Gravaa's New Wheels Will Allow Tire Pressure Adjustments While Riding

Jan 22, 2021
by Ed Spratt  

Gravaa has set their sights on solving the issue of perfect tire pressures with their new electronic wheels that will adjust your pressure while you ride.

The new system from Gravaa uses a miniature pump stored in the hub to allow tire pressure changes throughout a ride. Using the hub system you could potentially add pressure for harder surfaces or drop pressures when tackling looser trails. Gravaa claims their system will also stop the problem of small leakages dropping pressure as the system can continuously add in more air to ensure it keeps to your desired settings.

bigquotesWe all know riding on gravel roads and mountain bike trails can be demanding. Because the surface of the trail changes throughout the ride it’s always a gamble which tyre pressure you need for the front and rear tyre when you go out for your ride. In the end you often settle for the middle ground regarding tyre pressure. After years of research and engineering we have developed high-end wheelsets which enable you to manage your tyre pressure during your ride. Gravaa

Using carbon rims and their own 'advanced hubs' Gravaa has incorporated a miniature high-pressure pump, driven by the wheels using an integrated clutch unit that can be disengaged when it's not needed. A hose runs from the hub to the wheel's valve to accomplish the pressure changes. Gravaa has also fitted an electro-pneumatic control system to ensure the pump is only activated when it is needed. To control the system the hubs can connect to devices using ANT+ and they aim to be able to display relevant information about pressures onto cycle computers.

The idea of a tire inflation system is nothing new as off-road vehicles have been using these systems for years, but only a few companies have tried to bring these systems to MTB. White Crow also created a hub-based inflation product back in 2015; unlike the Gravaa wheels it used a mechanical system rather than an electrical solution. White Crow's solution meant it added a lot of weight with an additional 350 grams per hub and a 200 grams chamber inside each tire. It remains to be seen how much weight Graava's system adds, and the price hasn't been announced yet either.

Gravaa is looking to open orders for their wheels later this year. You can find out more here.


  • 396 57
 Holy smokes. Another solution for a problem nobody has.
  • 28 60
flag nufenstein (Jan 22, 2021 at 17:48) (Below Threshold)
 I mean it’s a decent problem; optimizing tires pressure depending on terrain.

It’s just the solution is dumb.
  • 18 3
 I actually think this would be bomb for riding trails that pop out at dirt jumps. That said, usually my car is parked at the dirt jumps with a full size pump in the trunk.. So I guess this would be better for trails with random dirt jump parks in the middle of nowhere haha. And even then I'd have my pump..
  • 343 4
 I'm old enough to remember when riders were badmouthing early suspension forks as heavy expensive unnecessary gimmicks. Real riders didn't need any of that fancy crap. Early disc brakes were heavy, had terrible modulation, and made the noise of the banshee. Again, real riders didn't need that fancy crap the bike industry was pushing. Good ideas get refined and become indispensable while the bad ones fade into obscurity, or maybe get a little display case in MOMBAT. The point is, it's a process that takes time. Being able to get a quick boost of traction might end up being as handy as being able to drop a seatpost for a descent. Step one is getting an idea to work at all, and I always applaud that.
  • 15 1
 @pixelguru: (1) I used to live in Wilmington, so we are brethren (although I prefer brandywine). (2) That was inspiring stuff. Great attitude, man!
  • 31 3
 I ride to the trails on the road. Having that automatic adjustability (vs manually having to deflate and inflate) would be really cool.
  • 1 1
 Lol, funnest but true statement I have heard on a long time.
  • 35 1
 I'll definitely be picking up one of these sweet units up as soon as I have the time... but it's taking me a while to get my bars straight.
  • 2 37
flag Kramz (Jan 23, 2021 at 0:01) (Below Threshold)
 Dude, I produce music, and it's over 9000. Like; take the ground floor, of basic necessity, and just float on a fricking wonderous, whispy, comfy, cloud, with a ruby, and gold cane, smoking a fatty, with 10 ladies. It's that bad. I'm literally 24/7 like, "is this illegal, WTF!?"
  • 2 2
 At least this stays fine mechanics, no battery or electronics here, so why not?
  • 12 0
 @Jacquers: My local ride is 20 minutes on road and then another 40-50 mins of climbing before the fun starts; this would potentially help
  • 19 2
 Personally I think its a brilliant idea. I hope it becomes mainstream and affordable!
  • 6 5
 @nufenstein: it's not even that it's dumb, it's that it's wildly overly complex fix to an issue that has up until now been 98% solved. it's like an F1 solution to a F4 problem.
  • 2 0
 @Richt2000: It's extremely unlikely you'll be granted both of those wishes.
  • 5 1
 @theteaser I disagree. I check my tyre pressures almost every ride and usually need to add a few psi. (Tubeless setup.) I've also noticed that tyre pressures can change by 1 to 2 psi during a ride as the day gets hotter or cooler. Something that kept my tyre pressures stable and allowed adjustments of a few psi during a ride would be gold. Bet it won't be cheap though.
  • 25 0
 @pixelguru: @pixelguru: and those new fangled V Brakes, 'They will be too powerful, you will go over the bars', they said in 1996!
  • 10 0
This. I remember when some 4" travel "freeride" bikes were coming out we thought they were lame. Likewise, there was a couple years when the pro DH circuit was split between V brakes and discs.

