ALL OF YOUR WHEEL QUESTIONS ANSWERED HERE

Okay y'all, I'm seeing a TON of questions on wheel size/offset, what's the best/worst, etc. While I can appreciate newcomers being unsure of what to do before they drop potentially thousands of dollars on wheels, many questions that get posted here can be answered pretty easily. So in an effort to consolidate as much info as possible without having to sift through pages of google searches and posts on My350Z that just answer questions with "google it nerd", I'm making this post.

#WHEEL SIZE AND OFFSET

Depending on your year and mode, you can have anywhere between 17x7 to 18x9 in the front, and 17x7.5 to 19x10 in the rear on your stock Z. For example, if you have a base or a touring '06-'08, which are 18x8 front/18x8.5 rear +30 offset, they will sit pretty significantly within the wheel well, leaving much room for improvement.

If you're looking to be perfectly flush and don't wish to modify your fenders at all, the most simple answer here is 18x9.5 front/18x10.5 rear, +14 to +22 depending on the wheels. Some people prefer 9" front/10" rear, as it's cheaper and more safe, but IMO it will leave you not satisfied. You can bump to 19s and most likely be fine, but that also means thinner tires, heavier wheels, and more money. The likelihood of rolling fenders goes up, too. But it will fill out the wheel wells better than 18s and look a bit more aggressive, so keep that in mind when considering your endgame. And a the risk of pissing a few of you off, don't get 20s. It looks like shit and you'll be on rubberband tires.

Offset

Okay, so offset is still a bit confusing to some, so here's the best way I can describe it. Offset is, in essence, the distance, in mm, from the hub mounting surface (where you actually slide the wheel on) and the dead center of the wheel. Positive offset wheels will have more inner barrel and less lip, and sit closer to the inner fender. Negative offset is the opposite; more lip, less inner barrel, will sit further out. 0 offset is dead center, period. The wheel is mounted right in the center.

The 350Z has some pretty wide fenders and can fit some wide wheels & fat tires, but there's still a limit. Don't expect to run a 0 offset, 11" wide wheel unless you plan on pulling your fenders and having some serious camber, or installing fender flares. Generally speaking, the max you safely run is positive offset in the mid-teens, on a 10.5" wide rear wheel. Some people run 18x10.5 square setups with +15 to +22 offset, (18x10.5 +15 square is a common setup for Enkei RPF1s), but you may have to roll/pull the front fenders a little bit.

Spacers

Firstly, what are spacers and what do they do?

Spacers are disks you slide over your wheel hub that decrease your overall effective offset and allow more width between your wheels. Example: Commonly sold in multiples of 5mm (ie: 5mm, 10mm, 15mm, etc), but sometimes 3mm, etc. Good for a more aggressive look without having to buy new wheels, but keep in mind you are adding unsprung weight to your car, if that matters to you. a wheel with a +20 offset with 15mm spacers installed will have an effective offset of +5.

Tires

Tire size is easy. My personal rule of thumb is to go 10mm wider in tire size for every .5" in wheel width from stock. ex: stock '07 base wheels, 18x8/18x8.5, tire size is 225 width front and 245 rear. If you jump to 18x9.5/18x10.5, you go to 255 front and 285 rear.

That's just me, you don't have to do that. a 275 width tire on a 10.5" wheel or a 245 on a 9.5" will be fine. Wider wheels will have a meatier sidewall so you'll fill out the wheel well better, and also have a more comfortable ride.

Pay attention to the aspect ratio, or tire profile, too, the second number in the tire size. That's your sidewall thickness, measured in percentage of the tire width. this means a 255/40/18 will have a widewall that's 40% as thick as the tire is wide (40% of 255, or 255 x .40 = 102mm).

When staying at the same wheel height, I prefer to keep the sidewalls as close as possible to the stock tire sidewall thickness. Example: stock 18x8/18x8.5 wheels has 225/45/18 front & 245/45/18, meaning 101.25mm front & 110.25 rear. Going to 18x9.5/18x10.5 means a 255/40 will have 102mm sidewall and a 275/40 will have 110mm.

Again, your mileage may vary. You might like a thinner tire especially if you have wide tires. I personally hated having 35 profile on my 255/285 width tires, and I drove around with a lingering feeling of regret for not getting 40s. Sometimes, too, the tires you want don't come in the size you want and you have to compromise. For instance, Pilot Sport 4S's in 18s don't come in 40 profile thicker than 265. If you want 285s, you have to go with a 35 profile. IMO that's worth it cuz 4S's are top tier tires.

If you have anything to add or any other questions, feel free to reply here.