No Love for the SLA Ranger Frame?

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tjm73
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No Love for the SLA Ranger Frame?

Post by tjm73 »

I have been poking around the site learning what I can, reading about a bunch of things. One of the things I was looking to learn about was frame swaps. To my surprise I don't see anyone using the SLA Ranger chassis. The longbox Ranger has a wheelbase of 117.5" and the supercab has a 125.7" wheelbase. Both have a front track width of 58.6" and a rear track of 57.3". And we probably all know the Ranger is 5x4.5" bolt pattern. Opening the door to many wheel options.

On face value they are not a great match to the '61-'66 F100, but looking closer I think they are a near perfect base for a frame swap.

First, look at the wheelbase. The '61-'64 trucks were 114" and the '65-'66 wheelbase is 115". For either vintage you can shorten the longbox or supercab frame to match, or to add a little wheelbase to relocate the wheel center lines in the wheel arches.

Next, let's look at the trackwidth. I'm not real keen on trackwidth measurements without OE wheel information. Here's a great example of why. The front track width in the SLA Rangers is spec'd at 58.6", but the OE wheels had an offset of +12mm. That's 0.472" on both sides. Adding that to the track width gives us the rotor to rotor width of 59.55". Which is very close to the stock Slick width.

Third, did I mention yet how easy it is to swap an Explorer rear axle into this frame? The Explorer 8.8 rear axle is perfect. It's width is 59.44" rotor to rotor. It's also 5x4.5" and it has 1.31" diameter 31 spline axles in big 3" tubes with the large truck bearings. They have integrated parking brakes too. Almost all of them came with traction-lok and either 3.73 or 4.10 gears. Some had 3.55's and some may have had open diffs, but most didn't. What's not to love?

Other benefits include rack and pinion steering, sway bars, large disc brakes that will work with 15" wheels and frames that are designed to handle and ride with modern day comfort. The Ranger frame is 32.8" out to out in width. The Slick is 34" in to in. So the Ranger frame is a little narrower, but not enough to matter.

I think taking a supercab frame and sectioning it down to an appropriate wheelbase seems like a lot of win and very little lose. And to be honest, I'm a little surprised nobody is using it. Plus it'd be cool to keep it all Ford.
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Toyz
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Re: No Love for the SLA Ranger Frame?

Post by Toyz »

Ok, step by step here. You posted on another forum that the Ranger had negative offset, which I found a bit unusual; and used that to suggest a wider track. Now you are stating positive offset, which is correct for the later Rangers, BUT has the effect of NARROWING track width. So now, you are around 57.5" track width, given oem spec wheels, considerably narrower than the original slicks. Since your frame width is also narrower, if you are going with an in-line engine, all might be well, except for that extremely tucked front suspension! That narrow frame width plays hell, however with both mounting a slick cab, and having enough real estate if your engine choice is a V-8, and believe me, those small differences DO matter.
The Exploder rear IS a good choice, although my personal preference is to fill the fender wells; now I am loading my bearings and suspension by moving the track width out where I want it. If I don't particularly WANT IRS, I can simply swap in a '73-up rear and gain width without disturbing bearing load.
Keep it all Ford? Easy to do with an Aerostar suspension clip, or if you want to stretch a point, the Jaguar. Even the maligned Crown Vic, since kits are now available to get rid of some of the width which seems to be a complaint of those insisting on incorrect wheels! Or, hey, make it easy; just go with Steve's purpose-built setup from Industrial Chassis!
The old disclaimer applies, these are MY opinions based on close examination. The items I mentioned may well be why one doesn't see a Ranger base under every second modified slick, however. :2cents:
Paul
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tjm73
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Re: No Love for the SLA Ranger Frame?

Post by tjm73 »

I did mention that the Ranger wheel was -12mm in another thread. But that was a typo and I changed it when I saw my mistake. If you are familiar with offset you know that positive offset moves the mounting surface out toward the outside of the vehicle and negative offset moves it in toward the frame side.

