Took my ds to the beach and dunes today. Very soft sand today, lost the front tyres completely in one hole, realised that the kendas are crap in the sand, let them down to 2psi in the end and still no good, what can i get to replace these that are good in the sand, don't want paddle tyres though-also PROBLEM going up a hill today in second was making it struggle a little bit and clunk clunk from the engine any thoughts as to what this could have been, only happened once? thanks..

 

Ohtsu radials, front and back, are the best non-paddle tire in exestance for sand. The front are rounded in profile, and very soft rubber for excellent sand performance with 3.5-4psi of air. The rears get awesome traction due to the radial sag, and soft compound as well (3psi).
Only problem is they are a lot easier to punture when you get on rocky trails, so you have to be a lot more carful. All in all, I consider them the best all around - from sand, to trail, to track.
Holeshots and Razors do well in the sand too - better punture resistance. If you ride a lot of rocks, fast, get one of these. I ride rocks with my Ohtsus, I just slow down for them. if you bottom the tire to the rim, the rock can cut her easy.

 

Hemmi, in the sand (especially with a big quad like the DS) you need paddles. Nothing will perform as well or even close. That clunk clunk sound is probably sand getting in the chain when your're trying to climb a hill as the rear end digs in a little. It sounds realy bad but it's actually normal. If you don't want to invest in paddles then maybe some of the tyres that hightower mentioned will help but again, the diference between knobbies and paddles is like night and day.