I have an integy (I think) wheelie bar in blue alum that has those small wheels that use oring like those do - its not very good - those wheels tend to catch in grass and other stuff where I run. I don't think they'd be that good on pavement either - too much wear, though I've never tried it on the pavement. It was a disappointment for as much as I paid for it.

I tried the trx wheelie bar on a lark and find it to be a lot better - especially with the bigger wheels.