Gen_Crunchytoes

Im looking to re-barrel my BBS RF's sometime after summer and since im new to having 3 piece wheels I need some help. Right now they are 17x8+15 in the front and 17x9.5+24 in the rear. I want to widen the fronts and rears to 9in +45 in the front and 10.5in +55 in the rear so i can fit more tire under the car since i plan to boost the car sometime next year, as well as just wanting more tire under the car.

My question is do i need to just replace the inner barrels or do i need new barrels and outer lips as well? And does anyone have a preferred place to order what i would need? My searches havent brought much back in terms of selection, availability, or fitting my faces. Ive also searched on here and only found threads pertaining to widening one piece wheels and that does me no good.

Thanks in advance darg

Fabrik8

Offset is measured from the centerline of the wheel, so you can figure out what you need to replace with some simple addition or subtraction. The wheel centers will stay the same obviously, and thats the point of reference for offset, and you've already listed all of the specs that you need. Grab a calculator.

Fabrik8

Ok I just did the math.

I'm assuming that the barrels will be the same rim profile, etc. so we can use the bead seat width (the 8 inch, 9.5 inch, etc.), because the old and new wheels will both be measured from the same locations.

Note that my numbers won't be exact barrel widths because I'm only comparing the same parts of geometry on the old and new wheels, and that's all that matters if you're wondering what you can reuse and what you can't.

So quickly converting the wheel widths from inches to mm, dividing by 2 (because the offset is measured from the wheel centerline) and adding/subtracting the offset to find the relative widths of the barrel sections, here's what I have:

Old front outer 86.6mm, inner 116.6mm
New front outer 69.3mm, inner 159.3mm

Old rear outer 96.65mm, inner 144.65mm
New rear outer 72mm, inner 182mm

If you notice, none of the numbers match, so it doesn't look like you can reuse any of the barrel sections unless you change what you want your new offset to be.

This is about 3 minutes of math, don't be scared to start playing with numbers. It took me a lot longer to post results than do the calcs.

Gen_Crunchytoes

hmmmm. thank you sir. im the first to admit i am absolutely shit ass dicks with math.

so what you posted will give me the width and offset im looking for then? ill convert that back to inches to determine what sizes ill need

Fabrik8

I don't know how the barrels are measured, and my dimensions are compared to what you already have.

So all we really know is that the front outer will be 17.3mm smaller, the front inner will be 42.7mm bigger.
The rear outer will be 24.65mm smaller, the rear inner will be 37.35mm bigger.

So whatever sizes you already have, if the barrel design is the same then those are the changes. And you'll probably have to do some rounding to the nearest common size up or size down.

Where are you getting the barrels from?

FLiPrayZin240sx

But you also have to take into consideration on where the pad of the wheel is measured at in reference to the where the 2 barrels split. Just because it's +15 wont mean the mounting pad would be 15mm out from where the 2 barrels bolt/split together. That could throw a wrench on the numbers if you do the math based on the idea that the mount pad is lined up exactly where the split would be. To get accurate numbers, he need to measure his current barrels and verify the placement of the mounting pad in reference to where it splits.

AirSick

I too have been wandering this since in the near future I will be going disc brakes on the bug with a 5x130 porsche pattern and will be running some type of 3 pc. wheel.

Fabrik8

Yes, and you're only partially getting my drift. I don't have to take anything into consideration if I'm trying to find out if the barrel sections will be re-usable. If the old and new wheels have the same type of barrels but are different width or offset, they'll still have the same rim profile, mating flanges, etc., so none of that matters. I can tell you whether they're different with simple math because of that. It's like algebra, you can cancel out the equal terms on either side of the equation. No, I can't tell you which exact width barrels to buy, but I can tell you the difference in width from what you have now. If you already know what you have now, doesn't it seem easy all of a sudden? Yes, you need to measure what you have now if you don't already know the specific dimensions.

I believe that sums up my previous posts.

Dough_Boy.

Mike forget all that jazz. Just do this and you can fit whatever wheel tire size you want.

POS DSM

There are a few companies that can make you custom lips/barrels to your spec if it comes down to it.

How many bolts does each wheel have? I think most old BBS's are 34 hole. If so you should be able to mix and match from other BBS wheels, just keep your faces.

A good start would be to measure the depth of your lips and barrels and go from there to get the offset you want. Remember 1 inch =25.4mm. Although since you want to widen them too, that makes the maths too confusing for me right now lulz