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- - Widebody and Fitment (https://my350z.com/forum/wheels-and-tires/620746-widebody-and-fitment.html)

Widebody and Fitment

I am having rocket bunny fenders installed on the front (extending an extra 40mm) and battleaero rear fenders installed on the rear (extending an extra 40mm)

My current wheel setup is with the 06 infiniti G35 coupe 19" double 5-spoke design. To have it flush, I added 25mm and 32mm to the front and rear respectively.
Through my researching, the infiniti wheels i have on are 19" x 8" 30mm offset and 19" x 8.5" 33mm offset.

Im thinking of downsizing from the infiniti 19" down to 18" with 9.5" F and 10.5" R.
I did some calculations and im thinking 15mmF and 20mmR offset should sit flush if i reuse my existing spacers (25mm and 32mm).

https://www.1010tires.com/Tools/Whee...et-Calculator#
Since my offset calculations were correct, this is what i am running right now:
19" x 8" 30mm & 19" x 8.5" 33mm with 25mm F and 32mm R spacers, it becomes 19" x 8" 5mm & 19" x 8.5" 1mm offset. (Mind you that it sits flush with my stock fenders)

Using the link above,
if i choose a wheel thats 18" x 9.5" with 15mm offset for the front and use the 25mm spacer i already have, the overall offset should be -10 and it says it will extend 34mm.
if i choose a wheel thats 18" x 10.5" with 20mm offset for the rear and use the 32mm spacer i already have, the overall offset should be -17 and it says it will extend 38mm.

I know this is all hypothetical and speculation, but if the overfenders i ordered are actually 40mm on all four sides, it should fit right? Of course, measurements will be needed to make sure and finalize before ordering wheels but theoretically they should fit right?

Im also planning to run 255/30/R18 and 275/35/R18 for the 9.5" and 10.5" wheels im planning to get. This should be no problem right? or should i do a 35 and 40 aspect ratio respectively?

about -30/-35 give or take to be roughly flush

Quote:

Originally Posted by Blackskiies (Post 10976093)

Quote:

Originally Posted by jdmfetish (Post 10976094)

about -30/-35 give or take to be roughly flush

Your effective offset calculations (with spacers) is correct.

While jdmfetish's recommendations are likely correct, just to make sure you do it absolutely correct, MEASURE the distance outward from the face of your existing wheels to see what you need to fill the new well. You may find that fitment by guesstimate may be off due to any type of inner lip or other clearance issues on the new fenders. Work backwards using the tire calculator ( https://my350z.com/forum/tire_rim_calculator.php ) to give you the closest approximation based on actual measurements.

Reminds me of nearly 40 years ago when we had to MANUALLY do all the measurements and calcs for flares. Now we gots us cornpooters to do it for us! Hahahaha.

Mic, i saw your input in this thread: https://my350z.com/forum/wheels-and-...-my-tires.html
Since your highly knowledgeable, i would really appreaciate your input. Others are welcomed tho :)

Im thinking of downsizing from the infiniti 19" down to 18" with 9.5" F and 10.5" R.
I did some calculations and im thinking 15mmF and 20mmR offset should sit flush if i reuse my existing spacers (25mm and 32mm).

https://www.1010tires.com/Tools/Whee...et-Calculator#
Since my offset calculations were correct, this is what i am running right now:
19" x 8" 30mm & 19" x 8.5" 33mm with 25mm F and 32mm R spacers, it becomes 19" x 8" 5mm & 19" x 8.5" 1mm offset. (Mind you that it sits flush with my stock fenders)

Using the link above,
if i choose a wheel thats 18" x 9.5" with 15mm offset for the front and use the 25mm spacer i already have, the overall offset should be -10 and it says it will extend 34mm.
if i choose a wheel thats 18" x 10.5" with 20mm offset for the rear and use the 32mm spacer i already have, the overall offset should be -17 and it says it will extend 38mm.

I know this is all hypothetical and speculation, but if the overfenders i ordered are actually 40mm on all four sides, it should fit right? Of course, measurements will be needed to make sure and finalize before ordering wheels but theoretically they should fit right?

Im also planning to run 255/30/R18 and 275/35/R18 for the 9.5" and 10.5" wheels im planning to get. This should be no problem right? or should i do a 35 and 40 aspect ratio respectively?

Quote:

Originally Posted by Blackskiies (Post 10976221)

Not going to say they'll fit or won't. I have no idea what the actual clearance provided by the flares are. When they say it widens the car by 40mm at each fender, that is the total width, not the wheel track dimension so I'd still go pull out the steel rule and measure before ordering anything.

A note on your proposed set up.... a +20 wheel with a 32mm spacer gives an effective offset of -12, not -17. (20 - 32 = -12) so you might want to re-check the poke.

I've said it many times, I don't like spacers but I use them on the front of my car. Conservative ones (up to 20mm) in order for me to run any of my 370Z high offset front wheels. I personally wouldn't run anything larger than 25mm but if you're not buying specific negative offset wheels for the flares then you have little choice.

On tires... in order to maintain the correct height (equal to OE), 18" wheels wear 255/40 and 275/40, with a minor width deviation one way or the other, e.g. 245 or 285 at opposite ends of the sizing spectrum; but in order to satisfy TCS, VDC, speedometer accuracy, you don't want to deviate from the OE diameters too much. Your proposed tire sizes has the front nearly TWO inches too short and the rear over an inch shorter than OE. 40 is the aspect you want on 18s. Period. (Unless you're running them in the correct ratio, meaning both 35s or a square for track purposes.)

So i should just do an aspect ratio of 40 for both front and rear or 35 for both front and rear? I didn't even know about the TCS, VDC, and other stuff that would be affected... Thanks Mic

Quote:

Originally Posted by Blackskiies (Post 10976093)

I just brought some new wheels and had the thought to wide body the rear. My wheel specs are 18/9.5/ 15+ F and 18/10.5/22+ R. What tire specs did you end up running? And id like to see some pictures of your z.