Do changes in wheel size require computer changes?
06-23-2009, 04:15 PM
#1
3rd Gear Member
Thread Starter
Join Date: Sep 2007
Location:
Posts: 906
Do changes in wheel size require computer changes?
I bought the 2007 GT with the stock 17" bullitt wheels and tires.
Then I put some 20" Ronaele wheels on (8.5" wide in front, 10" wide in back)
with low profile Toyo tires.
since the wheels are bigger, do the speedometer and odometer need to be adjusted?
If I get meatier tires with a larger sidewall do the speedo and odo need to be adjusted again?
If I do need a computer adjustment, where do I go, and what do I ask for?
Then I put some 20" Ronaele wheels on (8.5" wide in front, 10" wide in back)
with low profile Toyo tires.
since the wheels are bigger, do the speedometer and odometer need to be adjusted?
If I get meatier tires with a larger sidewall do the speedo and odo need to be adjusted again?
If I do need a computer adjustment, where do I go, and what do I ask for?
06-23-2009, 04:31 PM
#2
6th Gear Member
Any change to the stock tire's revs per mile will require a change to the stock setting. It's an easy change with a handheld tuner. My SCT xcal2 allows changes in 10's (i.e. 470, 480, etc).
06-23-2009, 05:05 PM
#3
Cut & Paste Expert
Join Date: May 2007
Location: NW Arkansas
Posts: 13,322
http://www.miata.net/garage/tirecalcold.html
http://www.1010tires.com/TireSizeCal...?action=submit
Rim size does not effect revs per mile or the tire.
Use the above OD calculator to find the revs per mile for both the
stock tires and your new ronaele (eleanor spelled backwards) and
compare the two numbers.
20" rims are bigger but the 'low profile' tires you have
on there should compensate for the bigger rim and give you
the same revs/mile. You dont state tire size so I cant figure out what
you are asking. Not enough info.
http://www.1010tires.com/TireSizeCal...?action=submit
Rim size does not effect revs per mile or the tire.
Use the above OD calculator to find the revs per mile for both the
stock tires and your new ronaele (eleanor spelled backwards) and
compare the two numbers.
20" rims are bigger but the 'low profile' tires you have
on there should compensate for the bigger rim and give you
the same revs/mile. You dont state tire size so I cant figure out what
you are asking. Not enough info.
06-23-2009, 09:12 PM
#6
3rd Gear Member
Join Date: Aug 2008
Location: Basra, Iraq
Posts: 660
Yeh those two sites are complety differnt do a 274/40/18 and its TWO differnt numbers on each site one says 780 rev the other 756 ...big deal cause at 60 ill be really doing 70.. SOOOOOO which site do i trust ..??