Ive done a bit of searching and its seems the safest/most common tire size up to the stock rims is 245f/255r. My question is has anyone had any issues with daily driveability?? Im looking to do this for a little more grip for autox. any info would be appreciated.thanks!!

-walt
06 base.

 

Missing vital info…

…Wheel size?

…Aspect ratio?

You said stock rims and I see you have a 2006 Base model, so I assume (but I’ve learned here never to assume anything) you have 18” wheels and thus are probably asking about aspect ratio’s f40 and r45 (but maybe r40… See why no one can assume?).

--Spike

 

If you are looking for a daily driver-autocross set up. the tires are more important than tire width. Crummy tires are crummy tires whether they are 235 or 255 mm.

 

sorry guys, i have a 06 base so my wheels are 8f and 8.5r. Im gonna go with some azenis but my question is more directed towards tire width.

 

bump

 

If I have it right, your wheels are f 18x8” and r 18x8.5”. I am also assuming you want to stay close to the stock overall diameter (which is wise for street use).

I’m running 245/40-18” front and 245/45-18 rear. I like this setup since it provides nearly neutral handling (i.e., very little if any under-steer); you notice the difference.

If you are considering a 255 width for the rear: There’s hardly any difference between 255 and 245 (10mm widthwise is insignificant). And, 255/45-18 is a rare size. And, 255/40-18” is a little short of the overall diameter for a stock wheel/tire setup. A 265/40-18” setup puts you closer, but still a little short of the recommended stock overall diameter.

If you want a staggered setup, your best bet with your stock 18x8.5” wheels is 275/40-18” on the rear (with 245/40-18” on the front). I realize this statement might attract the attention of the “size police” since the minimum wheels width for a 275mm tire is a 9” wide wheel. One half of an inch is small, and you can probably do this safely. If that deviation isn’t something you want to do, go all-square widths (245/40-18” front and 245/45-18” rear).

--Spike

 

The sizes I recommend in the previous post are best for street use. I did that workup because I guessed your desire was tire/wheel sizes/combos that work for both street use and the track.

If your plan is a track setup, there are no “hard and fast” rules other than gaining the best grip, lightest setup, better turn-in, and improved acceleration. For example, you might mount 275’s (or even greater, but less might be the choice) all around, maybe use 17” wheels, mount tires with a smaller overall diameter (for better acceleration out of turns), etc.

--Spike

 

spike,

thanks for the info. Its super helpful!!! Im thinking of copying your setup but instead running 245/40 all round. My biggest gripe is def understeer. Its good to know it will work and I wont regret it down the road. THANKS

-walt

 

Actually, running a short rear tire (albeit with a short front tire) would be benefical as it lowers your FD. It'll help with some acceleration. The 615s are great...When hot. Beware when cold.

 

I at the "size police" comment.

And btw, a 245/40 front and 265/40 18 rear is within the stock size rolling diameter range, *very* close.

 

Spike: I'm considering wider tires. Either 265/40/18 on an 8.5" or 275/40. I'd imagine running the 265 is rather safe. But do you really believe the 275 is safe, as well?

 

^^ The tire manufacturer’s specification is a wheel width of 9” for either a 265/40-18” or a 275/40-18” tire. So, with either tire, you’re slightly outside the recommended wheel width.

A 255mm wide tire does fit an 8.5” rim, but this is an unusual tire width-size, and not worth paying extra over a 245mm wide tire. 10mm is less than one half inch, and that difference is insignificant when comparing handling characteristics.

I guess all I am willing to say is the difference between a 255mm wide tire (which is within specs for an 8.5” wide wheel), and a 275mm tire is about three-quarters of an inch too wide, and hardly any different from a 265mm wide tire. I don’t think I would worry about this too much (275mm).

Sorry for the “no-answer” answer.

--Spike

 

I'd imagine then wrapping around my rim if I'm constantly doing donuts, taking hairpins going 80, and competing in autox. Otherwise, I suppose it should be fine if I'm going straight 85% of the time.

 

Lol, size police!

I'd worry that a too wide tire would feel a bit wobbly and bouncy. Might be plush down the straight, but given the relative lateral stiffness of the chassis, running on balloons into a corner might not be all that comfortable.

I doubt there would be any mounting issue tho. It would just not feel very direct steering wise. The word "vague" comes to mind.

I run (ran) 235/40R18 and 255/40R18 on the OEM Track rims (8.0 and 8.5). It is slightly under driven (3% range).

 

One more thing. Not all 275 wide tires are created equal.

Some are wider, others a slimmer...

 

^^ Good point. For sure mounting too wide a tire for the wheel results in a more convex sidewall (the sidewall must bend in a little to fit to the rim).

But then again, sidewalls with more height (i.e., 17” wheels would normally have tires with a higher sidewall than tires on 18” wheels, all else being equal) are going to flex and roll more. And, various tires have very differing sidewall characteristics. For example, the Eagles I’m running felt very “wiggly” at first compared to the tires with stiff sidewalls I replaced. I adjusted quickly to this, and actually no longer notice the difference.

It’s not my intention to recommend mounting a tire on a rim that is outside the tire manufacturer’s specification. But, 20mm is only ¾ inch. If someone chooses to do this, they need to realize the setup isn’t tested, and they might need to experiment with varying the psi (from Nissan’s recommendation of 35-36 psi). I don’t think it’s as much a safety issue as it is a possible tire-wear and handling (as you point out) difference.

Of course the best (safest) advice is to always remain within the tire manufacturer’s specifications.

--Spike

 

Another good point that no one else mentions here…

A 275 from one tire manufacturer often looks and measures significantly more narrow or wide comparing the same size to a different manufacturer. I don’t get this at all. I’m not sure how that translates to how the tire manufacturer determines the minimum rim width for their tire.

I’m guessing it’s a complicated interaction involving wheel diameter, tread width, section width, aspect ratio, sidewall flexibility, and maybe some other factors. I don’t know.

--Spike

 

That is true when it comes to tread width, but a tire's cross section (the width measured from the widest point of the tire) must be what the stated tire size is, mounted on the a specific width wheel rim as stated in the manufacturer's specifications. Anything else would be misbranding. With that being said, my recommendation for an 8" 8.5" combo would be 245/40/18 up front and 265/40/18 in back. A 275 cross section is just too wide for an 8.5" wheel.

Lou

 

Lou,

Not arguing, but I would point out that the tire manufacturer measures the section width at the tire’s maximum inflation (the psi inflation value you see on the tire’s sidewall). Of course the recommended psi for the Z is much lower, meaning the section width when the tire is inflated at the specification for the Z might be a lesser value.

--Spike

 

I think for the sake of safety, I'll go with a 265 in the rear - they're a bit less common, but not terribly so.