The tensioner is nylon because it tends to self lubricate as it wears away. The piece was machined on a lathe–it was simply a matter of cutting away a little from each side of a thin piece leaving a small runner to guide the chain (you could also cut a groove)–I’ll see if I can get some more detailed picture later.
We have been using nylon for tensioners since last year and have little visible wear on it even after two regionals.
We have used the nylon spring-loaded ones from McMaster and it is kind of clunky and hard to incorporate into the chassis.
Can you tell me which nylon round stock you used? I don’t need a picture but others may benefit from one.
Thanks
Amir
I believe it was McMaster part # 8664K15
Do a mcmaster search for oil-filled nylon rods I believe we used either the 1 1/2in or the 2 in rod.
McMaster part number 8664K15 is enough to last for a few years 
i have to say i do like the pulltrusion shape that easily makes what would’ve taken multiple pieces of other materials to make. And it would’ve most likely ended up heavier.
looks like a great drive base, how much did you lower the center wheel?
Do you know if the oil-filled nylon is better than the oil-filled UHMWPE, part number 5243T23? The reason I ask is that the chain guides you are using are made from UHMWPE not nylon.
Center wheel is lowered 1/8"
We used the nylon because we had it on hand–Either should work well.
When playing with the chain, the UHMWPE seemed to be a little more slippery. We used the nylon because we already had it, if I was ordering material for the tensioners i would go for the UHMWPE.