Can Someone Please Explain the Correct Way to Measure Bolt Patterns?

Do you measure from the center of one lug to the center of the next, or from the far edge of one lug to the far edge of the next?

 

measure from the far end to the close end.

gary

 

Tony, skip one lug, measure from #1 to #3..............OLDBEET

 

Googled how to measure wheel bolt pattern...

first response

WWW.RSRACING.COM/TECH-WHEEL.HTML

 

Measure center to center or edge to edge (Same edge) will both give you the same measurement. Remember your math. Pi are not square, brownies are square. Pi are round and cut in wedges.

I used to have a little card in my wallet that had the bolt patterns marked on it.
Even with the right bolt pattern tho there may be issues with lug nuts and stud sizes or center holes fitting. Best way to measure is to put the wheel on the car and see if it fits.

 

Ahhh...I'm in Canadian Rambler hell!

They're measuring out at 4 and 1/4...I've never heard of such a thing and every damn AMC source on the whole internet says it's 4 and 1/2. Maybe it's a Canadian thing?

 

4 1/4 sounds like a 60's Mopar A-body wheel. Someone sales a ring with the 5 lug patterns on it. Its the best way to go.

 

Canada, the land of Mercury pickups and 326 Chevys.

 

Attached charts'; measure from center of hole to center of adjacent hole or left edge to left edge.

 

use 35PU's link

you can get pretty close on the five lug by measuring from the center of one skip one and go to the far side of the second

and yeah, that should be the same as the early Mopar A body pattern

 

I place a piece of tape across the hole in the center of the rim, measure that center hole and and mark the tape in the center of the hole. Then measure from the mark you just made on the tape to the center of any of the lug nut holes. double what you read on your ruler to get the bolt pattern number.

 

Blown49's pic is great!!


The measure of a BOLT CIRCLE is exactly that ! With the bolt circle being the circle as it passes through the center of each stud. Of course the problem when trying to measure this diameter is that you don't have TWO STUDS directly across from one another. It is for this reason why you see some people measure from the CENTER of one stud to the FAR EDGE of the most diagonal stud. This of course is an approximation and will get you close enough for all practical purposs. Look at Blown49's pic and this should make sense.

Of course you could always measure from the CENTER of a STUD to the hub - double that measurement and ADD it to the hub diamter. Now you see why "short cuts' like mentioned above are useful.

Here's a picture - worth a thousand words!! For all intents and purposes the numbers are the same!

 

Damn I hate math! These numbers are right finally

 

Or....you can take the measurement from center to center (as in the illustration) and multiply it by 1.7.

Example : 2 15/16" (2.9375") X 1.7 = 4.994" (round up to 5")

That's for you folks that carry a calculator instead of a diagram.

 

On 5 lug, whoever said the far edge straight across to the center of the other hole is correct.

 

TONY;;;just for the record..your Rumbler 's bolt pattern should be 5 on 4n1/2,
small ford and dodge will also fit

 

Every Rambler I've ever had had a 4 1/2" bolt pattern, same as small Ford and Mopar. Measure from the center of one stud to the outside of an opposite stud. Center to center doesn't work and you dont' need a calculator or a diagram.

 

Actually if you measure from center to center a 4 1/2 patter will be 4 1/4. And a 4 3/4 will be 4 1/2. and so forth. As you can see from the drawing the reference of it being 4 1/2 is the fact that its looking at circumfrence and not stud to stud. And yes a 5" pattern will measure out center to center as 4 3/4. Sounds confusing but its not. If you have problems just get one of those idiot proof stud pattern tools

Satin

 

my favorite tool when i go looking for wheels, rearends & brake rotors...joe

 

60's Style and Roost have it right.

You get a close approximation using center of one stud to far side of the second stud away.

Dan

 

Bones-

This is an interesting and timely question, as I bet some other "greybeards" like myself, are wondering what's going on.

Having sold and mounted hundreds of wheels over the years (worked in three different speed shops in the late '60s - early '70s), I've just recently realized the "accepted" method of measuring "bolt patterns" has changed since "the days".

As long as I can remember, myself, every gearhead/racer I knew, and every wheel manufacturer I'm aware of, used the same, simple technique for 5-bolt wheels. You measured from the center of any hole (or wheel stud) - skipped the next closest - and went across to the center of the following hole/stud (that would be from #1 - where you're starting - to #3 - as you count clockwise). 4 1/4" was Ford/MoPar, 4 1/2" was Chevy and mid-sized GM, and 4 3/4" was full-size Buick/Olds/Pontiac.

From what I've seen at recent swap meets though (while searching for large B/O/P-pattern wheels for my '65 Pontiac rear end), the common procedure now is to measure from the CENTER of one hole (again, skipping across to "hole #3") too the OUTSIDE EDGE of the next. This essentially adds 1/4" to everything. That makes Ford/Mopar 4 1/2", Chevy and mid-sized GM 4 3/4", and full-size Buick/Olds/Pontiac 5". WTF?

Where did that idea come from - and why? The world-wide standard for ANY sort of measurement has ALWAYS been from a given point to the SAME point elsewhere - and the "old" method follows that time-proven guideline.

I think what has caused the confusion is this notion of measuring the bolt "circle". But why do that? There's no need - or reason - to complicate matters that way, as far as I can see.Once again, we've managed to take something simple and make it confusing. Now it seems no two people are on the same wavelength.

I wonder how many usable wheels I've passed over in the last year or so at swap meets, because the seller described what I wanted as Five on 5", rather than what I thought I should have been looking for - Five on 4 3/4"?

 

you pick your skirt up and buy one of these.

http://epage.com/js/mi/1680045.html

or they have thse red disks for like 1.00 i see at swap meets but these things are better..............

 

Well, I have been doing it center to outside for 30 years. Never heard it done the way you are describing?

How can something so simple be so confusing to many people?

 

or you can carry one of these business cards in your wallet that has blown49's dimensions already printed along the edge

 

Thats a cool link.

 

I'm with Tman..............OLDBEET

 

I bought one of these at a swap meet for like 3 bucks, works like a charm every time!!
http://www.made4uproducts.com/tools.htm

 

Wow who'd of thought that there would be so many different answers to this one. I always used the same method that Tman spoke of no math involved or crazy tools.

 

hell i better by a damn box next time i'm at the swap meet if the same guys shows up, since i only paid a buck for mine just like these, hell i'll even sell them to u guys for the buck & postage....joe

 

It might have been a buck, but it was like 3 years ago. Why sweat the little stuff.