Fabricated A-Body spindle ideas and discussion

[DionR]

I am going to start this thread to (hopefully) split it off the new COC thread that the discussion started in. Original thread here -> New Coil-Over Conversion Suspension

Since the argument is often made that OEM geometry is just as good, potentially better, than many of these COC’s, but not perfect/ideal, what is the limiting factor? Spindle? And what needs to be changed? If spindle, sounds like DionR and I share a similar idea of a fabricated upright with a Mustang rear wheel hub assembly. I’ve talked to Michigan Metalworks about building something and they’re all for it, they build them all the time for low riding trucks. Build into it a bigger brake option like a Mustang four piston caliper so everything is available off the shelf at your parts store of choice. So if it’s spindle, maybe it’s time to figure that out and get something done? My Suspension Analyzer is long gone for the similar reason someone else mentioned or i’d plot it myself and play with different ride heights and moving the ball joints around.

I am looking at my 4th revision on my custom spindle. I just duplicated the F-Body geometry though and haven't looked at making it taller because at the time it didn't seem like anyone was worried about the stock spindle height. I started with a bolt on setup for a stock disk brake spindle to use the 4 piston Brembo's and 14.2" rotors from a Challenger so I based the custom updright around that setup. I originally tried to use the Challenger front hubs but bought (and then returned) 2 or 3 replacement hubs to check the wheel bolt pattern and found they all used the 115mm bolt circle and wasn't going to go down that road. So I stole the S550 hub idea off the spindles RideTech introduced.

It's all just flat plates welded together and bolts, but I have been trying to come up with a better system to set the hub location. The distance from the hub to the caliper ears is pretty important and the plates have some tolerance on the thickness that can stack and upset things a little. But with flat plates and laser cutting from SendCutSend, I think it was only $500 for a pair but it's been awhile since I did up a quote. The biggest issue is the UBJ mount. I was planning a solid 1" thick bar and a washer to duplicate the stock spindle thickness there and it would require the taper to be reamed into it. More work to do there as well.

The real reason I started look at this was that I wanted to run ABS wheel speed sensors. So this setup has provisions to mount LX/LC sensors.

This most recent go round, I spent some time thinking about brake packages. I like the OEM stuff just because it seems like you can get parts for much cheaper than the aftermarket Baer or Wilwood stuff. Maybe it isn't as good, but hopefully good enough. I was going to jump up to the S550 6 piston 15" rotor package as my 18" wheel should still fit, but I decided I didn't want to put 34# rotors on the car. So I plan to stick to ~14" setups. The S197 4 piston setup seems like a nice package, but the S550 4 piston setup is junk. The only one I didn't look at was the Camaro 1LE stuff, but a Corvette hub, those brakes and a swap to a GM bolt pattern might not be a bad option.

One of the things I looked at was scrub radius. The stock spindle appears to have about a 7 degree SAI and with my setup, I am getting about 2.45" of scrub radius. I think that could be better. Note that my custom upright results in the surface the wheel bolts to being in some compared to the stock spindle by maybe 3/8" or so. Changing the UBJ location and SAI to reduce the scrub radius would require shorter UCA's or the aftermarket adjustable ones. So that's up in the air, too.

Another discovery is that the LBJ isn't centered on the spindle and there is about 0.5 degrees of negative caster built into the stock setup.

I've thought about moving the UBJ hole back about 1" as that would create about 6 degrees of built in positive caster and would keep the wheel more centered in the wheel opening. But I haven't figured out if I will try it, partly because I think I would have to move the caliper to the front of the upright and I'm not sure that won't create issues with the sway bar. I think it would be a better location in the end, just not sure it wouldn't snowball into a custom swaybar like Joe just built.

 

[DionR]

I am going to try quoting from the original posts to continue the conversation. We will see how that works out.

 

[DionR]

So glad you shared your design. I remembered seeing it but couldn’t find it anywhere. That’s what prompted me to go down the “what if” path on a spindle. I want to add ABS, a hub spindle, and better brake options. I recently found Michigan Metalworks who builds beefy spindles for full size trucks and that got me going further.

