I think many of you are barking up the wrong tree with the math calculations -- from here anyway. The speedometer on my "F" reads low... quite low. At 55 mph indicated it is actually traveling at 67 mph -- a 22% error. But... the odometer is right on! No perceptible error. A 10-mile trip down the expressway using mile markers at the beginning and end displayed 10.0 on the odometer. The GPS also recorded 10.0 miles. Speedometer and odometer error can be related, but isn't necessarily related. Whether there is a corresponding error depends on the cause of the error. The odometer reading might be correct as displayed, Larry -- and maybe it isn't. The speedometer and the odometer could both be incorrect, but with the odometer having a different rate-of-error (percent) than the speedometer. Mike Reed in Lake Odessa, Michigan ----- Original Message ----- From: JettLarry@xxxxxxx To: chrysler300@xxxxxxxxxxxxxxx Sent: Monday, January 26, 2009 7:48 PM Subject: [Chrysler300] Gas Math Back from trip to Temecula to hob nob with fellow 300'rs. Trying to get a handle on the MPG. In 772 miles I used 62.6 gallons of hi-test. Easy enough here. Divide 772 by 63 showing 12.25 mpg gross. BUT, speedo is widely optimistic. The GPS says when the odo shows 83, actual road velocity is 70. This appears to be 18 percent high. Do I multiply the 12.25 by 118 which gives 14.45? Or perhaps reduce the 772 miles which would also be 118 % high to the actual road miles driven? Maybe that is the same but cocktail hour is drawing near and don't want to damage the few brain cells left, that is Jack Daniel's job. Help. I was always asleep during math.....only woke up for lunch and auto shop. LJ **************Know Your Numbers: Get tips and tools to help you improve your credit score. (http://www.walletpop.com/credit/credit-reports?ncid=emlcntuswall00000002) [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/