[zeebo]

hi there..looking for the factory tire size for my 73 lemans. it came with 14" rallys..it now has 15" and i need to see how much i need to correct my speedo driven gear, if at all. and i need to know where i can convert the old size to metric. thanks!!!

[Jim Cody]

I had a 73 Lemans back in 78. It had 78R14's on it. Pretty sure that was stock since I had the full size spare too. The car was Lecurene Blue with the radially slotted hubcaps.

[Pontiac1976]

http://www.carbibles.com/vintagetyresizes.html




G78-14 should be around 205/75/14 / 215/75/14
G70-14 should be around 205/70/14 / 215/70/14
----
G60-15 should be around 205/60/15 / 215/60/15

hope it helps

[rexs73gto]

Once you get the tires on you can then measure the height of the tires & if the tire height is within 10% of the height of the original tires then your speedo should not need any thing. Once you go bigger in height more then 10% then you'll have to change you speedo dive gear , thats the one that is in the side of the trans that will come out when you take the drive gear holder out. It's the piece that the speedo cable is attached to. To take that out all you need is a 7/16's inch wrench & remove the 1 bolt next to it. It will just pull out after you remove the blot. Some trans fluid will come out with it but not a lot. But use a catch pan so the fluid doesn't mess up the floor. The gear just slides in the part you remove, ( you'll see when you pull it out) then you'll have to figure out which gear you'll need . You can usually go to a trans repair shop & they can sell you the gear(s) you'll need to make your speedo correct.The gears usually cost between $ 10.00-25.00.