There's so much specialization in mountain bikes now (remember there was a time when there was just XC and DH? and before that there was just mountain biking?) that these previously silly sounding ideas are going to pop up. There was a time that computers were mocked, and no one thought the internet would ever be more than a novelty. Anyway, it's pretty ridiculous to ridicule any innovation that might help someone else when you're hanging out with a fleet of bikes with an singlespeed, downduro, trail, and enduro bike.
  • 3 0
 @Richt2000: Me too! It's brilliant. Power down, ride in the winter, power up pathways, and sidewalks, and hardpack. I just wish it wasn't electronic. Why not, some sort of CO2 canister solution? Like 50 tiny CO2 cannisters, that you replace when they run out? Or just refill with a compressor. Maybe each one adds like 5 PSI? That's my dream.
  • 11 0
 @Kramz: I'm not sure it's just weed that you're smoking.
  • 4 5
 @pixelguru: hate to break it to you after that diatribe but suspension helps improve handling and performance of a bike and heavier hubs that include pumps do not.
  • 4 0
 @pixelguru: I remember when the first "dropper" post came out. In the early 90's, the bolt on self centering spring that you had use with a quick release. Why would anyone need to lower their post on the fly? Even when the modern posts arrived, why buy a $300+ seatpost that adds almost a pound to your bike. I've been around it for 35 years, seen a lot of crazy things. This would likely catch on in the touring/bikepacking/gravel world. Though the hub flange size would make for a more stout wheel for mtb.
  • 1 1
 Might be useful for mtb to drop psi for comfort and traction on the climb, then increase psi for support on the descent, and could be useful for gravel riding when you spend 50% on pavement and 50% on dirt. It all depends on weight and price.
  • 2 2
 Holy smokes. This certainly ISN'T how technological innovation is achieved!!!

Reminds me when all you idiots were decrying 29" wheels a few short years ago. Look at where we are now.
  • 15 2
 Had this problem yesterday. Like a caveman, I had to manually unscrew the valve cap, press down on the valve stem with my delicate cold fingers to release the desired amount of air. Once I realized I took too much air out, I had to pull out my absurdly small inefficient hand pump and begin to pump it furiously to once again put too much air in. It was a ridiculous amount of work that clearly a machine could and should be doing for me.
  • 4 0
 @Davetheripper: Counterpoint, lowering your seat post before a descent using a quick release is just as simple, yet dropper posts are practically seen as a necessity these days. Counter-counterpoint, I don't have a dropper post on my bike.
  • 3 0
 @seburkhardt: Congratulations on escaping Delaware. It's a low spot, so people tend to accumulate here.

I rode Brandywine (and Iron Hill, Fair Hill & Middle Run) on those rigid canti-lever braked bikes back in the day, and also for the better part of a decade on a rigid singlespeed. That gave me a great appreciation for the comfort of the full-suspension bike I now ride on those same trails. Fair Hill without suspension in the early days before we built the bike-friendly singletrack trails, was adventurous.
  • 6 0
 @Jacquers: I figured eventually someone would figure out how to build tires that became more aggressive at lower pressures - imagine the spaces between knobs "filling in" at high pressure and receding at lower pressure. Paired with the tire pressure control, the energy savings could justify the weight of the hub. I do a lot of mixed surface rides on my gravel bike, so stopping to adjust pressure every time I go from pavement to gravel to dirt is tedious, so I usually pick one "middle of the road" pressure and ride "middle of the road" tires. The above system would keep me from having to make these compromises. Just something to think about.
  • 4 1
 Guessing this would be fine for ebikes where a lil weight isnt really big deal.
  • 2 0
 Best coment ever!
  • 2 0
 Palm Canyon...air down for that sand wash exit.
  • 1 0
 For me personally I’d rather have this than tire inserts and when inserts came out people were laughing at them just as bigly. If they could get this thing down to like 150g with minimal added rim weight and it was like 100 a wheel I would consider it. Imagine it is way more than I want to spend.
  • 5 6
 Actually I have slept on this overnight and have some ideas. I like the 'busy-ness' of an aircraft cockpit and really would like to have the same number of controls on my bike. I deeply missed the left hand shifter when I went 1x and was overjoyed when the dropper lever replaced it. I just don't feel that I have enough controls on my bars. This would give me one more thing on my bars! Hurrah! I also would like a control to vary the size of my wheels - I hear than 32 and 36 is coming, but I could do with 26 still in the jumps. To this I would like to add a reach reducer/expander to enable me to remain seated throughout. Add to this a bar mounted lockout for the front suspension. And a compression changer. And a slow speed circuit changer. And for the rear too. I'd like a crank-length adjuster for those pesky ground-strikes (varying crank length from 165 to 175). Bar width adjustment on the fly would be excellent, for those trees in single track which was laid down before 800 bars appeared. Finally, I'd like a tyre knob adjuster - to be able to inflate the centre line of my tyre for the 50m of smooth gravel going back to the car would be just wonderful....
  • 1 0
 I think this is a pretty good idea for those who like to fettle, but carbon rims, integrated pumps... these aren’t going to be cheap and with more stuff to potentially go wrong I think buyers will be looking for a solid warranty offering for peace of mind.
  • 3 0
 @thomasjkenney1024: or ride it the morning after it rains! set my PR on the wash by over 4min back in Nov. with this technique! lol
  • 1 1
 @mkul7r4: Reminds me when all you idiots were telling all the other idiots that wheel diameter actually mattered. Look at where we are now.
  • 1 0
 @sundaydoug: Mostly on 29ers? Razz
  • 2 1
 @Jacquers: Mostly riding bikes in the woods while making fun of all the muppets that care about wheel diameter.
  • 2 0
 Really? Losing pressure on the tires is a problem nobody has? Is this a skateboarding site perhaps?
  • 85 11
 This checks so many boxes for us!

We want more moving parts and points of failure. [CHECK]
Also weight, hopefully that adds at least a pound. [CHECK]
Any chance of future updates to add a battery? Would love something to charge. [CHECK]
More cost and maintenance [CHECK]
Limited application [CHECK]
  • 5 1
 fixed: something 'else' to charge.
  • 5 7
 Mark this comment and look back at in 15 years.

This tech will be standard, along with on-the-fly transforming geometry (at minimum adjustable head angle), seat angle, smart shock pressure, fully wireless electronic shifting. Sensors everywhere detecting ambient temp, humidity, altitude, slope, and compensating for all of it in real-time. Integrated computer for all the calculations and real-time display of info. And it will weigh the same as your bike does now because of advances in materials and other optimizations.

