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## RE: RE: Spinning at 70mph

 To: tigers@Autox.Team.Net RE: RE: Spinning at 70mph "Fraser,Ron" Tue, 20 Jan 1998 06:50:41 PST
 ``` First you should measure the circumference of your tire and then calculate the RPM the engine is turning. According to www.powerdog.com/tiresize.cgi, a tire calculator, 205 - 60 - 13 has a circumference of 71.3" and the wheel turns 889 revs/mile. For this tire and the 3.07 gears you should see; 60 mph = 2729 rpm 70 mph = 3183 rpm 87.9 mph = 4000 rpm You should now check the calibation of your Tach against a good hand held tach. The stock tach can be adjusted. There is a potentiometer inside the Tach that can be reached through the hole for the lamp. Adjust the tach for accuracy in the 2000 rpm to 3000rpm range. The next problem is the speedometer, if it is stock , it probable is not the correct ratio for these tires. You need to know what gear is on the speedometer cable, stock is 15 teeth, and you need to know the speedo, revs / mile. The speedo has a number on the face , I have seen 980,1000, and 1020. The best ratio I can come up with for this tire, gear combo is a 1020 speedo, and a 16 tooth cable gear. Will a 260 run all day at 4000 rpm. Yes it probably will, but it will wear out sooner. Lower rmp = lower wear. I'm not sure what information is on page 65-67 of the Performance Tuning, please share the info you are referring . Ron Fraser --- ```
 Current Thread FW: RE: Spinning at 70mph, Parlee, Brad (ED&C,SLS) Re: FW: RE: Spinning at 70mph, Bob Palmer RE: RE: Spinning at 70mph, Fraser,Ron <= RE: RE: Spinning at 70mph -Reply, John Crawley Re: FW: RE: Spinning at 70mph, Anita Barrett FW: FW: RE: Spinning at 70mph, Parlee, Brad (ED&C,SLS)