Aluminum suspension tubes-- 88 Rear Suspension with Rod Ends

[The Dark Side of Will]

How far can you raise the inner pivots? I think that would be more effective than lengthening the links.

Once you have good geometry, just buy the appropriate wheels.

[Nemesis]

The inner pivot points are raised .75". There isn't much more room until the inner CV joint connects the mounts. IIRC, the links tilt up towards the wheel with the car sitting on the ground. So any upward movement is going to pull the bottom of the tire in even more. I wonder if offset links would help?

Getting the geometery correct is getting to be important. I'll be ordering wheels soon and they won't be cheap. The wheels will be custom made to my specs, so I have to get it right. So if I need to get longer axles, I'll need to do that before I order wheels.

Another thing I am worried about is the offset of the wheels stressing the bearings. Longer axles/links can help me move the hub out to help with some of the offset. I am using Koni struts converted to coilovers, so I can play with spring rates and I'll be using a splined rear bar. You can see the holes at the back of the cradle for the bar in one pic below.

Here's a couple of shots of the cradle I have.

[The Dark Side of Will]

You can raise the toe link pivot even further if you move it forward a bit and space the outer end away from the hub carier by the same amount.

How's the car's ride height relative to stock? It sounds like it's lowered a good bit...

Don't worry about your bearings. Stock Fiero 15x7's have 30 mm of offset. If you go toward zero offset, you will DECREASE your bearing loading in both straight line and cornering situations. Once you get to zero and start going beyond, you will start increasing static/straight line bearing load, but you will continue to DECREASE bearing load in cornering.

Bearing load in cornering is at a minimum when offset = (rolling radius) * (cornering g). IOW, for a 1G cornering load, bearing load would be minimized with 12-13 INCHES of offset.

If you maintain the backspacing of a stock wheel, 9.36" wide will get you 0 offset. From there, just maintain zero offset and widen the wheel until it fills the wheel house appropriately. With coil overs, a Fiero can take 6 1/4" of backspacing or even a little more on a 17" or larger wheel.

That's an interesting cradle. Is your car stretched? Got pics or build thread?

[Nemesis]

Well, my rear wheels (with stock axle length) will end up with a 6.5" or so offset (19x13 wheels with zeroish offset).

The car is lowered, but not exactly how much - about 2"?

Right now I have a 2.8 with a turbo mounted at the back, so moving the motor around might not be an option. I'm also trying to squeeze my Spearco liquid intercooler about where the cat. converter's stock location was. My exhaust now runs down behind the motor.

I don't have a build thread. My time is scarce for this project... I've been working on it for about 2 years now with not much accomplished. In the last few days I have done quite a bit. I installed an aluminum 2 row radiator, mocked up this cradle for motor and tranny mounts, installed a Spec clutch and a few other things. The cradle is mocked and goes in for some motor mount trimming and powder coat.

I'll get some more pics up soon. The car is an 88 Coupe with a turbo 2.8/Getrag 5 speed, t-top, with an modded IMSA body. All the trim has been removed. I'm also redoing all the wheel arches and making the rear even wider.

Some of the pics are of the other Fiero the body was on.




Basically I am doing tons of stuff to it and have no clue what I am doing.

[The Dark Side of Will]

Well, my rear wheels (with stock axle length) will end up with a 6.5" or so offset (19x13 wheels with zeroish offset).

The car is lowered, but not exactly how much - about 2"?

I assume you mean 6.5" of backspacing. That's going to be real tight. Measure twice, order once. What wheels are you looking at? Throwing down for HRE's like a baller?

Lowering is a problem... it screws up the '88 rear geometry. For best handling, the car should be stock height or even a little higher. If you're going to be reworking the wheel arches, just lower them a bit so you get a good wheel arch gap all around at a ride height that's good for the suspension.

[The Dark Side of Will]

Revisiting this...

Increasing the track by lengthening the lateral/toe links will increase the kingpin angle. This decreases the angle between the kingpin axis and the lateral link, which effectively places the suspension BELOW its constant camber range... compression would then increase camber.

[The Dark Side of Will]

Update.
$8 rod ends last at most 6 months. That's about how long it took the car to develop the symptoms of loose rear suspension component. A 9-3 shake test confirms.

Never buy the cheapest.

[Fastback86]

Just out of curiosity, how many miles did you put on them, and what kind of driving?

[The Dark Side of Will]

According to my log, I have about 9,000 miles on them right now. It was probably 7,500 or 8,000 when I started noticing symptoms of loose components. The car was my daily, but I make a point to leave at least a little bit of rubber out in the wide world every day I drive it. I also took a pretty nice driving road over Thornton gap probably twice a weekend on my way to/from parents' house.

