RTom919

Finally got my hands a set of the 19 inch coupe wheels for a great price




Came with stock tire sizes on the staggered setup (Ventus V12's), rears will need replacing very soon. Anyways, I installed them about an hour after I picked them up I was so excited. While I was away from the forum, I do remember that some people are using the stock tire size on staggered setup on AWD sedan, so I figured I'd be ok as far as the size difference being under the 3%. Was I correct?

I am going to call the tire place this week and get a quote on new rears. Should I continue to roll with stock rear size, or should i go 245/40/19 all around? I do live in New England so snow is a little bit of a concern, but I kept my OEM 17's that will be my winter setup. So hopefully the rear-dif won't be an issue in the summer and fall (as I understand the G is RWD until AWD is needed/sensed by the car).

Additional random question/thought: I have driven about 15 total miles since installing the coupe wheels (did NOT transfer TPMS from old wheels, ie; installed wheels have NO TPMS) and I have not tripped the TPMS light yet. I was sure it would be on as soon as I started the car. Any idea why I haven't gotten it yet?

Swifts will be coming in the mail soon!

rks

iTrader: (6)

TPMS will trip, just not on initial startup. The wheels are staggered so you can't rotate them properly so I wouldn't worry about a square setup. and yes 3% or under is ideal.

blnewt

iTrader: (13)

It takes a pretty long initial trip to activate the TPMS for the first time, something like 30 miles or so. Once it's activated initially it will activate immediately after that.

I believe 245/40/19 & 275/35/19 are the perfect combo regarding diameter, fitment and looks. Here's the calculator just to be sure. I think those sizes are less than 1% so you'll be aces!
https://www.myg37.com/forums/tire_rim_calculator.php

Car's looking nice and w/ the Swifts on the way it'll look real good

RTom919

Ok so I'm a little concerned. I need to replace the rear tires and am planning on using stock size 245/40/19. I am not going to replace TPMS because it's a PITA and you can't fail inspection in New Hampshire for it.

But I called a few tire places and the guys I spoke to were very against having staggered on AWD. I have read many posts, (including more than a few of yours, Blnewt - so much help) on how it is ok, but can someone tell me if this affects the rear-diff at all? I think the x models only use AWD when it is needed (or in AWD mode). I'm not in the place financially to burn out the differential and get everything replaced.

Again, I am only going to use this for my summer set.

blnewt

iTrader: (13)

The only critical factor is the outside rolling diameter, this is what the traction control, speedo, ABS, and AWD will see. If you keep the outside diameter within +/- 3% you'll be OK, but even better those sizes I listed calculate as follows~ Your OEM tire size is 225/55/17
If you go with a 245/40/19 in the front this is the diameter readout~
Diameter difference:
-0.03" (-0.10%)

If you go with a 275/35/19 rear here is the readout~
Diameter difference:
-0.17" (-0.62%)
And here is the difference between the new 245/275 combo
Diameter difference:
-0.14" (-0.52%)
Your at .62% max difference from OEM, so about 2.3% better than you need to be. The 0.17" difference in diameter is well within just the air pressure fluctuations or a rear set of OEM tires that's just a bit more worn than the front. You'll be fine with that setup

RTom919

Did some additional calculator research; feel better now. Anyone who has an X sedan and thinking of switching to coupe wheels please see below. I used stock x sedan tire sizes compared to stock coupe tire sizes. LOOKS ALL GOOD!

blnewt

iTrader: (13)

Since you've got a winter set why not set up a more aggressive summer set? Those sizes I listed above will give you a nice look and more rubber on the road, just sayin.............

G4FSR

OP,
If you want same OD front and rear, go for 225/45 F and 255/40 R
OD front will be 26.97 , 27.03 rear.
It's your best option if you want to have "almost" same OD front and rear
Tire Dimensions Made Simple - America's Tire