I have no idea if this will make your problem better, worse or do nothing. Now that I have put in the disclaimer. I was told by a friend that has done unbelievable things restoring very old tires for display that he used glycerin that you can buy at a drug store. It will soften and allow old dry/hard rubber to seal cracks and become flexible.
He has brought back some rare size tires that are not available at any price soaking them in glycerin but said you have to be careful because to long and the rubber turns into mush. He made a special pan that he could sit the tires in vertically and rotate ever so often so that it didn't take as much glycerin.
I have used the technique to fuse age cracks back together on some tractor tires by just brushing it on every few hours till the cracks melted back together.
Before someone waves the safety flag on fixing old tires, none of the tires that my friend or I repaired were used on the road after the repair, they were for slow speed or display purposes only.
Jeb
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