grand design tire warranty

That's common. The tire warranty is always administered by the manufacturer of the tires.

Components to rvs like tires, a/c, fridge, furnace, awning are warranteed by their mfgr. Its clear in your service and warranty package.
Grand Design will help you with an issue related to failure of the component. The rv assembler ( builder) only assumes responsibility for their build and installation of outside supplied components.
We see this many times a year in our camp , with rv problems. The mfgr.( final assembler) of an rv uses many outside suppliers for components, much like a sticks & bricks. They are warranted by their maker.
A home builder is not responsible for a warranty issue with the water heater or fridge, for example.
Hope this helps. Max

Give Grand Design Customer Service a call and ask them. That would be going straight to the source and they're a great bunch of folks up in Indiana (574-825-9679). Industry wide, though, blowouts are a tough situation. It's hard to prove the load, inflation, and lack of road hazards or debris.

You might also want to join the Grand Design Owners Forum. It's a very active group (not run by GD but they do monitor the "Technical Corner" sub-forum). Lots of folks with good experience over there:

Grand Design Owners Forum

The WestLake tires GD uses are "Super STs," load range "E" on the fifth wheels and rated for 75 MPH. Not a bad tire, really.

Rob

Found answer 12 months no questions free replacement, pro rated after that.

You can post your question on the GD forum:

http://www.granddesignowners.com/forum/forum.php