1" drop spindle, '70 drum style?

[69gmachine]

That's what I meant to say with the following

D'oh! somehow I missed that sentence!!

I have gleamed from this discussion that many user wish to use tires with larger backspacing and diameter than is currently feasible using the standard spindle. This spindle should be compatible with a performance disc brake caliper and it would be optimal if it had multiple tie rod mount points or a replaceable steering arm like on earlier Fords. It would be nice to reduce the rotating mass.

degins,
It sounds like you have a handle on a good design. I have confidence in your metallurgy, and wouldn't hesitate to take it out on the track. If I ever got good enough that I was able to generate the kinds of loads it would take to break it, I would be ready for a real race car anyway. If you keep the price in line with your other spindles, it will be one helluva deal.

 

[bnickel]

so Dennis, what do you think? might it be feasible? would you like to me to post a sticky poll at www.69stang.com?

 

[degins]

so Dennis, what do you think? might it be feasible? would you like to me to post a sticky poll at www.69stang.com?

The first thing for me to do is find some 70 type drum spindles and hubs. I assume 71-73 are the same? Also, is the desire for a "shorter" steering arm because the R&P users want the tie rod mounting point closer to the spindle (forward) or closer to the center of the car (inboard), or both? What about up or down? What size tie rod mount taper is need for the R&P tie rod mount point?

The sticky would be helpful.

 

[SNAKEPILOT]

For the drop spindle to be a worthwhile mod, it has to do two maybe three things.
1. Lower the front end. Obviously, but if that is all it does, even though it is a better way to lower the front end, front springs are cheap. Most won't buy them just to lower their car.
2. Allow wider wheels/tires. You won't be able to check every combination but a buyer will want to know if he can run say, a TT2 17x9.5 wheel with stock and/or GW/TCP contol arms. I think you would have to prototype a welded up original spindle with a 1.0/1.5/2.0 drop. Who knows, the tires may hit the frame and then it may be a moot point to even try to put wider wheels on.
3. Decrease turning radius. Since the main purpose of the drop spindles is to allow wider tires, and wider tires increase the turning radius, then a decreased turning radius designed into the spindle would be a desired benefit. But, do wider tires really increase turning radius? A wider offset wheel I think would but what about more backspace? And if in order to fit 275/40/17s you had to use a limiter, then your turn radius is screwed anyway. R&P users think a wider turn radius is a worth the trade off. Wide tires users may think the same way. I don't think the R&P users would incur a double turn radius penalty.

 

[bnickel]

The first thing for me to do is find some 70 type drum spindles and hubs. I assume 71-73 are the same? Also, is the desire for a "shorter" steering arm because the R&P users want the tie rod mounting point closer to the spindle (forward) or closer to the center of the car (inboard), or both? What about up or down? What size tie rod mount taper is need for the R&P tie rod mount point?

The sticky would be helpful.

70-73 drum spindles are all the same so any of them will work also the 67-67 are the same as well just with smaller pin and smaller tie rod taper, so any of them would work for a prototype you'd just have to change the bearings and races to the correct type.

the rack guys would want the tie rod location moved forward closer to the spindle pin NOT toward the center of the car. optimally the tie rod would be lowered to help with bumpsteer on cars that have altered UCA mounting points but most serious guys would probably still measure the bumpsteer and use a bumpsteer kit to correct for it, so i don't think that is critical.

the rack and pinion kits on the market all allow for the different tie rod tapers to be used using either stock tie rods (TCP, Randall's, Flaming river and unisteer) or an aftermarket style bumpsteer adjustable tie rod (Steeroids, optional on TCP). i would think that most users would want the stronger 70-up style tie rod.

i think that you might run into a problem going much lower than 1"-1.5" with the steering arm hitting the wheel so a 2" drop is probably not a good idea. i had suggested a 2" at some point but went out and looked at my extra set of 69 frum spindles and realized that 2" would probably be too much or at least too close for comfort anyway, however a shorter steering arm should cure that problem.

the biggest limiting factor to running a big wheel/tire on the front of a mustang is contact with the UCA, a drop spindle will alleviate a lot of that problem. if the wheel will clear a stock UCA it will clear any of the aftermarket arms pretty easily. you can still go too wide and have interference problems with the frame rails but that's a wheel backspacing issue not a spindle issue.

