645ci Wheel Offset Help

[cnp]

I am going to order a set of M6 replica wheels for my 645ci (either Miro or Moven). Anyway, what offset would be the best for my car? Does the wheel stick out further from the fender with a higher offset? If that's correct, would an offset of 35 front/40 rear provide a slightly more aggressive look or would that just look stupid? I think there are other choices around 15 or 20. Should the front and rear be the same?

THANKS.

[cobradav]

Regular 645 19" - 8,5 x 19 Front / ET 14 - 9 x 19 Rear - ET 18

M6 wheels - 8,5 x 19 Front / ET 12 - 9,5 x 19 Rear / ET 17

So a standard M6 rear wheel would be about 1/4 inch further out per side 1/2 of the 0.5 inch wider wheel).

So for another ~6.4 mm positive offset (approximately an ET of 19 on top of the wider wheel) you would be closer to the wheel arch by 1/2 inch. Figure about 1/4 inch per 6.4 mm of offset. If you did have a 9.5 inch wheel width with a offset of 40 mm I think you would look, well like a pimp mobile. If yuo could get you hands on some various size wheel spacers you could tril and error your way to the approximate offset you ultimately could use/like. Probably a top notch aftermarket wheel place could run some numbers for you.
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US '05 645 Coupe, Silver Grey, Chateau, Sport, Logic 7, HUD, Cold Wx Pkg, SIRIUS Sat Radio, Aux Input, Bluetooth w/ snap in adapter, V1 CIP 20.02 w/MP3 enabled - Great, great BMW!!

[cnp]

Thanks for the help so far. So then -- would 15 front, 20 rear look normal? I would be using 19x8.5 and 19x9.5.

Thanks again.

[cobradav]

My "opinion" yes but I sense you want an "aggressive" look so perhaps you could squeeze out a little more. Also depends on the mfrs offerings and if you try to go for max width on tire size. Just remember, if you go too wide you cannot come back, but if you missed the other way you could use small spacers, although generally not recommended due to added stress and chances for more things to go wrong.
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US '05 645 Coupe, Silver Grey, Chateau, Sport, Logic 7, HUD, Cold Wx Pkg, SIRIUS Sat Radio, Aux Input, Bluetooth w/ snap in adapter, V1 CIP 20.02 w/MP3 enabled - Great, great BMW!!

[cnp]

OK - I will go with the 15 and 20 offsets. No aggressive look necessary -- just want it to look normal. One last question -- Should I get M6 tire sizes or stick with the 645 19" sport package sizes?

Thanks.

[cobradav]

You will have a wider wheel I assume on rear so go for the recommended tire size for that wheel which will probably be the M6 size of 285/35x19 but the reg 6er tire of 275/35 fits nicely as well.
For front I would stay the recommended regular 6er sport size (245/40). The M size tire (255/40) versus wheel is at edge of tire mfr recommended wheel size (I used Michelin PS2 as a guide here). May be different for a different tire mfr. Tire rack (tirerack.com)is always a good source of info for all things wheel and tire.

In general M size tires are a total of 0.5 inches wider (both tread width and cross section) so stick out another 0.25 inches to outside and inside (wheel well). Your chances for rubbing do increase if you do plus up. Also M sizes are about 0.3 inches larger in diameter. No issue here other than inceased chance at rubbing.

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US '05 645 Coupe, Silver Grey, Chateau, Sport, Logic 7, HUD, Cold Pkg, SIRIUS Sat Radio, Aux, BT w/ snap-in adapter, V1, CIP 21.03 w/MP3 enabled

[cnp]

Yet one more question:

You mention using a spacer may be bad? So, you would not recommend using a 25mm spacer on the front? That's what the store is saying I could do to achieve a stock look. What type of risk would I assume in using the spacer?

I appreciate the time you have taken to help with my questions.

[cobradav]

An m6 owner replaced his OENM wheels and is selling them - no proce info. do you want to hook up with him? He is on both b i m m e r f e s t and e 6 0 .net
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US '05 645 Coupe, Silver Grey, Chateau, Sport, Logic 7, HUD, Cold Pkg, SIRIUS Sat Radio, Aux, BT w/ snap-in adapter, V1, CIP 21.03 w/MP3 enabled

[645Rascal]

cnp - thanks for the discussion. Would sure like to see some pictures when they are installed. And thanks from me also to cobradav for the info.