[bB626]

my brother wanted to know what's the best size/offset without dropping the xB? he is going with 18's but whats the width and the offset. thanks.

[TartanJack]

To ask another way . . .
(Piggyback question)

What is the stock weight and offset for the xB2 rims?

As the 16s are 55 ratio and 17s are 45 ratio, those are decent for street driving with the 16/45 ratio ones being popular for performance tires. Those both maintain the shock-absorbing element for general driving, preserving ride quality.
From experience with previous cars (sports cars), I'd recommend sticking to equal-to-lighter than stock weight and keeping as close to the stock offset. Thereby, the handling, acceleration, and braking characteristics of the xB is preserved and (potentially) improved upon.

So, what are the stock wheel weights, offset, and what sizes do you like for a non-dropped xB?
-Ideally, I'd like a balance for looks, high performance rubber available, and decent ride quality.

[TartanJack]

Addition:

I did some digging and there are very high performance tires for 16s. So, it gets to the difference between looks and ride.
Anything with a lower profile than 45 gets a fairly "rough" ride, as the tires act as "shock absorbers" for a bad road surface.
The 17s use 45 ratio tires, which is the same as stock tires on high performance sports cars and supercars.
If you want a more "comfortable" ride, I'd stick to the 16 size and get very high performance tires, as they will fit and work nicely.

Also, smaller rims tend to be lighter (less metal needed), so 16s would be lighter than 17, for the same wheel design.
The heavier a wheel gets, the more energy needed to get it moving, change direction, and stop. So, if you add a significantly heavier wheel (rim/tire combo), one may need to "upgrade"/"uprate" the brakes to stop it in a reasonable time.
Of course, for the common wheel sizes and vehicle weight of an xB, the wight issue is a "backburner" for most (though I WILL look at it as a major factor in any rim choice).

Looks/comfort, one needs to decide what they are after.

Edit:
Sorry, I just read the "best size." I didn't notice that he was already planning to use 18s.

I'll defer to those using 18s for advise, as I haven't looked into the preferences in that size, as I would personally want a wheel with more shock absorbing qualities-> ie. a 16 or 17.

[Padanky]

Not sure, there was a guy at scion expo with 22's. tire had about an inch before hitting the bottoms of the fender/bumpers.

My bad Johnny, thought you said "Biggest".

[TartanJack]

Reminder:
Johnny/bB626 is looking for ideal width and offset for an 18 inch rim.

(I had misread it and posted the 2 above posts.)

[FrankH]

Originally Posted by bB626

my brother wanted to know what's the best size/offset without dropping the xB? he is going with 18's but whats the width and the offset. thanks.

I think, from reading around a bit - not from experience, you want 18x8.5 with 38 to 46 offset. I hope someone else chimes in with more options or info. Info like what tires to use on this size rim.....

[MattyRattyPoo]

Ok so do front like 8.5 42-45mm offset and rear 9.5 35-38mm offset. You can go crazier but this is what I know works and looks good.