i have a mixed results report, i took a set of iroks on redcat wheels ( these wheels let air out really nice) on the trx4, my son drove that in the novice class and did pretty good for his first comp, 6th out of 15 participants, i could tell right of the bat that these tires can be pretty good on jagged edge rocks, and loose dirt on his run, these are the grey stock foams, i feel better foams would help a lot, then i went with some cheap plastic beadlocks on the vaterra ascender and no air holes, the tires had grip but bounced all over the place( same foams as the ones on the trx4) they did really nice on mud didn't bounce around in there, the difference in weight of both cars and the air venting definetly made an impact on the way these tires behaved, with weight and venting they reponded almost linearly to directions input, on the other hand the set with less wieght and no air venting turned them into almost undriveable tires because they were all over the place...so my assesment is, they are a great all around tires that can contend with the better known brands out there, just need to fine tune them, i am getting better foams for them and will report back after that.