I have used both Kojaks and Duranos, the Duranos are still on my velos (both of them). When I first got the Dash, the original tires was the Kojaks. Frankly speaking, both are equally good even when it rains. The reason I changed to Duranos ( it's just me, OK

) is because Kojaks are 1.3s and it's like not here nor there. Duranos are 1.1, slimmer, tire pressure is about the same. So, to get lesser resistance, the slimmer the better, right? So, I changed to Duranos. Just get the slimmest tires for tarmac riding, purely for speed. At that time Panaracer Minits Lites were out of stock and hard to get. Panaracer is only 1.0

and also the cross section is like a cone. When on flats , minimal surface contact and when cornering, bigger surface is in contact with the road.
In my opinion, the best tires fo a foldie is Schwalbe Marathon series. They are also puncture protected. YES, it does get punctured but needs a longer penetration. The bottom part of the tire is lined with a blue compound to make the bottom thicker. Tires like Kojak and Duranos, you need to be careful after a while of using, especially Kojaks which wears off fast. As the surface gets thinner, small grains of sand gets embedded into the compound. This is more so when riding hard as the surface gets hot and goes soft. If embedded the grain of sand sometimes gets rolled over and over until you might hit a small bump which hits the sand even deeper and finally pierce into the inner tube. This type of puncture is irritating because they deflate very slowly and sometimes you don't see what is puncturing the tube and it will happen again after replacing the tubes.
Once when I was riding my Dash in Genting Peras and was coming downhill, I didn't notice a small corner of the brake shoe was misaligned. As I braked, it was rubbing the walls of the tires and after that, there was an explosion. Luckily I was still upright and found a big hole on the tube and the tire. My wife have to continue and get the car to me later. No repairs unless you carry a spare tire.
As for the Kojaks, the ones you buy now are those being offered for the last stocks. You can get them in Kimbell Jaya for even less now. The usual price was RM110 but now it is offered for RM60 but my guess is the stocks are finished already but those using Kojaks are usually 451 users, maybe there still some left. But for foldie general use, I still advise Schwalbe Marathon series, either the Plus, Supreme ( minimal treads for less resistance ) or Racer ( Racer is 1.5 with deep treads ).
In speed and ease to pedal,durano is better than kojak significantly? SO,in short durano is more durable than kojak? demm,shud have opt for the duranos.
Saw the marathon too,but i was finding for thinner ones. And im using the bike on tar roads only so dont need marathon rite? Now i shud be more careful after hearing your story. SO for light usage and no long distance riding,usually the kojak can last for how long?
Btw,can we fit a 20x1.75 tube into a 20x1.35 tyre? The bike shop just fit the tube inside the tyre. He told me to use first,if get damaged ,baru chg the tube. Can meh like that?