In the afternoon, I mounted the two main tires. For the mains, I upgraded to the MATCO WHLWI600XLT. For the tubes I upgraded to the Michelin Air Stop 15/600-6 ply with the TR-20 valve. And for the tires, I went with Michelin Aviator 15-600-6 ply. I used lots of talc again, and the putting the tubes in the main wheels was easier then the nose wheel. While most builders use the straight valve, I may consider using a 45° stem next time. I did note that MATCO recommends Aeroshell 22 grease rather then Aeroshell 5 that Vans recommends for use on their bearings. Because I am using MATCO wheels with sealed Timken bearings, I ordered some Aeroshell 22 grease to pack the bearings at final assembly.