I have a pair of 28" tires on rims with no centers. I was wondering if I should trade for 24" on rims or sell them and buy 24". One tire is about 95% and rim is good. The other is about 75% with a small rust thru at the valve, does not hold air long on this one. They are not filled. Just looking for a set of spares because the tractor is about 300 miles from my house. Doesn"t get used much but I would be hurting with a flat and have to leave after the weekend with the tractor stuck. It is a 641. Fairly regular trip from Chicago to the UP of Michigan. I could drag them along if someone along the route wanted to trade.