Riding at lower pressure means better performance, but at the same time it increases the risk of failures. While low pressures offer greater grip and small bump dampening, the limit so far tends to be about 20 psi, below which you start to run the risk of burping a tyre, dinging your rims or getting a pinch flat if you’re running tubes. Schwalbe offers a unique solution to this problem with their Procore Tyre System, effectively a tyre within a tyre allowing you to run different pressures in the tyre’s double chambers. In the outer chamber, the air pressure is extremely low – ideal for maximum off road performance while the inner chamber runs a much higher pressure (90psi) – even a very strong impact cannot dent the rim edge. At the same time, the inner high-pressure system secures the tire onto the rim. The dreaded ‘burp’, or loss of air at low pressure in conventional tubeless systems is next to impossible.
Schwalbe Procore system
Procore – The Outer Chamber
The outer chamber is tubeless. Therefore, any tubeless compatible MTB tires can be used. The tire is filled with liquid sealant (approx. 60 ml) and should be at least 57 mm (2.25“) wide.
Procore – The Inner Chamber
Two special Procore components form the inner high pressure chamber: the special Procore tube and the Procore inner tire. This “core” is extremely high pressure stable and at the same time very light.
Of course, the rim must be tubeless compatible and sealed with a tubeless rim band. It should have an inner rim width of at least 23 mm. The wider the rim, the easier the installation and the better the performance under low air pressure. The very wide Syntace rims are a perfect fit.
The Procore Valve
The patented dual valve of the Procore tube distributes the air into both chambers. The upper part of the valve is a selector. With a simple turn, you select whether air is pumped into the inner or the outer chamber.
The Procore Air Guide
The small red component made of white plastic ensures that the air can flow past the inner high pressure chamber into the outer low pressure chamber.
Schwalbe Procore Install
While a little more time consuming as you’re effectively installing two tyres, fitting the Procore system is relatively painless and trouble free. The kit comes with everything you need including sealant and an Easy Fit fluid to help get the tight fitting inner tyre onto the rim.
Above: Schwalbe’s Procore kit comes with everything you need for install except the pump.
Fitting the special inner tubes with Procore valves, remember to include the red Air Guide which helps to direct the air to either the inner or outer chamber. It’s important at this stage that as per the instructions, you make sure to line up the valve setup with the markings on the inner tyre, failure to do so will mean that you won’t be able to inflate the main tyre chamber later on.
Above & Below: Install the inner tube and ensure that the valve is aligned with the markings on the inner tyre.
Once you’ve fully fitted the internal tyre it’s time to then install your main tyre as you would normally.
Above: Schwalbe Procore setup as it appears before installing the main tyre.
Once everything is fitted it’s now time to pump up both chambers. With the valve screwed in (below left), inflate the inner tyre to approximately 40psi, this helps the main tyre to seat to the bead of the rim making tubeless inflation a cinch, even with a regular floor pump. Once the inner tube is partially seated, screw out the valve (below right) and inflate the tyre until it’s properly seated then screw the valve back in and pump up the internal chamber to 85-90psi or the maximum pressure indicated by the rim manufacturer, whichever is less.
Above: Fully installed tubeless setup with a regular home pump.
How Does It Ride?
While there was some initial trepidation at adding approximately 200g of weight to an area you’re typically trying to keep lighter, the ability to subsequently drop the main chamber pressure was a game changer. Coming from a DH background and not being afraid to carry a little extra speed into a turn, for me running tubeless in the past has meant pressures up around 28-30psi in order to prevent burping air under high loads. With the Schwalbe Procore system installed I was able to run pressures in the main tyre down around 18psi, markedly improving the ride quality and grip offered by my WTB tyres. Even with the main tyre fully deflated, with the inner chamber at full pressure the tyre was incapable of being budged from the bead. This kind of security is extremely comforting and an added benefit when running lower pressures.
Having tested the system in a range of conditions from high-speed bike park trails to muddy slop and rooty forests, the improvement in grip was astounding. Expecting to lose traction on multiple occasions, climbing was improved as was confidence descending. In addition to the massively improved grip, the lower pressure offered far greater cushioning, significantly improving ride quality and comfort on the trail. Due to the extra traction and cushioning, steering, braking and traction control have been largely improved. In addition the added protection of the high pressure inner means that rims are extremely well protected from denting and should you get a flat out on the trail, they offer the ability to ride out of where previously you may have found yourself walking.
Generally the biggest benefits of running the lower pressures were found as the trails got rougher, more technical and particularly at slower speeds but especially so in loose climbing conditions. In high speed bermed corners there was a small amount of squirm noticeable so in this instance it might be worth adding in a couple of extra psi for support. Braking also benefitted from the added grip and I found I was able to brake harder and later than I had been previously.
If you’re looking for added reliability for racing or just general riding, Procore is definitely the one for you. While I wonder if it would be needed if most of your riding was done in a bike park where you’re never too far from home, the benefits when out on a long trail ride were undeniable. Even with all of the pressure gone from the outer chamber, Procore will keep the tyre on the rim and let you ride out, something that won’t go amiss when facing a long walk home.
As for the weight, adding 200g to the outside of your wheel does make a difference when it comes to acceleration and long days on the pedals but in my view, the benefits outweigh the concerns. For those overly concerned by the weight, the support offered by the system means that you can potentially run a lighter weight tyre to claw back some of that weight penalty and on the flipside, the greater gyroscopic mass did actually improve rollover and stability through bumps.
For some the elephant in the room may be the cost and I’ll admit, they’re not the cheapest. That said, the improved ride characteristics combined with the ease of seating a tubeless tyre with a home setup and the security it offers on the trail is well worth it, especially if you’re currently stuck running high pressures in order to keep your rubber on the rims. If you want more reliability and don’t mind the added labour then it’s great. Pump them up for high speed park laps one day then cut the pressures in half the next for those tech trail rides the next while your buddies are struggling for traction on the trails.