I was tooling today and found a dual bolt pattern C7 hub, and that paired with a set of readily available GM calipers can be a great option, just need to firm up a rotor.
my thought is to grab a C5 spindle and hub off eBay, get the measurements for the caliper ears and hub mounting, combine that with FMJ pick up points and go. But if going to all that work, it makes sense to go all in and determine what the optimal points are at X ride height for the UBJ and LBJ. If, collectively as a group, we could do that, we could possibly come up with a great solution, or at least know what it would take to get these really dialed in.
A link to Michigan Metalworks website and their fabricated spindle.
Custom Fabricated Spindles

 

[DionR]

I was tooling today and found a dual bolt pattern C7 hub, and that paired with a set of readily available GM calipers can be a great option, just need to firm up a rotor.

Are those the CPP hubs? If so, just be aware they don't have the ABS tone ring in them even if they look to have the rubber cover. I talked to them at SEMA last year and I guess the extra steps and machining to get the dual pattern make it impossible to put the tone rings on. Or something like that.

A link to Michigan Metalworks website and their fabricated spindle.
Custom Fabricated Spindles

Cool! Looks like they could certainly come up with something that would work.

 

[DionR]

Want a taller spindle with more SAI, use a nascar unit. These can be found on ebay for $100 each. Easily a couple inches taller than stock and with SAIs of 7-9*. They are stout. Use big bearings. Go look at the picture I posted back on page three. If you find late model units, they may even already have radial brake caliper mounts for the new 12.73" rotors the Cup boys use these days. If they are older, it wouldn't be too difficult to weld on new mounting blocks.

Concerned with mounting in the car? Use a late B,F,J,M lower control arm with a divorced steering arm and ball joint. Then you can fabricate the steering arms to dial in ackerman, or not, and improve bump curve, or not.

Of course them you need a new upper arm. I'd suggest a custom length tubular with fabricated mounting point's to eliminate the factory anti-dive, or not. Speedway makes tubular upper arms in length from 6-12 inches in half in increments, so I'm sure you could find the exact length you want. You just have to figure out how to mount it to the frame, and then you can dial in how much camber gain you want it to have as well.

BTW, Autoware is having a sale on suspension Analyzer CDs.

 

[DionR]

DionR. Why not just get your knuckle 3D printed as a test piece?

Have you thought about designing your knuckle to be 2" taller than stock from the centerline of the hub/spindle and drop the lower ball joint mounting location 1.5" to 2" from the centerline of the hub/spindle? Droping the ball joint mounting location would be the same as what Chris Birdson is doing with the lower ball joint drop brackets he is running on his B-bodies with a longer upper ball joint. I'm not entirely sure where he's ended up for upper ball joint length.

The S550 6 pistons Brembos can fit with a 14" S197 GT500 rotor in an 18" wheel with the right brackets. ;)

The S550 4 piston calipers will work if you machine/grind the outside of the calipers for wheel barrel clearnance.

I need to get back on finishing the bracket design. It currently works with drum brake spindles but I would like to come up with a solution for the disc brake spindles.

View attachment 1716390314

View attachment 1716390315

 

[DionR]

DionR. Why not just get your knuckle 3D printed as a test piece?

I actually printed my first design. Not ready to print another one yet.

Have you thought about designing your knuckle to be 2" taller than stock from the centerline of the hub/spindle and drop the lower ball joint mounting location 1.5" to 2" from the centerline of the hub/spindle? Droping the ball joint mounting location would be the same as what Chris Birdson is doing with the lower ball joint drop brackets he is running on his B-bodies with a longer upper ball joint. I'm not entirely sure where he's ended up for upper ball joint length.

I looked at raising the hub an inch (1" drop) but the outer tie rod end looked to become a limiting factor on wheel depth. Part of the reason to go to an 18" wheel is so you can run a 9" or 10" rim and a decent offset to get the tire under the fender. 17" wheels run into that problem and are limited in offset to like +30mm on an 8" wheel, and dropping the ride height 1" would put the OTR in about the same spot and create the same limitation.

And I don't think a 19" wheel work on an A-Body as the front tire is about maxed out at 26" OD. That would make the sidewall shorter than I am interested in running.

I haven't put much thought into making the spindle taller, but not out of the question.

Also, my understanding is that an A-Body has pretty good geometry with the LCA horizontal and any slope down to the wheel make it worse. And with the LCA horizontal, the car is pretty low. So a 1" drop spindle would end up with the LCA sloping down at the same ride height and wouldn't be the best idea, in my opinion.

