Nitto 275 60r15 measurements?

If you're actually mounting them on an 8" rim those should be very close to the measurements. Those measurements vary quite a bit by manufacturer and tire model, so, one 275/60/15's specs may not (and probably won't be) the same as another.

The other thing is the "measuring rim" is important. For a 275/60/15 the measuring rim is an 8" wide rim, so, the measurements should be close if you're using an 8" rim and doing the measurements correctly. If you use a 9" rim the measurements will be different, and if you use a 7.5" rim the measurements would be different again in the opposite direction.