Real Fiero Tech

When I installed the hubs on the car on 23 August 2023, the wheel one one side wobbled (the opposite wheel turned normally).

I figured that the cause was the hub face which had 0.015" of runout:
https://youtu.be/mytS2BFMlpQ

With prodding, sluppy123 agreed to make me a replacement hub (I would have also accepted a full refund), but he has not been very responsive to my messages. I haven't been blowing up his phone either; perhaps a message every week.

No sign of when a replacement hub will be prepared (my car needs this to be able to drive).

I'm close to the point where I'm going to make my own drawing of a hub, and have it machined at a CNC shop.

I'm not so happy with this transaction.

that's a bummer, everything I've bought from him has been ok. hopefully he makes it right soon, you're probably running out of time to enjoy driving your car this year...

He'd agreed in principle to produce a pair of my updated/improved design for multi-pattern hubs to go along with Street Dreams lowering spindles. I haven't sent a model or drawings yet because I'm focusing on getting The Mule running.

Thanks for bringing this up so I can get started on that in an informed fashion.

I normally stop driving the Fiero around mid-November, so yeah, I'm running out of time.

I'll re-ping sluppy123 on Monday to see if he has any updates.

In the meanwhile, I found this publication from Timken:
https://www.timken.com/resources/cv5-co ... l-bearing/

If I end up making my own hubs, I may push the wheels outboard some 2 mm or so. At at full droop/lock, the banjo fitting on the caliper comes close to the damper mount on the LCA.

A good friend of mine has a pretty serious CNC setup for producing aftermarket jeep parts if you ever want an introduction for an alternative producer.

The Dark Side of Will wrote: ↑Thu Sep 28, 2023 9:24 am He'd agreed in principle to produce a pair of my updated/improved design for multi-pattern hubs to go along with Street Dreams lowering spindles. I haven't sent a model or drawings yet because I'm focusing on getting The Mule running.

Thanks for bringing this up so I can get started on that in an informed fashion.

I sent another follow-up message on Friday 2023-10-06. No answer.

Looks like I'll end up having to deal with this on my own...

It appears that sluppy123 only answers messages when he has good news, otherwise, radio silence.

After some unanswered messages, sluppy123 told me last Thursday that he received the raw material: On Monday, he told me the replacement hub was done: So it may show up, possibly...

I don't like the poor communication; I'm not planning on any repeat business with sluppy123 after this experience.

pmbrunelle wrote: ↑Wed Oct 25, 2023 11:01 pm It appears that sluppy123 only answers messages when he has good news, otherwise, radio silence.

After some unanswered messages, sluppy123 told me last Thursday that he received the raw material:
1.png

On Monday, he told me the replacement hub was done:
2.png

So it may show up, possibly...

I don't like the poor communication; I'm not planning on any repeat business with sluppy123 after this experience.

pretty crummy that it's taking so long to get rectified... hopefully you have new parts in your hands soon. the lack of communications would have me pretty upset as well.

With some nagging, I finally got a tracking number (currently at label created) today, 72 days after I reported that my hub was scrap and that replacement was required.

The replacement hub showed up yesterday on 2023-11-22.

I'll check the runout in a week or so, the next time I go visit my parents (where my Fiero is currently located).

The replacement hub still has 0.005" runout:
Better than 0.015", but still too much. I asked sluppy123 to inspect his work before shipping (I told him that I was expecting 0.003" max); looks like he didn't.

The corner radius of the endmill used to cut the pockets changed from 0.0625" to 0.125" between the original hub and the replacement. Sure, the larger radius may be better from a stress concentration viewpoint, but this hub was supposed to be a replacement for the original one, and it's not the same, so I'm unhappy about the surprise change. Now the left and right hubs aren't the same anymore.

Overall, a poor experience. I don't think that sluppy123 quite has the machining skills to be selling this kind of part.

I'm looking into the possibility of machining the hub face flat, but I have some homework to do first.

Curious as to what the factory hub runout is? Maybe it's already been mentioned

I measured two factory Fiero rear hubs, and they had 0.002" runout.

I think that my expectation of 0.003" runout max for the replacement hub was more than reasonable.

You should have all of your parts cnc machined from this point forward. I would only park the finest quality parts in your mom's garage.

These hubs were cut on a CNC machine.

From what I see, the inboard and outboard sides of the hub were machined in two different setups.

When the part was flipped over to machine the other side, it wasn't well aligned with the machine; the offset between the different setups (and hence the bearing race bores) is what causes the runout.

CNC is fine and dandy, but it still needs a skilled operator behind it for good results.

No, you personally should cnc your own parts moving forward.

pmbrunelle wrote: ↑Sat Dec 09, 2023 8:25 pm I'm looking into the possibility of machining the hub face flat, but I have some homework to do first.

Machining the hub face flat would resolve the runout issue, which I can do relatively easily.

However, this doesn't address the root problem of the offset between the machining setups.

The offset between the machining setups causes the inner and outer bearing races to be offset from each other, so the bearing races operate at an angle relative to the axis of rotation.

I found a thread about a similar issue on the eng-tips forum:
https://www.eng-tips.com/viewthread.cfm?qid=282514

As tbuelna (an experienced member I trust) explains, the crookedness of the bearing race means that the roller is not equally loaded along its length (biased towards one end). The roller is made with some crowning to compensate for misalignment, but there is a limit to the acceptable misalignment. In the similar trailer stub axle application, tbuelna thinks that a 0.002" offset is the maximum that could be OK. To have 0.005" runout, I think that I have a 0.005" offset between the bearing bores, which is way too much. The replacement hub is good as a paperweight.

I'm now looking into modifying aftermarket Rockauto hubs for my application.

Brand-new CNC machined hubs from another shop are a plan B, but may not be the magic solution if they too have quality problems.

pmbrunelle wrote: ↑Sun Dec 10, 2023 5:48 pm These hubs were cut on a CNC machine.

From what I see, the inboard and outboard sides of the hub were machined in two different setups.

When the part was flipped over to machine the other side, it wasn't well aligned with the machine; the offset between the different setups (and hence the bearing race bores) is what causes the runout.

CNC is fine and dandy, but it still needs a skilled operator behind it for good results.

That's what I was thinking as well... There's not way to cut the part in one setup. His process did not adequately provide for maintaining register between the two setups. He could probably take a minute or two per part indicating to the hub flange on the second setup and keep runout <0.003.

Emc209i wrote: ↑Sun Dec 10, 2023 5:10 pm You should have all of your parts cnc machined from this point forward. I would only park the finest quality parts in your mom's garage.

I sense some sarcasm...

Patrick works in the automotive OE world and understands what's reasonable for a production part.

I'm not clear on the impact of 0.005 runout vs. 0.003 runout... Will it be perceptible via wheel shake under braking? Not sure.

I think Pat's point is more that the parts are being made by a hobbyist who has no understanding of process engineering or quality control. That's par for the course in the Fiero community.

Scorn and contempt, not sarcasm.

Put the fucking thing on your car and drive it until you have a failure, then complain.

Emc209i wrote: ↑Sun Dec 10, 2023 6:54 pm Scorn and contempt, not sarcasm.

You always did seem like a "rye whiskey, neat" kind of guy.