[DeTomaso] Upgrade List

JDeRyke at aol.com JDeRyke at aol.com
Sun Sep 16 16:52:35 EDT 2012


In a message dated 9/15/12 5:46:27 PM, steve at snclocks.com writes:

> But, in searching I read "One of the very week points of the Pantera is 
> the rear axle bearings. Ball bearings are use to support the axle and are 
> not very well suited to carry the loads that our big fat sticky tires can 
> exert on them. A ball bearing is just not a good bearing for handling heavy 
> side loads. On the Pantera, the single outside bearing carries most of the 
> side load forces. Roller bearings are a much better solution for handling 
> side loads and the big fat sticky tires."
> 

Absolutely wrong. What IS critical is the press fit of the outboard stub 
axles into the ball bearings; the OEM factory fit was too light or 
non-existant in many cases and was due to undersized AXLES made of low-grade mild 
steel, not to a weakness in the bearing type. Replacement factory axles available 
today have the proper 0.0007" interference fit and are made of 4130 or 
300-M alloy steel- both far stronger than original stock axles. They are 
suitable for any imaginable use of a Pantera including Pro-racing. 
Ball bearings run cooler and with less power absorption than roller 
bearings, which is why ball bearings are used in most racing cars starting with F-1 
and Indy cars and work down from there. The LeMans Gr-4/GT-4 Panteras also 
ran ball bearings and today, perhaps 90% of the Panteras on the road run 
ball bearings including the big-block conversions with monstrous power and 
torque & super-sized rear tires. Roller bearings are made to carry heavy side 
loads found mostly in the front end, not the back. The single advantage of 
tapered roller bearings is, they will tolerate a sloppy fitting axle. A good 
press fit is unnecessary, so its easier to tear down the upright. 
To verify this a couple of decades ago, I converted ONE of my '72s rear 
uprights to roller bearings in my shop since there were no commercial 
conversions that met engineering standards. I left the other upright with stock ball 
bearings, with a proper press fit on the axles. Today after some 50,000 more 
miles including many high speed runs, open track events, autocrossing etc, 
they are both still back there in good shape- no difference that I can 
detect except the tapered-roller side cost much more for parts and machining. I 
run 12" wide 295-50 x15"s on optional 10" Campy wheels. 
Boittom line: check your stub axles for looseness via the 'hip-test' and if 
any is detected, you likely need new AXLES, not a change of bearing type.

IMHO, It really depends on what you expect from your car. What you need to 
do for 21st century upgrades in a Pantera has been covered in many, many 
articles published in the POCA Newsletter and in the currently-dormant PI 
magazine over the last 20 years. The list runs to over 300 illustrated, multipage 
articles that have been vetted by engineers as true improvements. They 
cover handing, brakes, tires and wheels, aerodynamics, interior and a host of 
other topics. I suggest you join POCA; e-mail Judy McCartney <
JPOCA2 at hotmail.com> for more   info. Good luck- J Deryke, POCA Tech Editor


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