17x8 questions

[sdub]

I got a set of 17x8/7's in the mail and cant figure out the offset.
They are old american racing mesh.

They measure 9" outside rim to outside rim with 5" of back space. So i'm thinking offset is +.5" = +13 mm. is this right?

will post pics when i get a sec to see what you guys think.

Also they need to be refinished, do i need to reseal the barrels to the wheels? i have no idea obviously about how to go about this.

Any info is helpful thanks!

[Ant_e30]

ok so i know this is detailed like hell but i posted this on a couple of other forums i go on for people to know how to measure offset:

TO MEASURE OFFSET:

The formula is as follows:

backspace - (width divided by 2) = offset in inches

Multiply by 25.4 to get offset in the normal measurement of mm.

Now to define the terms in the above formula:

Backspace = this is the area behind the spokes/face of the wheel. To calculate Backspace, place your wheel face down on the ground. Now put a straight edge (such as a ruler) across the back of the wheel. Get another ruler or tape measure, and measure from the Straight Edge of the ruler down to the Hub Mounting Surface. This is the flat surface where the wheel stud holes are that mounts to your hub. This figure is your BACKSPACE.

Width divided by 2= this is the overall width of the wheel measured from edge to edge NOT the width on the sticker on the back of the wheel or in the wheel catalogue etc. As stated above, the wheel width quoted by wheel manufacturers is the captive wheel width, not the physical overall wheel width. Once you have this width you have to divide it by 2 for use in the formula.

Once you have these above 2 figures and use them in the formula above, you will get an offset figure that is in INCHES. This is NOT the numerical unit used for quoting offset, offset is quoted in MM. So you need to multiply by 25.4 to get MM.

An Example:

I lay my wheel face down. I put a piece of wood across the back of it, and measure down to the Hub Face. I get 6.5". This is my Backspace.

I measure the overall width of my wheel from edge to edge and I get 10". This is my overall wheel width.

I put them in to the formula:

6.5" - (10" divided by 2) = 1.5"... Then 1.5" x 25.4 = 38.1 round this figure = an offset of +38mm.

Thus, your offset has been calculated.

[sdub]

you could have just said i have it right:-) but thanks for the info!

now does anyone know about sealing the barrels after i get them all refinished?

[grippymonkey]

^ just look up the same info on sealing BBS RS... there's a million internet build threads for it

good stuff finding 17" old meshies... I wanna see!

[sdub]

here we go... actually wheels are 17x8 rear and 17x7 up front (guy was measuring by very outside of wheel)

anyways they are et13 for the rear and around et20 for the front... scary thing is they are 5x130 so i'm gonna have to run 20mm adapters, putting the front at 0 the rear at -7!!!

not sure if there is a way i can offset this to make it nearer to 0?? I'm considering taking the centers to a machine shop and having them shave off some mm's from the back? anyways onto the pic (doesn't do it justice)

also need one more center cap that screws into the wheel no idea if all the center caps on ebay are like this or not (i think most of them are just one piece)

and wheels only ran me $325. but they really need to be refinished so i think it was approp price.

[Pabl0]

we make adapters in 18mm, not that it helps much lol also shaving backpads is almost impossible with most wheels because you're taking away material needed for the lug bolt. there are on occasions that wheels like merc AMG wheels have really thick pads but most wheels dont allow enough material to be removed that it'd make a difference. fill n drill will be the best best as it would be cheaper and offsets would be more suitable as is.

[sdub]

^^^who is we??? I definately will pay for even the extra 2mm's.

but it wont be as bad as i thought to fit, thinking i'm only going to be running a +6 offset in the end since wheels is only 8" wide.

anyways lmk where to get them!