Don't just take our word for it...
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Why has ROCKSTOP® been designed this way?

Your technical questions...

Why doesn't it have the big round volume of other tyre inserts?

Using a high density shock absorbing material that takes up a fraction of the space in your tyre, lasts longer and doesn't affect the air pressure dynamics as much. Tyre manufacturers spend millions developing and testing tyres to work under various conditions, adjusting the tyre dynamics dramatically could adversely affect the tyre performance. This is why we designed Rockstop® this way.

Will it fit an E-Bike?

We've been testing Rockstop in a fleet of E-bikes and they perform just as well. The 27.5" X is perfect for handling the extra weight of those sharp knocks while still maintaining grip under low pressures. Retailers: If you run a hire centre, you will save a lot of mechanics time in repairing/replacing rims throughout the season - get in touch for dealer prices.

Does it require special valves or cable ties?

Nope! No extra faff here! We assemble the Rockstop® in our factory so it comes ready to fit.

How much does it alter the ride?

You can only tell it's there when you get the big hits, when you would normally have an "oh sh!t" moment, Rockstop® kicks in and protects your rim.

It doesn't fill the void of your tyre completely but you can be more confident in cornering under low pressure because the edges of Rockstop push into the side walls of your tyre keeping it seated.

It also gives a little more of a firm feeling on the side walls of the tyre in the bottom third as it approaches the rim. This stops the tyre feeling “squirrely” at lower pressures when you’re cornering.

Does it absorb sealant?

NO! This is a self skinning polymer. The clever design of the Rockstop® also allows the sealant to move freely around the wheel at all times and is never submerged in sealant.

Why does the weight matter?

Rockstop® is appx 250g. To have a highly shock absorbing, tough, reusable rim protector you need density and with that comes a bit of weight. If we make it lighter then it will be less effective. Future testing and development could reduce this weight but we know this weight works. Our PU polymer is a different material to EVA/EPDM tyre inserts which is why we've been able to design it with a low profile and shock absorbing properties.

What's the lowest PSI I can run?

The Rockstop® geometry forces the edges into the sidewall just above the rim and helps keep the tyre bead seated against the rim. If it does try and burp when cornering then it helps to keep the bead in position. How low you can go with tyre pressures depends on lots of things, tyre size, compound and rider weight all have an effect.

Our test riders tell us that 20-24 PSI is OK in most conditions for a rear tyre that has a reasonably good sidewall construction.

In a front tyre they’ve been going as low as 17-18 PSI

Can I finish a race on Rockstop?

We didn't design Rockstop® to act like an inner tube - we can't be all things to all people!

Rockstop® is a rim and puncture protector and in all honesty, we haven't had enough feedback from riders because it's done its job so far!

Inevitably, at some point there will be some tyre damage which no inserts could prevent.

If you’re mid race stage then because of the way Rockstop® pushes the tyre bead onto the rim you should be able to make it to the end of the stage with your tyre still on but probably not at the speed of an inner tube.

If this happens on any normal ride then put in your inner tube and sling your Rockstop® round your neck and ride home to refit it with your new tyre. Rockstop® is reusable!

Does it reduce vibration?

Yes. The flexible compound 'dulls' the chatter through hands and feet.

Could the rim slice through Rockstop?

We've tested on alluminium and carbon rims, a mixture of tyre choices, various tyre pressures and a bunch of hard riders and not had any 'slicing' or nicks to Rockstop®. The material compound we use is flexible, compresses under force and transfers the energy through the material, relieving the direct point of impact.

How is Rockstop joined together?

Rockstop cross section Rockstop® is made of 2 parts and joined together with 4 flexible pins and glue. Once set, it's going nowhere. We make this easier for you by assembling it at our factory.

Should I run Rockstop in both wheels?

Most of our riders have tested it in the rear but have been so happy with it, some are fitting it to both! We sell Rockstop® in singles.

Where is Rockstop made?

The Lake District, Cumbria, England. We're designers. engineers and manufacturers of polyurethane mouldings covering industries including automotive, aerospace and sports. Anything made in PU we are who people come to!

How long does it take to fit?

As you can see from the 'fitting' video, Pat does it in 3 minutes. He's had a few goes at fitting Rockstop so he's got the knack! This should take you between 5-10 minutes. TOP TIP: If you're fitting with a new tyre, hang your tyre and insert somewhere warm and come back to it after a brew!

Is Rockstop® re-usable?

Absolutely! The tough flexible material means you'll be able to swap it between bikes and re-fit when you change your tyres.

What is Rockstop® made from?

Rockstop® is made from a tough Polyurethane blown Elastomer. In simple terms it's a tough, highly shock absorbing rubberised polymer. Polyurethane Elastomer is often used in shock absorbers in F1 cars and aerospace industries.

It's the toughest flexible stuff out there.

Why does it need to be so tough?

The reason for using such a tough polymer is simple physics. The impact of you hitting a sharp rock at 20 mph is pretty much the same as the impact from someone jumping out of a 12 foot window - and landing on your foot - in stilettos!

Rockstop is the ultimate mountain bike tyre insert. Discover how quick and easy it is to fit, what it's made from, what sort of PSI you can run and much more, have a scan through the technical questions and if you can't find the answer you're looking for drop us a