I made one. I used 7 old car snow tires. Four wide bolted together with short 3/8 all thread cut 3" long with 3/16 thick 2x2 homemade washers. This came out to about 8'6" wide total. I placed another row of 3 tires in front of the line of 4 tires. At each tangent point I bolted them together. About 7' of old chain, the ends bolted on either side of the center tire of the row of 3 tires. A loop bolted in the chain at the center that will go over a 2" trailer ball or in a shackle.
Of course the good grass lies over with the weeds, but the good stuff seems to bend and come back sooner. The weeds tend to break and not come back well. At that it may take several passes over the summer to damage the weeds to where they don't recover.
Of course this rig works well breaking up cow pies and horse apples. I'm sure there are better implements for these jobs, but this was incredibly cheap for the good job it does.
