Understanding offset with 17x8 and 17x9 wheels

[daxbrook]

First off I’d like to thank you for reading this, I’ve spent countless hours searching for an answer to no avail.

The only “requirements” are that I need a 5x114.3 bolt pattern and a minimum of a 16” wheel to use the T3 brakes. Ideally I want to run TE37’s but I haven’t found many options with these specs. If it’s possible, I’m planning on running 17x9 wheels in the rear and 16x8 wheels in the front, does anyone know the offsets for these? I believe -10mm was the only option with negative option in these sizes, would this work? Or do I need a positive offset? I have 2 in ZG fenders in the front and 3in ZG fenders in the rear. 
first edit: 1973 240z

Edited December 4, 2020 by daxbrook

[primaz]

Really every Z will be slightly different depending on the suspension setup etc. Really the best way is to go a good tuner shop or tire/wheel company with your car as they will have the wheel tool to measure what is the maximum offset to fit the largest tire and wheel for your car especially since you have flares on the car.  As an example on one of my 240Z's that is stock body but rolled fender lips & BC Racing coil overs, we are running 16 x 8" with +13 with a 5" backspace and the car is running 245 wide tires on all four corners.  When you flare a car and done suspension mods you should easily be able to much wider than a 245 size tire.  I have seen some people max out a 240Z with no flares and even get 275 in the rear.  Thus with flares you should have cut out enough of the stock body to go way wider than limitations of stock body Z.

 

Do not skimp on the cost of the wheels is what I recommend and thus go with a 3 piece wheel that you like the design and have a shop measure it for you to find the ideal offset, etc. and stuff the most tire and wheel you can.  You can also rent that tool for around $50 to $75 dollars with a deposit of a few hundred dollars or so and measure it yourself.  You will never find someone with the exact same setup as you, etc. so l recommend to do it right and measure it then buy...  Also look at Tire Rack to see what is the available tires for that rim size as that might influence you to go to a different diameter wheel and tire.  16" sizes are getting harder compared to 17" and larger as newer cars dont use 16" anymore  but there are an ok selection with 16" but ultra low profiles are harder to find.  I find it laughable that people cut up a 240Z with flares only to put the same size tires I did with a stock body.  I am all for flares but to me you should be gaining with wider tires not just doing it for looks...

[jhm]

Good advice from @primaz....I'd add to it that you should probably wait to take your measurements until the brakes/hubs are installed.  And don't make your final decision on wheel specs until you've fully investigated tire options in those sizes....your tire needs (budget, comfort, performance, choice of compounds, etc) can often drive the wheel decisions as much as anything else.