This is how innovation is achieved. Nobody will buy this stuff now, and that's completely fine. But watch.

I'd rather see smart-bike tech like this ANY day rather than e-bikes too.
  • 4 0
 @mkul7r4: I mentioned this in another post, but tires that become more aggressive at lower pressures is something I'm betting will happen someday. That would fit right in with this pump hub.
  • 1 0
 @pixelguru: if by more aggressive you mean grip better then... all tyres kind of do this. Or am I missing something?
  • 2 0
 @BenPea: I mean actually alter the tread pattern from a smooth center line to a knobbed center. Imagine being able to turn your mountain bike tires from semi-slicks into fully knobbed at will. That would be on top of the rolling resistance gain you also get with a higher tire pressure. You also wouldn't wear the edges of your knobs down while riding on the road, so they would work better when extended at the lower tire pressure.
  • 1 0
 @pixelguru: ah, so you'd need the knobs to be based at the rim to stay deployed as the casing retracted. If someone can do that in a durable and lightweight package I'll be impressed.
  • 2 0
 @pixelguru: That would be another awesome innovation. Extra spikes that protract and retract depending on tire pressure.
  • 55 8
 I’m thinking through this.

Do I want lower pressure on the climbs for better traction, but then I roll slower.

Do I want higher pressure on the downs to not bottom out on the rim, but then I have less traction.

Maybe I want that sweet spot that I’ve already found.
  • 39 25
 actually you get better rolling resistance (not on road) with lower air pressure. Schwalbe did a study on it.
  • 24 0
 Makes a lot of sense for fat tires and bike packing
  • 25 1
 I mean if you ride to your trails from city it makes sense especially when you are going back to home, low pressure on tarmac sucks
  • 6 2
 Which is great that you've found the sweet spot, but the benefit to me would be keeping it there. If this made it so I didn't need to check my tires before every ride, that would be huge. I'd pay for that. But I wouldn't want it tied to a proprietary wheel set.
  • 8 1
 @jaydawg69: well look at the big brain on Jay......
  • 3 4
 Just NO. its simple and this potential fix/solution is not.
  • 4 0
 Cushcore then?
  • 3 0
 @jaydawg69: Linky? I'd be interested to see what they say.
  • 8 0
 @jaydawg69: Yeah, not sure why you got the downvotes. This study has been out for quite a while now. Like longer than 10 years. Seems rolling resistance at lower pressure isn’t a factor off-road.
  • 13 4
 Re: Rolling resistance & pressure

jaydawg69 isn't wrong, but there's a way to present it that resonates better with people:

The rougher the terrain, the lower the pressure. Saying it this way doesn't feel counterintuitive. We know a mountain tire at 60 psi would shake us to pieces on rocky terrain and the same tire at 5 psi is slow on smooth pavement.

Obviously, it gets a lot more complex if we try to find the exact, perfect pressure in a given situation, as it's a complex mix of roughness, tire construction, temperature, etc. For a supple XC race tire, as used in the Schwalbe study, on a typical mountain biking trail, the efficiency continues to improve past the point where the tire vulnerable to pinch flats and is laterally unstable. We can make the sweeping statement "lower pressures are faster" for this tire in this situation.

A stiff, double-layer DH casing with high hysteresis would be a different story, likely having a complex relationship between speed, temperature, and roughness. We couldn't make a simple statement about pressure and speed for self-powered riding. Uplift-assisted riding on fast, steep terrain would be different, of course, and once again the best performance would probably be at the lowest pressure that's safe to ride, but for reasons other than rolling resistance.
  • 3 9
flag seburkhardt (Jan 22, 2021 at 20:49) (Below Threshold)
 @R-M-R: Actually (s)he is wrong. Reductionist generalizations are almost always wrong when they hit some limit. Lower pressure sucks when you are riding on the rim, and doesn't help traction at all. The right way to present technical information is well-rounded (pun intended, baby!)
  • 7 1
 @seburkhardt: "Wrong" is a bit harsh for a statement that has truth at its core and only lacks limits.

It's a strawman argument to say "riding on the rim". I doubt that's what anyone was talking about and a disclaimer along the lines of "... to the limit of safe and practical operation" is implied.

The message is simply that higher pressures aren't necessarily faster, especially on dirt.
  • 2 5
 @jaydawg69: i don't know about you but none of my trails resemble a grassy meadow in the slightest so that "low pressure is faster" result that many people like to cite is pretty much irrelevant.

If they'd tested surfaces that people actually ride such as rocks, roots and packed dirt there would be some value but they didn't so there isn't.

Maybe rolling through meadows is more common in Germany.
  • 1 1
 @freeriderayward: what they say is that low pressure is faster when comparing a grassy meadow to a gravel road.

My trails don't look much like either of those things although when I lived in Brisbane the "gravel" results would have been applicable to many trails.
  • 4 0
 @PhillipJ: "This applies equally on hard gravel roads and soft forest tracks. Explanation: A tire with low inflation pressure can adapt better to a rugged surface. It sinks into the ground less and the whole rotational mass is held back much less by the uneven surface."

it's all about transfer of energy... Higher air pressure means your getting bounced around/deflected more slowing you down compared to a lower air pressure tire. Obviously there is a law of diminishing return but it's one of the reasons why people like inserts so much.
  • 8 1
 @PhillipJ: Two things to keep in mind:

1. English isn't the first language for the authours, so maybe the descriptions weren't perfect.
2. Even with what sounds like tame terrain, the results were that supple tires at lower pressures produced less rolling resistance. The effect is likely to be even greater on the kind of terrain you described. This is not a reason to completely dismiss the results.
  • 2 9
flag PhillipJ (Jan 22, 2021 at 22:31) (Below Threshold)
 @R-M-R: actually the "study" not studying the trails that I actually ride *is* a reason to completely dismiss the results.
  • 2 7
flag PhillipJ (Jan 22, 2021 at 22:33) (Below Threshold)

" It sinks into the ground less"

Yeah... I'm not sinking into the ground when riding rocks and roots so I'm gonna stick by my claim that their results are not relevant to the many many trails that are not soft grassy meadows or gravel roads.
  • 7 0
 ride roots/rocks at 50psi vs 25psi and see what is faster and more in control.... listen to @r-m-r as I can guarantee you he's smarter than you.
  • 2 1
 @PhillipJ: I agree that if it doesn't include your terrain, there's room for uncertainty. That said, there may still be relevant trends. Dismiss the "grassy meadow" test, if you like, but the gravel conditions may be relevant. (The authours describe their "gravel" as "level paths of fine gravel", which I take to mean loose over hardpack, not deep, soft gravel.)

