I have a front 7.50 x 20 front tractor tire which had(has) a bad case of thorns. Was visiting family about 2 hours from home, took wheel and tire with me to a good local tire place near family. He said it would cost me too much to patch the dozen or so holes he found in the tube and he didn't have a new tube in stock, but did get all the thorns he found out. I paid him for his work, took tube home, bought a box of patches, and patched the tube. Now thorns, which in this case came from a honey locust sprout, will keep working into the tire if they are not all removed and will make new holes. The tire developed another slow leak and I put some Green Slime for tubes in it and have mostly solved the problem. I'll probably have to go through the process again before the tire wears out, In which cas I may be closing in on the record for patches.