stryped wrote:

I have a trailer with 215/70/15 inch tires. Two of the tires
constantly goes flat over a period of about a week. I went to tractor
supply and bought a 14/15 passanger radial tire tube yesterday.

This isn't the answer you asked for but have you considered using Slime w/o the tubes?

My 20 year old snowblower's tubeless tires would go flat in about 2 days. I didn't feel
like buying new ones since sears seemed rather proud of theirs.

So I bought a bottle of Slime. It is a tire sealant often used in dirt bikes and such. I
tested it by putting it in the deep freezer for a day and it was still liquid.

I haven't put air in my snow blower tires in about a month. You do have to take your
tires for a trip to coat them. I thought at first this was a failure but after a few
times snow blowing, the air leakage stopped.

Wes