Help with 5x120mm wheel fitment

[HandOverFist]

I've been following along on the forum regarding using 5x120mm wheels on early muscle cars. The appeal is a greater selection of wheel styles with prices far below the custom wheel fare. The vehicle in question will be a '67 El Camino using drum brakes in the rear and upgrade to discs in the front. Hoping to keep wheel diameter to 17" if I can using a staggered set-up.

My question centers around the offsets offered and how to determine what the backspace is for any given wheel. Using these wheels as an example...http://www.ebay.com/itm/181798686864...%3AMEBIDX%3AIT



Would a set of wheels like these come close to fitting the El Camino? I will be ordering new axles which will include the correct 5x120mm bolt pattern. I'm open to suggestions as I am still searching wheel styles.

[Schwartz Performance]

Take a 9" wheel. It's actually 10" overall.
A 9" wheel with 0 offset means the mounting pad is directly in the center. So, 10/2 = 5" back spacing.

Most modern car wheels have a positive offset, meaning the center pad is toward the outside of the wheel.. This increases your back spacing measurement as well. So a +25mm offset on the same 9" wheel is approximately 6" back spacing.

If you want a visual, google Back spacing / wheel offset and there are plenty of diagrams to look at.

-Dale

[HandOverFist]

So, the wheels in that link would be approximately 5-1/4" BS for the front and 6-1/4" for the rears? I'm thinking a maximum of 5' for the front and 5-1/2" for the rear would be needed on the El Camino...sound pretty close?

[chpr1972]

If you use the 5x120m wheels use a little higher torque setting. Also take your torgue wrench with you and check the torque after going around the block and again in 25 to 50 miles and again at 100 miles. I have 5x120m wheels on a 66 Lemans and I drove about 6 blocks and they were loose. I check the torque every once in a while now but after 100 miles they are still tight. If you remove one do the same thing over again.

[HandOverFist]

If you use the 5x120m wheels use a little higher torque setting. Also take your torgue wrench with you and check the torque after going around the block and again in 25 to 50 miles and again at 100 miles. I have 5x120m wheels on a 66 Lemans and I drove about 6 blocks and they were loose. I check the torque every once in a while now but after 100 miles they are still tight. If you remove one do the same thing over again.

Are you using 5x120mm wheels on a 5x4.75 pattern axle/rotor? I would be using a true 5x120mm drilled axle flange in my case. Not committed at this point, but if I find wheels I really like at a good price I can see myself doing this.

[WallaceMFG]

If you use the 5x120m wheels use a little higher torque setting. Also take your torgue wrench with you and check the torque after going around the block and again in 25 to 50 miles and again at 100 miles. I have 5x120m wheels on a 66 Lemans and I drove about 6 blocks and they were loose. I check the torque every once in a while now but after 100 miles they are still tight. If you remove one do the same thing over again.

The reason they were coming loose is because only a small part of the lug nuts face is in contact with the wheel so it doesn't have very much holding power. Running a higher torque will work temporarily, but in the long run is not safe as one bad pothole can move the wheel enough that it would lose torque, especially if the wheel is not centered on the hub like it should be.

I got my TSW wheels machines to have the correct bolt pattern. If you compare the bolt patterns they're only 0.7mm off, so it is not a huge job to have them altered. I found a local machinist who worked on the wheels and placed a steel insert in the bolt holes to make the pattern correct. The only way you can tell this was done is if you look down the lug hole or at the mounting flange from the inside. He only charged about $50, and now I don't have to worry about finding parts to fit the other bolt pattern, and if I ever change wheels I don't have to alter anything on the car.