Trackwidth without offset is not terribly useful for determining rotor to rotor width on potential donor vehicles. But when you know the factory offset, trackwidth is very useful. A Google search will show that 15x7 Ranger wheels have +12mm offset (you can verify if you wish). The trackwidth measurement to is the center of the wheel/tire. But the wheel has an additional positive 12mm distance from the center of the wheel/tire to the inner face of the wheel mounting pad. That makes the true wheel mounting surface wider from the spec'd trackwidth by that amount on both ends. So the offset tells us that the rotor to rotor width is 0.945" wider than the spec trackwidth of 58.6" on the front. Making the distance from rotor to rotor roughly 59.55".

No math required on determining the width of the 8.8 Explorer axle. It's well documented at just about 59.5".

I will hang my hat on my math, but I will also say always confirm the math with measurements before committing resources to a project.

As for cab/bed mounts and having a V8.... If you can install a clip, you can fab new cab mounts. And the Ranger chassis is not so narrow that a V8 is hard to fit. Some V8's maybe harder to fit than others, but they fit. The 2WD Explorer chassis is nearly the same as he Ranger chassis particularly on the front end of the frame and they cam from Ford with 302's. So the 302/351 will bolt in.

This just seems like an obvious choice for a frame swap to me. At the least it seems like a better choice than a CV IFS swap. Just struck me as odd that I don't see anyone doing it. And I suspect it may be because nobody has realized how close the measurements are yet. But hey, what do I know?

I would probably never do the frame swap. Between cost, time, labor and fabrication I could achieve my goals with the OE suspension for a lot less. You can drop a '61-'64 up to 6" on a straight axle with a dropped axle and lowering leaf springs. But in thinking about what I'd like to do with a Slick, it became evident that the Ranger frame is likely a very viable swap.
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Toyz
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Re: No Love for the SLA Ranger Frame?

Post by Toyz »

Once again, you are contradicting yourself!
Might want to verify your info. You correctly state that positive offset does move the mounting surface outboard, IN RELATION TO WHEEL CENTERLINE, which is now moved inboard, thus narrowing the track! I believe you will find that positive offset positions the tire further inboard, as in fwd and late model applications with "high positive offset"! A simple tape measure will suffice to note that the Ranger is considerably narrower.
Paul
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tjm73
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Re: No Love for the SLA Ranger Frame?

Post by tjm73 »

Toyz wrote:Once again, you are contradicting yourself!
Might want to verify your info. You correctly state that positive offset does move the mounting surface outboard, IN RELATION TO WHEEL CENTERLINE, which is now moved inboard, thus narrowing the track! I believe you will find that positive offset positions the tire further inboard, as in fwd and late model applications with "high positive offset"! A simple tape measure will suffice to note that the Ranger is considerably narrower.
Paul


I may be new to this board, but I'm not new to the world of cars/trucks. I don't know you from a hole in the ground. I've no desire to start a pissing match, but I'll also not turn away from what seems like an attack.

How exactly am I contradicting myself? You've said that twice, but you don't elaborate on how. Please enlighten me.

You seem to not under stand that offset and trackwidth are two different measurements. You also seem to fundamentally fail to comprehend the written English language.

If you take an assembly that is measured 58.6" wide and put offset wheels on it it will indeed narrow the trackwidth measure down from the 58.6". That is not what is happening in what I explained.

You are the one that needs to check our info. Please see the graphic I've attached to show why your logic is wrong. If you still can't see why you are wrong, I can't help you.

Image
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Toyz
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Re: No Love for the SLA Ranger Frame?

