Group buy: Front Lower Spherical Bearing Shells

[The Dark Side of Will]

I'm looking at getting 8 (two vehicle sets) of my bespoke design of spherical bearing shells for all years of Fiero front lower control arms made. The quote runs just under $100 each shell for quantity of 8.

The CNC program development and machine setup are fully half the cost of the quote, so if I could run more parts, the price will come down significantly. A run of 20 (3 additional sets) should come down to around $70 each; a run of 52 parts (11 additional sets) should be around $58-$60

The shells are, of course, only one piece of the puzzle. Also required are spacers (bespoke; will get a price for those), Aurora CM-10 spherical bearings, ID snap rings and shaft seals.

The shells fit ALL years of Fiero front lower control arms.
They WELD in place. I have not yet developed a press-in model.

EDIT: To install the shells to your control arms, you will install bearings to the shells, then slip the shells into the control arms; install the control arms to the body and tack the shells into the control arms. Then remove control arms, remove the bearings and fully weld the shells.

EDIT: Welding as shown below does not distort the bore. I measured preload before and after welding and it only changed by +/-2 lnlbs across the 4 units.

A set includes: 4 shells, 4 bearings, 4 snap rings, 8 spacers. For installations to 1988 Fiero front suspension, sets will also include 8 shaft seals. Sets for '1984-1987 Fieros will not include seals as those units operate with angularity and eccentricity that seals won't tolerate.
An (simple/cheap) installation/removal tool will be available for an additional charge. It is required to install the rod ends without damaging them, but each purchaser only needs one tool.
Using the tool, bearings can be installed and removed with just a small bench vice. EDIT: And snap-ring pliers to remove the snap ring. Pliers not necessary to install.

If a few people here will commit to a set or two, I'll post this on PFiffle to see if I can get enough interest to make managing it worth my time.

EDIT: Installed photos (of a visually identical unit in a rear control arm):

Installed the control arms to the cradle with the spherical bearing shells loose in the control arm sockets, then had them tacked in place and removed for finish welding.
Caveat: The suitcase TIG was broken, so they had to be tacked with a very messy wire feed.
I biased the control arms rearward ~ 1/4"... mostly because I could, partly because the rear wheels sit 1/2" forward of centered in the wheel well openings.

[pmbrunelle]

Preface: I may be a bit of a tire kicker here, but I have a question.

Is it expected that a normal dude in his garage can weld these shells without distorting the bores into uselessness?

[ericjon262]

I think it's safe to say you can put me down for a set for my 85.

[The Dark Side of Will]

Preface: I may be a bit of a tire kicker here, but I have a question.

Is it expected that a normal dude in his garage can weld these shells without distorting the bores into uselessness?

Yes. I wouldn't make this your first weld job. I strongly recommend TIG, but you can tack-in-place with wire feed, then take the assemblies to a welding shop.

I measured the installed pre-load of the bearings before and after welding and it didn't change by more than +/- 2 inlbs

[ericjon262]

Preface: I may be a bit of a tire kicker here, but I have a question.

Is it expected that a normal dude in his garage can weld these shells without distorting the bores into uselessness?

Yes. I wouldn't make this your first weld job. I strongly recommend TIG, but you can tack-in-place with wire feed, then take the assemblies to a welding shop.

I measured the installed pre-load of the bearings before and after welding and it didn't change by more than +/- 2 inlbs

I think it's safe to say that 2 in-lbs is a negligible difference. you did this on the mule or your Formula?

[The Dark Side of Will]

I did some pretty careful evaluation involving a day on a jig grinder to nail down the bore diameter and tolerance to result in keeping preload mostly in the 20-40 inlbs range.

I've installed the '84-'87 rear units on The Mule, but only drove it a mile and a half to the shop where I pulled the engine.

The 8 shells I want are for The Mule and Storm Trooper front ends.

[The Dark Side of Will]

I've installed the '84-'87 rear units on The Mule, but only drove it a mile and a half to the shop where I pulled the engine.

Duh... I also installed my 4 prototypes of the front shells into a pair of '88 control arms which I have been and will be continuing to modify for a coil over conversion. They were tacked in place using a fresh crossmember which I will modify to raise the bump stops. This operation makes this crossmember + these control arms a matched set.

