Front 225/40/19 and rear 255/35/19.

vs.

Front: 235/35/19
Rear: 265/30/19


Which set will have a thinner side wall profile? Or are they similar?

Which set of tires will have a closer overall diameter similar to OEM specs so that the speedometer will give more accurate results? thanks.

235/35/19 and 265/35/19 are closest to OEM. (OEM = 225/40/18 and 255/40/18)

Use this website:

http://www.1010tires.com/tiresizecalculator.asp

The center number which is lower determines sidewall height. Lower is narrower.

^ To add,

The middle number is a percent.

On a 235/35/19 tire the sidewall height is 35% of the width.

On a 225/40/18 tire the sidewall height is 40% of the width.

^^^ Thanks. I get that it's a percentage...but just don't know which has a "thicker" side wall in real life. Hard for me to imagine the thickness.

Oh by the way...looking for the thickest side wall possible (for ride comfort and better protection from pot holes). But the tires still should be close to stock diameter.

Stagger set-up. Front 8 and Rear 9.5

Anyone know where to get tires cheap 265/35/19 to have diameter size as close to OEM as possible??

Or should I stick with these for the rear: 265/30/19 for now???

Any other feedback?

tirebuyer.com IMO has the best prices AND free shipping. Always buy most my tires from them

Couldn't help but think of this:

http://static.quickmeme.com/media/social/qm.gif

My current OEM = Front 225/40/18 and Rear 255/40/18. Got some 19" wheels so need new tires.

Probably looking for rear tires in 265/35/19 since they are closest to OEM. The tires that are on the wheel now are 265-30-19. Does it matter? Should I get new tires to be closer to OEM or just run the 265-30-19???

I went with 235/35 up front and 265/35 on the rears to keep the diameter as close to OEM as possible, but found out that the choices of 265/35 tires are a lot less and more expensive compared to a 265/30 tire. I think you should be okay with the 265/30's. I'm switching to this size next time around.

The 265/35/19 selection has gone up considerably...

They have a bunch on tirerack.com

Also note - you can run 265/30/19 (Like I am) ... but your speedo will be slightly off.. (I think somewhere along the lines of 3%)

They are all 19" tires so it's easy to see the difference

Front: 225/40/19 Sidewall height = 225X40% = 90.00 mm
Rear: 255/35/19 Sidewall height = 255X35% = 89.25 mm
VS
Front: 235/35/19 Sidewall height = 235X35% = 82.25 mm
Rear: 265/30/19 Sidewall height = 265X30% = 79.50 mm

So the latter pair give thinner sidewall by approximately 8-10 mm compared to the first pair.

What model your IS is? AWD or RWD?

For AWD car 225/35/19 is the closest overall diameter to OEM's 225/45/17.

So if you want stagger tires on AWD you can go:
Front: 225/35/19 Sidewall height = 235X35% = 78.75 mm
Rear: 265/30/19 Sidewall height = 265X30% = 79.50 mm

Closest Front-Rear match you can get is:
Front: 235/35/19 Sidewall height = 235X35% = 82.25 mm
Rear: 275/30/19 Sidewall height = 275X30% = 82.50 mm
Which is really really close between front and rear tires but your speedo meter will be off by about 1%

The closest match for OEM RWD diameter is:
Front: 225/35/19
Rear: 255/35/19

I have tried other combination but I couldn't find a better match. Actually, LEXUS recommends this combo for their F-Sport 19" wheel.

Problem for me is 225/35 is too thin for my preference, so at the end I went with

235/35/19 Front and 255/35/19 Rear combo.

For 235/35/19 Front and 265/30/19 Rear, The rear tire is actually smaller (in terms of overall diameter) than the front which is not right for IS RWD car. Factory spec, Rear tire of RWD IS is bigger than the front.

Looks like I'll need to choose between 255/35/19 and 265/35/19????

The front is good to go at 235/35/19