Could someone please tell me what the rear tread pattren looks like for a '72 750 K2. I know the front is a ribbed one but what does the Bridgestone (Super Speed 21R2) or the Dunlop (K87 Mark II) supplied tire tread looks like? A close up picture would be great or some reference to the tires in the Dennis Kirk or Chaparral catalog or a current tire manufacturer's website would be appreciated. Thank you all and have a wonderul and safe weekend.