Hey All,

Mid next year - I'm planning a trip, using my 2012 F250 across the Simpson Desert here in Australia, using the Madigan line. Its known to be one of the toughest and most remote tracks that one can do in outback Australia. i.e. one of the toughest and most remote tracks one can do in the world.
A bit about it if you are interested. The Madigan Line - February 2015

I plan on taking at least 6 new tyres (its not unheard of vehicles to destroy all 6 on this track!). My stock 275/65R20's are at about 50%, so I'm in 2 minds. If my tyres don't make it - towing fees are in the tens of thousands.

Do I replace them with factory 18inch wheels and 285/75 R18 or 295/65 R20 on my current wheels?

I really like the 20 inch wheels from a strength perspective (the look nice too - but that won't really matter where I'm going) - and I also like not keeping 2 sets of wheels and tyres on hand.

I feel the taller profile 18's will be much better in soft sand running at ~18psi or less, and that size tyre has been sold in Australia before (meaning, there might be a small chance of getting a replacement if needed), but wanted to get thoughts from people that have run either size.

Thanks in advance for any help you can be.

 

I'll start this by saying I have no experience with either of those size tires and or heavy offroading in a superduty.

I am, however, extremely experienced in off-roading in general. If it were me, I would get the tire that has the most rubber, as that increases your ride comfort and translates to less wear on the rig as the rubber is absorbing more of the impact. I'd also consider ditching the factory wheels and running a beadlock style wheel, as the ability to run 5 psi will translate to a more enjoyable experience. Plus, it is easier to switch tires with a beadlock as you only need simple tools to do so. That said, beadlocks are not street legal (most of them anyways), but since you are offroad, that won't matter too much.

Just my $.02.

 

I did look at Walker Evans beadlocks, but they are only 17" - and the only tyre size suitable in that rim size is a 35" and 37" flotation. I want a narrow tyre (I've found it better for the dunes - and less likely to puncture, also can run less backspacing so less wear on wheel bearings and ball joints), so it means either 18" or 20" wheel for the above tyre size. The rims are also very expensive. Beadlocks aren't illegal in Australia, so I don't have that problem however.

From experience, I much prefer factory rims, as I've found them to be made (and tested) to a much higher quality than aftermarket - there are some brands (such as Walker Evans) that are equally as good (or better), but most are not. I'm also likely to damage a rim. I'll feel better about replacing a much cheaper factory wheel, than something expensive.

If I do have to do beadlocks, I'll use something like Staun, but I don't think I'll need them, as I'm only traversing sand dunes (i.e. ~12-15psi at the lowest), not rock crawling and needing 5psi.

 

Skinnier tires will sink in the sand, especially with a heavy diesel. I had incredible traction in deep sand with 37x13.50x17 tires, aired down to 20psi. I wanted to go lower, but I was concerned with the bead coming off. I would highly suggest 17" wheels and at least 35's. You are describing a pretty brutal trip, and more sidewall is a good thing!