Tire question for stock 280ZX Turbo wheels

You're right, the 235/60s are only 5mm shorter than the 205/70s. I'm really surprised how little error is present in the change!

I did correct a couple of settings...I understand the stock swastika rims are 0 offset, and the wheels are 6.5" wide, not 6. (See EDIT below.) My main concerns are (1) whether it will clear the springs on the front struts - and the chart says the tire would be 15MM closer to the suspension, so I'll have to measure that....and (2) whether running a 235 tire that's 20MM/2CM wider is going to work well on the 6.5" rim. The chart does show the 6.5" rim as the narrowest that's acceptable for the wider tire.

EDIT AND MORE DISCUSSION: Specs available for the wheels online often conflict. Some sites list the wheel width at either 6 or 6.5", but most often 6.5". Offset is often quoted as Zero (0). The Xenon car website says the rim width is 7 inches, offset is +12 MM and backspace is 101 MM at XenonZcar.com 280ZX S130 Wheel Differences but I don't fully trust it. No other site lists those wheels as 7" wide.

The information that looks most reliable to me is at 1983 Nissan 280ZX - Wheel & Tire Sizes, PCD, Offset and Rims specs and indicates wheels are 6.5" wide:

NISSAN 280ZX 1978 .. 1984 ALL TRIMS
USDM

• Generation: 1978 .. 1984
• Production: [1979 .. 1983]
• Sales regions: USA+
• Center Bore / Hub Bore: 73.1 mm
• Bolt Pattern (PCD): 4x114.3 (4x4.5)
• Wheel Fasteners: Lug nuts
• Thread Size: M12 x 1.25
• Wheel Tightening Torque:
  unknown

On this forum there is an old thread about this. In post #3 there is a personal experience cited which is helpful. Max Tire Size under my 81 280zx non-turbo

"I have a set of 215x60x14's, that work great. I thought about going to a 245, but thought twice. Good thing I did. 245's will run close to the strut in the back, and they hit the strut up front. 225's fit, but not by much. It's not the rear you have to worry about, it is the front. You could run a 225, on a 7 inch rim, but I wouldn't do any more than that."

I'm planning on getting a set of BFG 205/60r-15 myself and put them on a set of 200sx turbo rims. Since I had a set of G50-14's (boy does that tire-size date me) on my 1969 Chevelle SS 396 convert, I plan to have the white-letters out. I liked how the car handled with them after I put solid bushing in the 4 rear control arms (they didn't make poly's back then and I'm sure those tires todays will handle better on my 280ZX. Since I blew up the first engine (spun 2 rod bearing, broke a connecting-rod and punched 2 holes in the block), I bought a 1965 375hp 396 short block, then advanced the cam 4 degrees, put on headers, Edelbrock Torker II 2-0 intake-manifold and a Holly 800cfm spread-bore carb. This moved the torque from the top-rpm to low-rpm and as a result I could spin the rear-tires in all for gears and even taught my wife to drive a stick in that car. When she said, "A freind told me I was unteachable, as I kept killing the engine", I said, "You've seen me drive, so just step down on the gas-pedel and you won't kill this engine".