Here is a specification: section width 237 mm. Here is the same specification with the thing that makes it useful: section width 237 mm, on a 9.0J rim, at 32 PSI cold.
Move that tire onto a 9.5J and the number changes. Inflate it to 38 and it changes again. Publish the first version and you have technically told the truth while telling the reader nothing they can act on.
It happens across the whole sheet
- Shore A hardness moves with temperature. Ours is measured at 23 °C, and we say so, because a hardness figure taken warm reads softer and flatters the compound.
- Overall diameter is quoted inflated and unloaded. Under load it is smaller, and how much smaller depends on the load.
- Maximum pressure is a structural limit for the casing. It is not a target, and it has nothing to do with the pressure you should run.
The flag matters as much as the figure
Some figures on this site are still our working values rather than something we have confirmed on our own equipment. Those rows carry a flag saying so.
That flag is not modesty and it is not a legal hedge. It is the only thing that makes the unflagged rows worth reading. If everything on a spec sheet is presented with equal confidence, the reader has no way to tell measurement from estimate, and the honest numbers get dragged down to the level of the invented ones.
When we verify one, the flag comes off and the number changes if it needs to. It will not be quietly adjusted toward what we published first.