When Schwalbe presented the Procore dual-chamber tyre system last year, it was immediately celebrated as one of the major innovations at Eurobike 2014. The experts were enraptured by the concept and the promised benefits. Our innovation check in BIKE 11/14 had also confirmed that the basic idea of equipping a tyre with two air chambers has great potential. A tubeless tyre with low pressure on the outside for optimum traction, comfort and control, and a high-pressure inner tyre on the inside that performs three functions: It protects the tyre from punctures and the rim from dents, but also fixes the tyre to the rim, which protects against air loss at low pressures.
So far, so good, but interested bikers have had to be patient ever since. Until recently, availability was simply a problem. That has now changed. Not only will Schwalbe's wonder weapon soon be on the shop shelves, there is now even a competitor. Presented for the first time at this year's BIKE Festival on Lake Garda, the Tube+ system from the small Italian tinkerer's forge DeanEasy is based on the same basic principle, but takes a different approach. Unlike Procore, where the approx. 33 mm high inner tyre is open towards the rim and can therefore be universally adjusted to the rim width, the system from Alberto Deanesi (hence the company name) is a closed tubular tyre with a wasp-waisted cross-section of 21 mm. Due to the small diameter, Tube+ must therefore be ridden at 9-12 bar, whereas Procore is designed to provide reliable protection against punctures at 4-6 bar. The two systems also take different approaches to the central question of how to inflate the inner and outer tyre. Schwalbe's Procore uses a double valve developed in-house, which hardly differs externally from an SV valve. By screwing the valve attachment in or out, the air is either directed into the butyl tube of the inner tyre or (with the help of the plastic air guide) around it into the tubeless outer tyre. For Tube+, the valve passage in the rim must be drilled out. A special ring valve is glued into this enlarged hole, through which the air for the main chamber is channelled to the side of the SV valve of the inner tube tyre. We have now been able to drive both systems extensively in practice and have sent them to Continental's laboratory test benches. On the following pages you can read about the actual puncture protection, rolling resistance and the like.
MANUFACTURER RELEASES - Just a formality?
At the moment, manufacturer approval is still the biggest hurdle for double chamber systems. Rim manufacturers claim that there is hardly any experience of the durability of rims and wheels with Procore. An official O.K. is currently only available from the development partner Syntace. Another sticking point with Tube+ is that the valve hole has to be drilled out - no manufacturer can authorise this. However, the development of a new generation of rims and wheels that are compatible with Procore and Tube+ is already underway. At the moment, anyone who wants to ride a dual-chamber system is in a grey area - whether Procore or Tube+. It is now up to the component manufacturers to get behind the new systems.
DeanEasy TUBE+
Info www.deaneasy.it
Price 220 Euro
Formats 26", 27.5" & 29er
Compatibility with rims from 21-24 mm inner width.
2 x special tubular inner tyres with SV valve, ring valves, airguides and mounting adhesive in the set. Sealing tape/milk and tools for fitting not included.
Schwalbe PROCORE
Info www.schwalbe.com
Price 195 Euro (as kit, parts also available separately)
Formats 26", 27.5" & 29er
Compatibility with all rims from 23 mm inner width.
Tyre system with open inner tyre, separate butyl inner tube with special valve. All small parts for converting a bike are included in the kit.
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WEIGHT
The rotating mass on the outside of the impeller has the greatest effect on acceleration. But this is precisely where Procore and DeanEasy are located.
As additional technology in the tyre, the dual-chamber systems inevitably add weight to the bike - with Procore it is approx. 470 g more per bike compared to the tubeless setup and with Tube+ approx. 330 g more. Compared to a tyre with a tube, the difference is less. As a counter-argument, manufacturers argue that the puncture protection of the high-pressure inner tyre also allows you to ride a lighter tyre. More on this under "Puncture protection".
In the end, everyone has to decide for themselves whether the advantages outweigh the extra weight - a decision that is certainly easier for enduro and all-mountain riders than for weight-conscious marathon riders.
