I'm using the OE bridgestone s20's on my MT. After around 1800 miles the rear was shredded on the edges and almost to the threads in the middle. After putting another s20 on and putting the bouncy rear shock as stiff as possible the new tyre has only lasted around 900 miles. Would a decent shock solve my tyre shredding problems or should I just use different tyres? Any help or advice will be greatly appreciated, thanks.