WyattH

This is also a common upgraded size on the E46 M3, but people have recently began speaking up against it. Sure, more traction, but at the expense of:

1. cost (perhaps)
2. increased rolling resistance
3. increased weight
4. less nimble (less precise turn in)

I can link the thread from M3forum.net if anybody is interested in the opinions.
Sure, the cars are totally different, but the M3 has 225/255 stock so it's a similar upgrade.

235/265 seems like it would make more sense for a a DD street car, and that's plenty of traction if you have an LSD and still NA...

Thoughts?

terrasmak

iTrader: (8)

Well the problem with the Z is 245/40 to 255/40 is the proper tire height. Same with 275/40 in the rear. If more companies made 265/40's i'm sure it would be more popular to the matching 245 front.

Do i regret it, hell no. Our cars just dont have enought rubber from the factory.

militia

no regrets here.

DavesZ#3

iTrader: (26)

1 & 2 might be regretable but 3 & 4 aren't always a problem. I went from 18" 225/245 to 19" 255/285 but my PS2s weighed less than the OEM Potenzas. I've never noticed that the handling was any worse than the Potenzas with respect to being nimble.

Sensi09

It depends on the car, but I went from 245 to 255s up front on the Z and didn't feel any effect on turn-in, nor did it become sluggish. Others have gone wider up front without any downside.

Wider tires will give more grip, but more stagger will yield more understeer. I'd opt for 255/275s over the 245/275s which are typical for 19s.

235/265 are the sizes that come stock on the CSL M3. I think that's the only reason why people opt for those sizes. Also for typical 10" wheel in the back, I'd want no less than 275s. With the typical 10.5 inch volks, I'd want at least 285s.

For a good handling, a square setup is recommended and the M3 is no different from the 350Z in this regard.

Z1NONLY

iTrader: (2)

255/40 17 and 275/40 17. (autocross and DD)

Only regret not upsizing sooner....

usmanasif

iTrader: (4)

I went from 245/265 to 255/285, and will go with 295 next time around. No regrets whatsoever. I love the greater traction around tight corners and a better look.

Spike100

For sure, 245/40-18” or 245/35-19” on the front provides a better handling Z car. This configuration does not result in “bump-steer,” and gives better/faster turn-in and neutral-steer (instead of under-steer with stock tires).

I cannot speak from personal experience on different rears since I’m running 245/45-18” there. But, the 245’s on the rear with 245’s on the front give a great handling car.

--Spike

WyattH

Good to hear. Thanks for the input.

Jarred@Z1

iTrader: (4)

im running 315 in the rear and that sh*t is off the chain.

WyattH

Unless you guys have a crap-load of boost, I can't imagine why you would need anything larger than 275 in the rear...

What about 245/265, or 255/275? More square than the 245/275 or 235/265...

FWIW, I'm not trying to justify the smallest sizes... I'd end up with whatever makes the most sense.
But a quality 225/255 would be better than cheap tires and upsized..

Sensi09

It's true, unless you're FI, 275s should be sufficient. Larger tires are mainly for looks, but again, on a 10.5 inch wheel which are typical on many aftermarket wheels, I'd run no less than 285s.

A square setup on 350Zs can cause issues with VDC. I have heard no such problems with the DSC on BMWs.

When I think of a square setup, I'm thinking of 275s all around, or something like 255/265s or 265s/275s. Granted it might be overkill on the street, but it will definitely offer more grip and a more neutral driving car depending on your other suspension components.

On the street, 255/275s would suffice.

Spike100

^^ +1 and… well said.

So that there is no confusion, when I describe “all-square” on a VDC equipped Z car, I mean something like:

Front 245/40-18” and Rear 245/45-18”


--Spike

z-u-later

iTrader: (43)

255/275 is the ideal setup for street. Square setup is ideal for the track.

Square setup is a square setup -- same size on all four corners. I have a track setup of 275/40s on all four corners. No TCS/VDC issues.

Chad68

iTrader: (1)

I regreted going 275's on 9.5's, so I fixed that problem

Otherwise no.

WyattH

^ By getting wider tires, or the wider wheels in your sig?

Does any of this vary between 18s and 19s?
Sorry - I am looking at tire sizes online and wondering which sidewall would be best.
For 19s, 35F, 30R, and for 18s, 45F, 40R? Would that be right for any range 245-255F, 265-275R?

Spike100

I think you may be confused on “sidewall height.”

The metric tire sizing system represents a tire size as:
[section width (mm)] / [aspect ratio] - [rim diameter (inches)]
For example: a tire size 225/45-18 is 225mm wide, has an aspect ratio of 45 and fits an 18" rim (wheel).

The aspect ratio (the second number) is not a measurement. The aspect ratio represents the tire's sidewall height as a percentage of the tires width (section height divided by section width). In the example above, the sidewall height is 101mm (101/225=45).

The aspect ratio is important since that (along with the wheel size) determines the overall diameter of the tire allowing you to match your stock overall tire height (diameter). For example, a 225/45-18 tire's sidewall height is 101mm, and a 245/40-18 tire's sidewall height is 98mm. So, both tires have nearly the same overall diameter.

--Spike

Jarred@Z1

iTrader: (4)

on the street ill have 275 on 9in rims all way round. I have 315 rear for the track and 275 front for the track on 9in rim yes the 315 bulg but i can keep up with most the FI cars due to a higher exit speed if they have any smaller tire.

Spike100

18" rims?

--Spike

z-u-later

iTrader: (43)

That's ballin' on 9" width rims! Do you have pics on your Z? I'd like to see pics of the 315s from the rear!