> On Fri, 01 May 1998 06:02:10 -0600
> "Janssen, Lee K" <lee.k.janssen@lmco.com> wrote:
> To: "'Lang, Robert M. (TR6)'" <blang@MIT.EDU>
>
> I was reviewing a TR6 e-mail and I wondered if you had started the
> following thread:
Frankly, I don't recall if I did start this one, but chances are that I did.
>> Somebody else wrote:
>>Robert,
>>Why go through all that trouble? 7/16 studs are plenty strong.
> I disagree. 7/16" studs are not strong enough for racing purposes
> on sticky tires which is what Bob does with his TR-6.
I agree with your disagreement.
The tires nowadays are _way_ stickier than they were not too long ago. In
fact what passes as a DOT approved tire for SCCA autocross now is
probably stickier than the compounds that were used for slicks ten years
ago. Tires have come a long way.
Now, take 7/16 studs, super sticky tires, old narrow wheels, metal twist,
_tiny_ wheel bearings (especially the outer front wheel bearing), various
"end float" compontents (as in wheel bearing "pre-load") and even the
torsional strength of the hubs and front spindles... there's a _lot_ of
room for twist.
A lot of these components cannot be changed if you run street prepared,
but from what I can figure - you can change the lugs (because the wheel
specs are "free"). Besides, I can always argue that this mod is a safety
issue. They cannot disagree with that.
I take my tires on/off at every event, this in and of itself can fatigue
the metal of the studs... especially if the studs are "dry". You do use
anti-sieze on your studs and lug nuts, don't you???
So, after playing at maybe 50 or more autocrosses, I've seen some pretty
bizarre stuff happen. The last autox I was at, a guy in a Scirocco had a
brake rotor fail - ever try to stop a car in a straight line with only
one front brake working??? My goal here is to be ahead of the curve as
being behind the curve can be _way_ more expensive. Last year, I saw
three dramatic suspension failures - wouldn't you know it that one was
because the studs sheared off under braking.
I'm going with fatter studs.
Also, the wheels that I picked up for this purpose have _really fat_
center sections - more than an inch! This also means that I have to go to
longer studs. I figure that if I'm going to longer studs, it makes sense
to upgrade to fatter studs. I like to say longer and fatter is more
betterer. Yes, I know its a triple comparative.
> If so what does it take to upgrade to 1/2 inch studs?
It takes a lot of work.
The fronts are easy. Pull 'em off, clean 'em up. Find someone with a
vertacle milling machine (I prefer Bridgeport), and ream the holes out to
the new diameter studs. I bought Moroso 1/2-20 studs that are three
inches long (roughly an inch and a half longer than stock). The trick
here is that the knurl diameter is .615 inches. So, in my case, I had to
obtain a .615 reamer - the shop where I got the work done did not have
one. I can't complain though - the labor was free! I did have to use a
hydraulic press to get the studs seated, around 2000 pounds of pressure
was required.
The rears are a freakin' pain. First, you have to yank the hubs apart.
This is not a job that should be taken lightly. I happened to have access
to the "churchill tool", and it took roughly one hour per hub to separate
them. The upside is that this job was somewhat similar to an hour
"pumping iron" at the local gym. So, I got to work on the car and workout
at the same time!
You might ask - why separate the hub. The short answer is: you can't get
the long/fat lugs past the part of the hub assembly that is the "outer
race" for the wheel bearings. There just is not enough room to maneuver
the stud into place so that you can press them in.
So, I've not actually finished this job as of this writing - I said the
labor was free, but a possible drawback to free labor is that it gets
done when time is available... the guy doing the work is very busy right now.
At any rate, when I get the drilled out hubs back with the new studs
installed, I then get to reassemble the hubs and check the end float and
all that.
It's pretty complicated is the short answer.
> Thanks for all of the suspension help you have given me in the past!
No prob. Maybe we'll meet at an autocross someday. Or VTR - you going to
Hudson, WI???
> Lee
rml
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