Tom Burnswrote a review of Cush Core Tire Insert Set on July 20, 2018
Familiarity: I've put it through the wringer
Below are the main benefits I found when running single-ply tires at lower pressures with the inserts. For reference, I run Maxxis DHF EXO 29x2.5 3C at @ 23r/20f on rocky / technical east coast terrain.
They eliminate tire squirm while maintaining good feel and rebound characteristics. The inserts stabilize the lower portion of the sidewall, but keep the tread portion supple – resulting in improved cornering + overall stability.
Reduced the air volume in the tire makes it more progressive – so it ramps up faster, then eventually engages the foam – making the tire behave more predictably + act more like part of the bike’s suspension.
They lock the bead of the tire against the rim, eliminating burping.
They do add rotating mass (vs running just a single-ply tire), but the weight is inboard (being on the rim side vs. the tread side). I was lucky enough to start with a pretty light set of wheels, so I felt like I had a bit of wiggle-room.
Installation and removal are actually no sweat if you follow the instructions and use plenty of soapy water. I did a tire change a couple weeks ago and it took me about 15 minutes, Stan’s & all.
Probably not for everyone, but it you are fussy about tire performance, run lower pressures and don’t want to drag-around DH tires, these are a pretty nice solution.