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Discussion Starter #1
I know someone with a set of 19" BBS RS-GT's on their M3 they are selling and it would be cool to offer to buy those from him for my best if they fit.

Anyone know the offset of our factory rims and those of the E46 M3?

Thx.
Robert
 

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@ 20 on the e39 M5 and 30/40+ on the e46 M3 ...bore size is also different IIRC 72mm (+-) for the e46 M3 and 74mm (+-) for the e39 M5
I know someone with a set of 19" BBS RS-GT's on their M3 they are selling and it would be cool to offer to buy those from him for my best if they fit.

Anyone know the offset of our factory rims and those of the E46 M3?

Thx.
Robert
 

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Discussion Starter #3
I think I found the following information from doing some searching:

E39 Factory Offset F/R: et 15/20
E46 Factory Offset F/R: et 35/20

I am pretty sure the hubcentreic spacers can fix the bore size issue, but can you go from a 15 to a 35 on the front wheel? I always forget with offset if a higher number means it is further out from the center or further in from the outside. I think that means it is 35 mm further out from cnter of the wheels right? If so, a larger spacer would work, but a 20mm spacer sounds kind of huge.
 

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most off the BBS wheels have a 80mm center bore with additional centerring for the specific car .
for all e39 and the M5 its a centerring off 74.1mm, for the M3 (and all other beemers) its 72.5mm.

i think the offset for the e46M3 is ;F/R et 47mm/et 22mm
so i think you going to fit a huge spacer in between them:3:...
i hope i'm wrong.


for members who have these questions later and use the search function here a chart for all beemers.

from left to right; type of car, wheelbolt pattern ,et size, centerbore. :hihi:

good luck in your search anyway :byee55amg
 

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Discussion Starter #5
Great post! Thanks!! WHere did you get that diagram? That is exactly what this board needs. Someone should sticky that so people can find it easily.
 

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some details to know when buying wheels

i found the diagram on a belguim bimmersite some time ago,and i knew it would come handy on later occasions so i saved it.:hihi::hihi: :M5thumbs:




so a bit more about wheels...

-from left to right; type of car, wheelbolt pattern ,et size, centerbore.
check diagram. pic 1.

-What is rim offset? [D="EinpressTiefe" or "ET" Value]
A:The distance between the rim's center line and its
mounting surface. From the picture below it should be
obvious why it's important to retain proper offset when
you change rims: tire not centered properly affecting
drivability (negative roll radius changes), bearing load,
rubbing on the struts or wheel arches, etc.
Cross sectional view of a rim, and how a ET value is calculated:pic 2

ET is calculated by the centerline off a rim(for instance a 10" inch wide rim)
so 10":2= 5" inches , there is your centerline.now on the inside of the hart of the rim where the centerbore is,and the difference between that and the centerline is the ET value. look at pic2 and it will be clear.:M5thumbs:
1)how lower the et, how deeper the wheeldesign/or bigger the lip looks (most off the time, and offcourse on what design the wheel is in the first place).
2)how lower the et is, the more the wheels is pusched to the outerside off the wheelarch.the higher the et, the more its pressed inside to the shockmount.


-how wide is a wheel??(for instance ,a 10"inch wide wheel)

the width off a wheel is allways measured from the inside off the rim walls
.so again a 10" wheel is measured from inside wall to inside wall from the rim.so in theorie is a 10" wheel actually 10.5" from outside to outside measured.see pic 3

-whats a centerbore?? see pic 4
what centerbore do i need for what car ?? first again check pic1 :M5thumbs:
now centerbores can be different for every car. most bmw's have a 72.5 mm centerbore, our e39 and e39 M cars are the only bmw's that has the 74.1mm centerbore. some company's(like bbs) makes wheels with a standard boresize off 80 mm for instance ,and can be adjusted by separate centerrings that fit the car. so always check centerboresize iff you buy a wheel new or second hand. a centerbore thats to big can cause bearingfaullures,unbalanced wheelbehavior,and in worst case a wheel that breaks by to mutch pressure on the wheellugs/bolts.


and then last but not least.... how to mount a wheel...
doesn't need to mutch explaination i think, as whe all are carfreaks..:M5thumbs: see pic5.

that about it i think:hihi: feel free to adjust where i am wrong,wrote faults or could be better explained :M5thumbs::M5thumbs:

hope this helps some people in there search :cheers:
 

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Discussion Starter #7
Man, good stuff!!! Wheel offset 101.... LOL!
 
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