Where's the logic

I am currently in the process of replacing/greasing the bearings on our travel trailer, and have just finished the first two wheels and am putting them back on the trailer. At least I was until I discovered the castle nut requires a 37mm size socket. I have been to five auto parts/tool vendors so far and am discovering that 37mm is so rare that no-one carries that size. 36 is too small, 38 is too large and the SAE equivalents do not work either. 1 1/2 is too sloppy and the next step down won't fit.

Why in heavens would a North American (Crossroads in the US) trailer manufacturer suggest the bearings be tended to every 6000 miles (almost one year for us) and make a part that is crucial to the operation in such an unusual size? They also demand the nut be torqued to a specific torque, so a large crescent wrench can't even be used. I suppose if I was experienced enough in torquing stuff that I could guesstimate with a crescent wrench, but I am not and I know some have/will suggest a method of doing this without using a torque wrench, but I prefer to follow the manufacturer''s recommendation if possible. How bizarre.

Anyway, anyone know where I can find a socket of this size (in the Vancouver Canada area), that I don't have to order and wait for off the net. I am scheduled to leave the Vancouver area for a long trip, in three days and I'm sitting here with two wheels off the trailer.

Thanks in advance,

Marv