Rear end for Model A with transverse spring.

I have a 1999 Explorer axle. From my builds previous parts selection. But I think it’s too narrow with a T spring under it. And the offset pinion is another hangup. It’s 3.73 with traction lock but it’s just not right I don’t think. I have 32” Jegster ladder bars that I’m going to run like radius rods triangulated to the center, so they have to pass under the spring as well.

What are some modern rears that might fit the bill? I’m only running 100-150hp ( may or may not turbocharge engine with a few psi ). Bolt pattern doesn’t bother me, but I’d like 5 lug. Not going to dismiss a 6 lug that works tho. I’m going to want tall sidewall narrow tires, I’ll end up running junkyard steel wheels painted up.

Edit: by modern rear, I mean something that can be found in a 10 year or older u pull it

I encourage you to measure that Explorer rear axle and the width you will need on your build. That era of Explorers that we have had all had wheels with six or seven inch offset so the axle is wider than you might think.
Good luck.

59.62” according to the internet. With 48” perch centers, the perches would mount 5.81” inboard from the wheel mounting surface.The pumpkin is also 2” offset, and the axles are stepped near the center

Also get the dimension of a Model A rear spring perch width. The spring has to be spread quite a bit. Then you'll know if your Exploder rear axle is wide enough.

Most are spread to 49” for an A spring or 48” for a T spring which is what I’ve been calculating. Whichever spring I get will come with an install spec. Narrow mount springs exist in the aftermarket, which can bring the spec to as little as 44”. I don’t know if the 2” offset is going to hinder the ability to triangulate the radius rods, because the diff is 2” off center

The Explorer wheels are set towards the axle centerline by 2- 3 inches on each wheel. If you run the regular older Ford car wheels with the mounting surface closer to the center of the rim, you gain a lot of extra axle tube before any spring mounting is going to be too close the wheels. Even with using the Explorer wheels, your spring mount is only an inch wider then the Explorer spring perches, I doubt that extra 1/2 inch per side is going to be a problem. There still should be plenty of space to mount your ladder bars outside of the spring perches. Bolt the wheels on the axle and make measurements. Depending on how the ladder bars attach to the axle, they my mount on the bottom side of the axle tube but the spring perches will mount on the top of the axle tube, both may be mounted at the same place on the axle tube without issues. If for some reason you intend on using the Explorer spring perches, rather then remove them, the narrow 44" perches should work and solve all your clearance issues.

As far as triangulating the upper radius rods are concerned, I would simply move the frame attaching points that same 2" offset as the diff. The concept of the triangulation is to keep the rear axle centered in the car. As long as both ends of the upper arms are centered from the same offset, the arm lengths are the same, and the angle of each arm to the axle centerline is the same, the axle should remain at a 90 degree angle from the frame. The slight movement of a couple inches either direction from dead center of the chassis and the rear axle is not going to make any noticeable a difference on the street with 150 HP. A drag strip with 700 HP may be different (but I doubt it), but that is not what is going on here.

That makes sense now. The ladder bars use brackets that have adjustment up and down and they mount below the axle. I guess I could run a spacer if I wanted a wider wheel as well. It’s got 16” Carevan wheels on it now and they actually work . I’m still not actually crazy about the disc brake rear. But this is more of what I have available. I don’t have any of the brake stuff because I got it from a not you pull it yard. The original plan for this rod when I was in my early 20snwas to run a 460 Ford, with a a T-18. A little crazy but that’s why I got the explorer 8.8” specifically with 3.73s and limited slip. The ladder bars and the rear axle survive from that rendition/ frame. I have the 200# rate coil overs as well but I’m going transverse spring in the rear.

If you bolt both wheels (with tires mounted on them) onto the rear axle, you will know exactly how your measurements are going to work out. The wheels themselves won't move once bolted in place, so 3/4" clearance of the wheel above and below the axle works out fine.

The backside of tire sidewall could bulge another 1 1/2" towards center from the edge of the wheels (depending on the width of the tires and wheels) but that will be another couple inches above, below, and to the sides of the wheel. You will want to be sure the ladder bars will clear the inside of the rear tires.

This is the kind of stuff that messes up first time builders, the stuff you just don't usually think about.

Not sure what happened. I tried to clear where I quoted myself. I’m thinking a 215/85r16 on the rear. With Carevan wheels as they fit and work. The only caveat is they are LRE tires. Tall and narrow dually tires.

I’m still trying to sort the title, which prevents me from really working on the frame.

Could I run the ladder bars parallel to the frame like on a T bucket with model A spring?

Matt167 said:

Not sure what happened. I tried to clear where I quoted myself. I’m thinking a 215/85r16 on the rear. With Carevan wheels as they fit and work. The only caveat is they are LRE tires. Tall and narrow dually tires.

I’m still trying to sort the title, which prevents me from really working on the frame.

Could I run the ladder bars parallel to the frame like on a T bucket with model A spring?

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I have a 2WD S10 rear end for my 28 Model A roadster pickup. It allows you to run 8" wheels fully under the fenders. With that I need a narrower spring than the factory A/T spring.

The ladder bars should be triangulated somewhat to allow the axle to pivot without stressing the frame. You should also run a panhard bar.

I was thinking about panhard bars. I’m thinking I might grab an S10 4x4 rear. The axles are not stepped in diameter so it makes it straight forward.

S10 4wd axle will be 2” wider than the 2wd version.

I know. Easier to find in NY and I’m running fenderless so It’ll be nice to have some wiggle room.

Matt167 said:

I know. Easier to find in NY and I’m running fenderless so It’ll be nice to have some wiggle room.

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Yeah, it will give you more options on wheel offset. I didn’t know if you were aware it was wider than the 2wd axle.

The other thing you can consider is the use of wheel spacers if necessary.

Ive considered spacers in case I need more width. I’m thinking I want a taller tire.

Would running an LT range E tire on the rear work okay? Considering a dually size is why, with an 80 aspect ratio

Matt167 said:

Ive considered spacers in case I need more width. I’m thinking I want a taller tire.

Would running an LT range E tire on the rear work okay? Considering a dually size is why, with an 80 aspect ratio

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The stiffer the sidewall (higher load range), the rougher your light vehicle is going to ride. You'll be better off with a passenger tire for ride quality.