In the pavement test, the rolling resistance decreased with increasing pressure. Switch to gravel and the trend reverses: rolling resistance increased with increasing pressure. More testing is obviously warranted, but it would be strange if this trend reverses as the terrain gets rougher.
  • 5 0
 @R-M-R: Coming on here with your coherent observations and explanations again.
  • 3 0
 @commental: Every seventh statement is a lie, just to keep it exciting.
  • 1 0
 @wheelsmith: no it doesn't. When I'm out on a camping trip I want a little complexity as possible and the greatest parts commonality. If I'm traveling 300-400 miles in a week, taking three-min to reinflate a tire is a non-issue, having a really unique part that could fail and strand me is a non-starter. My packing rig runs 3x9 because I can use nearly any chain and I use Shimano brakes since the pads are almost ubiquitous. Plus my bike has canti-mounts and brake-track rims just in case I needed a brake replacement and can't source disc parts.
Fat biking you don't want anything that will have issues in sub-zero temps and air systems end up with a lot of moisture, moisture freezes, valves stick pumps seize.
  • 1 0
 @BikesBoatsNJeeps: it may not to you but different strokes for different folks bro. If you're riding in the winter you're probably not commuting to the trail therefore just having a low pressure fat tire would be fine . If you're riding your fat bike in the summer and you're commuting to the trail and doing fire roads and loose Sandy climbs it does. As far as bike packing reliability goes the entire bike at that point is subject to reliability. If the system is made to work fine it will save a lot of hassle of taking the pump out and stopping to adjust. On top of that this system will always keep your tires topped off at the optimal pressure you desire I think it's genius.
  • 1 2
 Pulling off to the side for a quick minute to shoot a little co2 canister in your tires isn’t the worst thing in the world. I would sure prefer this to investing in new expensive wheels with ~500g deadweights on board with rubber hoses coming out of it.
  • 1 2

"ride roots/rocks at 50psi vs 25psi and see what is faster and more in control..."

I'm not arguing against lower pressure being better for grip on rocks and roots but that's got nothing to do with rolling resistance.
  • 1 0
 @PhillipJ: Are you saying rolling resistance is completely independent of pressure?
  • 2 0
 @PhillipJ: grip is not a factor but reflection and carrying forward momentum is.
  • 1 0
 @R-M-R: "it would be strange if this trend reverses as the terrain gets rougher."

Probably not reverse but certainly it's possible for the difference to be irrelevant. Gravel is too small for suspension to be effective so tyre flex is doing all the work. Rocks and roots are handled by suspension so tyre pressure probably won't contribute nearly as much.

But we don't know because the study is too narrow and shouldn't be quoted as some mountain biking gospel.
  • 1 0
 @R-M-R: no, and if you read anything I've posted here you'd see that.

What I am saying is the study is not particularly relevant to how many people ride so people should stop taking it as proof that lowest pressure you can run is best.
  • 1 0
 @jaydawg69: "one of the reasons why people like inserts so much."

People use inserts for grip. I've never heard of anyone claiming their bike rolls better from them.

You seem to be conflating the idea of low pressure being good for riding in general with the idea of low pressure being best for rolling resistance.
  • 3 0
 @PhillipJ: I'm aware of what you're saying. I'm trying to help you see the fallacy of entirely discarding all evidence that wasn't collected on your personal trails.

You can start by checking out the excellent information below. Much of it is from road bikes, which will surely tempt you to entirely discard it. All observed trends are toward lower pressures reducing rolling resistance for rough terrain and there is no reason to think this suddenly reverses in the presence of hydraulic suspension.

Josh Poertner, Part A
Josh Poertner, Part B
Tom Anhalt
Poertner & Anhalt
Jan Heine

"Probably not reverse ... "

I agree. If the trend is always toward lower pressures being more efficient in rougher terrain, it would be extremely surprising if this trend suddenly reversed in the presence of greater roughness on your personal trails or with the addition of hydraulic suspension.

"Gravel is too small for suspension to be effective so tyre flex is doing all the work."

Tires, forks, shocks, frame flex, your body: they’re all suspension. They all have different properties, they all contribute, and their properties and contributions can be analyzed.

Supple tire casings are designed to have as little hysteresis as possible. Forks and shocks with dampers are designed to have extremely high hysteresis – that's the whole purpose of dampers.

Hysteresis is a major cause of rolling resistance in tires. If dampers add a great deal of hysteresis, it is reasonable to assume the most efficient suspension is to have the component with lower hysteresis (tire) handle as much of the displacement as possible, which will occur at lower pressure.

The tire has a further advantage due to only a few grams of unsprung mass, while the hydraulic components have hundreds to thousands of times as much.

"Rocks and roots are handled by suspension so tyre pressure probably won't contribute nearly as much."

This statement implies the tire flexes less on larger impacts, which is clearly false. While it’s true the hydraulic components move more during larger impacts, the tire also flexes more. Both suspension elements are affected more during larger impacts.

"But we don't know ..."
"... proof ..."

