Expert: Brad Sears - 3/8/2010

Question
I have a 1964 Mercury Montclair.  When I bought this car it needed tires.  I was told that p215/75r14 would be the equivalant for the original factory size of 8:00x14.  I had the 215's installed (4) and was disapointed to find that the car sat to low and the tires didn't fill the wheel wells like they should. I went on line and checked out some tire conversion charts and they showed the same thing, the 215/75/r14 is equivalant to the 8:00x14. I recently purchased a 1964 Merc Parklane that has an old G/78/14 in the trunk that still holds air.  I compared this tire and my 215 spare side by side to find that the G/78/14 was considerably taller.  I also know from on line info that the 8:00x14 was slightly taller then the G/78/14.  Now here are my questions.   First of all, these guys putting together these tire conversion charts, aren't they doing their homework or am I missing something?  I'm considering the 8:00X14 Universal bias tires for my Merc as there seems to truly be no equivalent sized radials.  This is a 4 dr. Merc Breezeway w/ factory wheels,spinner hub caps, and fenderskirts.  I'm not going to be planting my right foot to the floor boards in sharp turns, or doing to much drag racing, but I am comcerned about the ride, and general handling characteristics. Do you think these tires would make me a happy camper?  This seems like a good one for Dick Benjamin to answer.  Thanks!      Dave

Answer
Hi there: i am not Dick Benjamin as he is no longer one of the experts. I am Brad Sears and probably as old as Benjamin and the auto industry was my lifes work. First for ride quality the bias ply tire is a softer ride and a radial by a pretty good margin. As far as the size conversions go the guys that put the charts together haf a bit of a problem, as most radials are fatter than bias ply tires and clearance becomes a consideration as well as tire height. Not excusing them just the facts as St. Friday used to say. As far as handling, the 64 Merc Montclair was made as a boulevard soft rider for Lord and Lady Plushbottom and the 8:00X14's as well as looking good with the right amount of tire filling the fender well opening showing off the correct wide white walls will probably make you a very happy camper.