When we started karting 6 years ago I bought two ZAMP RZ-35’s for my son and me. I believe they are now the RZ-36. That have served us well but I would agree as they have aged the padding has packed out and they fit looser now and can tilt back, but likely this is not enough to justify a smaller size. The liner is removable for cleaning and I believe they sell different cheek pads too to adjust fit. We have some at our track that use the FS-9 motorcycle helmet and seem pleased. I will likely replace mine with the FS-9 model next year.
What’s your budget for a helmet? Zamps will work fine, though I have heard about the riding up issue and I’m not a big fan of their interior material. For a karting specific model, I am always going to recommend Stilo, Arai, or Bell. You’re paying about twice the money for a karting-only helmet, but to me the quality is worth it, especially for a street race like RIGP.
$400 is a little tough. The Stilo ST5 KRT and Arai SK-6 are about $650, the Bell RS7-K runs $700, but the Bell K1 Sport is $460.
Not sure about all the others, but Stilo uses the same shell for the ST5 KRT and ST5 FN. The FN is the formula car model, and regulations have brought in smaller eyeports for safety since the drivers heads are exposed.
I’ve had a zamp helmet before and it was okay. It’s fair for the price but it rides up on your head a ton like everyone mentioned. I’d really recommend just finding the stilo karting helmet on sale as it’s a lot more than $200 better. I have no experience with bell karting helmets but in cars I’ve really enjoyed them.
I have a Zamp RZ-70 SA 2020 helmet. We race predominantly at Fremont OH which is not terribly bumpy (there are a few) but very busy. Generally I like the helmet but did find it tends to ride up sometimes. I found that a head sock seems to minimize that problem and helps keep the liner clean(er). I didn’t have much of a problem with the helmet riding up at Elkhart and there are some whacking great bumps in turn four. Made me very happy to be wearing a rib vest.