Nothing can be an absolute certainty, but that doesn't mean everything is absolutely uncertain. Given the evidence presented, the notion of an inverse relationship between trail roughness and pressure (within reasonable limits of tire safety and stability) in terms of rolling efficiency probably meets the "balance of probabilities" standard for burden of proof.

It is possible there exists a pressure so low that additional losses due to tire hysteresis overcome additional gains due to efficient suspension (excluding the obvious case of the tire bottoming against the rim). The Schwalbe study found no evidence of this. A lower limit on pressure is imposed by the need for tire safety and stability; factors other than rolling resistance are likely to prevent us reaching the point of minimum rolling resistance at low pressure.

If you choose to view the situation as completely uncertain, despite the provided evidence - and other evidence in the vastness of the internet - then feel free to continue using rock-hard tires while the rest of us place our bets on the lowest practical pressure when riding rough trails.
  • 27 4
 Funny how everybody is ready to drop $ for Kashima coating or carbon rims or any other marginal gains but disregard any biggest improvement.
With such a dumb conservative attitude, we would still ride bikes with no tires, no droppers, no suspension, and probably square wheels. Tire pressure is probably what affect the most the riding performance and traction. it would be incredible if i could modulate my air pressure from 15psi to 30 psi while riding.
If you don't like innovation, you can still ride a rigid single speed!!
  • 23 3
 just invent a bike that rides itself
  • 3 0
 @KK11: I'm giving Elon 6mos.
  • 19 2
 the only application this seems feasible is on fat bikes. Where weight matters a bit less, and you genuinely change tire pressures quite a bit day to day.
  • 13 0
 Too many folks here dont know what it was like to ride an early 90’s mtb (a gravel bike Wink ). 7x3, top shifters, cantis, rigid, huge saddle, huge frame.....
Innovation starts somewhere. People used to laugh at droppers....”why do I need that when I can just get off and use the quick release??!!”
Just saying
  • 3 0
 Hahah it’s so easy to forget the excitement of having a cutting edge 3x7 drivetrain on your garden gate of a mountain bike
  • 17 1
  • 1 0
 That about sums things up perfectly ????
  • 2 0
 @crazy-canuck BTW, loving your bike history - Zerode, Cove, Morewood, the've had some interesting rigs!
  • 2 0
 @arna86: Thanks. They have all been lots of fun. As much as I do enjoy riding something a bit different. My Commencal DH and current Commencal trail bike are among my top favorites though.
  • 15 4
 Are you serious!!!! I thought this was at least 20 years away! I will pay. I cant afford it but I have 2 kidneys and 2 testicals, as far as I know .
  • 15 3
 This reminds me when Homer Simpson designed a car.
  • 15 4
 Sorry bro, I can't ride today. I forgot to charge my wheels...
  • 11 0
 Does it work for penises as well? Asking for a friend
  • 5 0
 Schwalbe have research showing you don't need to be rock hard if what you're riding is nice and soft.
  • 3 0
 That's not what she said.
  • 2 0
 Yes but for the hub you need a boost rear end *wink*
  • 10 1
 This reminds me of the stuff that used to pop up in MTB Action mag 25 years ago.
  • 1 0
 near the "love wedge" in the back
  • 14 9
 What's with all the hate in the comments here? If the weight is low (and especially if the price is also low) this could be really beneficial. Maybe it could be paired with automatic traction requirement detection, like Fox live valve, to crank up tire pressure when the system detects riding on a smooth trail or road.
  • 20 1
 Seriously. Pinkbike Comment Community motto: "Try to do something new or different and we will tear you to pieces." It's a lot easier to criticize something than it is to create something, that's for sure. If, and this a big if, it didn't add a bunch of weight and cost, I'd love to have wheels that could keep themselves at a certain air pressure without checking them every ride.
  • 2 6
flag PhatBrett (Jan 22, 2021 at 18:57) (Below Threshold)
 @BiNARYBiKE: They're called tubes in your tires
  • 3 0
 @PhatBrett: Nice try. Please tell me you run tubes.
  • 8 1
 @BiNARYBiKE: man, agree with this sentiment so much. The hub isn’t for me, but it’s pretty awesome that somebody got off their ass and made something from their idea and it works. Kudos to them. A hell of a lot more initiative and work than it takes for someone to write up a 2-second snarky comment on their phone.
f*ck people, it’s this kind of stuff that makes mountain bikes so damn interesting ffs.
  • 9 5
 I think it’s a neat idea, though how many people will be in the market for one of these is a mystery. Maybe for XC, but it’ll add weight. It would definitely make Tubeless setups more foolproof, eliminating the need for constant fill ups.
  • 3 5
 Would actually be good for dh racing. Pump up for flatter pedal sections. Would need a toggle. Low and high or something. Would be nice to have another button for a slime charge to coat the inside if there's a puncture.
  • 5 0
 @makripper: Definitely true. It would be interesting to know how fast it actually inflates, because that’ll have a massive bearing on its effectiveness. It you assume it’s about as fast as other electronic inflators, it probably won’t be great, but we’ll see how it works out.
  • 5 0
 Yeah, man. I’m with you here. A lot of haters, but this is actually kind of a cool idea. Will I buy it? Probably not. But in theory, it’s a nice innovation.
  • 12 8
 This is perfect for e-bikers who spend 90%of their time on tarmac where higher pressures are needed and are too lazy to use a pump to adjust tyre pressure on the occasion they go off road, integration with the computer means they don't even need to get off the saddle to adjust.
  • 6 1
 This is really cool, but I've gotten quotes for similarly-complex machined parts and I have a bad feeling that the price is going to make everyone queasy.
  • 2 0
 No pricing on the website. Agree it is going to be silly pricing.
  • 5 0
 But the real question is, does it sound like the offspring of bees and rattlesnakes?
  • 1 0
 You could put a perfectly sized hole in your rim and hit whatever harmonic you wanted. Maybe even put a few different holes in the rim and play it as you rode....