Having the crossmember and control arms matched is probably NOT nearly as important on either front end as it is on the '84-'87 rear control arms.

The '88 crossmember has mounting ears that make +/-0.030 overall length tolerance still installable.
The early front end has the rear pivots welded to the body, but the forward pivots on the crossmember. This means that the crossmember bolts can be loosened to shift the crossmember to accommodate overall length tolerance mis-matches.
All this means that the front control arm shells could probably be welded in a fixture and then bolt in to any crossmember or chassis with minimal problems.

The design of the '84-'87 cradle is quite INtolerant of length variation. The shells for the '84-'87 rear arms should absolutely be tacked in place, and then become a matched set with that cradle.

[The Dark Side of Will]

Got a quote back with multiple quantities, and it's better than I thought it would be.

20 shells: <$50/ea
40 spacers: <$15 each

52 shells: <$40/ea
104 spacers: <$12 each

[ericjon262]

Got a quote back with multiple quantities, and it's better than I thought it would be.

20 shells: <$50/ea
40 spacers: <$15 each

52 shells: <$40/ea
104 spacers: <$12 each

20 shells, as in 5 sets correct?

[The Dark Side of Will]

Yes, that's 5 sets. With me taking 2, 1 for you and 1 for Brunelle if he's more than a tire kicker, that's 4 right there.
At that quantity, the cost per set for bespoke hardware would be $200 for shells (4x50) and $120 for spacers (8x15) + an installation/removal tool (need to get that quoted) + spherical bearings + snap rings (+ seals for '88's). That's if no one else jumps in... I think a few from Old Europe will join in, once I get my shit together and post a thread there.

I'm thinking it might be worthwhile for me to kit these up rather than providing a BOM and letting people find the other parts on their own.

[The Dark Side of Will]

Tools are $25 each with 20 shells and $20 each with 52 shells

[ericjon262]

More people will probably be interested in a kit, vice parts w/ a BOM. A kit will also prevent a ton of "will this work with xxx" type questions as well, that are bound to come up no matter how detailed your BOM is.

[pmbrunelle]

Even if I bought the package in kit form, I would still like a copy of the BOM, to facilitate future parts replacements.

Perhaps you could edjumacate me on the end-user benefits of spherical bearings in the lower A-arms. Presumably, you feel that the rubber squishes too much with applied forces.

Here are some thoughts:
Do the spherical bushings give a "tighter" steering feeling?
During cornering, does the bushing deflection allow the tire to tilt outboards (i.e. gaining positive camber), riding on the outside shoulder, reducing grip?
Do these issues take on more importance due to the grip afforded by modern tires vs. the 80s equipment?

Rebuilding the 35-year old original front suspension (all cracked rubber) is on my to-do list. I gotta decide if I'm going to do it with Moog rubber or Will's magic sauce. I just want to know why I'm buying a product instead of buying it blindly.

Pricing is OK, but if you were quoted those prices, you should charge more to compensate for your time/effort. I would agree to a profit margin.

[The Dark Side of Will]

Even if I bought the package in kit form, I would still like a copy of the BOM, to facilitate future parts replacements.

Perhaps you could edjumacate me on the end-user benefits of spherical bearings in the lower A-arms. Presumably, you feel that the rubber squishes too much with applied forces.

Here are some thoughts:
Do the spherical bushings give a "tighter" steering feeling?
During cornering, does the bushing deflection allow the tire to tilt outboards (i.e. gaining positive camber), riding on the outside shoulder, reducing grip?
Do these issues take on more importance due to the grip afforded by modern tires vs. the 80s equipment?

Rebuilding the 35-year old original front suspension (all cracked rubber) is on my to-do list. I gotta decide if I'm going to do it with Moog rubber or Will's magic sauce. I just want to know why I'm buying a product instead of buying it blindly.

Pricing is OK, but if you were quoted those prices, you should charge more to compensate for your time/effort. I would agree to a profit margin.