Post by Toyz »

When you have fifty plus years as a certified master mechanic, then come back and tell me I'm wrong! It appears you have read something but have little undertanding. Look at your own "graphic"! You have contradicted yourself again. Track width ( center of wheel to center of wheel) is as shown, 58.6. The line you are representing as a wider track is obviously NOT the center of the wheels. You stated correctly that positive offset moves the mounting surface outward, you are failing to understand that this is in relation to wheel centerline! So, positive offset, large backspace, narrower track. May be a description will help you. When a late model Crown Vic, high POSITIVE offset by design, is fitted with correct wheels, VOILA,!that "way too wide" concept is minimized. If fitted with "old school" wheels ( zero offset), wow , it's too wide! "Reverse" wheels, ( negative offset), worse yet! The info is all over the internet, try to understand the concept. Better yet, get a tape measure, find a "pick and pull" yard, and measure for yourself!
BTW, welcome to Slick 60's, contrary to the FB forums, you will find correct info here from people who have " been there, done that"!
Paul
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tjm73
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Re: No Love for the SLA Ranger Frame?

Post by tjm73 »

I am talking about basic elementary mathematics. And the concept can't get any simpler. I am not trying to calculate a trackwidth. I am talking how far is it from where one wheel bolts on to where the other bolts on.

+12mm is right there in the drawing and shows clear as day that the +12mm is from the centerline of the wheel/tire out away from the frame. It also shows that that +12mm is on both ends of the "axle". It shows the Ford specified trackwidth of the SLA Ranger front end from center to center of the wheels. And it shows that the in order to maintain those known dimensions, the rotor to rotor distance HAS to be 59.54" (+/- a tiny fraction). It cannot be any clearer than I showed in the CAD diagram I provided.

A + B + B = C

A = Ford's own published spec trackwidth
B = offset, which is +12mm in this case. Two wheels so include it twice.
C = The rotor to rotor distance

If you know any 2 of those 3 you can calculate the third.

I am talking about the factory items to establish a baseline width as measured from the left rotor to right rotor where the wheels bolt on when the Ranger is loaded at it's empty standard weight.

If I find out I am wrong I am the first person to admit my mistake. I own what I say. Right, wrong or offensive. It's mine.

I don't care if you have 50 years or 50 seconds of experience. You are wrong on this.

Thanks for the welcome. As you may be able to tell I enjoy a spirited discussion.
longcabjohn
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Re: No Love for the SLA Ranger Frame?

Post by longcabjohn »

Let's play nice. We don't need for this to expand to name calling and people leaving.



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Toyz
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Re: No Love for the SLA Ranger Frame?

Post by Toyz »

Your "graphic" show track width at 58.6.using a 12 mm positive offset. That IS the factory dimension with "offset" wheels. Any attempt to change that by use of zero or negative offset wheels is contrary to accepted practices. That 12 mm. POSITIVE OFFSET is Part of original suspension design. It's not simple math to understand why NEGATIVE offset is not advised on suspension designed for Positive offset, which includes most vehicles. Suggest you read up on such things as KPI before making assumptions. Positive offset moves the wheel inward BY DESIGN, so successfully that it has become the norm!
Thus, a properly setup A-arm suspended Ranger is too narrow for a slick, which might just help explain why it is not a popular conversion, despite your surprise. The "too wide" Crown Vic thinking is the result of the exact same fuzzy thinking. IF you install a zero offset wheel on a CV, it is going to be 3" too wide, while, with correct wheels , that is hardly the case.
I certainly like "thinking beyond the box", and, as they say, "to each his own". Build your Ranger conversion and let us know how you like it! As for me, if I am going to go to that much trouble and expense, I am going to IMPROVE the suspension, not needlessly compromise it!

Paul
The Ford Orphanage
Life's too short for boring vehicles!
My quest to develop a universal solvent is held up by the lack of a storage container.
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tjm73
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Re: No Love for the SLA Ranger Frame?

Post by tjm73 »

I never said a word about using negative offset wheels. In fact I never said a word about using any particular wheel. Only that the rotor to rotor width was very close.

As for using wheels other than OE, every change results in a give and take. If I swapped a Ranger frame I would run a 7" wheel with 0mm offset which would have no effect worth worrying about on handling or suspension operation or on bearing life.

Besides, I'm not sure I buy some of what I've read about offset changes and bearing wear. Seems anecdotal. And minor changes should not effect a quality bearing.
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