Ah me. Cant find that post I sent ___years ago...or was it last fall?
so some history---
First car I had radials on was 55 Chrysler St Regis HT back about 1970. Put
two recapped radials on the most critical end of the car, the end that
steered. WRONG!
Any info we see says IF you put radials and other type tires on a car the
radials GOTTA go on the back end. Took that wunneful highway car onto our S
curve and Yee HAH! Almost lost it at 5 mph below the posted speed. Front
end loosey goosey like crazy.
Why? Two reasons.
First due to tire construction radials allow the car to sort of shift over as
the wider more efficient radial construction grips the pavement while the
cars body weight continues in the direction it was moving laterally due to
shifting of the sidewall, until all equalizes per physics. So the front end
tires gripped yet the body continued to want to move, and corrections in
opposite direction did same. Front end does a Hula. Back end meanwhile
with its stiffer sidewalls (inherent with bias ply tire construction), stayed
stiff!!!!! Diverging, my first ride in a big time motor home was in about
73, the owner would not put radials on it for that reason- body shift vs.
'feel' of the vehicle.
Second, those jumbo radials were oversize for the Chrysler rims of those
days, or marginal? This causes the radial NOT to work as it was designed and
again emphasizing that shift, sidesway, the Hula.
Moved the radials to the back and could feel that sidesway but not the loss
of control. 2 weeks later on payday put radials on front too, and all was
fine. The sidesway was barely felt since both ends of the car were reacting
the same way. Seems like I could make it 150 miles to the Ohio line in just
over two hours, what a cruiser.
My first 'old' car was a 51 Merc, stock with OD, and about L78/15 Radials
back about 1984. The OD was not working so the big tires gave the 4.11 a
decent crusing rpm. But was that baby a truck to maneuver in town!!!! Must
be rolling and parallel parking and such was a bear. Super on highway,
great feel. I finally decided to get some CHEAP bias plys from Disconut
Tire, and thought the car had gotten power steering! gone was the Muscleman
steering in town. Also gone was that fine highway ride at speed. It also was
more enjoyable to drive in town on the bump thump.
Radials are on my 56 wagon, however there is a moderate problem with sidesway
as mentioned about the St. Regis. This is in spite of having driven it at
least 15,000 miles, at speeds up to 75 much on the interstate. Remember the
wagon has HD springs both ends, smooth roads fine but transverse tar strips,
expansion joints etc cause a jar. Potholes likewise. I drove my buddys 56 4
Ply dr with radials and same feel in town. Deteriorated ride. He couldnt
tell the difference. Everybuddys butt is different??!!!
Now if I was able to put 6" rims on the 56 the sidesway feel would be gone.
The P20575R15 Firestone 480's would have a wide enough foundation for the
tire to sit on, where now they are on a stock 4.5 inch rim width, standard
for my wagon with 11" drums. Recommended rim width depends some on the tire
mfg, but runs about 5.5 to 6.5 inches for the said tire. Bigger tires
require wider rims to stuffen that sidewall.
Cant picture all this?
Picture a tire tube inflated like at the beach. Attach that tube to a rim
ONLY at one bead around the periphery. Push sideways on the tube/rim and it
all wants to roll right off the rim.
Now if you can, glue that tube to the rim spacing the glue at both sides of
the steel rim. Push and you find the entire assembly is inherently stiffer.
Reason is due to rim width its that simple. And if U can picture adjusting
rim with to adjust overall tire stiffness vs ride comfort U R right! It all
interchanges and each is a compromise- Ride comfort vs. handling stiffness.
One of the recent posts with radials on the 55 Caddy had that same familiar
problem- doin' the tail waggin Hula with them radial tires.
Wheels- all the above wheels related in the history above were/are stock.
Note a large percentage of rims are drop center, with a recess to allow the
tire bead to drop into that recess when removing tire. Depending on the
amount of drop, using tubes could be a problem? But 99% of our tires are
tubeless, so not a problem. There ARE radial tubes, I have no details on
their construction.
As for me, I'd like better grip for both my 56 and 41. The OE wide white
BFG's on the 41 are abysmal for stopping, even slow cornering. The 56 with
the radials are fine on highway (high winds cause it to get a bit uneasy tho)
and generally acceptible in town. I am considering going to a modern tread
bias ply of about 7:10/15 for the wagon, on 6" rims, but even now I only have
3/8" clear at skirts to the rubber, and at times on turns the rubber will rub
on the skirt.
(FYI rear springs have new leaves and new eyes each end).
Aint old cars FUN? At least our cars are starting, wheels go round, and
we are dealing with some of the finer points....
or separating folk tales from fact?
L.
Numbers- for those wanting acccurate tire dia. tread width max width, etc,
simply call Coker TIre for their BIG color catalog 1 800 251 6336. It
covers literally ALL tires for old cars, except modern style radials.
Likewise surf the web, use Alta Vista and U can find some decent sites, again
mostly modern tires. There is an outfit in Chicago called 'Freds tires' or
somesuch with a full page ad in back of Hemmings but he sho were NO help-
just FYI.
PS- If U have a 55/56 Ply or Dodge and didnt get my 'sort of' questionaire
regarding tires, e mail me and I will send U one. Several addresses I culled
from the December calendar were either not good or I mistyped.
|
|
Back to the Home of the Forward Look Network