So what is the right size when you go plus 1?
Just been doing some thinking. Hard to figure what the right +1 size for tires is. My Ninety Eight came stock with 205/70-15'*. With the Touring Sedan or the performance option, they offered two different sizes:
Now the stock tire has a diameter is 26.3 inches. if I upgrade to either of the other two, I end up with:
1) 215-60-16 - Diameter - 26.2 - Speedo reads .5% fast. basically a wash.
2) 225/60-16 - Diamteter - 26.6 - Speed reads 1.3% slow. Little worse.
The big tire option talked about a lot is 245/55-16.
Diameter 26.6 - Speedo reads 1.3% slow.
Played around a bit and looked at other options:
225/55-16 - Diameter 25.7 - Speedo reads 2.1% fast
235/60-16 - Diameter 27.1 - Speedo reads 3.1% slow.
Point of the exercise? Really doesn't seem to be one "right" size. Any of the options listed seemingly would work just fine. I seriously doubt that Olds made any differences in speedos, etc to make up for a 1.3% speed difference between the two stock sizes.
Done with navel gazing.
2004 Bonneville GXP - Greystone