So my 941 d had one tire bad, leaked and had no tread, had a spare 13.6-28 that had been on my 740, checked it, had 10 psi, so swapped tires, used my old center, aired it to 12 to take out bulge, went to changing plugs in the 850 next to it, walked out of the shop and came back and the #%*-*%$ thing was flat! Tube went. Argh. Took me an hour to wrestle the old one off and the spare on and made no headway. Checked my box, sure enough, out of large tubes! Gonna wait till Fri to look at it again.. Aggravated. Right now. .. I keep telling myself in gonna stop messing with tires one day...