Tire size vs. Spedo Error
Thread Starter
Le Mans Master
Joined: Jan 2007
Posts: 5,485
Likes: 7
From: Peekskill NY
Tire size vs. Spedo Error
My 70 came with F70-15 origionally. Now has 245 60 15 TA's. Spedo is "slow". I guess it's around 45 mph when actually around 60 mph. I need to get a friend to ride next to me to be sure.
I saw a thread a few weeks ago with a tire size conversion chart but couldn't find it when I did a search. Any idea as to what speedo gear I might need to recalibrate my spedo. It's a L-46 and I believe it has the standard 3:36 rear.
Thanks in advance.
Glenn
I saw a thread a few weeks ago with a tire size conversion chart but couldn't find it when I did a search. Any idea as to what speedo gear I might need to recalibrate my spedo. It's a L-46 and I believe it has the standard 3:36 rear.
Thanks in advance.
Glenn
Safety Car
Joined: Mar 2007
Posts: 3,518
Likes: 37
Web page calculator
This is what you need: http://www.miata.net/garage/tirecalc.html
Put in the tire you have and the tire you plan to get and it tells you the speedo changes. You could have someone go in front of you at exactly 60mph and check your speedo. Or use a gps device in your car for exact measurement of speed. You can fix the speedo with new tires if not too far off.
Put in the tire you have and the tire you plan to get and it tells you the speedo changes. You could have someone go in front of you at exactly 60mph and check your speedo. Or use a gps device in your car for exact measurement of speed. You can fix the speedo with new tires if not too far off.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
A few hints here - not tire size - but GM gears available for speed correction.
http://chevelleengineer.home.comcast.net/speedo.htm
http://chevelleengineer.home.comcast.net/speedo.htm
