Originally Posted by
Sy Reene
However to note, a 2mm width difference can often change the PSI recommendation on some calculators by over 10psi.
And, again - think about the increased stiffness of the casing, the inaccuracy of most pump gauges and then the percentage of the overall deviation (I assume that this 10psi difference is on skinny tires are the pressures are probably in the neighborhood of 100 or more).
Originally Posted by
Sy Reene
Makes you wonder if something like what's being discussed here could be part of the reason for frequent disconnects on sensible tire pressures?
No, doesn't make me wonder that at all - I wouldn't place any blame at the feet of tread thickness variation, within a given WAM, as a factor for the disconnect. Even among forum members, the majority of whom would classify themselves as enthusiasts, WAM is a relatively unknown concept and the inflation calculators that use them are pretty new-school. Couple that with the anything goes over-sized tire casings that are still available on shelves, the newer, more conservative tire sizes, the wide variations in rim widths on the market, the factors listed previously and the old-school habits and "knowledge," etc. etc - it more than adequately explains the differences in opinion.