Working towards larger rear 88 hubs....

[Jinxmutt]

So after breaking another axle on wednesday, its time to start looking to upgrade the outer CV joint and the rear hub. The 84/87 guys have it easy, simply swap to a 6000 upright with the S10 splines. There doesn't seem to be an easy bolt on solution thats widely discussed for the 88s.

I'd like to find a hub that will fit the existing upright, even if that includes having to machine out the center a bit. I think I might end up being limited by the bolt circle of the 3bolt mounting flange. Here are the specs that I have for the 88 rear hub.

Code: Select all

Attribute	                    Value
Flange Diameter                 4.921
Bolt Circle Diameter            3.937
Bolt Circle Diameter Metric     100
Bolt Size                       M12X1.5
Bolt Quantity                   5
Wheel Pilot Diameter            2.244
Brake Pilot Diameter            2.274
Flange Offset                   1.66
Hub Pilot Diameter              2.795
Hub Bolt Circle Diameter        4.016
Bolt Hole MET                   12.96
Bolt Hole qty                   3
Number of Splines               33
Flange Shape                    MODIFIED TRIANGLE

The reason behind this is so that I can get the larger splines in the hub, so I can hopefully not break them once I go auto. There are expensive axles that can be purchased to retain the fiero hub, but if I can just use a larger unit from the grand prix, s10, cadillac, etc, I think it would be a better alternative.

This is the difference between the S10 and the fiero, from bubbajoe's site..


I think running that larger outer would help prevent breakage. I know the S10 necks down right where I've broken the axle, but that picture is just for example...

[The Dark Side of Will]

Did you post axle carnage pics anywhere?

[darkhorizon]

Did you post axle carnage pics anywhere?

I imagine they were similar to bigfieroman's. The splines broke off the outer on his.

[fieroguru]

I have looked into this for an 88, but there just isnt much material on the upright around the bearing to go with a much larger hole... I would love for there to be a solution.

[Jinxmutt]

I didn't take any pics yet. The long axle cracked at the inner CV and was gross as hell so I just threw it in the trash can at the track. I didn't bring rags with me to clean the grease enough to put it back into the front compartment. I still have the short axle that i can snap some pics of when I get a chance. I saved the short axle because the last one I broke just snapped the shaft.

[The Dark Side of Will]

Did the axle shaft itself break, or did it just break the inner tripod? Those long shafts are getting somewhat rare.

[Jinxmutt]

Opps, well then that was a bad idea. It was the tripod itself, not the actual axle shaft. I don't have a rear trunk any more so my only storage is the front. When I ran my 11.6, that was with both spare axles, a toolbox, and a small jack in the front compartment. After that long axle tripod broke, it was covered in grease and I wasn't about to put it back in the front compartment, so I chucked it.

[Atilla the Fun]

If someone can give me details on an easy Do-It-Yo'self way to press the stub axles out of the uprights, I'd be interested in investigating if my Bonneville stubs might be adaptable. Their outer splines and their CV cups both seem larger than what came with my '88 cradle.

[fieroguru]

The axles are not press fit into the wheel bearings, just take the outboard nut off and they will slide right out.

[Atilla the Fun]

So I just need to grind the threads down until I can get a socket to reach the nut...I can do that. Maybe not today, but probably this week. I'm not buying another deep socket. I see no good reason for the threads to be so long, that just adds unnecessary weight and aggravation. I will report back on the B'ville stubs versus '88 Fiero stubs. With pic(s).

[The Dark Side of Will]

Worst case scenario is that the axles will require a *tap* with a medium/large hammer to unseat them.

[fieroguru]

The way I see it there are two general paths to take with this solution... You could look towards an older setup (like the caddy FWD's of the 60's/70's when they used big block power) or go later model. The older stuff would probably be bullet proof, but harder to find. The newer stuff would be designed around the current trends of higher hp, larger wheels, and better tires.

