Quote:
Originally Posted by HughGJohnson
Is there a reason for these abominations... other than to save me some trunk space? I had to put one of those on and I made it maybe 10 miles driving very carefully over a snow covered mountain pass. It said not to exceed 55 mph right on the tire and coasting downhill I got up to 45 mph and the  spare goes flat. The car felt weird the whole time I had the spare on it and I wouldn't have been comfortable going faster than 45, let alone 55. I understand it's a temporary tire until you can get service, but I still don't understand it. Why not use a real tire? |
Your tire probably failed due to underinflation which is why it `felt wierd'. The proper tire pressure is ~65psi. When was the last time you checked it? There should be no reduction in traction or control with a properly inflated `spare' up to the recommended 55mph. Handling will of course be comprimised and the corner with the spare will sit a little lower.
As to their `existence' it is primarily for weight reduction. Cost reduction is another reason. The proliferation of alloy wheels as standard equipment with their wider cross sections require even more expensive tires. I would hope you replaced yours with one from a junkyard. Chances are those have never been on the road.
Our "Government" in it's mandatory Motor Vehicle Safety Standards uses the weight of the vehicle as one determinant of crash survival acceptability. That originally resulted in slightly smaller fuel tanks as less fuel carried also reduced the weight of the vehicle. Gas mileage has increased slightly so the lower fuel capacity has not caused grat `outcry'.
