Help me with spindle design

[degins]

Many of you know that I have been developing a disc brake spindle for use on classic Mustang. The spindle is base on the Granada design. This design is best suited for use on 67-73 Mustangs because the steering arm geometry of 67-73 is a bit different than 65-66. This is of particular note in performance applications. See my last thread for pictures.

Well I've ordered the first production run of the first model and now I'm working on a 65-66 specific model. This model will still be Granada based, but will have steering arm geometry appropriate to 65-66. I would appreciate your opinion as to which outer tie rod mounting stud hole to use. Should I have the steering arms bored to accept the taper of the original tie rod stud, or the larger one from Granada?

The issues as I understand them are that using the original taper allows the installer to use or reuse the originals. The Granada taper would necessitate replacing with the Granada type tie rods, but they are fairly inexpensive and much beefier. The drawback to the Granada is in power steering applications were a bushing must be used on one side along with the original type tie rod or a special high priced tie rod could be used.

What's your opinion? What would you rather use? Why?

 

[krash kendall]

I would prefer the mustang outer tie rod not only because it would make the swap that much easier and cheaper, but simply because it would be one less thing to explain when ordering replacements or having work done in a shop if replacing an inner/outer tie rod assembly.

 

[Tubo(2-bo)]

What I'd like to see you build, spindles that would correct the bump steer so prevalent w/Granada discs.
At the same time, you should add enough extra beef into the steering arm to allow relocating the outer tie rod mount closer inboard. From such spindles an inexpensive fox based rack & pinion to be developed & used, that doesnt have a diminished turning circle.
That would give your spindles a broader customer base.
As to which tie rods to use, I'd say the 65-66 type, as most of the people buying , would probably not have discs yet, and the new spindles would match their existing equipment. Though it probably would not stop a buyer, no matter which tie rods are used.

 

[bnickel]

he is basically building the 65-66 spindles with the correct steering geometry built in already. you couldn't use a fox based rack and pinion with any early spindle anyway since the fox body cars are front steer and the early cars are rear steer. in order for him to do what you suggest he would have to swap the steering arms from the rear of the knuckle to the front and then you would have interference issues with strut rods not too mention having to use a fox body oil pan, if you are going to go that far you might asw well chnage the entire front suspension so the geometry is correct for a front steer setup by the time you're done you might as well have just used a mustang II front suspension with a fox body rack, which is a fairly common swap by the way.

 

[brianj5600]

True that. There are many rear steer racks that would work if the arm on the spindle was shorter. I would buy the 67 up spindles if the tie rod mount was moved closer to the king pin. It would be good to offer that for people wanting affordable, good r&p.

 

[degins]

Although I appreciate hearing your wish list, my next model will definitely be a purpose built disc brake spindle with correct original geometry for 65-66. At this time, I think that the market for a R&P compatible spindle is not large enough to justify the design and modeling cost. If someone has specific engineering data (definitive dimensions for the steering arm) I would consider the product. Does anyone else have an opinion about the choice of tie rod type?

 

[Chris66]

My opinion is I would like a spindle that takes a 65-66 tie rod. I do not care if my care is stock, but there is something when you go to the auto parts store and you have to list all the different cars that you have on your ride.

 

[bnickel]

degins, the measurement you would need to for the tie rod relocation would be one inch forward of the curent location. i believe that would also move it outboard about 1/2-3/4" as well.

however there is already a bolt on solution for this that also helps correct the bumpsteer issue in the stock suspension. check it out https://www.pro-motorsports.com/store/bump-steer-main.asp

this is exactly what i plan on using when i get my randall's rack kit.

 

[degins]

degins, the measurement you would need to for the tie rod relocation would be one inch forward of the curent location. i believe that would also move it outboard about 1/2-3/4" as well.

however there is already a bolt on solution for this that also helps correct the bumpsteer issue in the stock suspension. check it out https://www.pro-motorsports.com/store/bump-steer-main.asp

this is exactly what i plan on using when i get my randall's rack kit.

So the Granada geometry is not all bad for the 65-66. The Pro Motorsports kit you referenced moves the tie rod mounting point 1 inch down and 1 inch forward from 65-66 stock location. Granada mounting is 1/2 inch up, 1/2 inch forward, and 1/2 inch out compared to stock 65-66 location. So the performamce change from Granada to 65-66 is 1.5 inch down, 0.5 inch forward and 0.5 inch outward. Does anyone have an opinion of the optimal mounting geometry? Preferably for street or mild performance.

 

[bnickel]

ok i double checked the outward measurement again and it isn't that much, it ranges from 0-1/4" also the other measurments of the pro-m bumpsteer kit are 1" forward and 1" lower. i think the problem with granada spindles is it moves the tie-rod down and out too far. probably mostly the outward move of the tie-rod. a liitle is good too much is bad.

i also remembered that the spindle mod that Randall had on his site was just straight forward 1".

