"""BMW""" wheel questions.

[LowBuckX]

I looked on Project supercarX web site and couldnt find what I need to know. Here is what I hope some one can answer for me.

1) what Is needed for a 5 on 120mm wheel to fit on a 5 on 4 3/4 bolt pattern?

2) Do you need a ring made to fit the hub center to the wheel?

3) What year and make BMW should I be wheel shopping for?

4) What is the back space on these rims. In inches not mm or how can I convert Offset in mm to backspace in inches?

Thanks. Ebay seems to be a good source for these wheels at a very nice price but I dont want to get something I cant use...

Thank you for the help.

[TonyL]

1) a lug wrench. (it'll bolt right on. no prob)
2) Not always. (but its a good idea)
3) think 90 and later.
4) Depending on what model the rims came from 4.5 to 5 inch backspace is common.

get familiar with what models are "performance" models. i belive you'd want something made for a 5 or 7 series.

[LowBuckX]

Ok Im having a duh moment do you meen 90 and newer? the word later is causing a dull burning in my brain...

[Martin71RS]

I looked on Project supercarX web site and couldnt find what I need to know. Here is what I hope some one can answer for me.

1) what Is needed for a 5 on 120mm wheel to fit on a 5 on 4 3/4 bolt pattern?

A- lug nuts

2) Do you need a ring made to fit the hub center to the wheel?
A- YES! (didnt do it on my first set of wheel....not good!)

3) What year and make BMW should I be wheel shopping for?

5 and 7 series, dont know exact years.... be aware that BMW work with ET and NOT backspacing! when ET stays the same and the wheel gets wider it will be wider to both inside and outside.

4) What is the back space on these rims. In inches not mm or how can I convert Offset in mm to backspace in inches?

http://robrobinette.com/wheel_offset.htm read here

First learn how it works, then see what fits your car!! Mine will work on my Camaro but will probably not work on a Chevelle (not sure)

( I just bought another set yesterday!!)

Martin

[TonyL]

yes, 90 and newer.

[LowBuckX]

Tony Thank you

Martin thank you. And could you do measure the back space on your wheels for me and tell me what you have. Im only looking for a 8 or 8.5 wide wheel. If you can do this for me could you answer these 3 questions

1) what is the claimed offset?
2) What is the wheel width?
3) what is the actually back space in inches?

This would help greatly

[LowBuckX]

Here is what I found out from ROH wheel. He claims a 5 120 will stress the wheels studs too much but i tend to beleive you guys who are running them that they will hold up.
he claims his ROH wheels with th 5-120 17x8 with 15mm possative offset is a 5.09 backspace. So now I will need to measure. to see if I need 5 inch or 4.5 offset.

[Martin71RS]

I still need to measure my BS...sorry, no time yet..I do know my new wheels won't fit without a 20mm adapter......the front axle on a Camaro is too long.....

the wheels I have on it now has spokes on the outside of the rim, so no prob there.....the spokes on the new are more to the center of the wheel.

Martin

[PzeroTA]

Cool, someone looked at my site. Sorry I didn't see this sooner, but the last week has been busy with getting an update ready and subscription material together.

About the wheels, did you look at the fitting 10" wheels (http://www.supercarx.com/projects/gallery8.htm) to the front gallery. In that gallery I give information about the backspace measurements, but those measurements were taken with the tires mounted. To me that makes more sense because backspacing measurements are intended to determine what rubs, but it isn't much of an issue if your tires width closely match the wheel width. The wheels themselves are 15mm offset (ET) front and 17mm rear. This translates to about 6.25 inches of backspacing for the rear wheel and 5.4 inches for the 8.5 inch front. These dimensions are estimates based on my measurements with the tires mounted. The page linked has the actual backspacing with the tires mounted.

If my front had a 255 or 265 tire mounted, I'd bet it would mount right up on your car. If you don't have the SS box then you have almost 39 degrees of steering up front and it will rub inboard components (swaybar and subframe). The SS box for your year is supposed to only have 32.5 degrees but the torsion bar is only 0.18 inches. I would look for a box from a third gen Camaro or Firebird with the handling package. It will limit your steering to 32 degrees with a .210 inch torsion bar for much higher effort.

Be aware that inner diameter of wheels vary and some 17's might hit things like the steering linkage. If you can live with the lower profile tires an 18 will avoid those issues. About the donor cars, the previous generation 5 series (E39 models) is your best bet. The 7 series (previous generation again) offer similar offsets and widths (although some of the 7 sport models offered 10.5" wide rears stock!), but the hub diameter is slightly smaller. Ripper from this site reported needing to grind some on his front end because the hub opening was too small for the wheels he got. It would seem he got the 7 series wheel. The 5 series wheel I got fit right on. If Martin needs a 20 mm spacer for his new wheels, it sounds like he got wheels for a 3-series car that have larger offsets (in the 35mm range) or perhaps more likely the new 5 series cars use a larger offset.

I'd recommend replacing and upgrading your wheel studs. I went with 12mm which is only marginally larger than 7/16" but at least they are new and higher quality. About the hub ring, it is a good idea. I would never recommend track or even heavy street driving without doing something there. I am working on putting together a "kit" that will address this. It will be available through the site. Properly torque the wheels and check them periodically, and you will be fine for street driving. That is kind of a long post, but I am sure you will have other questions. It is a daunting proposition to use a different wheel. I will try to check back more frequently to help if I can. I'll be doing a lot more with this through articles for subscribers too - something to consider.

[Martin71RS]

Casey,


If Martin needs a 20 mm spacer for his new wheels, it sounds like he got wheels for a 3-series car that have larger offsets (in the 35mm range) or perhaps more likely the new 5 series cars use a larger offset.

I have BBS wheels, 17x8.5J with 15mm offset....(for 5-7series)
The size and offset is nearly equal to the wheels I have now, but due to their design they will not fit without a 20mm spacer.

As you will see in the pics the wheels I have now (OZ racing) have the spokes on the outside of the rim, so no prob there.....the spokes on the new are more to the center of the wheel.
the front axle on a Camaro is too long.....!!! (it sticks out beyond the spokes of the BBS wheels.)

I think I will get away with the adapters, but will have to buy them to find out.

[68RallySport]

M5 or M3 rims fit???

[Martin71RS]

Ripper has M5 wheels.... but he also has corvette brakes, I don't know if that changes how much the spindle sticks out....

I just bought 20mm (approx 0.79") adapters, these are the type you screw on the axle. The wheels are mounted on the adapter using standard wheelbolts. So I will end up with front and rear 17x8.5J with an et of -5mm
I think the BS will be approx 4.75" (since I didn't measure the lip of the rim)

I will run smaller 225 tires upfront (now 255) and will see if I can retain the 275 in the back...I think I will get away with it when I roll the rear fender lip

Martin