More hub-upright failure data

[Curator]

My lr axle nut took about 1/2 turn recently to retorque,so its not one or two cars. Very might be these axle spacers are crushing,allowing some play at the axle nut.I don't think Brammo would have used substandard parts on the Atom though...

[DarthChicken]

Seems to me... that if something is able to be retorqued (and the nut hasn't moved) something is either stretching (the axle?  Unlikely) or being crushed.

And if something is being crushed.. its time to stop, and figure out why (and what).  And replace that part.  Not keep retorquing it, over and over until something snaps.  (No offense to those that have done just that, I know nothing about this subject, and I'm sitting here in my airchair drinking my hot cocoa).

And it seems as though Eddie has it figured out.  If the spacer is deforming, and he's replaced the deformed part and had no problems since.. is that the "easy" and "cheap" solution? 

Has anybody tried TMI's replacement hubs yet?  I thought I saw a post from Rnady saying that they had a stronger "factory" part?

[1965Cobra427]

And if something is being crushed.. its time to stop, and figure out why (and what).  And replace that part.  Not keep retorquing it, over and over until something snaps.  (No offense to those that have done just that, I know nothing about this subject, and I'm sitting here in my airchair drinking my hot cocoa).

And it seems as though Eddie has it figured out.  If the spacer is deforming, and he's replaced the deformed part and had no problems since.. is that the "easy" and "cheap" solution? 

Has anybody tried TMI's replacement hubs yet?  I thought I saw a post from Rnady saying that they had a stronger "factory" part?

"Retorquing it 'till something snaps' is not what happened. Breakage occurred when the spacer had peened down enough to loosen the clamping load on the hub assembly. Breakage was not a result of too much torque (or stretch) it came from the loosening. (Hubs broke when they were too loose.) Eddie and I began to torque it every session (to keep up with the crushing of the spacer). The hub breakage (failure mode 1) ceased. Failure mode 2 - hub flange breaking away from the center hub section) seemed to have no relation to the spacer crushing issue. In fact, both Eddie and I experienced most of the crush on the driver's side and much less on the passenger side. Failure mode 1 hub failures were all on the driver's side, failure mode 2 on the passenger side.

Failure mode 1 - driver's side
      


Failure mode 2 -  passenger side


With respect to the new TMI hubs, All of my failed hubs carried a constant thickness from the outside diameter of the flange to the point where it meets the hub center. Early hubs had about a 1/8" radius at this point. Later hubs (still constant thickness flange) had about a 3/8" radius. They still broke. The new TMI hub does not have a constant flange thickness. Just inboard of the lugs, the thickness is increased to the point that it is approximately 3/16" thicker where it meets the hub center. It also has a generous radius.

Except for Tom's hub-upright solution, the best OE combination seems to be the new hubs with increased thickness in the web and hardened spacers. As far as I know, no failures have been experienced with this combination.
   

[Positron]

I think FourFather and I are pretty close in sequence number. Mine show no sign of damage or needed more torque however I do not drive to the seriousness level of FourFather, or Randy. But I can see any crush would require addition rotational take up of the nut. Another reason I've stayed away from slicks.

Who's going to orchestrate the group buy of hardened spacers?

I'd be willing to pay the freight of someone's close-by take off uprights for cheap..

[Curator]

I'm not masking one mistake with another,and will spring for Toms uprights. Expensive.. maybe. Necessary.. for me absolutely.

I plan on running my Atom(s) extremely hard and do not want to worry about a problem that has already been addressed.

My 12" wide wheels are being made as we speak.

[DarthChicken]

Randy,

Understood.  I'm not sure you understood what I said about snapping.. but what I was trying to convey was that the spacer is crushing, and you were having to retorque to keep up with the crush.  Which to me says "something is wrong, stop".. and when I said "stop" I meant "stop driving" not "stop torquing".   Stop and figure out what is causing the issue.  Which has been figured out - crushing spacers, and a harder spacer is needed.  Which, as Spanky and yourself have stated, has been figured out.

Issue two is different, and seems related to design more than anything.. something that's been addressed in the TMI parts, and Tom's parts. 

Does anybody know if TMI's parts come with a hardened spacer?  And if not.. Spanky, are you sending the existing parts off to be heat treated, or are you making new ones out of a different material to be heat treated to a hardness of... ?

[whooops]

any pics of these crushed axle spacers?  I dont think I've seen the spacer before

[Stew Bartley]

12 inch wide wheels. Sounds real nice. What kind of design of spoke arrangement have you opted for?

[Curator]

"What kind of design of spoke arrangement have you opted for? "




HA! 


They will be just like Calscots. (I think 5 spoke star style) 

I don't care what they look like,as long as they are super light and strong.

 I didn't even ask what they looked like....

[1965Cobra427]

. . . and when I said "stop" I meant "stop driving" . . . 

Tell me you didn't mean it . . .  using that approach I'd have missed out on lots of awesome track time. Considering the failure mode 2 issue which might be solved by the thicker hubs (but took me months to get) I would surely have missed way too much track time. I'm OK with pushing hard enough to make the problems surface, replace parts and go again. My guess is that many other Atoms with 'soft' spacers will eventually have a problem. I'm just accelerating the wear and tear.

"You can always tell who the pioneers are - they are the ones with arrows in their backs"

[DarthChicken]

Sorry, I did mean stop driving.  When something breaks on my car... over and over.. I stop and try something different.  I would have been afraid of doing more damage.. losing a wheel, dying.. stuff like that.

[whooops]

Yeah, Randy.  I appreciate what you are doing and we all learn a lot from your experience  but I would have stopped because if I loose my car there is no way I could ever afford replacing it. 

[Curator]

Press on,regardless.!! 

[FourFather]

I sent an un-crushed and a crushed spacer to my expert machinist friend, Rex Earp, (yes, I think he's a distant relative of Wyatt), to show him the crushing problem and an undamaged one to get the dimensions to write the CNC program . He now has the program written and can manufacture them as needed.

Out of the first batch, I put two on my car, and gave Randy two. My new ones have run several days at Hallett, with Dunlop Radical slicks and just over 250 RWHP, with best lap of 1:21.7, and run two days at Eagles Canyon with a best of 1:58 something: and neither axle nut has moved AT ALL!!

Out of the two original equipment spacers, the lightly loaded (left) one was barely deformed, and its nut had gone only (!!) a half turn in or so, from the original paint-marked position. The OEM right spacer was HORRIBLY deformed, and that nut had been screwed in, a sixteenth or an eighth of a turn at a time, after EVERY session, until it had gone THREE FULL TURNS in from the original paint marks.

I had rather play with my Atom than get into the business of selling parts like this, but I am happy to donate what little time I have in R&D, to the Atom community, in return for all the help I've received with other Atom-related matters.

So, the spacer problem is solved, the heat-treated Stainless ones from Rex are tested and approved.

Rex scratch-built the connecting rods for my top fuel cars for years, and IMHO had the best rods in the industry. He builds fuel pumps for top fuelers and Indycars, marketed by Sid Waterman. He's done my critical machine work for years and never disappointed me.

Anyone interested in inquiring about/pricing/delivery time/ and or buying these, please get in touch directly with Rex.

Earp Machine, Safford Az, 928-428-3835

Eddie

[Lane]

Anyone interested in inquiring about/pricing/delivery time/ and or buying these, please get in touch directly with Rex.

Wow, thanks Eddie!

Anyone feeling ambitious enough to make the first contact and see if the machinist is willing to produce more of them?  Group buy, maybe?