Wait 1 second if it can pump tires could it not also propel the bike with some type of air motor?.....I coin the the term A- bike. I will need to reach out to these folks....
  • 5 0
 You guys wouldn’t it be RAD if we could change gears using compressed air?!
  • 4 0
 Oh but you can! If you happen to have a spare 4,200 Euros, you can pick yourself up a now 20 or so year old vintage Shimano Airlines pneumatic drivetrain:
  • 2 0
 @arna86: whoa that's really cool
  • 6 0
 The first step in innovation often seem clunky.
  • 2 0
 Maybe version 2.0 should just be a tiny compressor that could fit in your pocket.
Convenience of using CO2 but you could use it as much as you want.
Sooooo basically this:
but with a pressure readout (to 1/10th of PSO obvi) and ability
to charge phone/lights from it.
  • 1 0
 But that adds another thing to charge, which is a pain in the butt. Gravaa's thing is apparently powered by the wheel's rotation.
  • 2 0
 Seriously doubting this thing inflates fast enough for meaningful on the fly adjustments in mixed terrain. I'll bet you have to be transitioning for a while and you can't stop while this is happening, since the pump is driven by the wheels. Just what I am looking for a gizmo to focus on instead of enjoying my ride.
  • 4 2
 WhiteCrow commenting here:
Apart from the usual slate of non-believer that state tire pressure regulation is worthless without ever-ever trying riding with one (yep, I remember the same about dropper posts.. and before that 29ers!) , I can add the following clarifications on WhiteCrow Tech system that are misinterpreted in this article:

A) the added weight in the hub was indeed about 300gr in the last prototypes, but this was because we dimensioned the system to support both FAT and Plus tires, which require moving a lot of air. For standard “2.5” tires this could be dimensioned quite smaller and therefore at least 50gr lighter.

B) The added weigh of the last prototypes of the inner chamber by a-dugast was less than 150gr, and still less than most current current “mouses” (which btw: it’s a function that we also perform!). Everybody agrees that a some kind of tire insert is must to properly ride at low tire pressures!

C) the system was mechanical by choice, in the same way that SRAM stuck for mechanical shifters 11spd while Shimano went electronic. This was to enable max reliability and full range temperature compliance for fat bikes (try shifting on electronics at -30 F and you let me know how it goes!). To be clear, I’m actually a embedded IT engineer… and f*k making it fully mechanical it was very, very hard. Of course, it a total no-brainer making it electronically actuated, and our patents fully cover this.

Why did not get to the market… simply because pulling off this complex engineering/ manufacturing project in the European startup ecosystem was too hard due to much constrained risk capital availability.

And for the Pink bike editors.. .do you homework a bit ! The name of the company is “WhiteCrow Tech” not “White Crow” ( you don’t call RockShox - “Rock Shox” do you?? )
  • 2 0
 To me this is an opposition between great piece of engineering VS market reality, it just doesn't match.

Question is: who is financing the research of this technology, knowing that it won't sell? Does Gravaa belong to a big industrial group or something?
  • 2 0
 Definitively ingenious, but IMO we are reaching the flat portion of the curve of the diminshing returns when it comes to making mountain bikes better. I do buy the arguments about full suspension, droppers etc. However I still ride 1x11 not electronically actuated setup and I am not planning to go 1x12 electronic. And what happened to adjustable travel forks like Fox Talas? I had one on my 26 and loved it. Made climbing so much easier.
  • 4 0
 So when the clutch to the pump disengages will my bike make a fart sound? If yes I’ll take 6 wheels.
  • 3 0
 This maybe has a use in gravel racing or marathon xc type races with extended sections of differing terrain but that's really about it for applications of this tech.
  • 1 0
 It's a neat idea, especially for people who have no choice but to ride on the road to get to the trails. It seems hideously complex and prone to failure, also s pound a wheel? Wow, no wonder the weight weenies are up in arms.

Wouldn't it be simpler to strap a CO2 canister to the hub with a tiny hose to the valve and a miniaturised piezo powered or button cell battery 3 way micro solenoid valve to bleed air out of the tyre or fart more in from the canister? Or have a fitting on the end of the axle and have a CO2 cartridge tied to the frame or fork leg? Gotta be doable for less weight penalty, plus lots of people already carry CO2 on them.

Thinking out loud you could have a custom axle hub combo with a rotary seal inside the hub. Fit the axle to the bike, charge the axle/reservoir. With a hose to the hub you could house the valve on the hub itself to avoid having a large mass out at the rim which might cause off balance. No hideously complex pump clutch arrangement.

It's not appealing to me but I can see the benefits for some people. Like a lot of people said, suspension forks and disc brakes were poo pooed on bikes initially, look where we are today.
  • 1 0
 I’m concerned that this system can’t respond fast enough due to low airflow volume. Of greater interest than the self-pumping is the ability to modulate tire pressure as you ride. Perhaps if it was tied to GPS, a barometer, and a bunch of accelerometers?

Example situation:

—> arrive at a rock slab, tire pressure decreases.
—> just before the transition, pressure increases to help prevent bottoming out the rim.
—> chunky section? Slightly drop pressure
—> going off a jump? Tire pressure increases for the landing and immediately drops after that.
  • 1 0
 I actually wonder if a system was feasible for DH or Enduro but in a more light weight package using CO2 cartridges. IE start of a DH run it could emergency dump the CO2 (mounted on the hub) into the tyre if catastrophic pressure loss was measured, IE a full deflate rather than for adjusting pressures on the trail.
Same for enduro, system knows you want 20psi or something. If it drops more than 10psi it refills it instantly.
  • 3 0
 Can you deflate to 0 and reinflate? Would be useful when you are tired and want an excuse to rest during group ride while maintaining your status quo
  • 1 0
 Its a wonder there isn't something out there yet that wraps round the hub so you can fit it to any wheel sizes and the air tube just runs down the spoke into the wheel valve,if it breaks you just disconnect and just send it off to get service instead of losing your wheel. ????
  • 1 0
 Air in tires is so 2020, haven't you folks seen the Bridgestone airless tires.


