Panzer Aggressive Inserts

Note - After riding this inserts for a couple of months I found there was unacceptable damage to the rear. I rode it hard and did some time testing run flat but I have done this with other inserts without seeing excessive damage. See my follow up article here for more info.

Would this be the one? Every time a new insert comes into my crosshairs, I have little optimism despite holding onto a sliver of hope that this one will have all the ingredients to make the secret sauce; low weight, solid run flat performance, including good sidewall support, rim and flat protection, generous volume and a shape that pushes into the side of the tire to improve inflated cornering support. I have seen elements of each of these in inserts from Cushcore, Rimpact, Octamousse, Tannus, and Flat Tire Defender, to name a few. But none of them came with the entire package.

Cushcore Pro does everything well, but they are on the porky side at 260g. Rimpact is nice and light but I didn't appreciate the sidewall support. Octamousse has great volume, weight and run flat performance but doesn't support sidewalls well. Flat Tire Defender weighs a full 300g without doing anything much better than Cushcore. Tannus ticks a lot of boxes as well but once the air is out of the tire, it provides very little protection or sidewall support.

This wouldn't be so frustrating if, at least from the outside, it seemed impossible to meet all these goals at the same time. But in fact, it seems entirely doable. Each one of these pool noodles is extruded form a slightly different foam, each with somewhat different properties. Cushcore has an almost spongy feel which feels very well damped, while Octamousse seems to be made from an actual pool noodle but it manages to perform surprisingly well while weighing half as much as Cushcore. It seems only the shape is wrong, because it lacks supportive wings like Cushcore or Tannus. FFS! How hard is this people!

And then, along came Panzer. It's a Spanish product named after a fierce German tank. The shape seems good, mimicking Cushcore's wings, and in its heaviest 29" iteration, it weighs just 144g, or 116g fewer than Cushcore.

The foam has a relatively stiff feel which didn't discourage me and it seemed to be well sealed (or closed cell) to prevent sealant absorbtion. Installation was perhaps slightly easier than Cushcore, but the set that arrived came without appropriate valves so I used conventional valves at first. This failed and I could add air with some effort but not release it.* I gave us and used a Cushcore set so air could be added or released properly.

*If this happens, and you assume you'll need to destroy your tire to remove the air, fear not. Instead, loosen the lock ring on the valve and push the valve into the rim until air is released. If you fun a lot of pressure this make take some effort.

Once I had the valves sorted, and I could accurately measure tire pressure, everything began to feel pretty good. The support was there, but perhaps not as robust as Cushcore.* Once you drop pressure, Panzer has a less damped feel than Cushcore and I felt some harder strikes than expected, but without any damage to tire or rim.

*My most recent Cushcore rides have been on the eMTB version which is closer to 300g so this comparison may be slightly unfair.

Overall I was pleased with the full pressure (18 psi front/20 rear) performance and the lower pressure support as well. I did a little riding on pavement with a completely deflated rear tire and it seemed reasonable, but the real test would have to be on the trail, preferably something fast with some aggressive corners and bumps.

Deniz and I arrived at the top of Empress Bypass and I dumped all the pressure in my rear tire. I reduced about half the pressure in my front tire to destabilize things a little further. The trail is relatively fast with lots of berms and a few rougher sections; the worst conditions to keep control of once you've had a rear flat. I was a little tentative at first, as it felt like the tire might fold over but I gained confidence with each corner. The rear was squirming some, and much more so than Octamousse. The last time I tried this with those 8-sided pool noodles I was able to stay with my buddy and almost let it completely hang out.* Octamousse is the best run flat insert I have run overall, but Cushcore may have an edge in corners. Both are very good however and get the nod over Panzer. Despite that, the Panzers were totally serviceable. I was able to corner at perhaps 65% and more like 75% in a straight line. In other words, these are totally competent run-flat tires in my books, meaning for many rides you can get away without bringing a pump, tube or levers, as long as you don't have too long a ride back to civilization.

*The trail had fewer corners but was rougher and just as fast.

I feel like there's more work to be done here. A couple of the strikes I experienced through the Panzers, running slightly lower than my usual insert pressure, felt and sounded a little alarming. No damage resulted from these but I need to determine specifically what was going on. Perhaps these don't damp noise or sensation as well as some of the others, despite remaining quite protective? I'd also like some more time to see how they stand up to repeated hits and how durable they are overall. Early Cushcore inserts often looked like they'd been a Doberman's chew toy after a couple of months of hard use but more recent versions seem much more resistant to damage. My suspicion is that the chemical composition or the manufacturing process has changed to accomplish this but I haven't been able to confirm that.

For now I would have no problem recommending these for riders looking for decent protection, support and run flat performance from an insert that weighs half as much as a standard 29" inner tube.

Panzer Aggressive Inserts

Note - After riding this inserts for a couple of months I found there was unacceptable damage to the rear. I rode it hard and did some time testing run flat but I have done this with other inserts without seeing excessive damage. See my follow up article here for more info.