Tires: Sidewall cracking in Michelin lt245-75 16, michelin ltx, michelin tires

Question
I have a couple of Michelin tires on a church van that are cracking in the sidewall. I took them to the dealer and he said it is nothing to worry about and it was normal for  tires that were not driven frequently. These tires are only 14 months old and and have probably 6000 miles or so on them. I use Michelin LTX's (LT265-75 16)on my personal truck and have not had this cracking problem even on tires that were three or four years old with 40k+ miles. Is the cracking a defect (the tire tech said it was dry rot) and should they be replaced? The cracks are small, about 1/4 inch long and shallow.

Thank you.

Answer
Malvin,

Part of the natural aging process of rubbers is cracking.  It is a matter of degree rather than kind.

But if after 14 months the tires are cracking, I wonder what is causing this - and the usual cause is over deflection - either too much load or too little inflation pressure (or both).  So I would start there to be sure you aren't overloading the van and the pressures are what the door placard says they should be.