Originally Posted by BCRider

The cracking of the gumwalls isn't that big a deal. However the access it provides for water and air to reach the cotton belt threads and allow them to rot very much is a big deal. If you can see the threads through the cracks then it's simply time to sigh and replace them. If there's no big bulges or noticable degrading of the threads that you can see in the cracks you don't need to replace them today but it would be wise to get some over the next couple of weeks.