Tires: tire bulge, careless driving, pothole

Question
Barry,
We recently rented a car in the UK. A Vaukhall. Not that this should matter. When we returned the car the employee pointed out a bulge in the sidewall of the drivers side front tire. He said the car is inspected before each rental so this must have happened while I had the car and was a result of my driving. Since I did not hit a curb or such I argued it was not my fault and the bulge was either aleady there or was a defect in the tire. He said a defect would have turned up before the 9500 miles on the car. If I take his word that the bulge is new is it possible for a defect to show up with this many miles ? Or could the bulge result from a small but well placed bump, say from a pothole. If so I still argued this is a tire defect and not the result of careless driving. Needless to say he later charged my credit card $100 for the cost of the new tire
THanks for your answer
Steve Talajkowski


Answer
Steve,

There are several types of bulges:

1)  A bulge where the ply fabric is either stretched a bit or where it is missing altogether.  In either case, this might take a few miles to really balloon up, but would certainly be readily apparent within the first 100 miles.

2)  The second type is caused by the breaking of the cords when hitting an object, such as a pothole.  Sometimes you'll remember doing it, sometimes not.  It isn't so much that size of the object, but its shape and the speed of impact that determine the probability of failure.

From the sounds of it, you probably had the second.  It's unfortunate, but it's just one of those things that happen.