Thanks for the tips, guys! I went to Lowes and picked up a foot of 1" ID PVC hose (they did not have any rubber hoses that big). I cut a 2.25" section and it fits over the socket, but a tad loose. I used some epoxy that I had in the garage and coated the socket and inside of the tube.
The grip was great! And by "was", I mean until the epoxy started giving out and the tube was slowly sliding off the roller and getting eaten by the bearing support.
So I cut the remainder off and put on a new section with JB Weld, so far so good. After a couple miles, it looks like the PVC is not wearing off as much as it is compressing, so the contact patch with the tire is noticeably harder than the rest of the roller. We will see how long it lasts.
In the meantime I will be on the lookout for some rubber hose instead. I will try Pep Boys the next time I am in town. I like the idea of getting a super tight fit and heating the hose and cooling the socket!
Thanks again guys, it has been a ton of fun running around on the bike this weekend. The next order of business is getting one of those clamp-on cable stops for my clutch cable, the zip tie I am using to hold it in place is not working as well as I would like. I am looking at one of these guys: Amazon.com: ORIGIN8 Alloy Single Cable Stop: Sports & Outdoors
BTW, here is where this build all started, the pic from the freebie Craigslist ad:
And here is a video of my brother-in-law riding the bike this morning in our back alley (I usually wear my motorcycle helmet, he is a little braver than I, lol)
Ryobi 30cc Weed Eater Mongoose XR-75 - YouTube