How come 19" wheels always have larger lip that 18s?

[nathan]

I never fully understood this, but how come 18x8.5 rim's lip is always so much smaller than a 19x8.5 wheel? offset is both +38 (im refering specifically to the hamann hm2)

but i mean other wheels too, i can see how a larger lip can be achieved with a lower offset, but rim diameter?

or does it just 'seem' a lot deeper?

-nathan

[Jim@tirerack]

The diameter should not make the lip bigger unless the wheel is also a wider wheel. You are correct in the offset will get you a bigger lip.