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[window2time]

I read a lot of posts about wheel offset but there appear to be disparate views on the subject. There are two specific areas I would like to be educated on.

1) Aftermarket wheels are often wider than stock. Should wider wheels be selected with the same offset as OEM or should we select wheels that provide the same track as the stock car? If I buy wheels that are 1/2" wider than stock, I would be inclined to purchase the same offset as OEM so that the wheel would protrude an additional 1/4" on the outside of the car and an additional 1/4" toward the inside. My uninformed reasoning would be that this leaves the centerline of the tire in the same place and thus acceleration and braking forces are in the same place relative to steering pivots, etc. What is your advice and why?

2) Wheel spacers??? If the wheels we want are not offered in the correct offset should we use wheel spacers to correct the offset or should we only buy wheels with the correct offset? I have read some negative opinions of wheel spacers, but I am unclear why they are a problem. For those who don't like wheel spacers, can you tell me what performance or reliability problems I might encounter from their use?

[ben@tirerack]

1) It is good to stay close to the original offset, although in my experience it does not have to be exact. Aftermarket wheels usually run lower offsets for a more aggressive look (pushed out a little more). Within reason, this does not cause problems.

What actually fits is important as well. A wheel has to clear the calipers, not hit the fenders, and not hit the suspension. For a given width, this restricts the offset that can be used to within a certain range.

2) Spacers allow wheels to fit on a car that may not otherwise work, or they can help fine tune the look of the car, putting the wheel exactly where the customer wants it. The downsides are insufficient thread engagement (unless longer lug bolts are used), and more strain on the lug bolts. Cars that are run on racetracks, should change their lugs regularly (once a year or so) to avoid metal fatigue resulting in a broken lug. Like a shark attack, this is very rare, but has been known to happen. And like a shark attack, the results aren't pretty.

If you can fill your needs without a spacer, do so. If you must have a spacer, be smart: get proper length lugs for proper engagement, and replace them regularly if you run on the track.

[window2time]

Ben, thanks for the information, this is helpful. I assume that using thin spacers such as 5mm creates very little problem? Also, with such a thin spacer is it necessary to install longer lugs?

[ben@tirerack]

I have used 5mm spacers with no problem. I used 5mm longer bolts to ensure that I had just as much thread engagement as before.

[Johan@WSTO]

thanks ben for the information.

We as a vendor also recommend staying true to some of the OEM Characteristics.
for example, it is nice to go wide on the rear but if you go too wide on the rear, it will affect the handling characteristics of certain cars.

Cars like Porsche that are rear heavy will benefit from a wider rear with more rubber. M3's are closer to being 50/50 weight distribution. Therefore, even if it is a rear wheel avid drivers will benefit by staying with a difference of about 1 to 1.5 inch between the front and back. Some of the track guys that we know try to put as much rubber in the front as possible.

someting to consider as well...

[sayemthree]

Originally Posted by window2time

Ben, thanks for the information, this is helpful. I assume that using thin spacers such as 5mm creates very little problem? Also, with such a thin spacer is it necessary to install longer lugs?

I use 5mm spacers in the rear on my track set up. works fine, but use the 5mm+ lug bolts with them.