Wheels

brand front offset weight rear offset weight
Lotus base c 16 x 5.5 ET31 15.2 17 x 7.5 ET38 21.0
Lotus LSS f 16 x 6.5 ET31 13.2 17 x 7.5 ET38 15.2
SSR Comp 16 x 6.5 ET32 11.0 17 x 7.5 ET37 13.3
RAC Monolites 16 x 7 11.2 17 x 8 13.2
Toybox 48 16 x 7 12.0 17 x 8 13.7

f = forged
c = cast

The bolt pattern for the Elise is 4 x 100mm, lug nuts are 19mm/M12/1.5pitch, and the center bore is 56.6.

The J classification indicates the rim can mount a tire that is from .5 inch less to 1.5 inches more in width.

Wheels need to fit the car first and the tire second. The wheel and tire combination need to fit inside the wheel well of the car. A wider rim will allow the wheel to support wider rubber, which may improve cornering ability. The offset will determine where the wheel and the tire fit inside the wheel well.

Less weight has several benefits. First the wheel and tire combination are better able to follow the undulations of the road. There is also less angular momentum in a smaller and lighter package.

The original designers of the Elise wanted to fit 15 inch wheels but were convinced by marketing the car would look better. Unfortunately the suspension was tuned for the larger wheels so any benefit of fitting smaller wheels needs to be accompanied by a retuning of the suspension.

(Thanks to Ian for fixing the rear offset, an original misprint from Lotus.)

Spacers

Spacers are recommended for these wheels in order to center the wheel in the wheel well.