The only one that manufacturers 305/70's in Michelin although Continental had them listed. This was about 2 years ago when I put the 305's on the front of our DSDP. The Continentals weren't even being produced yet.
The 295/80's are over 2" larger and wouldn't fit out wheelwells, leaving the 305's as my only choice as we needed the add'l capacity they gave us.
Our unit came with a 12,000# front axle but it was overweight so Newmar had Spartan replace it with the 14,600# unit.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '05 Odyssey