[Aaron]

Off topic, but that is one of the very few Fieros I think could pull off a small (1-2") chop top.

Looks great!

[Series8217]

BUMP because I'm revisiting this project.

I guess 9,000 miles isn't that bad for cheap bearings that you couldn't even grease since the fittings popped out..

I see that the next price range is $20/brg and after that, $40/brg. I think I'm going with the $20 variety.

How did the 12mm to 5/8" adapters work out? Did you make something that threaded onto the factory bolt, or was it just a sleeve?

[Series8217]

I think I'm going to get these:
http://www.out-pace.com/7-8tubes5-8ends.html
The rod ends have grease holes in the shanks, and the grease fitting is in the big tube.. so it doesn't weaken the rod end.

This guy used them successfully on a Mini:
http://www.northamericanmotoring.com/fo ... -arms.html

I just need to find out the center-to-center measurement. I think the measurements given are only for the tube length.

[The Dark Side of Will]

I think I'm going to get these:
http://www.out-pace.com/7-8tubes5-8ends.html
The rod ends have grease holes in the shanks, and the grease fitting is in the big tube.. so it doesn't weaken the rod end.

This guy used them successfully on a Mini:
http://www.northamericanmotoring.com/fo ... -arms.html

I just need to find out the center-to-center measurement. I think the measurements given are only for the tube length.

That's a pretty cool find.

The minimum center-center length will be the tube length + 2x the thickness of the nut + 2x the minimum distance of the rod end. The nut and rod end dimensions will be substantively the same for all brands of jam nut and rod end. You can look at the dimensions I posted for my set earlier in this thread to figure see what'd you'd need to order.

Would you mind posting that link to the Hard to Find Parts thread?

[Series8217]

I can't find an online dealer for anything shorter than the 10" tube. I'll call the manufacturer sometime next week to see if they sell direct.

[Series8217]

I ordered from Out-Pace Racing products. They sell directly, prices are decent, and the guy that answered the phone was nice and helpful.

He recommends these rod end grease seals:
http://www.sealsit.com/rodend.asp
I think he said they plan to start selling them as well.

I ended up ordering 9" and 10" tubes, part numbers 1-090-M2, and 1-100-M2. Will used 8" and 10" tubes. The 9" tube should work for the tie rod, but there isn't much adjustment on the short side of things. However, I will just kick the lateral link out further if I need more toe. I want to extend the rear track a bit anyway, maybe 1/4" on each side.

Does anyone know how far the Fiero's CV axles can extend safely?

[Series8217]

I received the links from Out-Pace Racing Products today.

The rod ends and jam nuts add 2.75" total to the length of the tube, so a 9" tube makes an 11.75" link between the center of the pivot points.
There's 1.25" of thread left past the jam nut, so the maximum link length is 11.75+2*X where X is the minimum amount of thread engagement you'd be willin to have on each rod end. The jam nuts are 5/16" thick, so using thinner jam nuts would provide a bit more room for adjustment.

The rod ends are greased through the shank. I have not seen these available commercially. It looks like Out-Pace Racing takes a non-greased rod end and drills the shank through to the race (with the ball turned so the drill can pass through the center without harming it). On most of the rod ends I received, it feels like they could have done a better job deburring the inside of the hole. Some of them are perfect. Others I can feel the ball catch on some burrs somewhere. There are no scratches on the balls or races. I think these will hold up pretty well when greased.

The grease fittings are installed on the link tube, and the tube is plugged just past the grease fitting on each side, to ensure that the tube doesn't have to be filled completely with grease before the balls get it.

[Datsun1973]

FYI i have something similar to this on the lower radius rod on my race car. I used sprint car steel 5/8 fine thread rods with 5/8 3 piece chrome moly rod ends. You can drill the knuckle and the cradle to 5/8" to accept the new standard rod ends. You also need to space out the knuckle end toward the centerline of the car to keep the rod ends within their alignment specs. Works great so far but I've also eliminated the strut and gone to a pushrod shock/spring with a custom upper control arm (aka GT40 style).

[Series8217]

Sounds interesting. Do you have pics?

Is that setup adaptable to a Fiero spaceframe?

[Datsun1973]

kind of. Its a 88' lower fiero space frame that I drilled out the mounts to accept 5/8" bolts and heims. It's a lot of work and won't give you any benefit unless you're building an all out race car. I'll post up some pictures of my entire rear end with bell crank QA1 shocks and full true IRS once I finish the 12" wilwood brakes this weekend.

[Series8217]

I installed my links last Thursday. Already loving the cross bolt that stays tight all the time! No more toe change on acceleration.

Once the roads dry out and I get the alignment in spec I'll see how much of a difference it makes on cornering. I'm expecting quite a difference since the poly would flex so much.