Dynhamik

Hello all,




My name is Matt. I picked up my '14 GS350 F Sport back in November and I'm starting my build. Before this, I had a TSX. I just picked up some wheels I've been eyeing for a while and I'm researching tire size. The wheels are 20x9.5 +30 and 20x10.5 +42. I'm considering the following tire specs(stretched): 235/30/20 F and 255/30/20. I've gone through pretty much every wheel thread on this site and this is the clarification I'm looking for. I notice everyone running a 35 front and 30 rear profile tire. I know that's how the factory is setup, but would it be an issue to match the profile on each wheel, front and rear?

Thank you,

Matt




Here's my old TSX and my wheels I just picked up yesterday.

is150

iTrader: (10)

Seems like most are running 245/35/20 for the front and either 275/30 or 285/30 for the rear. Hopefully the wheel gurus will chime in since your running a 9.5 inch wide front wheel and will have a better idea on clearance issues. Wheels look awesome and cant wait to see them installed. I've been contemplating a set of Aimgain wheels for my GS350. What suspension are you planning on running?

TOPENDMS

You might have the tire readings mixed up. The 30 in the profile is not a measurement, it is a % of the width.

235mm x 0.30 = 70.5mm
235mm x 0.35 = 82.25mm
255mm x 0.30 = 76.5mm

Both 235/30 and 235/35 are virtually 6mm apart from the 255, so it only depends if you want thinner or thicker tire. 235/35 will be 1/2 of a mm closer in overall diameter to 255/30.

AIMGAIN's fitment on their 2016 GS350 is exactly what you proposed (along with spacers), however they run aggressive set-ups on their demo cars.

The factory setup is square wheels and tires 235/45ZR18

Dynhamik

Yes, I understand the 30 and 35 is the profile(or the thickness of the tire). I'm just wondering if anyone else is running the same profile in the front as the rear. It seems as if most are running XXX/35/XX in front and XXX/30/XX in the rear. I'm considering 30 in the front as well for additional clearance.

TOPENDMS

Excuse me if I'm mistaken, but it doesn't sound like you fully got it. 235/30 = 235 x 30% = 70.5mm side wall (Then double it because there is tire on 2 sides of the wheel). Thus 235/30 and 255/30 are not equal side wall profile heights.

Here's how you figure the best wheel/tire diameter.

Factory:
235/45/18 = 235 x 45% = 105.75 x 2 = 211.5 + 457.2 (25.4mm x 18" wheel) = 668.7mm <-- target

Your Specs
235/30/20 = 235 x 30% = 70.5 x 2 = 141 + 508 = 649mm <-- size AIMGAIN uses on demo GS
255/30/20 = 255 x 30% = 76.5 x 2 = 153 + 508 = 661mm <-- size AIMGAIN uses on demo GS

"Other Peoples" Spec:
235/35/20 = 235 x 30% = 82.25 x 2 = 164.5 + 508 = 672mm <--Closest to Factory diameter

Dynhamik

Got it. Thank you.

Dynhamik

Thank you. I'm excited and nervous to see them on the car. Ha. I'm leaning towards BC Coils with Stance Air Cups. I considered going bags like I used to have, but I just don't want to deal with the inevitable headaches from time to time.
So yea. I'm going to stick with my plan for 235/30/20 and 255/30/20. I did a little more research and the stretch isn't too aggressive.

TOPENDMS

I got all tied up with the numbers and forgot to honor your amazing wheels! Probably my favorite wheel at the moment.

Dynhamik

Lol thanks. I got a killer deal on them. And I appreciate the explanation. You definitely know your stuff. I really want the full Aimgain kit, but I'm to paranoid driving around with an FRP/CF kit. Ha