Hey guys,
SR owner here, but I lurk here sometimes. I just got some Heidenau K34s in for my tracker build (4.00x19). These are speed rated to 130mph and come in two compounds- a harder street compound and a soft race compound that AHRMA racers use. They also have a DOT #. Here are some pics of them mounted and side-by-side with a 110/90-18 tire. They're not as wide as a modern d.t. tire, but are replicas of what was used before those tires came on the scene in the late 70s/early 80s (with updated construction). I pinched the tube on the one mounted to the chrome wheel, so it's deflated in the picture, but you get the idea.
Cheers,
Bob