Wilwood Pro Spindle

Mike Pass

Supporter
The drawing of the Willwood Mustang upright shows a KPI of 11 degrees. This is much better than the Mk2 Granada KPI of about 4 degrees. The drawing shows a spacing of 8.15" between the top and bottom tapers. To get a true comparison of overall effective upright height you would need to measure both setups with swivel joints attached and take a measurement from the centre of the top swivel to the centre of the bottom swivel. You could then work out where to vertically position the mounting of the top and bottom chassis mountings for the wishbones using a "string computer" or similar to check out the geometry to get a sensible camber change in bump and droop and roll centre location. Once you have decided which rack to use you can work out where the wishbone mounts can be placed relative to the car centre line so as to eliminate bump steer. The top and bottom mounts and the steering arm inner ball joints should be in the same plane as a rough guide to avoid bump steer and then fine tune with small adjustments of rack height or fore and aft.
The rack determines where the wishbone mounts are relative to the car centre line and the spindle height determines the vertical spacing of the wishbone mounts.
The rack ratio combined with the length of the steering arm determines the turns of the steering wheel lock to lock.
Cheers
Mike
 
Are Cortina and Granada the same KPI?

I believe Cortina Mk3/4/5 are about 4.3° but I've only found that in one place and been unable to verify it (or if Granada MK2 are the same).
 
Jayson:
We did a couple of front suspensions using these uprights, They are very well built, the steering arm bolts on and can be run front or rear or as we opted to put it on top and steer the upright that way to increase the rack height, and therefore the steering shaft run was much straighter from the dash. Ball joints are easily available, and the parts to fab your own wishbones and mount the ball joints are also pretty common. I have used mono bolts, rod ends, and screw in type balljoints with good success.
There are a number of brake kits available, and they are all bolt up affairs and there is even a six piston kit with 12 or 13" rotors if I remember correctly.
All of the Wilwood brake kits come with an aluminum hub, and rotor hat, pretty lightweight stuff.
The ackerman on these uprights is almost perfect for a 95" wheelbase and there is very little scrub when turning.

Cheers
Phil
 
Hi guys.

Thanks for your input.

Phil

Did you use these uprights on a 40 kit or a different application?

Cheers

Jayson
 
Have you checked out Speedway? They carry the Mustang spindels & "A" arms, brakes etc. Very good prices usually.
SpeedwayMotors.com
Mike S.
 
Jayson,
The uprights were used on a different chassis that I built, but the wheelbase was the same 95", and ride height was also almost identical, I would think no problem using those on a 40 chassis.
I actually contemplated changing my chassis over to these uprights, but didn't as I am so far into the build that I didn't want to go a few steps back as it were. I just may do the swap in the future, but right now she is where she is.
I am in the process now of switching my design over to a new steer rack, and I will let you know how that works.
Cheers
Phil
 
Hi guys,

Are these still a good option for the 40; i haven’t seen anyone running them. Also would you use the standard or 2" dropped spindle (suspension isn’t my area of expertise obviously).
Further; who does economically priced brake and hub kits to suit this spindle and 15 inch rim combination? I did a search but only found expensive big brake kits.

Basically I’m looking for an economical front suspension/steering set-up that would please the engineers; the more fabricated items the more hassle. Original plan was import vette c4/c5 complete front suspension, brakes etc which I have seen on GT40’s and would be easier for compliance but I’m told not the best dynamics and steals precious leg room; I’m 6ft.
Vette parts when i quoted it a few years back was about $1000Aus to Melbourne but was a complete package. The ProSpindles might be $375-475 depending on if I buy new or locate some 2nd hand and shipping costs etc
Alternatively I’m open to any other options available in Australia.
Cheers
 
Hi guys,

Are these still a good option for the 40; i haven’t seen anyone running them. Also would you use the standard or 2" dropped spindle (suspension isn’t my area of expertise obviously).
Further; who does economically priced brake and hub kits to suit this spindle and 15 inch rim combination? I did a search but only found expensive big brake kits.

Basically I’m looking for an economical front suspension/steering set-up that would please the engineers; the more fabricated items the more hassle. Original plan was import vette c4/c5 complete front suspension, brakes etc which I have seen on GT40’s and would be easier for compliance but I’m told not the best dynamics and steals precious leg room; I’m 6ft.
Vette parts when i quoted it a few years back was about $1000Aus to Melbourne but was a complete package. The ProSpindles might be $375-475 depending on if I buy new or locate some 2nd hand and shipping costs etc
Alternatively I’m open to any other options available in Australia.
Cheers
Hi,
I am using the 2 inch dropped spindle on my 40 scratch build. The dropped spindle suits the 40 chassie pretty nice.
The geometry is good, lots of brake kits to choose from and the price is fair.:thumbsup:
I bought them from Jegs and i allso bought a big brake kit for a mustang 2.
JEGS Performance Auto Parts - Holley - Billet Specialties - Edelbrock - MSD - Moroso - Mr Gasket

About the vette parts, these spindles are made for wheels with a lot diffrerent offset from GT40 wheels. If you are planning to use replica wheels, dont choose vette parts.

