Hi, so I've been researching and looking at pictures until I got tired of doing so. I need assistance figuring out the last details for wheel widths and offsets, looking to get 275/30/19 F and 305/30/19 R for tire sizes. From what I gathered from research a popular width would be 9.5 F and 11 R for those tire sizes but I have no idea about offsets. I'm on S-tune springs and have camber arms front and back, rolled all around as well. Looking to be flush to slightly tucked, no poke if possible.
Any help is appreciated, here is a picture of how the car is currently sitting.

 

You're pretty close with those fairly aggressive tire sizes albeit a tad short (diameter) as the comparison below shows.

OEM Sizes and Diameters
225/45-18 25.97"
245/45-18 26.68"

Proposed sizes and diameters (roughly a half inch short but workable)
275/30-19 25.50"
305/30-19 26.20

S'far as offsets for 9.5 and 11" wheels, you should get familiar with this: https://my350z.com/forum/tire_rim_calculator.php
Plug in the various combinations and compare with how much physical (measured) clearance you have to play with.

But will just say off top of head that a front offset on 9.5 wheels of between +17 and +25 will pretty much get you where you need to be AND a rear offset of +22 to+25 on 11" wheels will put you right at the fender lip. If you insist on 11s, go with +25.

My usual visual aids 9.5 +22 and 10.5 +22 (static suspension at -19mm and alignment is stock (lowest end of camber range). Keep in mind that I'm "only" running 255/35 & 285/35-19 so tire clearance might be more of an issue running the sizes you want to run.



Rears (above, below)




Front


Or my current setup... Nissan LMGT5 19x9.5 +20 effective & 19x10.5 +23 natural


Final point.... pyrometer readings have told me I can't even get these "smaller" tires up to proper temp on a long, hard run in the hills. (Maybe in track use, they'd be fine but for my needs, overkill) Your sizes - depending on grade of tire - will be even worse. Other than for aesthetics, cannot see any need for tires in the sizes you're considering; but all good if that's what you want.

 

Thanks for the info Mic, what tires are you running and what power levels. My concern is I don't want to have to buy another set of wheels for the future and I do want to supercharge eventually. Power goal would be around the 400-500 range and I want to have a rear tire that can grip and put that power down. As far as the 11 R I said that because was under the impression that its needed for 305? The other thing is its getting a bit harder to find matching tires that would match the stock sizes. Do you have any other suggestions on sizes? Tire I'm looking on getting would most likely be Michelin if it makes a difference.
Thanks again.

 

On another note the fitment on your car is nice, I'd say I'd want it to be close to that, maybe just a hair more tucked in.

 

Good thoughts! As most know, I have about 850WHP.

<Let that sink in a bit before I tell you the actual truth>

No, bone stock motor with a little tuning magic. Thassit.

In all honesty, any of the modern day super tires will easily handle 4-500whp. Case in point, my Benz dynos 447 at the wheels and it's "only" sitting on 285/35-18s (Conti Extreme and "only" 255 up front as well) with absolutely no issue, no washouts, no sliding even under hard acceleration, etc. Yes, different car, different chassis dynamics, but tires are eliminated as any source of ill will. But you're right, size AND powerful grip are good to have on a blower car. The 275/305 you stated is fine but as I said, in all honesty, the 255/285 combination is more than I need and I feel that my chassis setup (incl tires) could easily hold up to more power/TQ.

S'far as 11" wide, well, you can go 11" but the minimum for a 305 is 10". The rule of thumb is the tire should not exceed 120% (the 1.2 factor) of the wheel width. Sure, you can mount/fit a larger tire on a slimmer wheel but once beyond 1.2x, performance starts to head down the other side of the performance bell curve. So, 10, 10.5, 11" all fine (and you'll find a LOT more reasonably priced 10.5s than 11s).

Good luck!

 

Thanks! I've been looking at pics of 11+ 25 and +30 I think 30 is better for my taste, that considered would you say the 9.5 + 22 or +25 would match better? Or something else?