The S550 6 pistons Brembos can fit with a 14" S197 GT500 rotor in an 18" wheel with the right brackets. ;)

The S550 4 piston calipers will work if you machine/grind the outside of the calipers for wheel barrel clearnance.

I could get behind a 14" rotor and 6 piston caliper. Have to keep that in mind.

I haven't heard good things about the 4 piston S550 setup. Vorshlag has nothing good to say about them, partly because of the way the venting is on the rotors but I didn't get the impression he liked the calipers either.

I need to get back on finishing the bracket design. It currently works with drum brake spindles but I would like to come up with a solution for the disc brake spindles.

View attachment 1716390314

View attachment 1716390315

I like it!

 

[DionR]

Have you thought about designing your knuckle to be 2" taller than stock from the centerline of the hub/spindle...

With an 18" wheel with any decent offset and width, I don't believe a 2" taller knuckle would fit. @BergmanAutoCraft has said he is running 1" taller balljoints so that would work, but I would bet that is the limit.

Note that the "inside" of the wheel above is just a line at 9" from the centerline. The wheel is going to take a chunk out of that distance.

 

[DionR]

When I suggested making your knuckle taller, I had forgotten how much room there isn't between the UBJ and the barrel of the wheel.

 

[DionR]

We should probably move this conversation to a thread of its own to discuss this more and hopefully get others involved. That said, I have a friend with a waterjet that I can use for cheap so I can cut test mules, but we should get details dialed in, which is where mapping out the geometry, and other smart suspension folk, come into play. Then we can determine additional height available and if the pickups can be moved to improve overall geometry, while deciding on a brake combo. I wonder if we can use the smaller rotor with the six piston caliper?

 

[DionR]

I wonder if we can use the smaller rotor with the six piston caliper?

@Mopar_Taxi_Guy said it would. Only question in my mind is whether the S197 knuckle is used or the S550 knuckle.

If I remember correctly, the guy at Vorshlag found 18” wheels that fit on a Dark Horse and said that they fit the 15”/6 piston setup as well. So it’s not like someone couldn’t have the whole package. I just decided I didn’t want to do the work to figure out new caliper mounting locations right now.

In the future, the smart play would probably be to set this up for the S197 14”/4 piston setup since that can accept an S550 6 piston caliper with an S197 15” rotor. So plenty of upgrades even without going outside the OEM stuff.

My current design could do the Hellcat 6 piston kit, but I don’t think those will fit in an 18” wheel.

 

[DionR]

In the attached picture I have a 2017 S550 6 piston caliper over a 14" 2012 GT500 rotor. The wheel is a 18"x10" Weld. Keep in mind, this is all mocked up on a '73-'76 A-body 10" drum brake kunckle. I have yet to get to a bracket design that would work on the disc brake knuckles.

It's tight in the wheel barrel and tight to the backside face of the wheel for sure. I would have to measure the clearnace as it's been a few years since I have messed with it.

I am going to pick up a 14.2" SRT front rotor to use for mockup. The SRT rotor will move the caliper back from the rear face of the wheel for more clearance. Not sure I can afford the extra .100" on the outside though.

View attachment 1716390977

I'm also wanting to work on fitting 2018 GT350 radial mount calipers in there too as they are also cost effective like the regular S550 6 piston Brembo.

Here is the picture above so no one has to click on the link to see it.

 

[DionR]

In theory, that should bring us up to current and we can continue to talk about it outside of the thread this started in.

 

[DionR]

I went out last night and bolted up the Scat Pack brake adapter setup I have onto my '73 Hemi swap car. The car is on jack stands with the torsion bars loose and the spindles in their "natural' location (i.e. calipers to the front) unlike my '74 so it was a great opportunity to see if those massive Brembo calipers could be mounted to the front of the spindle. I prefer them in the back, but it doesn't work well with my idea for moving the upper balljoint to introduce some built in positive caster.

Looks like there are miles of room with the '73+ front suspension:

Might even be enough with the earlier sway bar, but just a guess.

Even with the suspension (mostly) compressed:

The only caveat to this is, the caliper is actually back a little on the fabricated spindle compared to this. My current design appears to be 3.4453" from the back of spindle to face of the hub while the stock spindle and cut down rotor is 3.875". So the caliper will move back about 7/16" compared to the above mock up.