 

[Tubo(2-bo)]

he is basically building the 65-66 spindles with the correct steering geometry built in already. you couldn't use a fox based rack and pinion with any early spindle anyway since the fox body cars are front steer and the early cars are rear steer. in order for him to do what you suggest he would have to swap the steering arms from the rear of the knuckle to the front and then you would have interference issues with strut rods not too mention having to use a fox body oil pan, if you are going to go that far you might asw well chnage the entire front suspension so the geometry is correct for a front steer setup by the time you're done you might as well have just used a mustang II front suspension with a fox body rack, which is a fairly common swap by the way.

Sorry bnickle, but your wrong!
Several early attempts to make R & P fit a classic used the fox rack MOUNTED BEHIND THE FRONT AXLE, thus no problem using 64.5-72 spindles. The fitment is just like the current batch of R & P's. The problem with using the fox rack came as a greatly reduced turning radius. Thats why, I'd like to see more beef in the steering arms, to allow moving the tie rod attachment closer to the hub, immitating the length of a MII steering arm. thus allowing a tighter turning circle. It's simple mathmatics to figure the proper location.

 

[Edbert]

My opinion on rod end type would be to use whatever is strongest. If I were doing a full upgrade of my suspension like that I'd be replacing them anyhow, and all I'd want is very clear instructions as to which ones i should use. Part numbers to take to the store etc., just so I don't have to explain why I want Mustang inner rods and Torino (just making stuff up here) outer rods to the kid with the acne.

 

[bnickel]

Sorry bnickle, but your wrong!
Several early attempts to make R & P fit a classic used the fox rack MOUNTED BEHIND THE FRONT AXLE, thus no problem using 64.5-72 spindles. The fitment is just like the current batch of R & P's. The problem with using the fox rack came as a greatly reduced turning radius. Thats why, I'd like to see more beef in the steering arms, to allow moving the tie rod attachment closer to the hub, immitating the length of a MII steering arm. thus allowing a tighter turning circle. It's simple mathmatics to figure the proper location.

sorry man but you are wrong. there is no possible way to use a fox rack in a rear steer application without some serious mods to the rack, namely relocating the pinion gear. the reason for this is because if you were to use a fox rack (front steer) mounted to the rear is that when you turn the steering wheel any direction the road wheels will move in the opposite direction, for instance if you turn the steering wheel left the car would turn right. simple physics man.

i beleive the rack conversion you are thinking about is the taurus rack which is a rear steer rack.

you'd better haveyour facts straight before calling someone out dude.

 

[1320stang]

My tie rod preference would be the stock ones.

Now about the whole R&P deal. Not sure which rack we're talking about here, but if one could be proven to work with documentation, could the new knuckle be designed with a boss that is machined top and bottom, but with no hole, only a centering dimple for drilling the correct hole for the R&P? This way it could be used in a normal situation and strength not be compromised, but if someone wanted to do the R&P, they'd drill/machine out the new hole and could saw cut off the part they don't need.

Not sure if this would work, but it would seem to make one knuckle for two applications. Just an idea.

 

[Tubo(2-bo)]

sorry man but you are wrong. there is no possible way to use a fox rack in a rear steer application without some serious mods to the rack, namely relocating the pinion gear. the reason for this is because if you were to use a fox rack (front steer) mounted to the rear is that when you turn the steering wheel any direction the road wheels will move in the opposite direction, for instance if you turn the steering wheel left the car would turn right. simple physics man.

i beleive the rack conversion you are thinking about is the taurus rack which is a rear steer rack.

you'd better haveyour facts straight before calling someone out dude.

I dont want to get OT on this thread, HOWEVER
bnickle exactly what you said "you'd better have your facts straight before calling someone out dude"
I have seen two early attempts(around 1989-90) at making a R & P setup for classic stangs, that utilized the fox rack.
Yes they were behind the axle, and yes they were "flipped" to better orient steering shaft alignment. They dident work out well because of the afore mentioned turning radius problem. IIRC "Mustangs and Fords" did an article on one in California, about that same time.
You really should not assume that I'm fresh out of the cellophane wrapper, because I havent posted 2,400+ times.
EDIT. on rerflection the "M&F" article used an MII rack

 

[bnickel]

you cannot just "flip" the rack to make it turn in the correct direction, "fliiping the rack would make the steering shaft input face the ground and and forward. it is just impossible to do with out some super serious modification and fabrication.

even a Mustang II rack would do the exact same thing. the only way to to do it without serious mods is to use a gear drive setup on the input shaft that reverses the rotation of the steering input, it can be done but even that is an expensive proposal. most likely what you are thinking about is mustang II conversion kit that coverts the entire front suspension. if you can find the article you're talking about and post the year/month and page number of that issue i will go through all my mags to find it aif it was in any mustang magazine at all i will have it. and i will look at it just to see what you're talking about.

oh, and i don't really care how many posts anyone has, good tech is good tech and bad tech is bad tech.

 

[HistoricMustang]

You guys are killin' me!

HistoricMustang
www.historicmustang.com