http://www.ebay.com/itm/29x12-50-15-Comp...=item564969822dThese are a 29" tall
You will want to verify they are a 15" rim, and not a 12.5 rim with a 15" width. Sometimes tractor tires are sized different than vehicle tires.
Getting something in a 15" rim size and 33" height in an AG tread is going to be hard to do, if at all.
Your best bet is to search around for Compact Tractor tires. and you will be looking for the front assist tires.
You can also look at skid loader tires, but again height is going to be limited.
