Thanks again for everyone's help! I'm really stoked!

2Hip, thanks for the pic! Are those 18s? If so, that's the first time I've seen those 18s on a Scion and it looks pretty sick. Definitely can't wait to get mine!

 

Yep...18's and thanks for the compliment.

 

i am lookin for 18's also but i dont know the offset i need.. 18/7.5 what offset do i need to make them sit flush? please help..1 week old 08 xb

 

Something in the 30 range would put 7.5" wheels flush. I'd say start looking at 18" wheels first to find something you like, then see if they come in 7.5" or 8" width with an offset that will flush them out, if that is what you want. BTW, the rears sit in farther than the fronts, so you will need spacers to get them flush with the fronts unless you go staggered.

 

I'm a little confused with regards to my mileage with the Kosei K1's. My combo is about 4lbs lighter per corner over stock but since I've put the combo on I've lost about 3mpg. I've looked at the tire sizing calculators and there doesn't appear to be a significant difference in sizing to say that maybe my mileage is not being properly calculated. Am I missing something? I really thought I would gain 1 to 2 mpg not loose any. Could it be my PSI? I'm running 225/40/18's with about 35psi per tire. Is this the right PSI or should it be what is recommended on the door jam?

Thnx - 2Hip

 

2Hip you could try higher pressures. Is there any chance your mileage is down a little because the car is more fun to drive now? j/k
I would think you would see better mileage too. I'd play with the pressures a little.

I run 39 front and 37 rear in my 235/35/19's. I would think you should definitely run at least 37 front and 35 rear at a minimum. With front wheel drive the front pressure is almost always recommended somewhere around 2 psi higher than the rear.
Maybe try 37/35 and if that is OK try 39/37. Let us know if you see any improvement in your mileage.