rear
2. 255/40-18 front with a 275/40-18 rear (might unbalance the car a bit, but would look pretty sweet)

So, now you just have to find out if you can get the T1-S in those sizes. Also, you can check TireRack for the recommended wheel widths for various tire widths (they have lists from each tire MFG). For the street, it's best to stay as close to the recommended sizes as possible, but racers who are limited in wheel width often stuff on tires far wider than recommended with no adverse effects. It just comes down to how daring you are.

On the stock rims I am running a 245/40-18 in front and the stock 245/45-18 in back. My race wheels are 8" wide and I am running 265/35-18 all around (AutoX with VDC off so I don't care about problems with that - but I drive to the track in my race tires with VDC on and have not yet had a problem).

-D'oh!

Riceboy369

Hey D'Oh ... Thanks for all the info ... i Really really appreciated ...
But yah, i'm not really into racing (Im going to do Auto X , using stock rims/tires for those ... thats why i wanna get another set of tires for regular driving ... but dont need anything "daring"..

Ok ... So ... If i go with 18x8 Fronts and 18x9 ... Then i am thinking for the tire size : 245/40-18 Fronts & 245/45-18 Rears...
(Like D'Oh suggested) ... Then the car should be well-balanced ...hopefully

But i had a quick question on the front tires ... Why should i make it from stock 225/45-18 to 245/40-18 ? Does it make it look better/Proportional? Or are there other reason's too? I understand that making the width wider and reducing the aspect ratio still keeps the diameter close to stock !

2003z

iTrader: (7)

going to 245/40 front and 245/45 rear will reduce the understeer. That would be a good setup for autocross. Currently, I am running 255/40-17 f and 255/45 r race tires for autocross, but also run 275/40s all around.

slaponte

iTrader: (2)

D'oh, I would like to thank you for such a well explained process. This stuff can drive newbies (like me!) crazy.. I had not realized I can step up to 245/40 on front and keep the ratio front to back... Great info!!!

D'oh

No prob guys. I went through all this when I had to get new tires and when I looked into race wheels and tires, so it is nice to be able to share the info with others.

As far as going to 245 in front, I did it primarily to help balance the car for AutoX (before I got my race tires). When I took my car to Thunderhill (I used my street tires at the big track) the 245's in front and back made the car seem more balanced. That made VDC much less obtrusive, and seemed to help the handling overall (or at least made the car more fun).

If I were not going to be tracking the car, then I'd pick either a 245/40 or a 225/45 based primarily on price and treadlife (since I commute 80 miles a day in the Z).

Really, the only advantage to the 245 is more grip, so it may not be necessary for what you want to do.

For a sweet looking street setup, I think the 255 front, 275 rear combo would look really nice. My 265's look good, but since they are such a low profile the wheel well looks a lot bigger. That wouldn't be a problem with the correct size tire, and that extra width might really accent the wheels nicely. Of course, the tires would probably be a bit more expensive and may add noise and weight, so in the end it all comes down to preference.

-D'oh!

slaponte

iTrader: (2)

I won't track, but at 13K miles thread is going out, so it might be a good time to consider options. I am sticking with the 18s for now (Touring).

Mine is a daily driver as well, so I might move to something less sporty with better thread wear...

Riceboy369

After a few days of research and gathering info... This is what i am going to do .....

DTM Kreuz 10 - 3 piece Rims - Gunmetal

Rim Size: 18x8.5 Front, 18x9.5 Rear

With

Toyo T1-S Proxes Tires: 245/40/18 Front , 275/35/18 Rear

As for the TPS, i know that these rims dont support it ... but i called the company and they said they are able to do it for me .... so thats good ... Now i just gotta get them off from the stock ones and send them over...

Thx for all the help !

slaponte

iTrader: (2)

offsets??

ranger5oh

If you go with 245/40 front and 245/45 rear, the tires may look a little freakish.. not by much, but your rear tire will have a taller sidewall than the front but the same width. I think you would be best suited to increase the width of the rears in proportion to the fronts. You will be able to launch harder, and the car will handle better around turns because the sidewall profile wont be so tall compared to the width of the tire.

Also, there is no point running 8"F and 8.5"R if you go with 245s all around... you are just wasting money.

And as someone earlier said, increasing the width of the fronts gives them more grip, which the Z car definitely needs.

Last thing to think about, is rim protection. If you go wide on tires, compared to rim size you will have better curb protection for your rims. If the sidewall is flush with the rim, you will have no protection when you parallel park and what-not.

slaponte

iTrader: (2)

As compared to cars who have same size tires all around, these combo would be 5% taller in back than front. How could that be "freakish"? I don't even know if you can notice!