Introduction:
“Hey bro stick this pool noodle inside your tire. You’ll be faster.”
A few years ago, tire inserts were all the craze. These foam inserts surrounded your rim, saving it from cracks and dents. They also dampened trail chatter and provided sidewall support, which many riders claimed made their race times faster. Most EWS riders and DH riders were found using an insert.
Today, the insert craze has died down a little. Many DH racers ride no insert at all due to stiffer DH casing tires, concerns about “unsprung mass”, and concerns about the sidewalls actually being too stiff. Those that still do typically only run a rear tire insert.
Rimsaver, a small company out of Vermont, has decided to enter the market at an unusual time. While tire inserts are dying down, they’ve created a new tire insert that stays close to the rim. It doesn’t offer sidewall support, dampen trail chatter, and you can’t run flat on it. So why would anyone want one?
The Rimsaver isn’t like other foam inserts. It’s a single piece of plastic that stays tight to your Rim.
Rimsaver claims the “Trail” model absorbs 18% of impact to a single edge on the rim, which rivals other inserts of similar weight.
In this article, I’ll discuss the benefits and the drawbacks of the Rimsaver, and give my overall opinion on the product. I used the “trail” model, which weights 170g, the same weight as my Tannus inserts. Previously, I was a loyal Tannus tire insert user in both the front and rear. I’ve been using the Rimsavers for about a month now, where I’ve gone on about 10 trail rides and competed in one small enduro race.
First Impressions
When I first installed the Rimsavers “trail” model, I rode my local tech trail and thought to myself “Man… tires sure are harsh without an insert in.” I’d gotten used to my tannus inserts. I’d gone soft. If pro DH racers don’t need a tire insert, than neither should I. However, I’ll say this: Inserts (tannus, cushcore, etc) really do take some of the “edge” off the trail.
Fast forward to my race run in early June. This was a small local enduro race about an hour from my house. I’m not racing much this year, so I wanted to make an effort to practice my lap and find good lines. I did four practice runs, and put down a time of 6:42. Not a “bad” time; It’s enough for a mid-pack finish. However… I knew I missed the alt line in one area, so I was shooting for around a 6:30 on race day.
When it came time to drop for the race, I was thrilled. I always get excited for the start of a race. I felt good, my bike felt good, and it was just starting to rain; a good omen for the dry trails in Colorado. I dropped in, took three hard pedals, and let off the brakes completely, careening into a rock garden with reckless abandon. Queue rim ping number 1; It was such a hard impact that my water bottle fell out of the cage, leaving a landmine for the next riders (sorry guys). However, my rim was fine, and the impact felt ok. After my first foam insert-less ride, I had gotten used to the Rimsavers. They just feel like a bare tubeless tire. The rest of my run went well. I lost some time in the pedal sections, per usual, and I gained some time in the DH sections.
When I finished the race, I checked my time. I finished in a 6:00 flat. I was thrilled. This was a massive improvement over my expected 6:30 finish. These rimsavers clearly didn’t hold me back, so what really is the benefit of a foam insert versus the Rimsaver? These “trail” rimsavers offer pretty good protection in the tech trails around CO. The “DH” Rimsavers are arguably on par with Cushcore pro, or even more protective.
Why run a Rimsaver?
Rims are expensive. Racers don’t ride inserts in part because their rims are free. Are your rims free? Yeah… I didn’t think so. I rock a carbon rear wheel (WeAreOne) with a lifetime warranty. However, if I break them, even with the lifetime warranty, I still have to wait for a new rim, pay for the labor of building/installing it to my existing hub, and wait for it to be installed. This is roughly a $180 endeavor each time I break a rim, assuming the rim is free. It’s also a lot of time off my only bike. To keep myself riding and saving money, I have a vested interest in keeping my rims working. The point of the Rimsaver is to… well… save your rim. This keeps you on the bike and keeps your cash in your wallet, with the upfront cost of the Rimsaver of course. For me, this cost is well worth it. I have one analog bike and I recently brought an e-bike for the frequent times where by analog bike is broken, but not everyone has this luxury.
The other speculative benefit I have about the Rimsavers is they really do “feel” better on punchy sections of trail. They climb better and don’t absorb as much energy with each pedal stroke. Although you may not “hit” your insert during a normal pedal stroke while climbing, you’re still compressing the tire which in turn compresses the foam sitting on the sidewall. This process is definitely not lossless, but it’s so hard to design an experiment and actually measure this; No one has done it successfully. All that to say, I feel like the Rimsaver is more efficient than a Tannus tire insert, even though they both weigh the same. Rimsaver does claim that some inserts hold onto sealant, so they may weigh more than they claim, but I can say with certainty that my Tannus inserts do not absorb sealant. Rather, sealant can pool/dry on them, which the Rimsaver is not immune to either. That’s why it’s important to clean out old sealant every now and then.
