I don't think axial is really a tire measurement. The tire run out that I am familiar with is measured in lateral or radial.
By definition, radial is measured at the end of the radius (outside of the tire) to make sure the tire is perfectly round. Not really applicable to tires but my assumption is that axial is measured at the center of the axle to make sure that the point the tire is rotating around isn't the source of any radial run out issues. (consider a worn out axle or bearings with 2MM of slop....that 2MM will make it's way to the edge of the tire and would be the source of 2MM of Radial run out...but it wouldn't be because the tire was out of round.
Adding to the above concept, I suppose you could measure a kind of axial run out by measuring the run out at the rim (which would also be the bead of the tire) So...if you had a rim with 2MM of run out, it's likely that the run out high point of the tire would correspond to the high point on the rim. I would expect the tire would minimize the rim's run out though so 2MM at the rim would probably be less than that at the radius (outside edge of the tire)
Bottom line....if measuring....just start with radial. If it's within tolerance, you should be fine. If it's out, then you might pay attention to the axle or rim to make sure their run out isn't causing the radial run out to be out of spec.
2016 KTM Super Duke GT
2015 Honda Grom
2015 Yamaha FZ-09
2013 Honda GL1800 ABS
2004 Suzuki GSXR 750 (Track)
Last edited by 2WheelNut; 06-15-2017 at 11:38 AM.