I have 14hrs on my 36'' RH and seem to have encountered something that gouged the sidewall pretty good. it's not flat but not sure how long it'll last and would rather replace it while the machine is new so one tire isn't larger than the other and i don't have to replace both. problem is I can't find the carlisle multi trac in an 18x8-10 anywhere. says its discontinued. what gives and how can I go about getting one? can i buy one direct from wright?