Another benefit of the newer model of Rimsaver is that you can run a tube over them if you flat instead of awkwardly carrying your foam insert around your neck for the rest of the ride. I’m not sure when this newer design will be released, so stay tuned for more info.
Excuse the crappy picture, but the new Rimsaver model allows you to take out the existing valve and throw a tube right over it. No more needing to wear your tire insert as a necklace when you flat.
Why run a foam insert (and not a Rimsaver)?
Foam inserts certainly dampen the trail. On my first Rimsaver ride, it was extremely noticeable. However… I didn’t notice any “harshness” in subsequent rides, and my improved race time down a tech trail demonstrate that I wasn’t really struggling in rocky sections. As usual, my best times were still in the steep, rocky, tech sections, demonstrating that the Rimsaver didn’t really hold me back. I think you get used to foam inserts, but you also quickly get used to not having them. However… I think a foam insert, at least in the rear, might still be a good move for a mostly bike park setup. It should reduce your hand fatigue and allow you to ride for more laps.
You can also run flat on a foam insert. You simply can’t do this on the Rimsaver. However, you can’t run a tube with a foam insert; It’s all about tradeoffs. I personally like being able to run flat at bike parks instead of waiting for a shuttle to take you down (or walking down). On longer trail rides where I’m pedaling, I’d prefer to throw a tube in though.
Typical foam inserts let you “run flat” down the trail with no pressure in your tires. Something you might need to do if you hit a square edge rock on your 50 pound e-bike.
One of the main reasons people run a foam insert is because they can simply run lower tire pressure. The foam decreases volume in the chamber and absorbs impact from the ground, meaning that less pressure is required. This helps in flat corners, loose trails, and with grip in general. However, there’s a limit; Fast DH riders need to run high pressures so they don’t fold the tire on itself in every turn.
“Sidewall support” is the last reason why people like foam inserts. However, sentiment on “sidewall support” is shifting; Some of the fastest riders in the world are claiming that a DH tire is plenty stiff while still allowing for some compliance, which actually feels nice. It’s the same reason why many actually prefer the feel of a slightly flexible aluminum rim to a super stiff carbon rim. I’m going to refrain from speaking personally on this, as I can corner fine in both a Rimsaver and foam insert. I’m nowhere close to these uber-fast DH riders, and quite frankly, I don’t have the talent or speed to notice a major difference. Ryan, the founder of Rimsavers, designed the Rimsaver because “I just want a bottom-out bumper for my rim. I want my tire sidewall to absorb terrain for maximum grip. I don’t need or want anything else, and it has to be easy to use so I’ll actually use it.“
Why run no insert?
There are a few reasons why you might not run an insert, but I certainly don’t fit into one of these categories.
- You’re made of money
- You don’t mind having your bike in the shop a lot
- You are a professional athlete with a rim sponsor
- You don’t break rims.
Installation
One of Rimsavers claimed benefits is that they are easier to install. They are. I won’t spend much time on this section, as I had no major trouble installing these. The key is to watch the technique from the installation video very very carefully. You simply hold the rimsaver in place with your elbows and lock it into the wheel while holding it with your elbows. Beading up the continental tire was leagues harder than getting the Rimsaver on. The Rimsaver added maybe 5% more difficulty.
Conclusion
Rimsavers feel like a normal tubeless tire while providing rim protection equivalent to a foam insert. They roll better than a tubeless tire, and you can run a tube over them in emergencies. However, you cannot run flat on them. They’re easy to install and priced appropriately. The Rimsaver is a novel new design targeted at trail riders who want to protect their rims, wallet, and maximize their time on the bike. It accomplishes that mission well.
Personally, I see myself using the Rimsaver for enduro races and trail rides, but keeping a foam insert in during park season. Having to walk/hitch down a bike park sucks depending on which park you’re at. I also really value the added vibration dampening of a foam insert for long park days.
I’m not going to “rate” this product on a scale of 1-10. It’s a unique product that’s a new entry to the market. There is no “best” insert on the market; It’s all about tradeoffs.
Notes and Disclaimers:
- I received these Rimsavers for free after requesting access to them for review. Rimsavers did not screen this review and had no input in my review process.
- I’m on a new model of Rimsaver “trail” that shares the same mechanical design as the previous model but has an updated valve area that allows you to throw a tube over the rim saver. I’m not sure when these will be released to the public.