I love the DMCNEWS.com website, some years ago I found a great information there....which said 60mph = 1000rpm.... yesterday we swapped speedos and my self calibrated speedo which shows 60mph @ 1000rpm was only 1-2 mph off compared to GPS ! --- In dmcnews@xxxxxxxxxxxxxxx, Joe Angell <jangell@...> wrote: > > > I don't know what it is officially, but I did the math out and got > ~2030 RPM @ 85 MPH. I'm assuming that one turn of the tire is equal > to one turn of the speedometer cable, but I'm not entirely sure if > that's the case (there might be some kind of gearing at the angle > drive that I don't know about; I'd appreciate it if someone could > confirm this): > > Here's the math, based on the diameter of the front tire: > > Tire Circumference: 43.98" = 14" diameter tire * pi > Tire Revolutions per Mile: 1440 = 63360" per mile / 43.98" > Miles per minute @ 85 MPH: 1.41 = 85 miles per hour / 60 minutes > per hour > RPM of front tire: 2030 = 1440 * 1.41 > > You can get the RPMs at any speed with this formula: > > RPM = (MPH / 60) * 1440 > > Obviously this value will vary based on the amount of air in your > tires at any given time, but hey. > > -- Joe > > > Does anyone know what RPM the speedo cable operates at? > > > > Bob > ------------------------------------ To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/