[DeTomaso] Rim Offsets

[Stephen Nelson]

Mike - thanks for the extensive comments.  I do plan to drive 5332 for a
while, get used to it and see how it all hangs together.  

 

Right - scrub radius.  As I understand it, increasing scrub radius makes it
easier to park the car but more sensitive to external forces acting on the
tires when rolling down the highway - like uneven brake application.  Oh,
and "excessive" scrub requires more steering effort when going down the road
and increases the "feel" of the steering.  

 

In my feeble brain, if the inside of the rim is at the same place with both
7 and 8 inch wide rims, well, going to an 8 inch rim increases scrub radius
by a quarter inch.  Of course, I don't know that inside edge of 7 and 8 inch
rims are at the same point.  But, since you indicate that the 8 inch rims
improve handling, I assume this means that the offset is increased a bit.
You indicate that increasing scrub radius improves handling - does that
include reducing tramlining?  Or am I really just asking too nit-picky of
questions?

 

>From your e-mail I conclude that a set of four 8 inch wide original rims is
the way you would recommend for my situation - if the Coddingtons leave me
feeling like I would want to make a change?

 

Which Coddingtons.  The gentleman who put them on told me that they were
special, an early set with a flat center section instead of the dished shape
of the later ones.  This apparently requires unusual lug nuts which are
counter sunk.  I am speaking from my notes here, and will have to see what I
can figure out when Passport drops it off this afternoon.

 

See what you think.  5332
<http://www.provamo.com/Members/Registry/RegistryImages/RTHPNNU05332/RTHPNNU
05332.asp>  

 

Looking at the pictures one more time, I will have to see how it drives and
rides.  You are right - gads, good looking rims.

 

 

 

Stephen Nelson

 

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From: MikeLDrew at aol.com [mailto:MikeLDrew at aol.com] 
Sent: Wednesday, July 03, 2013 7:48 AM
To: steve at snclocks.com; detomaso at poca.com
Subject: Re: [DeTomaso] Rim Offsets

 


In a message dated 7/3/13 6 58 37, steve at snclocks.com writes:





Thank you all for your quick responses!

My new car comes with a set of early Coddingtons - which I gather are good
rims for the car if one wants to drive it hard on a track. 


>>>Not especially.  Big wheels like that are heavy.  You want much lighter
wheels for serious track work.  They are quite good for the street though.




> But, that is not
my goal.  As I think I mentioned in previous posts I have put 130,000 miles
on a Jag XKE.  Originally the XKE came with 185/70 15's.  Today it rides on
205/65 15's - pretty much the same height as the originals, so pretty much
the same, or even better ride, with the more flexible sidewalls in current
radials.  I did upgrade the rims to gain 1 inch width and went with
stainless spokes.  The car rides like a dream.


>>>Sounds like a great cruiser.




>My goal is to drive 5332 on trips, explore country with it.  Perhaps not
like I have done with my XKE - not sure I would even take it again over some
of the jeep roads it did years ago when exploring Colorado, but I want to
put miles on it, enjoying driving it. 


>>>Which is exactly what they're for!




>I was talking to a friend yesterday, he has a variety of cars, think Aston
Martin, GT40, that sort of thing.  He also has an XKE that he modified much
like I have modified mine, with a focus on reliability and ride.  He is
continually blown away by how well it rides on 205/65 15's when compared to
his other, much more expensive rides. 


>>>Much of that is down to the Jaguar's excellent suspension, don't forget.
It was well ahead of its time.




>I've test driven 5 Panteras so far, and know I will not be keeping the
Coddingtons on the car for most of its miles.  Heck, they are easy to put
back on for shows, but I am looking at putting tires under it that will not
unduly flex the frame from excessive loadings on corners, or overstrain the
original brakes, or shake me to death on roads that are less than perfect.


>>>Your wheels will do none of those things.  The strains that a chassis
sees are directly controlled by the nut behind the wheel.  If you beat the
car to death, it won't matter what kind of wheels are on it--stresses will
be felt.  If you drive it like an old lady, you could have Fred Flinstone
wheels and the car won't feel a thing.  




>And, if the rear tires spin on take off - heck, that is part of the fun.  


>>>That's down to tires, not wheels.  Old, hard tires, or new, high-mileage,
cheap tires, will provide less traction--no matter what size they are.




>Of
course, if I wanted to have serious power I would have bought a different
car - like the one up in Seattle with a Windsor crate engine.  It spun its
wide tires with no problem.  And heck, you didn't even need your hands on
the wheel - it would follow any groove in the pavement with no help from the
driver!  OK - that is a scary thing on a badly dished road.



>>>True!




>Long e-mail, but, bottom line, I am looking to go back to the original
width, or even (gasp) 7 inch rims front and rear.  With this in mind, any
suggestions will be appreciated on the options that are out there.

>>>Putting narrower than stock wheels on the car would be ridiculous.  The
stock 8-inch rear wheels were arguably too narrow, from an aesthetic
perspective.  The 7-inch front wheels had insufficient scrub radius, and
generally handling is improved (even with exactly the same tires) if 8-inch
wheels are installed in front.

Given your desires, IF you wanted to put different wheels on the car, you
could not possibly do better than to install stock, original wheels.  They
are beautiful, lightweight, and most importantly, they are *right* for the
car.  Back in the 1970s and 1980s, so many people removed the stock wheels
and replaced them with cheap, tacky, junk hot rod wheels, under the mistaken
apprehension that they were 'upgrading' the car somehow.  All they did was
cheapen how the car looked.  It's still possible to do exactly the same
thing today.

As there were several different styles of original wheels between 1971-1974,
it's important to get a matched set, and a set matched to your car.  Yours
is a '73L, so that should help narrow your search, as L-model wheels are
decidedly different from pre-L wheels.

I happen to be a big fan of original wheels, and have them on my car (albeit
in 8- and 10-inch sizes with much wider tires than the car originally wore).
But having said that, I think you should just drive your car as-is for
awhile, and see how you like it.  If it drives nicely, leave it alone.  If
you are committed to getting rid of the Coddington wheels (and I must
confess that while the wheels they used to make for Pantera East are great,
I find their current offerings to be absolutely vile-which kind do you
have?), you should be able to sell them and/or part-exchange them and get
nice, original stock wheels and suitably-sized tires on the car, and end up
with some cash in your pocket when you're done.  An average set of stock 7
and 8 inch wheels is probably a $200-300 proposition; the nicest ones in the
world shouldn't cost more than $500 for a set.

It's unlikely that you will feel much difference, except that the steering
will probably be lighter with narrower front tires.  The original tire size
for the Pantera L equates to 205/60 front and 255/60 rear.  BF Goodrich Comp
T/A tires in those sizes are available from several sources.

Mike