I like buying stuff on Amazon and most of the tires there are foldable. I bought a GP 5000 foldable tire and kept getting flats maybe 1-2 per month sometimes. I stopped using them and went back to my Victoria Zaffiro non-foldable and stopped getting flats. Does this have anything to do with the tire being foldable? Picture of the GP 5000 I bought.
The two characteristics are not directly linked, as they involve two different parts of the tire structure:
The link is that non-foldable tires are considered entry-level, so no manufacturer will now sell a non-foldable tire if they target mid-range or upper-ranges. Performance tires, that are often mid-range or high-end, need to be supple because suppleness directly impacts rolling resistance. It's however difficult to make a casing that is supple and puncture resistant. So yes, I would say that in general, foldable tires are less puncture resistant than non-foldable ones, but not because they are foldable, but because most are "performance oriented". But there are also puncture resistant foldable tires.
The best recommendation here is to check on Bicycle Rolling Resistance, they also test puncture resistance. What they indicate confirms what you have noticed: the Zaffiro score 56 to 58 (out of 100, two versions are tested) on puncture resistance, while the GP5000 are between 31 and 49. The road tire that score the highest is the Pirelli Cinturato Velo TLR 26 (103), that is a foldable tire — but its rolling resistance is higher than the Zaffiro. If puncture resistance is your priority, it may also be worth having a look at "touring" tires, there's definitely some overlap between high performance touring tires and puncture resistant road tires.
If performance matters and puncture resistance matters, it's worth noting that tubeless is also an option that works well if the punctures you get are from thorns or similarly shaped objects. However, tubeless doesn't work well with high pressures, so for road bikes, it's only a good recommendation for the wider tires - above 30mm.
Does this have anything to do with the tire being foldable?
No. It has nothing to do whether the tire is foldable. Foldable tires have a Kevlar bead whereas non-foldable tires have a steel bead. The steel/Kevlar in the bead does not have any effect on puncturing the tire, because the bead is hidden beneath the rim, and nothing can hit it.
Do not confuse Kevlar in the bead with Kevlar in the casing of the tire. Some tires have Kevlar puncture protection belts. It is questionable whether these work: they increase rolling resistance and probably can still be punctured. Another way to increase rolling resistance is to make the rubber thicker, and that reduces punctures, not sure if it reduces more or less than the Kevlar belt.
So this has nothing to do with being foldable. It has everything to do with the fact that bicycle tires are made non puncture resistant and low rolling resistance, because in most conditions this is the right thing to do. In most cases, when riding on paved roads, that are free of sharp gravel fragments, the time you lose to repairing punctures is more than paid off by being able to ride faster if there's no puncture protection.
According to bicyclerollingresistance, Zaffiro Pro has 16.3 watts and GP5000 has 10.7 watts at "extra high pressure" (whatever that means), and at 42.5 kg load and at 29 km/h. So two tires have 11.2 watts more if you use the more puncture protected tires. The difference between those is about 23.7 km/h vs about 24.7 km/h. So you lose 1 km/h due to more puncture protection. In 1000 km, that's a difference of 1.7 hours. How many punctures do you repair in 1.7 hours? I repair about 7 punctures in that time, maybe more. So with 1-2 punctures per 1000 km, you still win if you use GP 5000 and not Zaffiro. Besides, I ride GP 5000 and get fewer than one puncture per 2000 km so maybe you should consider your riding style? Avoid situations where the tire is punctured, for example don't ride over glass fragments and avoid locations where paved roads have sharp gravel.
So as you can see, bicycle tires puncture for a reason. The reason being is that non puncture protected tires are faster, and a faster tire saves you more time than you lose by having to repair punctures.
In conditions where I would get a puncture every 100 km (sharp gravel distributed to icy roads after the ice has melted but the gravel hasn't yet been collected, to prevent pedestrian injuries due to falling), I use the most amount of puncture protection I can, Tannus tire armors. But in other conditions, I minimize the puncture protection I have to maximize my speed.
Depends on where you ride. Kevlar helps but it's not perfect. Here in my neck of the woods we have goatheads, nothing stops them. Nothing. You might get something resistant. You can prepare for broken glass, sharp rocks and other stuff, but goatheads are the killer. Kevlar is a fabric, fabrics are woven. A goathead can and will poke between the threads of kevlar that would stop a piece of glass from cutting. I've stopped and helped a ton or roadies not prepared for them. If you're in the middle of nowhere, California, and a truck stops to help you and your flat, it might be me. I WILL give you shit.
