As of right now I have new wheels on the car. Front are 18x8.5 and rear is 18x9.5. I have the original tire size on the which is 225/45/18 front and 245/45/18 rear. I am wanting to go up in tire size and go 245/35/18 front and 285/35/18 rear. Will I have to make any adjustments to the wheel well in order for those tires to fit because they are substantially bigger especially in the back.

 

what is your offset?

 

Front is 25MM offset and back is 35MM base for both is 28 front and 30 back

 

Well, first off, your desired TIRE sizes are not so desirable. Compare with stock/OEM height....

225 45% 18 25.97 Stock Reference Size
245 45% 18 26.68 Stock Reference Size

245 35% 18 24.75
285 35% 18 25.85

You're looking -30mm F and -21mm R which will affect speedo and if you have VDC, likely that as well as wheel speed differential F to R is close to 4% delta (where VDC tolerates standard 3%).

Generally acceptable F to R sizes for height and proper wheelspeed diff are:

255 40% 18 26.03 FRONT
275 40% 18 26.66 REAR

285 40% 18 26.98 Alt. Rear
You can push to this but again it's outside VDC range but not by a lot so you might get away with this; plus it's right at the limit of rim width:tire width ratio.


S'far as wheelwell fitment, another question: is your car lowered (or going to be)?

Also, not sure I get your offset description. The new wheels are +25/+35 F-R?? (Not getting the 28/30 numbers other than guessing your OEM wheels - which still don't make sense as there are no OEM wheels with 28mm offset (17s maybe??) but no matter as those aren't the wheels to be concerned with.)

Neither of those with 275 or 285 rear should rub with +35mm offset wheels. Those are higher offsets than stock and even with the extra width (which isn't a lot wider), should fit OK. Front 8.5 +25 no issue.

And, if you choose to run the sizes you mention, there'll be no problem with clearance as they'll barely be tall enough to contact the fender lip.

 

245 and 285 is too big of a gap in width. Prepare for a lot of understeer, especially on this car which is already prone to understeer.

 

Do +30 9.5 clear the suspension on the inset? Willitfit says it will reduce by 19 mm while +15 only reduce 4 mm. (Noob)

 

why are you trying to sink the wheels in? the higher the number the more sunk in they are, the lower they are pushed out

 

you mean the barrel correct? I just want to know if I will have the 19mm of clearance 😬

 

To be honest I am not entirely sure as to what all of that means as I am still new to the car scene. But What I am getting is that the new tires won't rub against anything and I won't have to make any adjustments to the wheel well. Please tell me if I am interpreting this wrong.

 

Also I do plan to lower the car after getting the new tires

 

You'll have plenty of inboard clearance with +30mm of wheel offset on a 9.5 wheel. Stock is +30mm so the net you'll be adding inboard and out is 12.7mm (1/2") from the 1" wider wheel (with no change in offset).

You won't start running into inner clearance problems until you start to decrease inner wheel clearance by about 25-30mm (maybe more.)

 

What you need to take away from this is the height of the replacement tires should be at or relatively close to the original tire specification in overall diameter (height).

275 rears on a reasonably offset wheel (+20 and above) will (or should not) rub.

If it's the offset issue you're confused about, read this:

https://my350z.com/forum/wheels-and-...t-novices.html

 

Yeah I was just concerned about the rubbing. Thank you for being helpful and clearing this up for me!!

 

i ran a 9.5 +23 and didnt rub, even added a 5mm spacer and didnt rub.

 

thank you good sir! But isn't the rear OEM size on a performance model 8 inches? (Confused)

 

True dat. Either way, a gain of 19mm (1.5" wider x 25.4)/2=19mm) at the rear isn't a big deal.

There are a lot of us here running 10, 10.5, 11.0 wide wheels with no inside rubbing when you run proper (or conservative) offset wheels. There are plenty of "Honda offset" wheels out there that are passed off as fitting Z cars. Sure, the bolt pattern and hub holes will fit but with a 40mm+ offset, you start running into clearance issues. Key words: "Proper" and "Offset" used together.

 

appreciate the knowledge bro!