Part of why I am thinking about swapping side for the caliper is so I can move the upper balljoint mount back an inch. It would look like this if I left the caliper as is.

This would build in about 6 degrees of positive caster. I might bump that to 7", it's all just speculation right now.

Here is how the stock spindle looks with 6 degrees of positive caster.

I haven't looked at the steering closely enough, could be tilting the spindle back makes it better. But it also moves the tire back, which helps with clearance at the front lower fender, but it hurts the clearance to the rear edge of the fender. Keeping the spindle more vertical and building in the caster would also keep the wheel centered in the opening.

Here is what a 2020 Mach 1 spindle looks like so the offset isn't a new idea.

 

[Mopar_Taxi_Guy]

So when you say your fabricated knuckle is based off of the FMJ knuckle geometry, does the include the 3/8" added height as well?

 

[DionR]

So when you say your fabricated knuckle is based off of the FMJ knuckle geometry, does the include the 3/8" added height as well?

The F-Body spindle is about 3/8” taller at the UBJ mount than the A-Body spindle. And I matched the F-Body height. So it includes the 3/8”.

I had a drum brake spindle that I measured and compared to the F-Body spindle and confirmed the difference in height. I will post a comparison later.

 

[DionR]

Looks like the distance was actually closer to 1/2"

 

[swisswill]

This is awesome. I agree with you, I think we need to get geometry mapped out, see what it takes to optimize, and maybe the fab'd spindle can seal the deal. I'll throw some coin in to help defray suspension analyzer costs and pay for time. If there is a lift near me I'm happy to throw my car up and take measurements, but I'm probably not the best guy to map it all out, I paid somebody for help with my '69. I have SPC upper's on my car with a bunch of caster already, but I don't think that would mess with designing caster, or additional caster, into the spindle. But maybe plotting out a neutral position with the UCA, then look to optimize the UBJ? I've heard, and read, that the LCA being level is ideal, but don't know for sure. I know my '76 is much lower than stock, and I'd like to go lower yet but if too low is messing up handling/geometry then I'll make a change. None of it will be perfect, but I'll bet we can find optimum ride height, caster, camber gain, then maybe some tweaks of a custom steering arm can dial it in. When we have something, I'm happy to take it to my guy to get thoughts on machining but @bjkadron already meantioned he's in on that as well. I could also take the design to Michigan Metalworks to get their thoughts on producing it.

I read your comment on the other thread Dion about the hub being pulled in 7/16". That could be tricky for some that already have 18" wheels and big offset. Originally I was planning to match the factory hub/rotor offset with the hub/rotor combo I pulled together, but haven't taken measurements yet.

I appreciate all the work you've done so far, and letting some of us jump in with you.

 

[DionR]

I think I just did up the knuckle and let the hub land where it was. But I have already bought (4) 18x9 +35mm wheels so wasn't excited about a different offset. That said, I struggled to find 9" +35mm wheels that would work and a +30 or even +24 wheel seemed easy. So it might actually work better if it is a new build to keep the rotor back.

That said, all of my designs have been a flat plate welded assembly that could potentially be a bit modular so it could maybe be build both ways with just the addition or subtraction of a couple of plates.

I should add that I have been trying to keep this thing free from having to access a machine shop. I have been very happy with SendCutSend so far and my plan have been laser cutting all the plates and then plug and stitch welding the parts and depending on the bolts for the hub and LBJ to make it strong. The only caveat is the UBJ mount, that would take a real weld as it is designed right now.

The new stuff I have been toying with was started due to this spindle.

https://www.speedwaymotors.com/G-Co...9413wU4zcp9si-MiFHoE5w_tQnO9MdmvVWoAP0lul_ZaM

But I don't have much of anything more than an idea so far, and most of it would still be much like I have posted already. More just a bent spacer to offset the hub from the caliper mounting surface.

 

[swisswill]

That makes complete sense and certainly would keep costs down. I’ve seen that speedway spindle also. I imagine it’s quite a bit lighter than all the plates welded together. If that design was used, a similar idea could be used to push the hub surface out further if needed by adding and welding flat stock, and longer bolts; adding the same to the caliper mounting ears. I wonder if the hub would have to be raised to allow for bolting on the steering, I.e. a drop spindle.

