When i said CHANGE to a modified unit I meant for the TR-6 stub axle. On
the GT-6 we finally made up a forged unit. I had to have the die made and
that of course is long gone, but we did indeed break the hubs alot on the
rotoflex car., The design in my mind was in need of some serious help for
BEEF. There is answers out there with guys that are running these events
now, sooooo "What are you doing to keep that little hub togeather now??"
----- Original Message -----
From: Barr, Scott <sbarr@mccarty-law.com>
To: <fot@autox.team.net>
Sent: Wednesday, February 16, 2000 12:30 PM
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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