I remember the parts they used at Group 44 worked great and as far as I know
never had to be changed again so listen up guys there is an answer here.
----- Original Message -----
From: Jack Wheeler <jwheeler@seidata.com>
To: 'Barr, Scott' <sbarr@mccarty-law.com>; <fot@autox.team.net>
Sent: Wednesday, February 16, 2000 1:48 PM
Subject: RE: The Hub of the Issue
> As I have mentioned before on the list, I have plans that were provided to
> me in 1976 by Group 44 (sorry, Kas) for rear hubs for the TR-4A through
> TR-6. I won't bore the whole list with the details, but if anyone is
> interested, I will be glad to help.
>
> By the way, I put these hubs on my SCCA TR-4A in 1977, and never had a
> problem again (I had broken a rear stub axle in each of the previous two
> seasons).
>
> -----Original Message-----
> From: Barr, Scott [SMTP:sbarr@mccarty-law.com]
> Sent: Wednesday, February 16, 2000 3:30 PM
> To: fot@autox.team.net
> Subject: RE: The Hub of the Issue
>
> << Several people have found great solutions to the axle problems and if
> you
> have a serious racer take their advice and MAKE THE CHANGE. >>
>
> You're absolutely correct, Kas. The question is WHICH change?
>
> That decision is driven by a determination of the source of the problem
> -- if the hubs are fine when they're new and it's just that they get old
> and can't take the abuse created by cornering forces after so many
> years, that's one kind of fix. If the basic design of the hubs is such
> that they are insufficient to handle the increased loads caused by
> newer, stickier tires, that's another kind of fix altogether.
>
> To summarize, then: Sounds like the opinion of most people is that the
> design is fine for its lifetime. But the lifetime is not forever,
> particularly if you're going to bolt racing tires to it. I'm going to
> check into having new hubs made, to the original design, out of good
> materials. Anybody that has a suggestion on proper material, or is
> interested in finding out the cost of the new hubs, just drop me a line.
>
> Scott
>
> > -----Original Message-----
> > From: R. Kastner [SMTP:kaskas@earthlink.net]
> > Sent: Wednesday, February 16, 2000 1:54 PM
> > To: Bob Lang; Barr, Scott
> > Cc: fot@autox.team.net
> > Subject: Re: The Hub of the Issue
> >
> > I recommended the change of axles on the TR-6 as that was the term we
> > found
> > was the LIFE of the unit. We ( as factory guys) could not use other
> > componets and so lost a few to find that the life was a real tihing
> > and to
> > pay atention to it. The late axles are of course ianduction hardened
> > but
> > some of the early axles shafts in the TR-250 and early TR-6's were not
> > and
> > they would be probably half the life of the induction hardened units.
> > Several people have found great solutions to the axle problems and if
> > you
> > have a serious racer take their advice and MAKE THE CHANGE.
> > ----- Original Message -----
> > From: Bob Lang <LANG@isis.mit.edu>
> > To: Barr, Scott <sbarr@mccarty-law.com>
> > Cc: <fot@autox.team.net>
> > Sent: Wednesday, February 16, 2000 6:35 AM
> > Subject: Re: The Hub of the Issue
> >
> >
> > > Hi,
> > >
> > > I'm not a metalurgist, and I've not been a racer for eons, so my
> > offering
> > > is more along the lines of a "lint picking session"... but to answer
> > > the principle question: why do hubs break? I'd have to say "for a
> > lot of
> > > reasons".
> > >
> > > Have the cornering forces increased? Well, in a word: yes. Think
> > about it
> > > - have lap times changed since these cars used to race?? Yes. _If_
> > you
> > > can find a track that hasn't changed. But tire compounds are
> > stickier,
> > > suspension settings generally tend to be quite a bit harder than
> > they
> > > used to be - something's gotta give somewhere.
> > >
> > > But wait - there's more. Even when your car can slide, there are
> > plenty
> > > of big forces on your little GT6 hubs... the metal will twist a
> > little
> > > bit each time you stress it. Eventually, you can develop stress
> > cracks at
> > > the surface, and if these pieces are stressed further - they will
> > fail.
> > >
> > > There's also the bigger problem (at least from my perspective) of
> > > determining the lineage of your parts. Take for example that pesky
> > hub
> > > that someone heated cherry red to take apart... I can't say with
> > > authority that such a process doesn't change the temper of the part,
> > but
> > > my best guess is that it has to effect it somehow. If you're lucky,
> > you
> > > get to see the cracks on the surface - if you're not lucky - well
> > then
> > > you'll know how good the part is eventually.
> > >
> > > If you want to be sure of the integrity of the parts - get 'em
> > x-rayed.
> > > At the very minimum crack test the parts that get stressed the most
> > on
> > > some sort of regular basis. Your local welding supply store will
> > have the
> > > stuff you need to check for surface cracks.
> > >
> > > But basically - things wear out. And when in doubt - replace.
> > >
> > > Now, a quote (from memory, so forgive me if I'm slightly off-base
> > here)
> > > from the TR6 competition prep manual suggests replacing the TR6 rear
> > hubs
> > > every _four races_. I'll bet this was suggested because that's how
> > many
> > > races they would see before the all important bearing end-float
> > would go
> > > into the "critical range" and likely fail if run any more, but Kas
> > could
> > > probably provide some insight there. On TR6's, one of the failure
> > modes
> > > is that one of the bearings will spin in place when the bearing
> > end-float
> > > gets excessive, and this will score the axle stub and form a nice
> > little
> > > place for cracks to start. And I further know that Spitfire axles
> > are not
> > > made any more betterer (!) than big Triumphs - so I'll bet bearing
> > > end-float is real important and more important when they fail (the
> > > bearing spins, for example) you're wrecking the axles.
> > >
> > > The GT6 (and Spitfire) parts - being smaller and lighter, are
> > probably
> > > just as prone to problems if things get "out of whack" regarding
> > bearing
> > > end-float and torque spec and the like.
> > >
> > > Bottom line - if you don't want to ball your car up, you need to
> > check
> > > this stuff on a very regular basis.
> > >
> > > And do as I say, not as I do. But I'm not a road racer, so a failure
> > in my
> > > persuit would likely be less "life threatening" (well to me anyway,
> > > apologies in advance to any cone pickers should my car ever suffer
> > an
> > > axle failure) than a road racer's might be. By way of example - if
> > you
> > > doubt your car would be able to go full tilt through Road America's
> > > "kink", you're probably not doing enough preventive maintenance to
> > get
> > > your confidence level where it should be.
> > >
> > > Hmmm. I'm overly wordy today. Sorry for rambling. X-ray your hubs,
> > please.
> > >
> > > rml
> > >
> > ----------------------------------------------------------------------
> > ----
> > -----
> > > Bob Lang Room N42-140Q | This space for rent.
> > > Consultant MIT Computer Services |
> > > Voice: (617)253-7438 FAX: (617)258-9535 |
> > >
> > ----------------------------------------------------------------------
> > ----
> > -----
> > >
> > >
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