System weights without tyre weight
- Schwalbe Procore (29")
Special inner tube 109 g + inner tyre 135 g + Airguide 4 g + sealing milk approx. 60 g
Total weight 308 grammes
- Tubeless
Sealing milk approx. 60 g + tubeless valve 12 g
Total weight 72 grammes
Conventional (with 29" tube)
Butyl or latex hose
Total weight 125-200 grammes
DeanEasy Tube+ (29")
Tubular inner tyre 175 g + Airguide 3 g + sealing milk approx. 60 g
Total weight 238 grammes
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TRACTION AND COMFORT
The showpiece discipline of Procore and Tube+. Low tyre pressures always mean more grip. The double-chamber systems are designed to make these pressures rideable even without extra-wide tyres.
It's almost a truism, but the lower the air pressure in the tyre, the greater the traction and comfort. The reasons for this: the tyre adapts better to the terrain, the larger contact surface can interlock better with the ground and small obstacles and bumps are better absorbed by the tyre. Especially where the trail becomes demanding, where slippery roots or wet rocks push the tyre to its traction limits at normal pressures of 1.6-2.0 bar, the lower pressures between 0.9 and 1.4 bar provide a noticeable increase in grip and control. The tyre's limit range is significantly extended and good-naturedness increases noticeably. The "working range" of the outer tyre also plays an important role here. With the smaller inner chamber of Tube+, the same outer tyre can deform around 13 mm more than with Procore. Procore partially compensates for this shortcoming by keeping the inner tyre a little more flexible due to the lower internal pressure. However, sensitive riders can feel the difference when riding. In direct comparison, Tube+ offers a slightly higher level of grip/comfort than Procore.
With their low operating pressures, the dual-chamber systems deliver a significant increase in grip and comfort. Tube+ even a little more than Procore. Anyone riding one of these systems for the first time is amazed and often delighted. In terms of grip and comfort, the systems come very close to the Plus formats.
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CONTROL AND DRIVING STABILITY
Low tyre pressures not only mean that the tyre can adapt better to the surface and provide more traction. It also offers less lateral stability when subjected to lateral forces - in bends and on sloping landings, for example. This is precisely where Tube+ and Procore tyres differ.
Looking at the inner chamber sizes, it becomes clear that the outer tyre still has plenty of room to move with both systems. With the larger inner chamber of Procore, the clearance is smaller, but there is still enough space between the tyre carcass and the inner chamber to make the ride feel spongy under high lateral forces. Normally, bikers don't find the reduced lateral stability very disturbing under normal riding conditions. It only becomes negatively noticeable when very high lateral forces are applied (inclined landings, extreme bends or hard braking in bends). Bikers for whom such extremes are part of everyday life should experiment with the air pressure. Often just 0.2 bar more is enough. The second way to stabilise the tyre better: a wide rim. And this is precisely where the open Procore inner tyre currently has a major advantage. In its current form, it can be ridden on rims from 23 to 40 mm (!) and thus indirectly provides more riding stability. Tube+ is less flexible and currently only fits rims with a rim width of 21-24 mm. DeanEasy is already working hard on a version for wider rims, but as long as this is not on the market, the point clearly goes to Procore.
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ASSEMBLY AND HANDLING
Procore's uncomplicated solution requires a little more manual dexterity with Tube+.
DeanEasy Tube+
To fit the separate ring valve (red), the valve hole in the rim must be drilled out to 9.8 mm, the valve screwed on and carefully glued. Not for two left hands or for carbon rims. Then just push the SV valve of the tubular inner tyre through. The car valve fills the main chamber, the SV valve fills the inner tyre. In practice, the ring valve has stuck several times due to sealing milk. As a result, no more air can get in or out.
Schwalbe Procore
Modifications to the rim - as with DeanEasy - are not necessary. Any tubeless-ready wheel with an inner width of 23 mm or more can be converted. To do this, the inner tyre, inner tube and Airguide must be fitted one after the other and aligned with each other. Depending on the design of the rims, there may be combinations on which the inner tyre is very difficult to fit or the valve thread is too short.
Here you will find detailed assembly instructions for DeanEasy Tube+ and Schwalbe Procore ...
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TUBELESS
For many, tubeless is still a spectre. But this is precisely where Procore can score points.
When it comes to tubeless and low-pressure tyres, you have to be careful. Nobody wants the tyre to come off the rim when cornering. Tube+ and Procore create a lot of safety here by actively fixing the tyre to the rim. The fixed diameter of the Tube+ tubular tyre only supports inner rim widths of 21 to 24 millimetres. Procore is more universal, but requires an inner width of at least 23 millimetres for mounting. But the Schwalbe Procore system has another advantage. Due to the open design, the inner tyre actively presses the bead of the outer tyre against the rim during inflation and thus seals it to a large extent. This makes it possible to inflate most tyres tubeless even with a hand pump.