We will have adaptive profile, addaptive tread and addative ride soon enough. Just soon enough to get outdone by the hover bikes.... we wont even need tires. Oh and I forgot infinite wheel size adjustment ( 26 aint dead!) will be part of the bridgestone bike wheel/tire. I hear they are partnering with the guy at Superwheel on some extra features.
  • 1 0
 If they can put a bluetooth etc in there so you can adjust the pressure from the handlebar that would be great. Even better if the remote would have some programmable presetting buttons to make things easier like on your suspension.
  • 1 0
 Don't get all these negative comments. I don't really care about changing pressures while riding, but the pressure control is priceless. Tires lose pressure, whether they are ridden or not. Tires burp. Tires puncture and take time to seal, losing pressure. If I'm racing enduro, I'm lucky to keep pressure for a whole run, let alone the whole race. If you ride with too little pressure you are endangering both the rims and the tires. Never having to check pressures again would be beyond amazing. I think I could handle the extra 250 grams for never having to pick up a pump or pressure checker again. As for the money it depends, but dropper post level money would be acceptable without thinking too much.
  • 5 1
 Does your tire go flat when you run out of batteries?
  • 5 0
 Does your chewing gum lose its flavor on the bedpost overnight?
  • 3 0
 I don’t think you all understand the Gravaaty of the situation.

This will make riding absolutely Gravaay
  • 1 0
 This is a better solution for autos than bikes. Then cars can automatically maintain proper air pressure. Please message me to send me a commission check when you make billions my idea. Thanks.
  • 1 1
 Ti-marc - I had the same reaction. I stuck a fork in my leg to try to wake up. Nope, still January 23 not April 1.

There is a lot of venture capital around. It gets put into some marginal things.

Things which have rightly ‘stuck’ in the industry:

Light, well designed suspension from Canyon, Transition and the Big Guys - excellent
Mondraker, Transition, Cotic, and Dan Stanton’s shift in geometry - excellent
Tubeless which works - excellent
Disc brakes from Hope and the two Big S’s - excellent
Droppers with no sag (you know who you are) - excellent

And pushing for marginal gains can add up all over the place - lighter, stronger, wider rims; Kevlar beads in tyres, carbon bars (thanks Nukeproof and Renthal), and so on.

And then....I’ve seen a lot of dead-ends in MTB engineering since the 90’s....Darwin knows best
  • 1 0
 Cush core is going to bring out run flats and these guys will have an invention that does the same thing that’s more expensive with too many parts and thus prone to stay on the shelf
  • 1 1
 For the record I absolutely love what they're after here.

But it would seem to make a lot more sense to mount the pump/canister on the frame and have it directed to each tire through a sort of CTS system like on military vehicles. Keep the weight off the hubs and have 2-3 preset tire settings to switch from fed though small airhoses.

Done right you wouldn't have to even swap wheels to have the same control unit on multiple bikes.
  • 1 0
  • 1 0
 Or, you know, just check your tire pressure before you go on a ride. And also carry a mini pump with an air pressure gauge, which costs a fraction of what these wheels will eventually retail for.
  • 6 0
 Jesus Fried Chicken
  • 6 4
 Thats a cool idea. Im sure they will continue to lighten and refine it in which case I would defiantly check it out.
  • 10 8
 I legit hate pumping up my tires. I would not be mad if this came standard on high end bikes.
  • 5 3
 downvoted by people who love adding air to their tires? Smile
  • 3 4
 Don’t be lazy!
  • 5 1
 @tomich1: Exactly. In my quest to be as un-lazy as possible, I don't even use a pump. I use my mouth to blow up my tires.
  • 3 0
 Don't these dyno hubs add extra drag?
  • 1 1
 I can't speak to these particular hubs, but dynamo front hubs such as are currently in use to power headlights do not add any significant drag when you're not drawing any power. You can actually spin the wheel with the headlight off, and it will keep spinning like any other hub. Then turn the light on, and the wheel will noticeably begin slowing down.
  • 3 0
 This looks unnecessary and impractical. I want it.
  • 2 1
 Man you guys will complain about anything and everything. This is so good for bike packing risking running a leak. It has its uses for sure
  • 2 0
 I wonder how big of a hole you could put in the tire and just let it pump to make up what is lost through the leak?
  • 2 1
 Another adjustment to a simple thing that is riding a bike. Complicating something that is simple by nature - a bicycle! and so on and so on......
  • 1 0
 Installing this wheelset on my bike increased my trail cred 74%, grew new hair on my butt, and added 1.37 inches to my pens length. #Facts
  • 1 0
 Neat idea, but I'd like to see this brain power going into into making ultra lightweight, grippy, puncture proof tires. Just say'n
  • 1 0
 This would be great for the fat bikes of the world where changes of air pressure durning a ride actually could take place if it was super easy.
  • 1 0
 Wow, what peace of mind this must bring, until you happen to bust the spoke the hose is on, which punctures the hose and the tire slowly deflates.
  • 1 0
 If complication is more of a feature than a defect I guess this is good. Personally, it solves problems that I don't really feel like I have.
  • 4 2
 Just because you can doesn't mean you should.
  • 2 1
 Welp, I'm overweight, slow and drunk a lot but this might just be the thing I need to get faster.
  • 2 0
 Let the e-wheel/tire/hub hate begin!
  • 2 1
 Can you put SIRI in that hub so she can tell me when to put air?
Thank you!!
  • 1 0
 I’ve found a pretty good solution is a tire gauge and my finger or a pump.
  • 1 0
 Did you guys hear my eyes roll out of my head? Im curious how far away that THUD was audible.
  • 2 1
 You’ve got thumbs. You’ve got arms. Carry a pump. This is like idiocracy for mtb...
  • 2 4
 Any new mountain biking invention should be judged on its ability to grow the sport. I think this will be great on Ebikes with automatic transmissions and ABS and traction control that uses autonomous vehicle technology to read the terrain and apply the perfect amount of torque and traction to the ground so that anyone can ride up any trail even if it’s their first time as long as they can balance. We need gyros to get over the balance problem to really grow the sport but this is a step in the right direction.
  • 1 0
 Kriky you can get this type of tech on off road vehicles, the fat and SLOW kind,
  • 1 0
 Strange but intriguing idea. If it works I would be interested in trying it out.
  • 1 0
 Another set of wheels that will cost 2-3 times the amount of my bike ????????
  • 1 0
 Because people want their back wheel to weigh as much as a air compressor..............
  • 1 0
 Yeah MTB who cares, but assuming it doesn't weigh a ton I'd be all over this for long distance mixed surface stuff!
  • 1 0
 should flog this for the 4x4 off road crowd. more use there but woudnt surprise me if they already have it.
  • 1 0
 If it managed to pop tubeless tires onto the rim I'd buy them immediately !
  • 1 0
 this would actually be totally wicked for winter fat biking. People riding epic 100 km race series would greatly benefit.
  • 1 0
 Used to say "gimmick" about dropper posts. Until i used one! Would not be without one now.
  • 6 4
 Take my money.
  • 1 0
 Wow the mtb world keeps surprising me!
  • 2 0
 sounds sketch I'm in!
  • 5 7
 People: absolutely nothing
Mtb industry: here's another stupid f*cking idea from the pile of useless expensive shit pile we keep throwing at you because we don't want to keep 1 standard to keep simplicity and costs down
  • 7 6
 this is Q anon level stupid
  • 5 1
 WHAAAT? You mean the pizza-wielding daywalking vampire pedos aren't real? I may have to change my credit card number. Note, I was only in it for the pizza and the vampires. Not too much of a loss since they never put garlic on the pizzas.
  • 1 0
 Anybody else read White Claw in the last bit?
  • 1 4
 Cool idea but why the hubs? If the concept is inflate tires while your pedaling deflate tires while descending why not put the compressor system in the bb? are people that tired of pedaling? Kinda defeats the purpose of a bike. I understand the idea of a new company that's going more for conversions then actual partnerships with frame designers but its not a concept that's going to last.
  • 6 0
 Because the hub is part of the wheel and rotates with the tire.

