The aluminum or "Light Alloys" as mentioned in the FSM, come in 2 widths.

The 240D used a 5 1/2 inch , and the 300D used a 6 inch.
There is a broken silver stripe with the 5 1/2 inch and a solid silver stripe with the 6 inch. the stripe is in the enter of the wheels. another way of identification, there is a solid row of quarter size holes around the circumference of the wheel.
The steel rims have 4 slots where the inner and outer part are welded together.
or use a magnet.

the 240 light alloy weight 9.70 lbs, and the steel wheel weighs 18.75 lbs.

The hub cap clips for the light alloy have a plastic piece on the clip to keep it from digging into the aluminum.

In my owners manual is states,
Hint: Do not use hub caps designed for light alloy disc rims on steel rims.

Don`t know what this means, except maybe the clips are different. I have noticed since I went from steel wheels to light alloy, the hub caps do not fit as flush as before. the clips are expensive, $5.75 ea, and 4 per wheel.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works