To recap brake setup currently, you have designed in the four piston caliper from Dodge and the Dodge rotor as well or did you change it to the Mustang rotor for the bolt pattern?

 

[gzig5]

I find these fabricated spindles very intriguing. Never considered something like that but they certainly can solve a lot of problems. The bolt in bearing/spindle assembly is just icing on the cake. The stacked plates is a clever path around lack of tooling. I'll be following along closely. My current project is an E-body but I'm sure there will be some crossover. I've got MIG, TIG, Plasma cutter, milling machine, hydraulic press brake, and metal lathe in the garage and a 3d printer in the basement to make it happen. I just need to get better with the Fusion CAD software. It's been 30 years since I last made CAD drawings from scratch, and a few things have changed in that time.

 

[bjkadron]

This is awesome. I agree with you, I think we need to get geometry mapped out, see what it takes to optimize, and maybe the fab'd spindle can seal the deal. I'll throw some coin in to help defray suspension analyzer costs and pay for time. If there is a lift near me I'm happy to throw my car up and take measurements, but I'm probably not the best guy to map it all out, I paid somebody for help with my '69. I have SPC upper's on my car with a bunch of caster already, but I don't think that would mess with designing caster, or additional caster, into the spindle. But maybe plotting out a neutral position with the UCA, then look to optimize the UBJ? I've heard, and read, that the LCA being level is ideal, but don't know for sure. I know my '76 is much lower than stock, and I'd like to go lower yet but if too low is messing up handling/geometry then I'll make a change. None of it will be perfect, but I'll bet we can find optimum ride height, caster, camber gain, then maybe some tweaks of a custom steering arm can dial it in. When we have something, I'm happy to take it to my guy to get thoughts on machining but @bjkadron already meantioned he's in on that as well. I could also take the design to Michigan Metalworks to get their thoughts on producing it.

I read your comment on the other thread Dion about the hub being pulled in 7/16". That could be tricky for some that already have 18" wheels and big offset. Originally I was planning to match the factory hub/rotor offset with the hub/rotor combo I pulled together, but haven't taken measurements yet.

I appreciate all the work you've done so far, and letting some of us jump in with you.

I looked at the examples of the spindles that Michigan Metalworks produced the best one seems to be something like this which is a large departure from what @DionR had been working on.

That being said, I think the best approach would be to either do a modular design like the below, Or basically just work together on the geometry and then everyone fabricates them how they think best. Though that would lose any opportunities for bulk discounts.

I have Fusion 3d that I can model things in but don't have a suspension analyzer currently. I Have some old information about the stock, raised B-joint and F body setups run through Performance trends but it is from about 15 years ago and I know it's not conclusive. Also my car is not currently in the state that I could accurately measure geometry.

 

[gzig5]

Is there a viable bearing/spindle cartridge that uses 5 x 4.5" lug spacing? My intention is to run a square tire setup so I can even wear on the tires a bit and having the same bolt pattern front and back would be required. I haven't figured out if the backspacing will allow that, but I'm heading that direction until I find out that I can't.

 

[bjkadron]

Is there a viable bearing/spindle cartridge that uses 5 x 4.5" lug spacing? My intention is to run a square tire setup so I can even wear on the tires a bit and having the same bolt pattern front and back would be required. I haven't figured out if the backspacing will allow that, but I'm heading that direction until I find out that I can't.

View attachment 1716391340

Yes, @DionR Has been using the S550 Mustang rear wheel bearing: More Information for MOTORCRAFT HUB395

And seeing as our cars are generally a few hundred lbs lighter, it should be sufficiently overbuilt.

 

[DionR]

I wonder if the hub would have to be raised to allow for bolting on the steering, I.e. a drop spindle.

My first design had an issue with the bottom hub bolt interfering with the LBJ, but the later iterations fixed it without changing the hub centerline.

To recap brake setup currently, you have designed in the four piston caliper from Dodge and the Dodge rotor as well or did you change it to the Mustang rotor for the bolt pattern?

I used the Dodge rotor. Bolt pattern on the LX/LC cars is a conundrum, but they fit fine over the Mustang hub. Only issue is the center bore on the rotor is a touch bigger than the pilot on the Mustang hub allowing the rotor to move around some. My plan is some feeler gauge material cut down to make small shims that center it up until the wheel is bolted down and are captured by the wheel.