Vintage Mustang Forums banner
1 - 12 of 12 Posts

·
Registered
Joined
·
57 Posts
Discussion Starter · #1 ·
Hi - i asked this a while back, but looking for more detailed feedback
i am using 70 mustang drum splindles on my 65 fastback. getting ready for first track day. i have hoosier TDR bias racing tires. 68 mustang manual steering box. baer tracker bump steer kit (70 tie rod ends to match the spindles)

I find when driving down the street, the car is all over the road - when there are bumps or uneven pavement, it is really horrible. perhaps at least some of this is from the bias tires?
when I drive on a big empty flat industrial park parking lot, the car steers much better. the effort is very high, especially when trying to turn while parking. But even on the large flat industrial lot, the effort is still high when turning. the steering just feels awful.
i have a manual steering rack and pinion Pantera, and it is much nicer to steer. so is my 69 mustang with stock power steering, and my 08 corvette on the track.
i adjusted bump steer using a laser - it was bad at first. With the Baer tracker kit, and ALL the spacers inserted, it is better, but still a good bit of movement as the suspension arms move up and down.
the alignment seems is set right - max caster (something like 3-4 degrees if i remember correctly), and toe in is set at between 1/16".

Is anyone else racing on 70 spindles? i wonder if the "knuckle" for the tie rod end is just really far off from where it is supposed to be. i'll see how it goes on track, but it is really poor the way it is now.

i dont want to install a rack and pinion. stock power steering has too much free play for my liking. I am thinking about installig electric steering assist under the dash, but i am just not sure the whole geometry is right. it really feels awful
 

·
Registered
69 Mustang R code Mach1, 428
Joined
·
15 Posts
Hi - i asked this a while back, but looking for more detailed feedback
i am using 70 mustang drum splindles on my 65 fastback. getting ready for first track day. i have hoosier TDR bias racing tires. 68 mustang manual steering box. baer tracker bump steer kit (70 tie rod ends to match the spindles)

I find when driving down the street, the car is all over the road - when there are bumps or uneven pavement, it is really horrible. perhaps at least some of this is from the bias tires?
when I drive on a big empty flat industrial park parking lot, the car steers much better. the effort is very high, especially when trying to turn while parking. But even on the large flat industrial lot, the effort is still high when turning. the steering just feels awful.
i have a manual steering rack and pinion Pantera, and it is much nicer to steer. so is my 69 mustang with stock power steering, and my 08 corvette on the track.
i adjusted bump steer using a laser - it was bad at first. With the Baer tracker kit, and ALL the spacers inserted, it is better, but still a good bit of movement as the suspension arms move up and down.
the alignment seems is set right - max caster (something like 3-4 degrees if i remember correctly), and toe in is set at between 1/16".

Is anyone else racing on 70 spindles? i wonder if the "knuckle" for the tie rod end is just really far off from where it is supposed to be. i'll see how it goes on track, but it is really poor the way it is now.

i dont want to install a rack and pinion. stock power steering has too much free play for my liking. I am thinking about installig electric steering assist under the dash, but i am just not sure the whole geometry is right. it really feels awful
I used to race back in the day, and id say the culprit is the biosed ply tires, i made the mistake of mismatching sizes and when I got on it, it about tore my arm off and put the car in a spin. And dont mix and match, like radials on front and biosed ply on back. They will give you terrible stearing.
 

·
Registered
Joined
·
1,655 Posts
Depends on your definition of poor but I have a 65 with 1970 spindles too and I don't find the steering poor. It is heavy during slow driving and parking but is fine once you're on the move. That is with Shelby quick steering pitman arms with a roller bearing in the idler. Don't forget to lubricate the steering box properly. I found this to make a huge difference. Check here for advice: Steering Box Lubrication (stangerssite.com)

My steering is "lively" on a bumpy road but when I checked my bump steer but I didn't seem to have much. It could probably use some fine tuning though and I actually have a bump steer kit but never installed it. I'm surprised you needed so many shims/spacers. Are you sure you measured it correctly? When I measured mine, I lowered and raised the car with the springs removed and measured toe.

Again, it all depends what you compare it with. I feel mine drives like a proper 60's Mustang with manual steering but my 2006 BMW E46 steers a lot better. I'm sure your Corvette and Pantera will too! But your 1969 Mustang should be a better comparison, apart from the obvious difference in steering effort.
 

·
Registered
Joined
·
664 Posts
I will be following this. I can tell you that I have a similar set up with 65 spindles and Hoosier bias ply tires. Handling on the street is not great. The roads are rough where I live and test and tune sessions the car darts around with the ruts and patches and potholes, I think that is mainly the nature of the tires. On track handling is fine. Looking to upgrade to the beefier spindles in the future. Good luck
 

·
Registered
Joined
·
57 Posts
Discussion Starter · #5 ·
I dont want to take this post off-track, but checking bump steer is tricky. if you simply look at where the tire is pointing as it goes up and down, you can be fooled because the tires move in and out as they go up and down. you have to measure the change in toe, which i suppose would be possible if moving both wheels up and down together. i put a laser on the disc brake rotor, pointing sideways toward the wall, while i moved the suspension up and down without a spring in place. i then created a line on the wall of change in toe. Having negative caster will tilt this line as well. also, looking at the suspension geometry from underneath, the tie rods need to move about the same center of rotation as the suspension arms - with stock steering linkage, and especially with 70 spindles, the attachment of the tie rod end needs to be much lower than stock to get close.
 

