Front Wheel Offset Help Needed

verde2002

verde2002

Well-Known Member
Site Donor
Messages
1,044
Reaction score
62
Location
Los Angeles
I am going to install a set of E38 750IL wheels on my 2800cs and needed a bit of help on the proper offset. The wheels are 16x8 with a +23 offset. These are almost identical for the rear with the Alpina specs so I have no concerns. For the front I can either use a 5mm spacer for a +18 offset or a 10mm spacer for a +13 offset. Anyone have experience and can give me a definite answer as to which will work better? I am running 205/55/16 tires on these wheels. Without spacers the wheel rubs on the shock and wont even fit the hub flush to be tightened. Also if I do go with 10mm spacer I will need extended wheel studs. What is the size and pitch for the wheel studs?
 
I would run the thinnest spacer possible to clear the strut by about 5mm, the closer the wheel is to the strut the less chance you have of rubbing the guard / fender.
Would be nice if you can have some sort off centre locater for the hub to spacer to wheel combo so that everything is nice and true, and yes, if you space out by more than about 5 mm you should get longer wheel studs
 
i haven't measured the inner clearance w/ the alpina wheels ... i just know that the outer clearance is too close unless you roll the fenders. you will cut the tire edges / run the risk of catching the fender lip. perhaps the negative camber plates will help slightly. i would like to mill a few MM off of my wheels to reduce the offset. keep in mind that spacers on these cars are tough because you can't use longer lugs ... as we have studs of a finite length. i wouldn't use a 10mm spacer - not enough thread grip on the lug nuts for my taste.
 
I finally had the time to test fit the wheels. The rears fit without issue although I would love to have had them out a bit more. The wheels I have now are from the 840ci and the fit is perfect where these E38 wheels don't sit out far enough. The 840ci wheels are 16x7.5 with +15 offset. Maybe a +18 offset with a 5mm spacer rather than the +23 would look better. The fronts without spacers rub the tires on the struts. I bought a cheap 8mm spacer from Pep Boys to test fit and the tire cleared the strut but was still too close for comfort. With a 10mm spacer it should fit perfectly. The studs were definitly too short for comfort. They are 25mm in length. If I can find 35mm it would be perfect. Are all the press in studs universal or vehicle specific? Can anyone lead me to a supplier for them with the correct width, thread and pitch or give me the specs. so I can search for them?
 
Photo

my old 840ci Wheels
 

Attachments

  • IMG_4816.jpg
    IMG_4816.jpg
    95.4 KB · Views: 204
One of the peculiarities of the E9 coupe is while the rear track is narrow enough to stuff wider rims & tires with more offset under those quarters the front track is already too wide to do the same :sad: without at least rolling up the fender edges (I found this out the hard way). It sounds to me like your rim & tire choice is either too wide or is going to need too much offset for our coupes. You might possibly get away with it because the front of your coupe seems to sit pretty high but I personally wouldn’t bet on it.

Another thing to consider is spacing out the front wheels isn’t really recommended because of the extra leverage (from increasing the tires distance from the steering axis) is going to increase the feedback you feel in the steering wheel from every bump & expansion strip in the road besides being harder on suspension parts like ball joints, tie rod ends and even the steering box. Good luck, it cost me a $130 tire :oops: to figure this out. ~ John Buchtenkirch
 
John Buchtenkirch said:
One of the peculiarities of the E9 coupe is while the rear track is narrow enough to stuff wider rims & tires with more offset under those quarters the front track is already too wide to do the same :sad: without at least rolling up the fender edges (I found this out the hard way). It sounds to me like your rim & tire choice is either too wide or is going to need too much offset for our coupes. You might possibly get away with it because the front of your coupe seems to sit pretty high but I personally wouldn’t bet on it.

Another thing to consider is spacing out the front wheels isn’t really recommended because of the extra leverage (from increasing the tires distance from the steering axis) is going to increase the feedback you feel in the steering wheel from every bump & expansion strip in the road besides being harder on suspension parts like ball joints, tie rod ends and even the steering box. Good luck, it cost me a $130 tire :oops: to figure this out. ~ John Buchtenkirch
Click to expand...

The fronts I was running on my 840ci wheels were 225/55/16. Pretty tall tires. The new ones are 205/55/16 and are considerably shorter. This gives me a lot more space. Is a 10mm spacer wide enogh to cause strain on the front steering?
 
verde2002 said:
The fronts I was running on my 840ci wheels were 225/55/16. Pretty tall tires. The new ones are 205/55/16 and are considerably shorter. This gives me a lot more space. Is a 10mm spacer wide enogh to cause strain on the front steering?
Click to expand...

I can not tell you how far is too far, I’m only making you aware of what some of the effects could be. The more you move the wheels outward the more these problems come into play, there is no set distance where good suddenly becomes bad. The problem is the more you move the wheels outward the more you are swinging the tires in small circles rather than rotating them on their contact patches when you turn the wheels if that makes any sense. Other effects are harder steering (might not notice it with power steering), shorter wheel bearing and McPherson strut life as well as more road dirt thrown on the side of your car. ~ John Buchtenkirch
 
You must log in or register to reply here.
Back
Top