Tires

I discovered I have the wrong sized tires on my car. When the speedometer reads 60mph, the GPS says 52 mph. To get to 70 mph, I need to peg the speedometer to 80 mph indicated at 3000 rpm. Car has 3:07 TT rear What size radial do I need? Thanks

BG

Reply to
Bill Glass
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Bill, Relax. Do the tires look good on your car? Does the car ride nice? No rubbing? Go to a speedometer shop and have your speedo calibrated and forget about it.. You drove it happily until you got that electronic troublemaker, didn't you? Jeff

"Bill Glass" wrote...

Reply to
Jeff Rice

Bill, I am also running a 3.07 gear in my 4 speed lark. I have

235-60-15's on it . According to this calculator at 3,000 RPM I am running along at 75.91 mph .
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plug in your numbers andsee what the calculator says.My tire diameter is only 26.1 inches. Youmust be running something taller than me. You would have to be goingfaster than 70 mph at 3,000 RPM unless your transmission is slipping.They have a spot on that site to calculate your tire diameter as well,just type in your size tire. I believe the calculator is correct. I runaround 3000- 3,2000 RPM on the highway to stay in the left lane on theGarden State Parkway and New York thruway.Judging the traffic flow itseems right. One more thing how accurate is your tachometer ? I am running a Sun Tach which has to be more accurate than a 50 year old stude tach.I don't see any stude racers using a stude tach to shift by. Let us know what you find out, Joe Flannery
Reply to
jflan63

look at the brite side, it will reduce your risk of a speeding ticket.

Reply to
oldcarfart

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