/Markus
 

Attachments

Well i did a little research on these. They look like a better choice than the Granadas. I found them on sale for 140 dollars a piece with free shiping. So i threw the dice and ordered a pair , will give them a try. Will be making my own control arms so will see......
 

Kevin Box

Supporter
Wilwood spindles look good
What are the Pros & Cons of using either stock height (Mustang 2) or 2" dropped spindle
It would appear that standard may be better with standard inboard mounting position which then has both arms tilting down toward the chassis so lower roll centre.
I'm curious about how everyone feels about this ???

cheers
KB
 
Wilwood spindles look good
What are the Pros & Cons of using either stock height (Mustang 2) or 2" dropped spindle
It would appear that standard may be better with standard inboard mounting position which then has both arms tilting down toward the chassis so lower roll centre.
I'm curious about how everyone feels about this ???
I worked it out and assuming the same geometry and it's literally moving the spindle 2" down on the upright then it reduces the scrub radius. Where using uprights designed for narrow tyres with big fat ones you can end up with a significant amount of scrub radius (some 4"/100mm in the case of the Cortina/Granada for example) so this could be advantageous. It does however as you say mean that the arms "start" at a different angle. This really will depend on how the suspension is designed but typically shouldn't be an issue if you're designing your own as you design it so it behaves as you'd want through its range.
 
The original front upright "axle" centerline is approximately centered vertically to the ball joints. That puts the lower control inner pivots' height just above the bottom of the chassis where the lateral forces can fed into the chassis most efficiently.
 
Willwood Mustang upright shows a KPI of 11 degrees. This is much better than the Mk2 Granada KPI of about 4 degrees
I have been lead to believe that the exact opposite was better as you get less camber change when the steering axis is turned.
You can then design in any camber gain (outside wheel) or loss (inside wheel) with the suspension arm lengths and angles. I'm no expert in this area though. lots and lots of variable. I'm sure compromises in one area can be overcome or reacted by changes in other areas. ie if your designing with 11° KPI you would do one thing with the suspension arms. if its 4° you would do something else.

Ryan
 
Generally, king pin inclination is built in to decrease the distance from the center of the contact patch to the virtual ground level pivot point. The smaller the distance, the less feedback from uneven surfaces, especially under braking forces. It's a tradeoff between kpi effects, castor effects and steering effort. If you want to see an interesting approach, look at BMW's dual-pivot lower control arm design.
 

Terry Oxandale

Skinny Man
I have been lead to believe that the exact opposite was better as you get less camber change when the steering axis is turned.
You can then design in any camber gain (outside wheel) or loss (inside wheel) with the suspension arm lengths and angles. I'm no expert in this area though. lots and lots of variable. I'm sure compromises in one area can be overcome or reacted by changes in other areas. ie if your designing with 11° KPI you would do one thing with the suspension arms. if its 4° you would do something else.

Ryan
I've struggled to have a suspension that 100% accounted for all roll via camber gain. I've found kingpin to be another tool in obtaining an optimal camber in suspension settings and design. And it is the most practical means of eliminating scrub for most designs.
 
If you want to see an interesting approach, look at BMW's dual-pivot lower control arm design.
A number of other manufacturers also use that, GM/Holden on the VE onwards Commodore had it. Meanwhile Audi and Ford have used the dual outboard ball joints on the top knuckle as well, one that curves over the top of the tire.

Then there are Toyota that move the ball in front of the axle line on the top and bottom to increase the pneumatic trail whilst still giving a very low scrub radius. Mazda go the other way having the ball joints behind the axle line, reducing the pneumatic trail.

I find it a very interesting area, but have little practical knowledge to add.
I have taken note of the cars that i have liked driving, or having a steer of and looked up their specs as well as images of their knuckles. These include the likes of the Lotus Exiege, Toyota Supra, BMW E92 M3, Mazda RX8 ect. I will no doubt gravitate towards the set up that i felt most comfortable. with. Well that is what I plan on doing.

To get back to the OP's question, I think the Willwood pro spindle is somewhat in the middle of the range when it comes to the settings and angles. It's KPI will work well with the deep offset dished wheels that we normally use on the GT40. It keeps the axle line on center between the two ball joins axis. it has a bolt on steering arm that can be flipped for front steer, rear steer, high tie rod or low tie rod. If you used longer mounting bolts and spacers you could also alter the Ackerman angle if desired. So lots of options to get it to work with your application.
It is also available in 5 x 120mm (5 x 4.75") PCD as well as the popular 5 x 114.3mm (5 x 4.5") PCD, so you can probably make it match your rear suspension.

The Willwood is on my short list of knuckles.
 
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