JPP

Is it a measurement from lip center to lip center? Inside edge to inside edge? Outside edge to outside edge?
I did a couple of searches but didn't find anything .. just a bunch of threads about offset..
TIA
JP

JPP

Ok .. I googled it! Google is my frend .. yesh....

polo classic

inside to inside

JPP

You are correct sir ....

Bill Verburg

JPP

Hi Bill, Thanks for the illustration, it's very helpful to understand what's going on.
So, generally when people quote rim width, do you think they are thinking of overall width or bead to bead? I'm asking because my new 996 Turbo rears are quoted as 11" here and by Porsche, but when the tire folks measured them for tires, they said actual width is 10.7" .. I'm assuming that measurement is bead to bead or inside lip to inside lip ...

Bill Verburg

The generally accepted practice is to talk about bead width, that is what is important to choose and fit tires and close enough for chassis fitment when you also know the ET.

If the overall width is 10.7" you probably have 10" bead width though most aftermarket overall widths are a full inch wider than the bead width. But there is some variation, notably BBS and Fuchs which both have narrower lips and so are more like .75" wider overall than at the beads

JPP

Thanks Bill. I'm pretty sure the 10.7" measurement on my wheels was bead to bead .. it was done at the tire shop to determine if the 285's would work .. I'm assuming the overall is 11" or a tad over ..

Bill Verburg

bead widths are always in .5" increments.

if the overall is 10.7' then you have a 10" bead width which is the minimum for a 285/30 x18 tire

unless you have a wide body and or a very high ride height an 11" wheel just does not fit in the given space

It's easy enough to measure for your self

cut a couple of pieces of stiff wood so that they can lay across the lips w/o touching the tires, hold them in place w/ rubber bands, measure the perpendicular distance between them. That is the overall width.

Bill Verburg

Just to illustrate , here are some wheel specs

JPP

Yep, she's a widebody so no problems on the fit .. the 996TT 11" wheels fit perfectly .. just needed to go up to a 295 tire from the 285's I was running on the stock 993 10" Turbo offset Technology wheels that came on the car from the factory.