“Typical” pre-runner frame to ground clearance?

[fb503]

Hello all, new member here.... I tried searching but I could not find the result I was looking for.

I am embarking on a bit of an odd project... I am building an prerunner but I am starting with an unconventional vehicle. I am looking for some general information on prerunners that I can’t seem to find. I found some information on Brenthel Industries that suggest travel would be ballpark of 22 inches front and back depending on the design. What I need to know is what the typical ride height or frame-to-ground clearance that prerunners typically run are. Once I get this information, I can put my frame on stands and level it so I can take some more measurements.

I greatly appreciate any information or guidance.

-thanks

 

[Ol' Curmudgeon]

You have to have enough ground clearance so that when your suspension is in full compression, you don't do a number on your spine by slamming no-longer-sprung-weight into the crown of the road.

Is this a live axle or IRS vehicle? If the former, taller tires are in order to help pumpkin not be a plow.

 

[fb503]

thank you for the response,

The vehicle is a live axle. I was focusing on ground clearance first, but it sounds like I need to figure out the safe max travel and pick a ride height where I'm not bottoming out; also considering the appropriate amount of uptravel vs droop.

 

[Bert is my name]

Overall tire size will dictate ground clearance. But drivetrain strength, gearing, and engine power will dictate tire sizing. 4 to 6 inches at full bump seems to be the number that a lot of people shoot for.

 

[Bert is my name]

And as far as odd vehicles go what exactly is odd. If you go back to the beginning of off road racing those guys beat the hell out of anything with an engine and wheels.

 

[fb503]

Hey guys... sorry... life got me distracted for awhile. The vehicle is a Crown Victoria. I was apprehensive to disclose that because I know with forums, new people tend to hop on and talk about their crazy projects and most of the time nothing ever comes of it. Some people are going to think I’m crazy or full of poop, but I guess that’s how it goes.

I “raced” it in the Gambler 500 and after spending more money than I should have on the car, it’s kind of turned into my crazy project. People hack these cars up to beat on, but I decided I wanted to do something different. I am in Oregon which is nowhere near the desert racing scene. The best I have are the dunes about 2 hours away.

I drew a heavy inspiration from Jon Baker and his trophy LTD. I do not plan on copying his build by any means whatsoever, but I like the idea of a pre-runner styled car that I can drive up in the mountains when I go shooting, or compete in local rally cross.. If the vehicle were to be built to a class, I would guess it would be a 1400 series?
The car has a dodgy lift on it now with 32s and I want to redo the suspension and fit some 35s that I have. From my research it seems I want to have a 90 inch track width but I see mixed information on if that’s tire CL to CL or Outside to Outside. Trunk, Hood, and Front Fenders will be fiberglass, and a tube cage will be built on the front. Thinking custom tubular a-arms up front with boxed re-enforcement, and either a triangulated 4 link or a 3 link in the back.

I will create a build thread if there is any interest. So far its a lot of planning because its winter, and I have no garage to work in.

2004 Ford Crown Vic
3 inch donk lift
3 inch body off frame lift
LED lighting

If there is any advice shy of selling or burning the car, I'd be glad to hear it. I am new to off-road racing, but not new to wrenching and metal fab.

 

[Bert is my name]

90 inch track width is huge. Check the local laws for max vehicle width if you plan on street driving this thing. Too wide will require permits to drive on public roads. I believe 88 inches is the max here in .ca. that is over all width. Outside to outside.

 

[isdtbower]

^^^ ??? I am pretty sure that anything below 96" (outside-to-outside) wide is CA/Fed street legal most everywhere. Trucks and trailers to 102", except some cities, etc. Lots of offroad race "cars/trucks" are over 90" O-t-O.

I see track width having more to do with designing the suspension "geometry." If I was designing a new rig. I would decide on outside of tire and then back-into the track width. Carry on.

 

[fb503]

^^^ ??? I am pretty sure that anything below 96" (outside-to-outside) wide is CA/Fed street legal most everywhere. Trucks and trailers to 102", except some cities, etc. Lots of offroad race "cars/trucks" are over 90" O-t-O.

I see track width having more to do with designing the suspension "geometry." If I was designing a new rig. I would decide on outside of tire and then back-into the track width. Carry on.

I looked up Oregon, and they list 8 foot and 6 inches. The stock mounting locations for the control arms are on the Frame Rail on the Crown Vic. My original idea was to use the stock mounting locations on the front with either Camburg Ranger arms or custom arms. To get the travel I want though, I might have to integrate a bulkhead into the front crossmember or switch to a TTB setup, but the first one would raise the car a whole lot, and the second one might as well start with a new frame. Your idea about working from the outside in seems like the best approach, but I do have to work about the stock frame. The hardest part for me on any project is figuring out where to begin

 

[43mod]

so what vehicle are you building ? Galaxy,Crown Vic or pick up ?

 

[fb503]

so what vehicle are you building ? Galaxy,Crown Vic or pick up ?

Crown Vic. I just added the other photos to show what the front suspension looks like. The Galaxie is my fathers car.

 

[Bert is my name]

My mistake. 96 inches or 8 feet. I read the wrong side of the tape measure.

 

[Ol' Curmudgeon]

A good time to see some video?


Crown Vic Handles Red Rocks of Moab - Video

At speed, I fear stuffing it might be an issue. What can be done to improve approach angle?

 

[Bert is my name]

Lots of cutting and the biggest tires you can fit. That rear overhang will help with traction and weight balance. Rock rails and plates will be your friend in the rear. Umhw or a roller for the rear.

 

[Bert is my name]

I've seen that video before. It proves that talent and throttle control along with a small amount of d.g.a.f. Will take you far.

 

[Bert is my name]

Approach angle doesn't appear to be a concern of the guy in that video.

 

[Bert is my name]

I had a 2000 Chevy Malibu that I drove to the bypass at the lower willows in coyote canyon. Should have seen the looks I got from the j.k. crowd.

 

[Ol' Curmudgeon]

Approach angle doesn't appear to be a concern of the guy in that video.

Yes, but suspension isn't at full droop hitting a berm or whoop.

 

[Bert is my name]

I've always wanted to put a cst or fabtech upper and lower kit on a Monte or a regal. After owning an s-10 I found out the front suspension is basically g.m. g-body stuff. I'm completely on board with the "long travel " crown vic.

 

[fb503]

So I plan on running it out to 90 inches wide, and trying to get the most I can get out of the front arms. I should have roughly a foot on each side that I can make the arms longer if I keep the mounts in the stock location. I am shooting for 20 front and atleast 20 rear on travel, but I may be optimistic. I already plan on making fiberglass fenders so I’m not worried about wheel arches. I’m going to make fiberglass overfenders in the back. My biggest obstacle on the rear is the control arms. They mount on the hip of the rear frame the lower arm is 18.5 Stock, and the upper is 10.5”. I’m guessing the arms are going to need to be around 48” long to get the travel I want in the rear. I am also looking into a cantilever type suspension. Worst case scenario I notch the frame rails or wait until I get a wider axle and move the arm mounts outboard of the frame.

I am not too worried about approach angle as the headlights sit relatively high on the car. See pic