 

[69gmachine]

For the drop spindle to be a worthwhile mod, it has to do two maybe three things.
1. Lower the front end.
2. Allow wider wheels/tires.
3. Decrease turning radius.

Amen brother! For the vast majority of people I believe these are THE 3 issues that would absolutely have to be addressed before it's worth it to go to the trouble of replacing the stock spindle. I only have to worry about my car, and since I have a coilover front suspension, I can easily drop the front 1 to 2 inches without a dropped spindle, and I still have plenty of travel. The 1" drop for me is only to allow a 9" wheel to fit. However, it may not be enough for every wheel/tire/suspension combination out there. It is just as important to let customers know what will work as what will not work. I know that not everyone wants a 17" wheel, and I doubt a 15x9" wheel can be made to fit without making the spindle incredibly short, and then you would compromise the geometry, so the wider wheel assumes a willingness to use larger rims. The 2 most common 17" wheel styles being installed on classic mustangs are the 94-99 SN-95 17x8s and 17x9s, and the TTII 9.5s. It would be a worthwhile exercise to verify fitment of both the 9" wide OEM and TTII 9.5" wide wheels with at least the stock UCA. I don't think it has to actually work with both combinations, but it definetly has to work with at least one, and we need to know which one that is.

the rack guys would want the tie rod location moved forward closer to the spindle pin NOT toward the center of the car.

Agreed, and moved along the same axis as an imaginary line from the tie rod centerline to the lower BJ centerline to maintain the factory Ackerman. I wouldn't try to resolve bumpsteer by dropping the steering arm as there are too many variations of steering and suspension kits already out there. Keep the drop relative to the lower ball joint the same as the stock spindle, and it will work with most kits. Also, I would highly recommend using the larger Granada tie rod end rather than the 70-73 taper. The people who are installing this spindle aren't going for concurs judging, they want performance, and should expect to install new tie rod ends anyway.

 

[bnickel]

the granada and 70-73 tie rods are almost identical. the granada is very slightly larger but not enough to make a big difference IMO. also, the granada parts can harder to find whereas the mustang parts are actually more common because there is a larger aftermaket for them. also, if the spindle is based on a 70-73 part it MIGHT be legal for vintage racing, the again it might not be too. but i think it would have a better chance if it was based on the 70-73 stuff. that's also one of the reasons i suggested basing the spindle on the 70-73 drum spindle to be able to use vintage legal brakes as well as all of the aftermarket stuff too.

another advantage would be that the earlier than 69 cars would be able to run a 15x8 inch wheel, whereas now they cannot, 7" is the widest possible with 15" wheel. maybe 7.5" wide. i would think you would be able run a 15x9" wheel on 69-up cars with no problem, especially with the 1" or more UCA drop.

 

[degins]

the granada and 70-73 tie rods are almost identical. the granada is very slightly larger but not enough to make a big difference IMO. also, the granada parts can harder to find whereas the mustang parts are actually more common because there is a larger aftermaket for them. also, if the spindle is based on a 70-73 part it MIGHT be legal for vintage racing, the again it might not be too. but i think it would have a better chance if it was based on the 70-73 stuff. that's also one of the reasons i suggested basing the spindle on the 70-73 drum spindle to be able to use vintage legal brakes as well as all of the aftermarket stuff too.

another advantage would be that the earlier than 69 cars would be able to run a 15x8 inch wheel, whereas now they cannot, 7" is the widest possible with 15" wheel. maybe 7.5" wide. i would think you would be able run a 15x9" wheel on 69-up cars with no problem, especially with the 1" or more UCA drop.

I will design it with Granada type tie rods. The Granada parts are not going away. In fact I now manufacture 3 types of tie rods with the Granada stud including the original, a 65-66 PS to Granada type, and a 6 cylinder 65-66 Mustang type. I have and will continue to stock them.

I can build a tie rod boss into the steering arm at the place suggested, but projecting it along the steering arm toward the lower ball joint will necessitate lenghtening the tie rod train. I think that it would be better to project the new mount forward and on the existing arc of the tie rod (with the inner tie rod's ball joint as the foci). This would result in a tab/bump on the inner part of the steering arm. Comments?

