Hi Michael
I returned a few months ago from Chambers Pillar and I can assure you the track will rip the Goodyears to shreds as there are a lot of stones as well as sand.
The road to Maryvale Station is not too bad but very stoney in places but when you leave Maryvale is where the track gets bad.
I bought a set of Cooper LTZ (19") and used them for the trip and afterwards put the Goodyear back on for the bitumen trips.
I have not travelled on the Oodnadatta track but I have heard it is a tyre shredder; look up the Pink Roadhouse site for further info.
Cheers, Graeme (The other one)

