Tire Insert Review
Cushcore Tire Inserts: Shore Tested
Three foam tire inserts recently arrived on the scene and each one has been making significant inroads for riders of several stripes. Racers have been the earliest adopters and not long ago we learned that for all of last season Aaron Gwin was running one of the systems; Flat Tire Defender. While Gwin praises the rim protection and flat prevention qualities of FTD, he raves about the way square-edged bumps are smoothed out and how the feedback that reaches his hands and feet is reduced. I was intrigued by all three right from the beginning. Better suspension? Fewer flats? Rim protection? I want some of that.
These three systems, Cushcore, Flat Tire Defender and Huck Norris all followed Schwalbe's Procore which aims to achieve. a similar result with a road bike diameter tire acting as a secondary tube inside your tubeless tire. Procore has had mixed results and reviews but the early reports I got were extremely positive. I heard from some of the journalists who were among the first to ride Procore and they raved about the way they could reduce pressure (increasing traction) without having the tire squirm too much. For the often wet condtions we ride in this sounded ideal.
Most riders I know aren't interested in adding Cushcore's 260g (29" size) of rolling weight to the outside of their wheels. My gut reaction was along those lines as well. Of the three systems, my impulse was that the one that weighed the least (Huck Norris) would be the most beneficial to me, but as luck would have it I ended up trying Cushcore first.
My initial Cushcore impressions focussed on the installation challenges and the goals and design of the system. Now that I've had a couple of months using the inserts on two different sets of tires and wheels and three different bikes, I'm prepared to make some bold pronouncements.
Hey guys, just some quick feedback to let you know (and give thanks) that Cushcore definitely saved my race here in Madeira. - Jared Graves
To begin, I swapped to a slightly lighter front tire, a Schwalbe Magic Mary, but stayed the course with a Maxxis DHRII, my rear tire of choice. The results were impressive immediately. I became intentionally lazy about keeping my pressure up between rides without any negative result. I could drop below 20 psi without compromising cornering performance or feeling much squirm under breaking or acceleration. Cushcore's shape does an excellent job of bolstering sidewalls so the integrity of the tire is preserved at lower pressures allowing solid cornering performance to be maintained.
Suspension performance improved as well. Similar to Gwin's experience with FTD, I found that the added damped bumper within the tire smoothed out nasty jagged sections of trail and made abrupt rim to rock bottom outs a thing of the past. I wouldn't say I have enough rides on Cushcore to make any proclamations about flat prevention but I haven't punctured since I began using them.
Cushcore makes many claims about the product but in the FAQ section of the website the product's ability to provide run flat protection is presented modestly; "While CushCore is not intended to be a run-flat tire, it is possible to 'limp home' short distances with significantly reduced risk of rim damage." This needed to be tested further so I did a little riding around with no pressure in either tire and not only could I climb and descend fine, cornering capability was also shockingly robust. These short bursts for the camera were no substitute for being stuck on the top of the hill without air, but then my overly casual bike prep came to the rescue.
When it came time to saddle up for the next ride my rear tire was low so I gave it a jolt from the compressor thinking everything would be fine. I'm generally over-prepared during a ride but I decided to leave the pump at home and of course, the tire would lose air after about 5 minutes of riding. I bummed a pump a few times and Trevor had a pair of CO2 cartridges I deployed at the top of a couple of trails, but much of the ride both up and down was spent riding with a new carbon wheel supported by no tire pressure whatsoever. Climbing up the Mt. Fromme fire road it sounded faintly like I had a flat, but without any rim on dirt and rock noise or feel. The ride was entirely comfortable and I could maneuver the bike just fine. Going down I took things a little more slowly to preserve rim and tire but I could ride with confidence. If I was a spawnserd racer with no concerns about destroying equipment I could have gone much faster. The tire was securely attached and my rim felt extremely well protected. When I checked everything at home the rim and tire were free of damage.
I asked Adam Krefting, the owner of the company, about the gap between my experience and Cushcore's messaging; "At first, we didn’t realize at first that run-flat performance would be such an important capability. Then Fairclough finished Lourdes DH with a flat on CushCore, and Jared Graves sent us this email last night:
“Hey guys, just some quick feedback to let you know (and give thanks) that cushcore definitely saved my race here in Madeira.
CRAZY rocks on stage 3, managed to flat, but with the stability in the tire could limit the time loss and still manage a 20th place for the stage despite riding almost 5 minutes with the flat. There was no way I could have pushed anywhere near as hard as I still could with it, not to mention I would have for sure broken my wheel and that would have meant race over.”
Run flat performance is incredibly important for Cushcore for a couple of reasons. The first is that the secure hold the product puts on your tire makes removal more challenging. After doing a few I'm getting the hang of it but breaking the tire free from the rim bead takes some effort and I wouldn't want to do it on the side of the trail. Once you've got it open, unless you have a tube with a 45mm valve stem to push through the insert, you'll need to remove the Cushcore to put the tube inside. It's not going to be an easy thing to carry and leaving it out in the bush isn't an option either. I also found it challenging to get my DHRII to seat, even with a compressor.
My most recent act with the inserts has been to mount some (comparitively) pinner tires. I'm testing a set of Mavic XA Pro carbon wheels and they come with Mavic Quest Pro XL 29 x 2.35 tires. Normally I'd put them aside for something that works better in our neighbourhood but kept them on but with Cushcore inside. They weigh under 800g so I'm saving close to 200g a tire over what I normally run, and they feel great. The supple casing has excellent trail feel and the side knobs dig in nicely with the help of the inserts. They bite like a much more robust tire but with the feel of a nice light casing. So I've got the weight penalty of Cushcore down to less than 100g per wheel, which I'm happy to give up for the performance I'm enjoying.
As it turns out I'm not the only one digging Cushcore. Adam Krefting told me that Finn Iles, Loic Bruni and Miranda Miller are all running the product along with Jared Graves, Richie Rude and, as mentioned above, Brendan Fairclough. Several other teams are running trials with Cushcore as well but apparently none of the riders is getting paid to use them.
Obviously, a system like this makes great sense for downhill or even Enduro, where preventing flats is mission critical, but I'll be keeping a set in for the foreseeable future despite never riding against the clock. There are certainly some downsides to Cushcore, the most obvious being weight, but you can add installation and removal challenges and the absence of a practical trailside flat repair solution to the list. Choosing lighter tires and rims could erase the weight penalty and the run flat capability should get you out of the woods in most situations making those compromises easy for me.
There are several factors that may lead you to consider this product. For me, the main factors are the improved traction and suspension performance because I'm not prone to destroying rims. If you are hard on rims and tires and/or you are a racer, this product is well worth the US$149 price per pair (with valve stems). If you only race your buddies but you are keen to squeeze as much juice as possible out of your bike in aggressive terrain, you may want to give them a look as well.
For me Cushcore is one of those products that seems to be increasingly rare; it has increased my stoke for riding and for my bike. Given the choice I can't imagine riding without it for the foreseable future.