I can't attest to the 20in ability on sand, but I do have 17s on mine that I am interested in swapping (with cash) for some 20s. Unlikely, but if you are interested, let me know. I'm just down the road at Maitland too.

 

Not wanting to hijack the thread... but..

Would 18in or 17in be better for 2nd set of wheels when going off the beaten track a little. Which would give better overall choice of tyres and stil maintain same OD as the 20's?
Also, would appreciate suggestions on what would be a good choice of all round touring tyres, ie they must be quiet, but reasonabley capable off road. nothing crazy extreme but something that could be comfortable at Fraser and then some outback trails as well.
Shall be towing 15ft single axle off road pop top van with air suspension as well.
The new Treg will be my daily drive, so I'll use the 20's that come with it for that, but when on hols shall change to a better all rounder tyre & rim.
Been thinking maybe a set of 18inch might be good compromise?

 

Not good news but the tires seem to be the culprit rather than the size.

http://www.clubtouareg.com/forums/f67/r50-on-fraser-island-82098.html

 

Cooper Tyres have an option for you. This tyre could fit both your on and off road requirements. I haven't tried them, and am just going by the manufacturer supplied recommendations on the website and what they say about the tyre. Suggest you do some more research using independent reviews etc.

ZEON LTZ High Performance
70% Road & Sand, 30% Dirt & Mud
The Cooper Zeon LTZ was developed as a hybrid between a sports truck tyre and an all-terrain tyre. The aggressiveness of the LTZ can tame any road surface while providing excellent ride and handling capabilities.

I am told this is a $600+ tyre, but would still be cheaper than maintaining two sets of wheels and tyres.

PASSENGER CONSTRUCTION
Size Approved Rim Width Ply OD mm Load Index Kms* Wty
20" 275/45R20 XL+ 8.50-10.50 0 B 757 110S 50,000

Cooper Tires - Tyres

 

but would still be cheaper than maintaining two sets of wheels and tyres.

Have to disagree with you here, you can pick up a good set of 2nd hand 18" VW/AUDI/Porsche wheels for a few $100 and there is more choice in suitable tyres in 18" available under $400 each.
No matter how good the OEM state the tyres are one set will not perform your daily driving requirements and still give you that off road capability you may need a few times a year. Go a 2nd pair, this will allow you to place a higher profile tyre on (better ground clearance) and stratch the hell out of your rims off road without having to worry about the looks for the rest of the year.

 

Buy some 17s, fit something like these, and go where you want!

VWVortex.com - Firestone Destination M/T Mud Tires

 

I can't attest to the 20in ability on sand, but I do have 17s on mine that I am interested in swapping (with cash) for some 20s. Unlikely, but if you are interested, let me know. I'm just down the road at Maitland too.

Thanks but I will probably hold onto the 20 inch rims, but I think will look at getting a set of 17s or 18s to put on when I'm on holidays and looking for some adventure! Cheers.

 

I wouldnt take the 20s on sand, even on bitumen the ride is harsh.