The latermodel stuff while many still use a 33 outboard CV spline, its splined shaft is much, much larger in diameter than the fiero units, but the CV cage remains about the same. Here is a pic of the torrent axle next to a fiero sized one for comparison. I have never checked out the torrent wheel bearing, but I am pretty sure its housing is much larger:


I am looking for larger axle shaft diameter along with larger stub shaft on the CV's. It will most likely require a bolt pattern change, but that just opens up more options for larger/wider oem wheels.

[Jinxmutt]

I'm not worried about the larger bolt circle, I would just really like to get a larger splined section, and therefore a larger hub onto the 88 upright, which doesn't seem possible.

[The Dark Side of Will]

There was a guy on the Fiero Racing List that machined the '88 hub carrier to do the job of the outer shell of the larger bearing cartridge, then disassembled a larger hub and reassembled it around the modified knuckle. It seems like a hack to me and I suspect will to you also, but I thought I'd bring it up. There are pics of it on the interwebs also.

Take a look at the rear knuckle for a 1st gen W-body. That *may* be adaptible for the rear of an '88 Fiero.

Whenever I think about this problem, I keep coming back to the idea that I'd just have to make a new knuckle to upgrade the rear bearings on an '88. Such a piece could easily be aluminum. Not sure if that would be fully fabbed from water jet cut components or CNC'd from a piece of 3" plate with the strut mount welded on after the fact.

[Atilla the Fun]

So what's the goal? More torque capacity, or more load capacity? From the OP, I thought torque, which shouldn't need larger bearings. In fact, it should need smaller bearings to make more space for larger axles. After all, it seems the hubs won't accept a larger-O.D. bearing assembly, so the balls or needles in the bearing assembly will have to be smaller. So it seems the issue isn't which axles, it's which bearings.
What's needed is to measure the O.D. of the bearing race on the '96 Bonneville axle, and measure the O.D. of the '88 Fiero rear bearing assembly, then start searching for bearings to suit.

[Jinxmutt]

The problem is that the axle breaks at the splines. If I could get a bigger axle in that area, i was hoping it wouldn't break as easy.

[p8ntman442]

How about a cryo treated axle?
the reason being is that swapping the hubs fixes the axle issue on the outside, but the inside will be the next weakest link i would think, and then your onto another issue.

[Series8217]

There was a guy on the Fiero Racing List that machined the '88 hub carrier to do the job of the outer shell of the larger bearing cartridge, then disassembled a larger hub and reassembled it around the modified knuckle. It seems like a hack to me and I suspect will to you also, but I thought I'd bring it up. There are pics of it on the interwebs also.

Did he use Camaro brakes? I remember seeing a picture of a modified knuckle with a hub that might have gone together like that. I don't remember what the hub was from but I remember he was using Camaro calipers and/or rotors.
I'll have to look around for the pics I saved.


EDIT: I found it: http://www.fiero.com/forum/Archives/Arch ... 65.html#p3
Scroll down for pics and more details. I don't know if these hubs use different axle splines. From the pics it looks like they might be the same as the Fiero.

[The Dark Side of Will]

There was a guy on the Fiero Racing List that machined the '88 hub carrier to do the job of the outer shell of the larger bearing cartridge, then disassembled a larger hub and reassembled it around the modified knuckle. It seems like a hack to me and I suspect will to you also, but I thought I'd bring it up. There are pics of it on the interwebs also.

Did he use Camaro brakes? I remember seeing a picture of a modified knuckle with a hub that might have gone together like that. I don't remember what the hub was from but I remember he was using Camaro calipers and/or rotors.
I'll have to look around for the pics I saved.


EDIT: I found it: http://www.fiero.com/forum/Archives/Arch ... 65.html#p3
Scroll down for pics and more details. I don't know if these hubs use different axle splines. From the pics it looks like they might be the same as the Fiero.

That's the setup to which I was referring.

[Atilla the Fun]

You guys are chasing the wrong lines of thought. Doesn't anyone have access to a bearings catalog?