While Tube+ prevents the tyre from losing air at low pressure or even slipping off the rim, Procore also takes the fear out of "tubeless". A good argument for tubeless sceptics to finally take the plunge into the modern age. Now all that remains is for the industry to follow suit and supply wheels with the appropriate approvals.
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PUNCTURE PROTECTION AND RUN-FLAT PROPERTIES
The violent puncture with subsequent snakebite is the biker's worst enemy. The double chamber systems should finally provide a remedy. They do indeed do a remarkable job here, but even they have their limits.
So far, none of the manufacturers, neither Schwalbe nor DeanEasy, have published any data on this. So our expectations were high. Remarkable: At only 1.1 bar in the outer chamber, the puncture protection is already higher than the identical outer tyre alone at 1.7 bar. The enduro tyre with reinforced carcass still delivers better values at 1.7 bar. It was also noticeable that the butyl inner tube from Procore leaked with every defect, in some cases even before the outer tyre. In this case, the outer tyre suddenly had a tyre pressure of 2 bar. The tube + inner tyre offers greater rim protection and could not be destroyed in the laboratory test. For the sake of objectivity, we carried out the tests in Continental's test laboratory in Korbach. The fact that we were unable to provoke any defects while riding, despite deliberately aggressive manoeuvres, also speaks for the high, effective puncture protection of both systems in practice.
Breakdown values
On the Continental test bench, we determined the drop height at which the drop axe first hits the rim (lower bar) and the point at which a puncture occurs (upper bar). A Continental Trailking 2.4 Performance served as the reference outer tyre. It is easy to see that Tube+ protects the rim a little longer, but defects occur equally early with both systems. The Tube+ inner tyre remained intact.
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ROLLING WIDER STAND
A tricky issue for dual-chamber systems: The rolling resistance is significantly higher.
According to the values of our roller dynamometer test (right), the tyre inevitably has a higher rolling resistance at the optimum pressures for traction and comfort. In practice, however, the tyre absorbs many bumps as a sensitive additional suspension and thus reduces the vertical movement when driving over obstacles. This saves energy and protects the driver. In addition, tyre slip is reduced on loose surfaces, which also increases efficiency when riding uphill. The fact is that rolling resistance increases on hard and flat surfaces, so it can make sense to increase the tyre pressure here. The negative effect is much smaller off-road.
The laboratory values
The graph illustrates how rolling resistance on the standard drum test bench increases as tyre pressures fall. Accordingly, it increases particularly sharply below 1.5 bar - precisely the air pressure range in which the dual-chamber systems operate.
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WHAT THE ENDURO PROS SAY
René Wildhaber, Trek Factory Racing
"I don't use Procore in every race. Only when the conditions are right for it - on steep, slippery tracks with lots of roots. I'm still not entirely satisfied in high-speed sections, as I often have to correct the bike in corners. Incidentally, I've won my only EWS race so far with Procore."
Nico Lau, Cube Action Team
"The main advantage is that you can continue riding if you have a puncture and the tyre doesn't come off the rim. It also protects the rim from punctures. If the rim is wide enough, the tyre pressure can be lowered further, which offers real advantages in slippery conditions."
My conclusion: Christian Artmann, BIKE test author
When I rode Schwalbe's Procore system for the first time in summer 2014, I was impressed by the extra traction and comfort. And the fact that I haven't had any punctures with it since then also speaks in its favour.
Based on a tubular tyre, the DeanEasy-Tube+System is the product of a small Italian think tank. It is very convincing in terms of riding performance, but still has shortcomings in terms of handling and is too time-consuming to fit for the first time. Only hardcore racers and technology enthusiasts will go to the trouble of drilling out their rims. For me, Schwalbe's Procore wins the duel.
The most important arguments against both systems are the high additional weight, and the not insignificantly higher rolling resistance will also deter certain types of riders. Above all, however, due to the fact that the wheel and rim manufacturers have not yet given their approval, the systems are still a niche product. However, as soon as the industry follows suit and supplies the appropriate rims and wheels, dual-chamber systems will become much more important on the market.
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