Used 345 Tires

[Spider]

I am looking for used 345 or 355 tires. The brand is not important, a street legal looking tread would be fine. It's for an art project and the sidewalls of the tires will be cut anyway, so it does not really make sense to spend money on buying new tires.

I need 3 tires for the project and probably a few more for training/testing. Any idea where I could get them? As you know, it is not the most common size at the local tire shops...

Thanks!

Marcus