When I bought my '65 MGB it was wearing the skinny 5.60-14's
found on VW beetles. They were the correct bias-ply tire for disk
wheels but not for the wire wheels on the car. That bias ply size was
5.90-14. On a friend's recommendation I bought Firestone 175-R14s
which were made somewhere in South America, Brazil I think. It was a
closeout sale so I got a good deal. That was over 5 years ago, and I
don't know if they are still available. The car must be jacked up
higher to clear the wheel well to remove the tires, but the standard
body jack is up to the task and it is only a minor inconvenience. The
tires are fairly noisy, probably because of the more aggresive tire
pattern and the inflation pressure, which is 21 lbs/sq. in. front, 24
rear instead of the 18 lbs/sq. in. recommended inflation pressure of
the bias plies. I am not an aggresive driver, and the handling
satisfies me.
I cannot detect any speedometer error. I checked by placing
the car on a flat paved surface, measuring the rolling radius of a
rear tire/wheel, calculating the effective circumference and then the
distance traveled/ hr. using the tach reading at an indicated 60 MPH.
My answer was 59.7 mph, certainly within the range of error of my
ability to read the speedometer. I am pleased with the tires, having
put about 5,000 miles on them so far.
I have always heard that you don't mix bias and radial tires,
but how bad could the handling be? Answer: pretty bad. I hadn't gone
three miles on a radial-front, bias-rear combination before a minor
front wheel vibration was translated into a fish-tailing motion- a
rear-end sine wave of ever increasing amplitude! I stopped with the
rear of the car on the shoulder of the road and the front end on the
center line. Needless to say, I had the rear tires changed to radials
immediately!
I hope this proves interesting if not inspirational.
Lew Dove
Dept. of Biological Sciences
Western Illinois University
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