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Bump-steer or shocks?

If you have negative camber gain as you compress the suspension from ride height, wouldn't this show as toe in if you have a plate sitting on the floor? This is something I need to address on my 66. I'm thinking bumpsteer should be measured between the spindle and a control arm. I would think with zero bump steer, the spindle would not rotate in relation to the control arms but would show up as toe in when measured against something stationary on the floor. What you would see IMO, is camber gain.
 
This might be oversimplifying - but I'll be the Taurus is front wheel drive and the truck is much heavier (and probably not going as fast around the turn). With rear wheel drive (and specifically a live axel), when the front comes up and your steering is reduced, because you ran over train tracks, the rear is still driving the car in the original direction from when you lost steering. I'll bet if you are cornering right, as soon as you hit the tracks, it seems like you are going to fly off the left side of the road.
Both my 65 FB and Dodge Ram do the same thing. The higher the speed, the worse it gets...while my wife's AWD explorer never has that problem.


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Never thought of it that way. But yes you are right. The pickup is about 4,500 lbs. empty.
The Taurus is FWD. the truck is 2wd and fairly low.
But regardless, what can I do to improve the Mustang?


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Something interesting I noticed on my 66. The outer tie rod runs runs out of travel and binds before the suspension runs runs out of travel. I have a bump steer issue too. I was talking with someone who also has the same SoT suspension except he has coilover and R&P. He has no issues. What we noticed is his car has a lot less travel. I suspect the excessive amount of travel is the issue we have.
 
huskinhano said:
Something interesting I noticed on my 66. The outer tie rod runs runs out of travel and binds before the suspension runs runs out of travel. I have a bump steer issue too. I was talking with someone who also has the same SoT suspension except he has coilover and R&P. He has no issues. What we noticed is his car has a lot less travel. I suspect the excessive amount of travel is the issue we have.
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I will have to too look into that, I do not think I have that issue. I was recently changing the steering gearbox and playing with the suspension while it was on the stands (turning radius) and I didn't notice any binding but I wasn't checking with suspension under load
 
I really noticed it when I installed my Baer bump steer kit. When it was fully extended, I couldn't slip the rod end on the stud. I had to jack the control arm up a bit so it would slip on. Slowly releasing the jack, I could see the rod end start to bind at which point I stopped. This was with 72 spindles if anything had less of an angle problem as far as binding. I went back to look at this photo I took just before I removed the stock 66 spindles. Look at the angle of the outer tie rod. I'll bet it's at it's limit and the whole tie rod assembly has stopped following the lower control arm at which point it forces toe in. I measured 3" of toe in. I'm going to remove the spring and look at the actual travel. I'm making a bump steer gauge also. First I want to finish up the brake lines,disk brake swap. I'm going to limit travel, I'm going to install spacer under the shocks on on top.



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I'm not expert but I have read that the geometry of the 67 and up spindles is different than 1st gen Stangs. I don't know if that might be what is coming into play on your car. I have Granada spindles on my 67 but the geometry is supposed to be the same as the 67
 
That's with the 66 spindles, not the 72. According to Dennis from CSRP, the 67-73 and Granada have a 1/2" less offset than 65-66. I did a little calculation the later spindle with 3.5* caster put the tie rod in exactly the same spot as the 65-66 with stock 0* caster.What I'm thinking as the tie rod assembly approaches the limit of travel either the tie rod binds the tie rod assembly stops traveling and forces the tires to toe in or the leverage at the limit of travel cause the toe in. I work out of state during the week but when I'm home this weekend, I'm going to check the old tie rods to see if there is any sign they did run out of travel.

If anything the bump steer kit will take care of the difference. I do have the 72 spindles in as well as the bumpsteer kit. From quick visual from bouncing the car as well as jacking it up, there's a significant reduction of toe in. Toe changes, again from a quicky check appears to be no more than 1/2" vs the 3" before. I do have to limit the travel, it's too far. Onnce I get my brake lines done, I'm going to get more into this.
 
I also have the bump steer kit in. My observation is just a quick, unofficial opinion. Do a search on VMF for "Applejack" he posted some bump steer charts he did on his 66. With later spindles and Promotorsport bump steer kit, he had the best results, almost none. When you add caster, not only is the top ball joint moving closer to the firewall from tilting back but every thing moves, the tie rod arm moves closer to the pavement as well. Think of the whole spindle rotating to get a perspective. As I see it adding caster could help on the later spindle. Like I said, 3.5* caster with the later spindle seems to be it.

I'm new to all this, what ever trouble I get myself into, I have to get my self out of.

Do you have stock control arms? My car was down right scary to drive on the highway before I started I literally could not drive next to some one, it was that bad. When I removed my stock lower arms which were Ford service replacement and not chinese, they were totally shot. The bushings were really thrashed. How are your lower control arm bushings? They take a beating from following the arc of the strut...especially if you add caster. I can do it on my car, I have Street or Track parts. I have absolutly no rubber bushings, all bearings. I'd do it in a heart beat if I did another Mustang!
 
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