How do you measure bbs rim halves?

[jax911]

Question is ; Do you measure from inside lip (bead area) or outside lip?
I know its only about 1/4" difference but I need to be precise.

Thanks.

[Sboxin]

Measure wheel halves inside the bead -- more like 1/2" difference - 10" outside is 9" inside.
A shell will measure 7" outside half and 6 1/2" inside the rim bead.

This drawing (from CCW ) may help. We used this when buying used wheels on this forum.

Regards,

[jax911]

Right and thank you, but if buying a rim half how does the manufacturer measure the width?

[Jim2]

This picture by Philip from his WTB thread is the way BBS halves are measured. Halves are measured on the INSIDE surface where the tire bead seats.

Regarding being precise, read on....

BBS halves come in half inch increments, however, they will measure a bit under size which is made up with a sealing ring, if you decide to use one. The sealing rings are about 3mm thick, so a rim assembled without a sealing ring would be width XX minus 3mm/ ~1/8".

You can just make out the slight difference on Philips 7 inch half, looks like about 6 15/16".

Hope this helps.

Originally Posted by philip j

for a 7" inner barrel.