I would bush your wheels. I use an eyelet from Sig that fits the gear wire. The 1/8 gear wire I use works great with the 1/8 id brass eyelets from Sig.
Drill the wheel hub out to snugly fit the eyelet, put a little CA on the hub and push the eyelet in to stay. Make sure the bushing is square so the whell spins true. Now there is no problem with plastic-on-wire heat, breakdown of the plastic at the wire from fuel,oil,nitro, etc.
In direct opposition to your friend Rudderless in the post above, I put a little oil on my wheel's bushing as they will chatter on long landings. A little cleaning will keep your wheels and gear wire clear of too much dirt.
Chris...