Anyway, I am going to SEMA and AAPEX next week, then I have a massive shipment coming in. I'll try to locate some spindles, AutoCAD the mods, then send them along to the foundry for modeling.

 

[bnickel]

i don't think the bump on the steering arm would be a problem. if anything, people could grind it off if they feeel the need to do so, though i don't know why anyone would go to the trouble.

if you need a set of spindles to look at and measure for the modeling process i have a set of 69 spindles i'm not using at the moment and i would be happy to let you borrow them for a while, but i would like to have them back, unless of course i can get one of the first sets of spindles for a really good deal, LOL. let me know if you want to use them.

 

[Helmantel]

Also, is the desire for a "shorter" steering arm because the R&P users want the tie rod mounting point closer to the spindle (forward) or closer to the center of the car (inboard), or both? What about up or down?

A shorter steering arm not only reduces the turning radius, but of course also quickens steering. Shelby quick steering kits achieve the same thing but are only available for the early cars. Plus such spindles may attract those with 65-66 cars who are considering a quick steering kit (~$150) but rather spend the money on spindles that have the quick steering built in.

If you decide to shorten the steering arms, I would try and maintain the factory ackerman geometry. This means that the tie rod hole should move along the imaginary line from the ball joints to the tie rod. Since this line points rearwards and inwards (it intersects with the centreline of the cars somewhere back of the differential), moving the tie rod forward along this line it should move a little outward.

The 65-66 and 67 and up cars actually have different Ackerman, so which one to use is the next question (it never ends, doesn’t it J)

Moving it down to reduce bump steer would be nice. I would then optimise it for a 1” Shelby drop. Many people have done this to their cars already, especially those who are into modifying (which dropped spindle customers probably are). This would require a mock up to see how much is needed. Those who lowered the arms more can always buy a bump steer kit and fine tune for their application.

Again, these are just ideas I can think of. They may not be feasible. I can understand if you don’t want to overcomplicate things.

 

[bnickel]

i'm only guessing here, but i would think that if Degins decides to do this spindle he'll start out with the 67-70 version as he's done with the granada kits and then branch out to the 65-66 version if the 67-70 sells well. i could be totally off base on that, however, and look like a total ass but it's ok i can take it, i have thick skin.

also, i thought part of the reason for using the shelby quick steer kit was to reduce the ackermann somewhat and that a small reduction in ackermann was desirable. i swear i read that on C-C.com somewhere. again i could be totally wrong on that as well. either way, i'm not too concerend about the ackermann either. i think the lowering spindle with stock geometry would be perfectly acceptable though the relocated tie rod attachment point for rack and pinion/quick steer would be nice. anything else i think would overcomplicate the design resulting it too many options to feasible with one spindle or even a second bersions for the 65-66 cars. this is totally up to Degins of course. i just really would like to have a set of these spindles so i'm trying to keep the ideas simple enough to ease production.

i have a TCP power rack, a set of opentracker's roller perches and i plan on getting at least opentracker's roller lower arms and hopefully a set of roller upper arms as well with the 1-3/4" drop. for now, i'll be using my 750lb coil springs but i'd like to upgrade to a coilover setup someday or even make my own by modifying the opentracker parts. i also plan on using the new design TCP strut rods or possibly the new Maier racing delrin strut rod bushings that they just realeased. for the rear i plan on using either the Fays 2 or Evolution watts link or even better the Evolution watts and 3 link rear suspension. all of this will be going in the 69 cougar i'm getting after i sell the mustang so i should have some cash to spend at that time as well.

 

[69gmachine]

also, i thought part of the reason for using the shelby quick steer kit was to reduce the ackermann somewhat and that a small reduction in ackermann was desirable. i swear i read that on C-C.com somewhere. again i could be totally wrong on that as well. either way, i'm not too concerend about the ackermann either. i think the lowering spindle with stock geometry would be perfectly acceptable though the relocated tie rod attachment point for rack and pinion/quick steer would be nice.

The length of the pitman and idler arms will quicken the steering if they are longer than stock, but they have no bearing on Ackerman. The Ackerman angle is solely a function of the length of the wheel base, the width of the track, and the angle of the steering arm on the spindle, all of which are fixed on any given production car. Here is a link that gives an excellent explanation of Ackerman: http://www.rctek.com/handling/ackerman_steering_principle.html.

