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Tire Insert Review

Cushcore Tire Inserts: Shore Tested

Words Cam McRae
Photos Dave (unless noted)
Date May 17, 2017

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.


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Taking a flat loose corner at reasonable speed, with no air pressure at all in your tires, is remarkably straightforward with Cushcore. 

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. 


cushcore

Cushcore is a foam insert that has a similar profile to a teacup. The company calls it 'inner tire suspension' because it adds an element of damping to the air cushion in your tire.

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. 


Cushcore graphic

Photos don't do this product justice because it's the cross-section that is important. Unlike other inserts, Cushcore supports the sidewalls of your tire to improve cornering response, even at lower pressures.

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.


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More grip. No squirm.

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. 

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This photo was taken with all the air squeezed out of the tire. As you can see the cupped shape of the insert allows your tire to keep its shape.

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.

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Cushcore bottoms out on standard valve stems blocking air and sealant, so custom ported valves are included with the kit. Unfortunately, long stems aren't yet available (but they should be by June) so I cut a cross hatch in the bottom of a set of E*Thirteen valves to allow air and sealant to flow. It worked perfectly.

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.

Jared Graves

Cushcore didn't prevent Jared Graves from flatting in Madeira, but it did allow him to finish the race. Without it, he says, his wheel would have been destroyed. Photo - Duncan Philpott

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.”

Richie Rude

Richie Rude (above), along with Finn Iles and Loic Bruni, are all running Cushcore according to the company, but they are doing it on the DL because any identifying decals would violate their wheel and tire sponsorship agreements. Photo - Duncan Philpott

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. 

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Cushcore gave me confidence on several fronts. I felt that my rims and tires were well protected and I could smash through rough sections with more control and grip than previously. 

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. 


Cushcore on rim

Cushcore recomends mounting the insert first and then manipulating the tire so it wraps around before mounting. I have also had luck with mounting one side of the tire and pushing the product in from one side. After several mounts and removals, I am getting the hang of the process but 

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. 

For details on installation etc. head over to our preliminary article here. For more from Cushcore head this way...

Comments

Xorrox
+1
Brad_xyz  - May 17, 2017, 10:24 a.m.

I'd really like to hear more on the pro's and con's of the 4 options compared ( Cushcore, Flat Tire Defender, Huck Norris and  Procore) In other words a comparison of weights, rider feel, pinch flat protection and protection from burping.  This does not have to be done shoot out style but more as a way of highlighting each option's strengths and weaknesses in one place.

I've been running Procore over a year now and have generally been happy with it.  I have still managed to have two pinch flats in the rear in that time (in one instance the regular outer tire pinch flatted but I was able to limp home (mainly on the road) on the inner high pressure casing and in the other case I actually managed to somehow pinch flat or snake bite the inner high pressure tube only and did not even notice until I got home because the air was contained in the regular outer tire which somehow did not get a hole in it).  I have since taken to running the maximum pressure (85 psi) in the rear procore tube which does not do much for tire feel or progression but I have not pinch flatted again (I was running 70 to 75 psi previously).   I am definitely on the heavy end of the spectrum (at least 225 lbs riding weight) and love to just plow through stuff and have not dented or cracked a rim since going with Procore (I went though a couple rear rims the previous year).

I am curious how these closed cell foam options would work for heavy riders such as myself.  Since the density of the foam is tuned for the "average" rider, I wonder if these tire inserts would provide enough support and protection for us "gravitationally enhanced" riders.

Reply

craw
0
Cr4w  - May 17, 2017, 1:21 p.m.

I'm in the same weight range with the same concerns. I wasn't able to run Procore because last year there wasn't a good way to run the system on deep rims. I'm still leery of the extra weight especially on a 29er. Huck Norris seems like a good compromise even if it seems a bit rudimentary.

Reply

cam@nsmb.com
0
Cam McRae  - May 17, 2017, 1:35 p.m.

Unfortunately at under 165 lbs I can't be much help for you Clydes in terms of reference but it does make sense that the foam would be aimed at an average weight.  At the same time if dudes like Fairclough are running it that may be a pretty good indicator.

JBV
0
James Vasilyev  - May 18, 2017, 12:04 p.m.

and i've since learned of a couple more versions of these in the last couple days. i don't know how many that makes in total but they are coming on fast and furious. it's a cottage industry. they do seem almost race specific in application other than HN. i'll consider one of these only once they start showing up in the LBS but i don't think i really need it.

Reply

metacomet
+1
Metacomet  - May 19, 2017, 6:12 a.m.

Nice review Cam.  I have yet to flat since running CushCore as well, and have not experimented with super low/no pressure so it is great to hear about how well it held up to that!  Gives me even more confidence.  I am absolutely loving the inserts so far as well. 

I wonder if it would be possible to fit a 650b long stem road tube into place as a last resort trail repair if you got a big hole or sidewall tear that a plug and sealant could not close, by pushing the stem of the tube right through the cushcore and out through the valve hole, so the tube is still against the tire.  Or a mtn tube with a valve extender.  I can't see why it wouldn't work for that type of long ride/last resort scenario.  Because I agree, pulling that thing out is not really much of an option out on the trail but you should have some type of backup solution if you are hours from anywhere.  Might be worth experimenting with anyway.

Reply

metacomet
0
Metacomet  - May 19, 2017, 11:39 a.m.

Dohh! I must have completely missed where you said that exact thing about pushing the long valve stem of a tube through the insert.

Reply

cam@nsmb.com
+1
Cam McRae  - May 19, 2017, 12:54 p.m.

Haha! No worries. The guys at Cushcore told me that but you figured it out yourself! I had an idea that I think would mainly apply to racers for tubeless in general but could work for Cushcore as well. It involves drilling a second valve hole and having an uninflated tube (the lightweight plastic ones like Schwalbe sells would make sense) lying reserve inside your tubeless tire. If you flat you just give it a shot with a CO2 and you are going again in seconds. My concern is that the tube may get damaged inside the tire- but perhaps not with Cushcore in there.

metacomet
+1
Metacomet  - May 23, 2017, 9:46 a.m.

That is a clever idea with the tube in place for race situations!  It might have a chance in there with the cushcore in place!

I had emailed with the folks at cushcore with some questions a while back regarding 26", and they said you can buy a 29" insert, cut out a 8.5" section and glue back together with super glue using some bench clamps to hold it in place and it makes a strong bond once set.  Worth mentioning for any 26ers out there that are feeling left out.  Also mentioned they have several new sizes in the works.

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