Weather cracks don't automatically indicate the tire needs to be replaced. If they are under the manufacturers specified depth. This depends on age of the tire of course but check the manufacturers web site, or with their reps as either source should be able to tell you if the cracks are too deep or if the tire is too old to be trusted.
Also, Amazon carries 22.5's and if you're a Prime member, shipping is free. The brand and style I bought came to $200 each. And most Love's Truck tire stores will M&B them even if you didn't buy them from them. And they have a balancing machine big enough to balance them. Cost me $40/tire to get the M&B done there. So as low as $1500 for a full set M&B'ed if you want to work a little at saving money. Also drove up from California to Oregon to have it done up here.