Ok guys, I measured the bolt circle on my Ford 9, and I came up with 5 on 4-1/8. 4-1/8? Have you guys ever heard of that? I don't know much about this rear end, don't know what it came out of or anything.
Never heard of 5 on 4.125. It can range from 4.5 to 5, I think maybe some of the older trucks or broncos might have been 5 on 5.5 but don't hold me to that. Take a look at this old pic I robbed from an old speed parts catalog and check your measurements again. its pretty easy to miss.
I don't think so. Either you didn't measure correctly, or maybe you don't actually have a Ford 9" rearend.
sounds like a measurment mistake - follow the guide above. Pork is right - lots of trucks and broncos had a 5x5.5" pattern - that is what mine is (out of a late 60's early 70's bronco)
Ark, Thanks I thought they were but I just wasn't sure on that one. Colorado snap a pic or two of the houseing ends also. The A body Chrysler rear resembles the 9" ford if you don't know what you're looking at but it had an adjustment on one houseing end of bearing thrust.
Bolt CIRCLE - since 5 is an ODD number you CANNOT measure from the center to center (you can ONLY if wheel studs are 180 degrees apart) . It might be tad hard to see in the illustration above, but the APPROXIMATION is to measure from the CENTER of one stud to the OUTSIDE of the other. This is done to approximate what the number would be IF the studs were in fact 180 degrees apart. The other problem you might encounter is that with really long wheel studs you could have a bent one that throws off your reading.
That's gonna be 5 on 4.5. The other thing you got going against you is that you are measureing lugs that have the ends swedged that will easily loose you an eigth of an inch.
That's a nine inch, and it is 5 X 4 1/2". You don't measure center of stud to center of stud. You measure center of stud to back of stud. Look closely at the illustration provided by porknbeaner.
looks like 4 1/2 to me. check the diagram again. measure from the center of one to the far side of the other.
Man, you guys are making this way too difficult. The easiest and most accuate way to measure a 5 lug bolt circle is to measure from center to center and add 1/4". Exp. A ford will measure 4.25" from center to center plus a 1/4" = 4.5". It works for any 5 lug standard bolt pattern. Adding the 1/4" instead for measuring from middle to outside a stud gets rid of all the problems he is having. Thats a 5 on 4.5 BP. By the way, The small Mopar BP is 5 on 4". The only things that are 5 on 4.25 are taurus's and mid 30s Chevy Standards Jimmy
Here is the quickest way to measure - I do this all the time....it will work on any Ford rear end. Take a small piece of string and wrap it around each of the wheel studs two times, going from one stud to the next, in the same pattern that you would use to tighten the lugnuts. When you complete the 2 wraps on the last stud, run the string around the diameter of the brake drum or rotor. Cut the string precisely at this length. Remove the entire string from the drum and each of the studs. Now measure the length of the string. You may need a friend to help with this part. Take this measurement and post it here on the HAMB, and someone will get back to you on what bolt pattern you have. It works every time. Unless it is a 8 3/4" rear end - and that takes an entirely different process.
i make it real easy, but one of these at the swapmeet for $2 don't know if it will work but here's a template: http://www.northerntool.com/downloads/bolt_circle_template.pdf
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