I'll provide PNs for the replacement parts. If nothing else, that's to make sure that the replacement bearings perform the same as the ones I send the kits with. The prices above reflect reasonable pass-through profit for me. The kit prices will reflect something for my time to get them together, boxed, shipped, etc. I have to buy packaging materials, for example. I know better than to try to recoup my R&D time from the Fiero community

Spherical bearings get rid of the squish in rubber bushings. Mostly you'll feel this with the chassis heavily loaded through corners, as the spherical bearing suspension will hold its camber better and make better, more predictable and less variable use of the tires at maximum lateral g's. You'll also feel sharper steering precision and better ability to place the car where you want it on the racing line.

NVH will be slightly increased. I've actually never driven a Fiero with spherical bearings in the front suspension. I have had rod-end lateral links in the rear of my Formula for years and years... I did not notice any change in NVH *AT ALL* with those.

Modern high performance tires blow '80's tires out of the water. With very short knuckles, bushing deflection in a Fiero matters a lot more for camber with lateral load than it does in a car with taller knuckles.

The spherical bearings I've designed these shells for are Aurora teflon lined units. The bore size and tolerance in the shell keep the bearing preload in the 20-40 inlbs range, with a few creeping up to 60, due to Aurora's manufacturing tolerances. This is WAY less preload than any other option. Polyurethane is infamous for stiction, requiring regular greasing, and of course shearing a rubber bushing acts like a second spring. Delrin or UHMW PE bushings have theoretically close enough to the stiffness of spherical bearings that you won't notice the difference driving, but they have to be custom made.

All bushing materials wear out. Replacement of rubber, polyurethane and hard plastics is difficult, with hard plastic units requiring me to make new ones at every replacement. Of course the spherical bearing wears as well; I really do not know its service life. The higher the preload, the longer the service life, per Aurora. However, replacement parts are <$20 each from a HUGE network of suppliers and replacement of the part is easy using a bench vice once the control arm is out of the car.

[pmbrunelle]

I'm convinced. I'm in for a set!

As for the stiction of polyurethane, I haven't noticed much when it's being used in a normal pivoting manner.

However, in the front of the 84-87 with the binding due to the design disaster, there's a bunch of stiction there.

[The Dark Side of Will]

Group buy is live:
http://www.fiero.com/forum/Forum1/HTML/099464.html

[The Dark Side of Will]

Spherical bearings:

I finally installed the bearings into the '84-'87 rear control arms I had welded and powder coated
Here's one with the snap ring that retains it. The press fit is rather light in order to keep the preload torque in a range that it reasonable for a suspension pivot. Most of these are in the 30-40 inlbs range. The bearings are easily installed with a bench vice and the installation tool I designed.
Yes, there is a gap between the tips of the snap ring and the ball. However, that doesn't really matter much, since these bearings won't see any misalignment. The worst that could happen would be that the snap ring lobes would score the ball a tiny bit, but that part of the ball would never be under the race, so meh.



Here is one of the shaft seals I'm trying out:



And here's the finished product with the spacer installed. The seal retains the spacer well enough that it doesn't fall out.

[The Dark Side of Will]

Extra eye candy from the development process:

The spherical bearings are Aurora COM10T's. I bought 12. 8 of them had preload in the 2.5-7.5 inlbs range, while two were <2.5 inlbs and 2 were >2.5 inlbs. I used the 8 in my shells. However, based on some bad advice I have the installation bore too small. The bearings had >60 inlbs of preload when installed. Ooops. I need to have the shells modified from a smaller bore with a +/-0.0005 tolerance to a slightly larger bore with a +/-0.0001 tolerance. Weeee.

[pmbrunelle]

What kind of raw material are the shells made from? I want to know what I'll be welding.

What are the spacers made from? I would like to know if they need anything (could be user-applied) to resist corrosion, such as paint.

I suppose that the corrosion question also exists for the shells, since the bores on the unsealed 84-87 application will be exposed.

For the snap ring ears, if users find them close to the ball, we can just grind back the ears a hair. I might do that.

[The Dark Side of Will]

The shells are 1018 basic low carbon because they get welded.
The spacers are 12L14 because machinists like it and they don't need to be welded.

I guess I could get SS quoted for the spacers. If the kits are already $500, an extra $20 for stainless isn't a big deal.