·
Registered
Joined
·
1,655 Posts
Yes you're right. Was about to write something like that but didn't know how to summarize it in a few words, so I waited to hear how you had done it. It looks like you took everything into consideration. I did measure the change in toe (front and back of the wheels), rather than just the front of the wheels, if I remember correctly. At least I should have :)
 

·
Registered
Joined
·
8,420 Posts
Roads are crowned and those bias tires will follow every imperfection. That’s one reason why they are for track use only. Try putting a set of std size radials on it before messing with the steering/suspension.

If it’s smooth on track that’s what you want.


Mark
 

·
Registered
Joined
·
57 Posts
Discussion Starter · #8 ·
I would love to try some regular tires on it, but i would have to buy an extra set of wheels or tires - so it would be an expensive experiment
we will see how it does on track in a few weeks, hopefully
 

·
Registered
Joined
·
57 Posts
Discussion Starter · #9 ·
circling back to the original question, has anyone run 70 spindles on a 65? it sounds like no one so far has actually done it? I found older internet postings about doing this, but cant seem to find any first hand experience. i just wonder if the knuckle for the tie rod end is incorrectly located for a 65, adversely affecting steering geometry. a manual steering box is supposed to have more than 4 turns of the wheel lock-to-lock, but i only get 3.5. I also wonder how a 65 idler arm works with a 68 pitman arm. the 68 pitman arm looks to have same geometry as 65 arm - the difference is the hole for the steering box is larger on 68 and up arms.
 

·
Premium Member
68 Mustang Coupe
Joined
·
4,586 Posts
Copied this from @CHOCK website.
68-73 Spindles can be installed on all Mustangs from 64-73. Ball Joints will boltn up fine, even on the 6 cylinder cars!!!

Tie Rods are Different, as stated,and will need the Year of the Spindle to fit the Application
 

·
Registered
Joined
·
1,264 Posts
circling back to the original question, has anyone run 70 spindles on a 65? it sounds like no one so far has actually done it? I found older internet postings about doing this, but cant seem to find any first hand experience. i just wonder if the knuckle for the tie rod end is incorrectly located for a 65, adversely affecting steering geometry. a manual steering box is supposed to have more than 4 turns of the wheel lock-to-lock, but i only get 3.5. I also wonder how a 65 idler arm works with a 68 pitman arm. the 68 pitman arm looks to have same geometry as 65 arm - the difference is the hole for the steering box is larger on 68 and up arms.
Sure, there are many/most in Vintage racing using the big bearing spindles from the '70, including me. Mine is actually very stable and has no issues with transitions or bouncing curbs, it stays stable. I'm running a rack and pinion, and with modified tie rod ends that correct the geometry; perhaps the correct tie rods will help.

Total Control has bump steer tie rods that may be what you need; the big bearing spindle does move the location as you suspect.
TCP.pdf (totalcontrolproducts.com)
 

·
Registered
Joined
·
21,492 Posts
I don't race but I have 72 Mustang discs on my 66. I'm a novice but I've done all my own set ups. My suspension is a non coil over Street or Track along with a camber kit. Reading for alignment specs, it's almost exactly like mine. I run 4° positive caster, 1.125° negative camber and 1/16" toe in. It drives wonderful. Zero trace of bumpsteer. However that's probably due with my street tires, 215/60/15's.

When I put my 72 spindles in I was going to need new tie rods so I just bought the Baer bumpsteer kit. I started to make a bumpsteer gauge, I was looking for something flat and true to bolt to the hub, that's where I stopped. I thought to myself, I didn't have to know a specific amount or number, I just needed it to drive as best as possible. So I did my bumpsteer "tuning"if you want to call it that the back yard way, how it drives. After all at the end of the day, that's what's important, at least to me. So I drove my car. The road in front of my house is 35mph and just happens to have a crest which was sufficient to induce problems. My caster was already at 4°. I just kept adding spacers until it felt good. Same here, all the spacers. I live in NEPA, the area is called the Endless Mountains for a good reason. It's all up and down twisty roads. I can go blasting down any road with impunity. It just drives great, no hint of bumpsteer. Maybe with stickier tires something may show up. I want to add a comment about my idler arm. I no longer have a stock idler arm. It's a roller bearing idler arm. Personally I think this is one of the best things you can do to the steering, I'm sold! Getting rid of the rubber bushings eliminates a lot of monkey motion. Steering is aot more precise. I wouldn't be surprised is some of the slop in the stock idler arm may be part of your issue?

I want to give a shout out to @Helmantel Years ago before I started to do any suspension work, I tried to learn as much as possible about setting up and faults of the stock suspension before I bought anything. This way I could better select parts that suited my intended use. If I had to do it all over, there is very little I would have done differently. My only change would have been stiffer springs. The steel bearings eliminated so much binding and friction, it really knocked the legs out on the spring rate. I never thought about it at the time.

I remember a post Helmantel made a about bumpsteer with later spindles on a 65-66. He said you needed about 5° caster to offset it. I knew it was a important comment but couldn't quite grasp the reason. One day it hit me like a ton of bricks. The difference I see between the 65-66 and later is the later tie rod arms have 1/2" less horizontal offset, they're flatter. They're also shorter by about 7/16" and they are angled in more by about 3/8". I did a quick trig calculation and that 1/2" difference works out to about 5°. This puts the outer tie rod about the same height off the road surface as the stock spindle with factory caster spec of 0° which keeps the over all tie rod assembly about the same length to reduce bumpsteer.

From playing around on my car I've noticed the front suspension has a lot of travel. I think the range of toe is probably more then you can somewhat easily fix. It comes down to making the best of a bad situation.
 
1 - 12 of 12 Posts
Top