Steering rack options....

Hey guys....im in the process of converting my F100 over to a strut style frontend setup. Im ready to find a rack and start playing w. mounting locations. What brand and style would ya'll recommend?
Whats the main difference from the mustang, pinto and foxbody....just the mounting?
Where can i get one at a fair price and what should i expect to pay?
Im hoping to be able to get the bumpsteer at or near zero w. the correct mounting location...any advice on this?
Thanks,
Mike

check ur messages

i got the pinto type for the easy mounting.any of them will work fine when your building it all yourself.just make sure the tie rods are straight with the lower a-arms and it'll drive good.

It's turning out to be such a simple and inexpensive swap. I think I might go w a new Unisteer mustangII.

If the Pinto/M II/Fox body type racks have/are close to having the correct main body inner pivot point measurement you need (to work with your lower control arm pivot point measurements) then the breakdown (in my opinion) is like this.........

On a 100% track only and/or light weight race car, the lighter Pinto rack is usually fine. For street-strip use and/or a heavier car, use the heavier/beefier M II or Fox body type rack. And if it's a "true" street/highway machine most of the time you might as well look at possibly using a power rack as well.

Always map-out the suspension geometry & see what is happening during the entire suspension travel when modifying anything in the front suspension. It's the only way to find out how much unwanted bump-steer might possibly be there after doing any mods.


Some possible causes of bump-steer with a front-steer rack........

If need be, company's like Flaming River will make the inner pivot point to a custom width for you. What it will cost is another story, but to me that cost would be money well spent to have a safe car on the track or street .

I needed to shorten a Flaming River rack about 4 1/2" a while back, it was fairly easy to do. Hardest part was matching the metric threads FR used on the inner pivot point knuckles when I shortened/re-threaded the passenger side of the main shaft. Then I shortened the passenger side of the rack main body by just cutting off the pass. side bushing pocket, shorten, & welded back on.

Don't remember what brand they use but Rick Jones/Quarter max and A.R.T. both sell an off the shelf 5" shorter inner pivot point Pinto rack for a few dollars more than their normal length rack.

And if price isn't an issue Chassisworks used to make/sell a billet "street machine" rack that they could make with inner pivot point lengths from about 15" to about 29" (IIRC) in 1" jumps. They still might make them, they were a bit pricey though.

Thanks for the reply's guy.
I think id better check into a custom length deal. The second depiction in Daves post is what i likely would have using the stock rack dimensions.
I didnt like the way it would looked w. the front tire's tucked so far into the fenders and opted to keep the front stance at or near factory width.
My lower control arms pivots are gonna be about 30" apart. What is the pivot of the mustangII and fox?
I was thinking it was around 24", is that correct?
Originallly i was gonna build longer lower control arms. Would that be a better option?

I am no expert...but you will want your rack pivots to be approx. the same as your lower control arm pivots....based on a 56 1/2" hub to hub centerline, the lower arm pivot points should be 22 1/4" apart and the rac I believe is some where around 23"..this is just an example!

Did some measuring today on some factory siht for the hell of it. On a factory M II crossmember the lower control arm inner pivot point centerlines are aprox 22-3/8" apart. Pinto/M II racks have the inner pivot point/knuckle centerlines aprox 24" to 24-1/4" apart (hard to judge the exact center on the knuckles). And because of Ackerman geometry the outer tie-rod hole sits aprox 1/4" to 5/16" (maybe even 3/8") farther out on M II spindles than the lower ball joint hole does.

And on a '96 Fox strut spindle because of Ackerman geometry the outer tie-rod hole sits about 9/16" to 5/8" farther out than the lower ball joint hole does.

Dave you mentioned shortening one.......what about lengthening? How tough would that be?
Thanks for all your help,
Mike

dirt_worker wrote:Dave you mentioned shortening one.......what about lengthening? How tough would that be?

I guess someone could try to find a way to safely lengthen a stock length rack. But I don't think I would want to try it myself. Splicing tubing in to make the stock length rack body longer probably wouldn't be the deal breaker. But finding a way to make the stock length solid main shaft longer (and perfectly straight & strong) could be pretty tricky.

dirt_worker wrote:Originallly i was gonna build longer lower control arms. Would that be a better option?

Of two options mentioned for a wider than stock strut track/tread width...............

#1 stock length control arms moved outward (and thus wider inner pivot points distance) + wider rack body/inner shaft (and thus wider inner pivot points distance).

#2 Stock inner pivot point distances (for both control arms & rack) + longer than stock control arm total length.

..............it could be a coin flip as to which one would truly have the best overall working geometry without first mocking both up & mapping out thier geometry during full travel.

I guess for a drag car that liked/had/needed less suspension travel ("short" struts or travel limiters on the struts) either option might work equally well. But it could be a different story as suspension travel is increased more & more.