Yes, that's correct. I did the calculations in the other direction (going from 195 to 185). Thanks for the correction. Regards, Jon Heese ________________________________ From: dmcnews@xxxxxxxxxxxxxxx on behalf of gmfm1@xxxxxxxxxxx Sent: Wed 11/14/2012 9:04 AM To: dmcnews@xxxxxxxxxxxxxxx Cc: dmcnews@xxxxxxxxxxxxxxx Subject: Re: RE: [DML] Tires Hi Jon, Wouldn't it be the other way around? If the total diameter of the tire/wheel is smaller (6mm x 2=12mm total less diameter) the wheel will have make more revolutions to travel the same distance, therefore the speedometer would read faster than you are really going, ie. speedo reading 60mph, but actually going slightly slower in reality. If 2.1% is the correct differential, if you are doing 60 mph, the speedo should show just over 61mph. Most speedo's aren't 100% accurate in the first place, but only an approximation of the speed that you are going. Just asking? Thanks, Gary Masie ----- Original Message ----- From: Jon Heese Date: Monday, October 29, 2012 4:24 pm Subject: RE: [DML] Tires To: dmcnews@xxxxxxxxxxxxxxx > Remember that the sidewall height is measured as a percentage of > the tread width. So yes, a 195/60R14 is 10mm narrower than a > 185/60R14, but it also has a 6mm shorter sidewall. > > 185/60R14 means: > 185 mm tread width > 60% of 185 mm = 111 mm sidewall height > 14 inch rim diameter > > Going from a 195/60R14 to a 185/60R14 will make your speedometer > read 2.1% slow-- when your speedo says 60, you'll actually be > going 61.2 mph. > > http://www.miata.net/garage/tirecalc.html > > > Regards, > Jon Heese [Non-text portions of this message have been removed] ------------------------------------ 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 [Non-text portions of this message have been removed] ------------------------------------ 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: dmcnews-digest@xxxxxxxxxxxxxxx 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/