Now there is no particular benefit for a Mustang to have "true Ackerman" as it is most beneficial for solid wheeled vehicles that turn in tight arcs such as warehouse fork lifts or RC cars. Our cars don't have solid wheels and we don't spend most of our time making tight turns in parking lots. Moving the pivot point inboard will increase Ackerman, which as I said is no particualr benefit, but the potential downside is there is a possiblity of increasing bumpsteer. In the most simple CT dirt and asphalt designs, the steering linkage is exactly the same length as the LCA, there is no Ackerman angle at all built into the spindle, the lower BJ and the steering arm are on the same plane, the inner pivot point of the LCA and the steering linkage are on the same plane, and also the same distance from the centerline when the wheels are straight ahead. With this layout, there will be zero bumpsteer through the entire arc of travel. Who cares if the tires squeal on the pavement when going slow? These cars don't go slow, and there's enough slip angle on a dirt car that it doesn't matter anyway. I doubt that the slight movement inboard will have a significant impact, but these are the kinds of considerations that generally require an engineer when taking on something like designing a spindle. I would highly recommend that degins take his final design and pay an engineering consultant firm to do an analysis to verify the geometry of the finished product before going to production.

 

[Helmantel]

The pitman arm length, or better said, moving the centerlink forward does in fact affect Ackerman. This is similar to the effect the position of a steering rack has on Ackerman. Race car designers sometimes move the rack back and forth to adjust Ackerman.

Although "true Ackermann" only applies to solid wheels and low speeds, it doesn't mean that Ackermann can be ignored as soon as you mount rubber tires and leave the parking lot. I don't know how much you need though. I can imagine it has a lot to do with tires you use.

I agree that asking a knowledgable suspension designer would probably be the best thing to do. The results are likely better than designing a spindle based on 53 internet forum replys Or actually, just 47 replies. My 6 contributions are of course highly valuable

 

[Decurion]

without reading all 3 pages, has anyone thought to put the idea on ebay and get initial bids? Make the auction for say $25 as a deposit on the new spindles, make a qty of 100 available and if enough people bid, decide from there whether or not to go into production with them. Seems to me it would be a good way to judge general interest, IMO.

 

[degins]

without reading all 3 pages, has anyone thought to put the idea on ebay and get initial bids? Make the auction for say $25 as a deposit on the new spindles, make a qty of 100 available and if enough people bid, decide from there whether or not to go into production with them. Seems to me it would be a good way to judge general interest, IMO.

I know what you propose is done, but ebay rules dictate that the seller have the auctioned item in hand and available for shipping.

In any case, I intend to produce the spindle. I will also eventually produce caliper brackets for use with them.

 

[bnickel]

I know what you propose is done, but ebay rules dictate that the seller have the auctioned item in hand and available for shipping.

In any case, I intend to produce the spindle. I will also eventually produce caliper brackets for use with them.

WOOHOO!!!!!!!!!!!!!!
now where's that little bowing smiley when you really need it?

we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy

 

[degins]

WOOHOO!!!!!!!!!!!!!!
now where's that little bowing smiley when you really need it?

we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy

Come on, give me a break (or should I say Brake)!

 

[bnickel]

Come on, give me a break (or should I say Brake)!

a brake!!! actually Dennis, i can't thank you enough fro deciding to go ahead with these. i feel the market has been severely lacking with this product for several years. Thank You.

 

[TheShagg]

I am in for a set, IF AND ONLY IF THERE ARE PROVISIONS FOR A SHORTER STEERING ARM.

A beefy arm drilled in two places would be fine as well, as I could simply cut the end off.


The reason is two fold: bigger tires, and better steering. Also note, people with a TCP rack WILL BENIFIT FROM THIS. All the good racks are made for much shorter steering arms on the spindles. Its just how it is, and this is the way around it. Any vintage racer who would be allowed to run this spindle WILL.

I've been pushing for this for years, and if I wasn't so busy getting my degree I would be designing it myself!

 

[70vert]

So, to get this straight - the shorter steering arm will allow those with R&Ps to regain their original steering radius? Is the issue with the R&P reduced steering radius the fact that it is pushing on a longer spindle than it was designed for? And pushing on a shorter spindle/shorter point on the spindle will regain that original steering radius?