Words and photos: Will Shaw


While tyre inserts started as a component aimed towards gravity racers, the benefits of well-designed inserts quickly led to products for all disciplines. Nowadays, the insert market has options from cyclocross all the way through to World Cup Downhill. Rimpact are a UK based company with three models of tyre insert that have been refined over a number of years now. Their line consists of two mountain bike inserts, the Original and the Pro, as well as a CX version, which you can read our review of online.

I was sent a combo pack consisting of one Original and one Pro, the Pro/Original Mix pack which includes valves. The Original weighs less and provides less protection than the Pro, and is often used in the front, with the beefier Pro in the rear.

Rimpact also offer both the Original and Pro as standalone sets. They have a handy guide on their website about what insert is best for your style of riding. Essentially the harder you ride, or the more you want to insure yourself against both flats and rim damage, the more you’d lean towards Pro inserts front and rear.

Out of the box, the two Rimpact variants are markedly different. The Original has a softer feel, whilst the Pro is much firmer and does feel heavier in the hand. The packaging is fairly minimal, with a cardboard folder holding the two inserts as well as a set of valves.

Rimpact inserts must be used with their valve, similar to CushCore. Our insert set came with two valves; however, you can also purchase inserts without valves as replacements. The Rimpact valves use 4 horizontal holes to inflate your tyre, which means they won’t get blocked if the insert shifts within your tyre. They can be used with sealant injectors as well as in regular tubeless setups.

Rimpact inserts are made of High Density, Closed Cell, Cross linked, Polyethylene Foam. This meant nothing to me on face value, so I’ll quickly run through what all of that means.

According to Rimpact, an increase in density past a certain point begins to transfer force through to the surface below (your rim). As a result, Rimpact inserts aren’t the highest density out there (compared to something like CushCore). Rimpact’s inserts are supple at rest and stiffen under force (similar to knee pads with D30 inserts). This means that the insert is easy to fit and can absorb low to moderate vibrations (trail chatter), whilst also stiffening up to prevent flat tyres and rim damage under big hits.

The Closed Cell component means the insert doesn’t absorb sealant. This is something I can report is a great feature of the Rimpact inserts. In my experience with Huck Norris and CushCore inserts, both of them have absorbed sealant and required frequent top ups. With the Rimpact inserts I’d feel comfortable replacing the sealant at the same intervals as a regular tubeless setup. Rimpact recommend you use 25 percent more sealant to compensate for the added surface area.

The Cross-Linked element gives the inserts superior torsional strength to resist tearing and stretching. Over the course of four months of testing, the inserts showed relatively little sign of wear, which is great to see. There was a couple of small cuts but compared to other inserts I’ve used the lack of wear was impressive.

Lastly, the Polyethylene element of these inserts refers to the fact that the inserts will not leak dye into latex based sealants, thus rendering your sealant useless. Over the course of testing, I noticed no discolouration of both the insert and sealant.

In terms of weights, the Original weighs in at 95 grams, whilst the Pro weighs in at 160 grams in the 29” size tested. Whilst the Pro is a fair bit beefier, it’s still a lightweight compared to probably the best-known gravity insert in the CushCore, which weighs in at 260 grams in the 29” size. On the lighter side of things, a 29” Huck Norris weighs 84 grams out of the box.

Fitting the Rimpact inserts was once again somewhere between installing a Huck Norris and a CushCore. Rimpact have a handy guide on their website, and following those instructions worked a treat. Once installed, my tyres beaded with a floor pump and a bit of elbow grease. When I re fitted them after topping up the sealant it was much easier than the initial install.

So how do they ride? Once again, I’d put the Rimpact between the Huck Norris and CushCore in terms of ride feel. I was running the inserts in an eBike, and the rear insert was particularly noticeable in preventing rim dings that were occurring prior to installing the insert. I’d feel comfortable moving to a slightly lighter casing with the Rimpact inserts, as my total wheel system weight was pretty beefy with the Pirelli eMTB tyres I was running.

In terms of smoothing out trail chatter, the Rimpact inserts are much more comparable to CushCore than other options, and they allow you to drop your pressures a few psi without tyre roll or rim impacts occurring.

Rimpact have partnered with Australian distributor 32 spokes for Australian purchases. To purchase their inserts head to the 32 Spokes website. The Original/Pro mixed set I reviewed comes in at $157.50. This puts Rimpact in the middle between a Huck Norris ($110 per pair), and CushCore ($260 per pair). The Original kit retails for $130, whilst a set of Pros will set you back $185. For trail riding and Enduro racing I think the mixed kit is the way to go.

All in all, I would recommend Rimpact as a great middle of the road option when it comes to inserts. Whilst I still feel that CushCore offers the ultimate in rim protection, Rimpact offers all of the ride features except for the very top end rim protection at a lower cost, which makes it a great option for many riders.

RRP: From $130

From: 32 spokes

Hits:

- Strikes a nice middle ground in the insert market

- Relatively inexpensive

- Doesn’t absorb sealant

Misses:

- Not quite as protective as CushCore