How would you get air from the bottom bracket into moving wheels?
  • 1 0
 @longstrangetrail: Run Magic Marys
  • 1 0
 @longstrangetrail: You could do it easily they do it on trucks with CTIS systems but goot point just adding more complex parts to a more complicated system.
  • 1 0
 @longstrangetrail: Bluetooth. I have a Bluetooth garden sprinkler.
  • 1 0
 Honestly might as well just play Rune Scape.
  • 2 5
 I'm too late to this comment thread but for like real, can we for ONCE look at proper bike set up instead of making stupid products? Like dudeZ if your suspension, fit on the bike, and tire pressure are even remotely close to your weight/size, not even bringing up personal preference, you should be totally fine!

What, you smack your rims on your rides? Well dude ride freaking better. Smacking rocks fast af doesn't mean you are a good rider you choom.
  • 1 0
 Not too late for me . it's 7:20 am where i am. (-:
aside from that i incompletely agree . This inflator invention is trying to convince riders that they have a problem where none exists .
  • 1 0
 pick your tire pressure and be a dick about it!
  • 1 0
 More riding, less dicking about. YES!
  • 1 0
 Also no more carrying a pump. EXTRA YES
  • 1 0
  • 1 1
 My good when does it end, its a freaking bike not a God damn car or phone, stay creative, but simple guys come on.
  • 1 0
 Awesome, more weight, like I need it. Maybe for ebikes?
  • 1 0
 I know somebody who would use this.
  • 1 0
 Gone full Enduro.... 35psi transfers, 28psi stages runs....
  • 1 0
 Best of luck! Reminds me of the adjustable/dropper stem system.
  • 1 0
 Save weight claims with no information about the weight
  • 1 0
 !st of April arrives early due to Covid !
  • 1 0
 curious what brake rotors those are?
  • 2 1
  • 7 8
 This is stupid. Can’t these engineers put their efforts into something we need, light handlebar alignment tools?
  • 18 1
 Sorry for the salt but I get frustrated with this attitude. Every cool thing humans ever created came because somebody had the brains and the guts to try to make something that didn't already exist. Sure, the vast majority of those attempts are failures, but we don't get the cool stuff without all those failures. While I may not want to buy everything they come up with, I applaud everyone who tries to make something new and beneficial.

PS Pinkbike ran the article on the people who created a handlebar alignment tool back in November, and everyone hated on that too.
  • 6 0
 @BiNARYBiKE: totally agree. However, I think OP’s comment on handlebar alignment tools was sarcasm as well.
  • 4 0
 @KeeganPelton: Well if that's the case my righteous indignation blinded me to @gtill9000 cleverness and I beg forgiveness! That would make more sense.
  • 3 3
 The price?!? What is the price for that thing?!?!
  • 4 4
 Another example of COVID driving people kookoo.
  • 4 4
 More shit to leak Frown and how do you keep sealant out of the pump chump?
  • 1 0
 I'd probably use a check valve.
  • 2 3
 The were so wrapped in the fact that they could, they never stopped to think if they should.
  • 1 0
 2021 Jeff Goldblum award
  • 1 0
 what a BS
  • 1 0
  • 1 0
 Uhhh lmao
  • 1 0
 Or carry a mini pump....
  • 1 0
 A must for Fat Biking!!!
  • 1 0
 Priceless! Big Grin
  • 1 0
 For real?
  • 6 6
it is 1 April ?
  • 3 6
 The lol is beyond on this one!!!!!
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