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Discussion Starter #1
This is on a small truck I'm building. I would ask the question on the Mazda truck forum, but that forum don't really get into custom stuff. Its mostly a site for repair advise, etc.

Anyway, I ditched the factory linkage, and used a rack from a Mustang II as it was nearly the perfect size. It is a front mounted rack vs the rear mounted racks on our early Mustangs.

I got everything bolted on today. I've got the tie rod ends almost perfectly level to the lower control arms at ride height.

My question is does the tie rods have to be perfectly straight from front to rear with the lower control arms?

It would really help the steering linkage if I could move the rack towards the front of the truck about an inch or so, but that would make the rod ends angle slightly back towards the rear of the truck, at, I'm guessing about 15-20 degrees.

Thanks in advance.
 

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I'd suggest you take this question to the "Track" forum where you're more likely to encounter the folk who really understand suspension/steering tech.
 

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When you say the MII rack was almost the perfect size was that in reference to the overall width?

Without plotting a bunch of dimensions in a proper program like solidworks there is no way for us to know how and where the rack needs to be positioned. The only other way to see what you've got is to 'soft' mount the rack where you think it should be and set toe at 0. Then pull the suspension down one inch and see which way toe has moved and by how much. This will at least give you some ideas as to where the rack can be moved to.

-J
 

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Anyway, I ditched the factory linkage, and used a rack from a Mustang II as it was nearly the perfect size.
So you mean that if you drew a line through the lower control arm pivots, then offset the point at which those lines contact the rack by the vertical and horizontal planar distance between the lower ball joint and the outer tie rod end, they intersect the inner tie rod end pivots? If not you've got bumpsteer in your future.

I assume you plan on pulling your springs and measuring the bumpsteer through the range of suspension travel?

Moving the rack forward/back affects the Ackermann angles of the wheels in turns. Google it and do some research.
 

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Discussion Starter #5
So you mean that if you drew a line through the lower control arm pivots, then offset the point at which those lines contact the rack by the vertical and horizontal planar distance between the lower ball joint and the outer tie rod end, they intersect the inner tie rod end pivots? If not you've got bumpsteer in your future.

I assume you plan on pulling your springs and measuring the bumpsteer through the range of suspension travel?

Moving the rack forward/back affects the Ackermann angles of the wheels in turns. Google it and do some research.
The rack is the same length as the old link system tie rod end to tie rod end.

The rack is in alignment horizontally, at the point where the tie rod ends connects to spindle, with the front suspension at ride height with 1 deg neg camber, and 1 deg positive caster.

Speaking of Ackermann I think that was a problem with the Sunbeam Tigers, and their rack setup.

If the front to rear will make a negative effect on handling then I will just leave it aligned with the toe at 1/8th in.
 

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Discussion Starter #6
When you say the MII rack was almost the perfect size was that in reference to the overall width?

Without plotting a bunch of dimensions in a proper program like solidworks there is no way for us to know how and where the rack needs to be positioned. The only other way to see what you've got is to 'soft' mount the rack where you think it should be and set toe at 0. Then pull the suspension down one inch and see which way toe has moved and by how much. This will at least give you some ideas as to where the rack can be moved to.

-J
Thanks for the info. What is the acceptable range of movement in or out when the suspension is lowered?
 

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The rack is the same length as the old link system tie rod end to tie rod end.
The inner pivot point dimension of the rack is critical. It is best to have it match the width of the lower control arm pivot point. If they match then your idea of leveling/straightening everything will get you very close to where you need to be.

Thanks for the info. What is the acceptable range of movement in or out when the suspension is lowered?
For a deal like this I would be happy to keep it under .100" for the first inch of bump.

-J
 

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Discussion Starter #8
Thanks, I will do that tomorrow. If there was a rack made for these little trucks {87-92 Mazda B series} I would have gladly bought one.

However, no one make's any such kit so this is why I went on to fab one myself, since I already had the Mustang rack.

Also the neck of the rack that bolts to the steering shaft is in the best location that it can be since its slightly angled towards the frame.
 
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