Once Again: 20s In My Is250 Awd

[biturbo]

Sorry for posting a new topic, but I did't get a proper answer for m question... I'm VERY confused and I don't know what to do now.

I'm gonna start explaining from the beginning:

I'm about to buy rims - 20s or 19s. You guys said that 20s are too big for such a small car as IS, so I decided to buy 19s, but I found out that AWD has higher springs than RWD. Look how much space is between tire and fender (it's IS250 AWD on 20s and stock suspension) so maybe there's enough space for 20s on AWD IS

Now general question about rims and tires:

Do those rims with tires gonna fit ?????

a ) Front + Rear (the same size):

20"

Rim Width: 8.5J

Offset: 38mm

Tire size - 225/30/20

OR

b ) F+R (the same size):

19"

Rim Width: 8J

Offset: 40mm

Tire size - 235/35/19

Thanks for any helpful answer.

[TigerFish]

The space between fender and wheel isn't the issue. 20's would fit, I think what people are saying is the wheel just "looks" too big. With the correct profile tyre, they will be no bigger in overall diameter than the 19's. You will however have a deeper side wall on your tyre with the 19's and will get a slightly better ride and of course less chance of denting your rims on rubbish roads with pot-holes etc.

[Tango]

F+R (the same size):

19"

Rim Width: 8J

Offset: 40mm

Tire size - 235/35/19

Thanks for any helpful answer.

Right, I'll try again.

Good idea to fit the 19" with the 40mm off set ...they will fit and the +40mm offset will move the inner edge and outer edge of the rim outwards by 5mm which is in the right direction to look better than standard . The AWD that you have does not have a staggered wheel width setup like the RWD so 8J all round is correct. Explained here http://www.1010tires.com/WheelOffsetCalculator.asp

The rolling diameter or radius shouldn't change more than 2.5% or less from that of your original wheels. The 235/35/19 you suggest on the 19" would give you +2.02% so at an indicated 70 mph you would actually be doing 71.41%. A better tyre for the 8J would be 225/35/19 which would give you only +0.91% on diameter...check yourself with http://www.alloywheels.com/tyrecalc.asp

Re. the arguement between 20" & 19", the bigger the rim diameter the lower the tyre profile needs to be. I have to be extremely careful with my 19" to avoid damaging the rims on rough surfaces because they're not far off the road...20" will be even more vulnerable as the rim will be 0.5" closer to the road than mine. The only way you're going to reduce the gap between the wheel arch and the tyre is to fit coilovers or lowering springs, the rim size doesn't alter the gap at all......

Is that helpful???