Graava KAPS tyre inflator the next big thing?

Could the Graava KAPS tyre inflator change the way we ride on multi-surface events? Would being able to change your tyre pressure during a ride be an advantage?

You may have noticed a flurry of stories (this one included) lately about a hub-based tyre inflator. This was trialled in the WorldTour race Dwars Door Vlaanderen, by Jumbo-Visma rider Edoardo Affini. But what is the Graava KAPS system and is it for real?

Who are Graava?

According to the company website the idea for the Graava KAPS system was born during a Dutch beach race in 2015. Graava’s founder Gertjan van Gindere, had taken CO2 cartridges with him with the idea to stop and inflate his tyres after leaving the sand and hitting a long tarmac section. His plan was to run super-soft tyres to deal with 25km of sand at the start, but this would put him at a disadvantage on the tarmac. So stopping and adding more air to his tyres to deal with the hard stuff seemed a good idea – would have put him at a disadvantage when he hit the final 8km of sand though! In the end the race was so fast that he just ran the same pressure all the way round, stopping was not an option.

During the race van Gindere asked himself, “why there wasn’t a system that made it possible to increase or decrease the tyre pressure while cycling”. There followed various other instances of leaking or slow punctures that finally led him to start working on the KAPS system. After gathering a team of engineers and a few years of tweaking, Graava KAPS wheels are ready to pre-order now, with delivery expected to be January ’24.

What is Graava KAPS?

So what is Graava’s KAPS system, how does it work and do you need one? Looking through Graava’s website and the system seems fairly simple, although technically difficult. At the heart of the hub is a multi-stage membrane pump. These pumps are activated when a cam mounted on the rotating axle passes under them, forcing a piston up, a spring then returns it. Repeat that action three times every rotation and you have inflation. A clutch separates the pump, so it only works when you activate it, power loss during operation is claimed to be 4 watts.

An airline runs from the hub, down a spoke to the valve and into the tubeless rim. The valve also has a standard Presta top to it, so you can still inflate with a normal pump if needed. A PCB in the hub has sensors, antenna and miniature electropneumatic valves. This allows the system to monitor and control air pressure. This is all communicated via BLE 5.0 and ANT protocols to your head-unit and the bar-mounted controller. The hub also has a charger port to keep the electrics running.

Three wheelsets to choose from

And all this is built into the Graava KAPS line of wheels, of which there are three covering road, gravel and Mtb. The road model is the GRAVAA R-40|44 this wheelset uses carbon Reserve 40|44 rims with DT Swiss Aerolite/Aero Comp spokes and DT Swiss hub parts. The aero profile rims measure 40mm at the front and 44mm at the rear in height and has a 25.5/25mm front/rear split for the internal width, weight is 1970g. Price for the R40/44 is €4299.

The Graava GX-30 is the gravel/touring wheelset. This has a 30mm high carbon rim, with a 25mm internal width. DT Swiss provide the Competition Race spokes and freehub, weight is again 1970g. For the MTBers Graava have the Graava XC-28. This uses a Boost hub and has a 28mm high rim with a 30mm internal width. DT Swiss provide the Competition Race spokes and freehub, weight is 1990g. All the wheels are disc-brake only, tubeless and can run SRAM XDR, Campagnolo or Shimano Microspline freehubs. Both the GX-30 and XC-28 are available on order for €2929.

Do you need them?

So that’s how they work and the wheelsets Graava are intending to sell, but why would you want them? Well going back to van Gindere and his beach race or Edoardo Affin at Dwars Door Vlaanderen, if you’re riding on surfaces that are changing from hard to soft and loose, then tyre pressure is important. On tarmac you want higher pressures so your power isn’t wasted nor are you unsafe on fast corners. But if you then hit a section of sand where you want super-low pressure, or cobbles where you want something in between, how would you set up your tyres? With this system you can adjust your pressures on the fly gaining control over soft sand, not being bounced over the cobbles and still able to power away on the tarmac.

Other advantages?

And according to Graava that’s not the only advantages of KAPS. You’ll be able to monitor your tyre pressure in real time. So if you get a puncture and lose air pressure while the tubeless tyre seals, you can add it back without stopping. You’ll also spot a slow puncture early, before it can become a problem. With the Spring Classics about to kick off, it’ll be interesting to see if Jumbo-Visma use Graava KAPS at the Tour of Flanders or Paris-Roubaix. Team DSM were going to use KAPS at Paris-Roubaix last year, but changed their mind at the last moment.

The Graava KAPS wheels are definitely an interesting idea and I’ll be keen to see how they fare if they start to appear in some of the cobbled classics. They also look to be very useful for off-road racing, where pressures and punctures are a constant issue. It will be interesting to see how robust the unit is, if it can survive Paris-Roubaix that would be impressive. There’s a lot of technology hiding in there and although it is very protected inside the shell I would feel better knowing it has had some long-term real-world testing under its belt. Head over to the Graava website to read more about this clever idea. And finally what does KAPS stand for? Kinetic Air Pressure System.