CrankPump - the invisible bike pump
CrankPump - the invisible bike pump
Crankpump is a CO2 pump that lives in the hollow axle of Shimano cranks. Slot it in and forget about it
Crankpump is a CO2 pump that lives in the hollow axle of Shimano cranks. Slot it in and forget about it Read more
About this project
What is CrankPump?
Most new bicycles have a hollow axle between the pedal cranks. That hollow space is the perfect size for a bike pump. CrankPump is a CO2 pump for Shimano Hollowtech cranks. Simply unscrew the existing plastic bolt, screw in CrankPump, and forget about it until you need it.
Bike pumps are annoying. They live on a bracket that hangs off your bike getting ugly, dirty and lost, or they live in your back pocket beating up your kidneys. Sometimes they live forgotten in your drawer at home or on the road where they fell off. The pump and other stuff needed to repair a tyre hangs off your bike, making it look ugly and un-aerodynamic. CrankPump is a simple way to keep all that stuff from ruining the clean lines of your bike.
How it works
Shimano Hollowtech cranks have a plastic bolt that covers a hollow axle. CrankPump is a CO2 pump that is a simple screw-in replacement for that plastic bolt. CrankPump lives in the axle, hidden out of the way until you need it.
Fixing a flat tyre
When your tyre is flat, remove CrankPump from your crank, and screw it onto your tyre valve - instant inflation. It works for road and mountain bike valves. CrankPump is simple and tough, with no moving parts.
CrankPump also has a pair of TyreZip levers that work in a patent-pending new way to “unzip” your tyre from the rim. It’s a similar method to how a mechanic removes a car tyre.
TyreZip works in three simple steps:
1) roll the TyreZip under the tyre bead
2) pull a section of tyre bead over the rim
3) slide along the rim to unzip the tyre.
The TyreZips clip onto CrankPump for easy storage. When the TyreZips are clipped together in a locking arrangement, they stop the CO2 canister screwing all the way in and touching the piercer.
What do I get?
You get the CrankPump CO2 pump axle bolt, removable with just your fingers. The alloy part is made using high-quality CNC machined anodised aluminium, and a tempered steel cartridge piercer. The plastic part that screws in, is fibre-reinforced nylon. You get two TyreZip levers that click onto CrankPump.
You don’t get a CO2 canister, because it is illegal send them air freight. You can pick up CO2 canisters easily from your local bike store - just make sure you ask for a 12g threaded canister (a 12g canister can inflate a road tyre to 90PSI / 6.2 bar).
CrankPump comes in a package that also doubles as a tool to remove your cranks' plastic axle bolt.
You also get an anti-vibration foam insert, that prevents the CO2 cylinder from rattling inside the axle.
and you get a washer that lets you set the axle tension using the standard Shimano bolt, and then remove it after clamping the crank arm pinch bolts.
The first version of CrankPump fits Shimano Hollowtech II cranksets that have steel axles. It fits most recent Dura Ace, Ultegra, XTR, XT Shimano cranks. To check whether it will definitely fit your model of cranks, take a look in the FAQ.
What we've done so far
CrankPump started as one of those “aha!” moments, noticing that the hollow axle was exactly the right shape and size for a CO2 canister to pop in. Maybe you've had a few of those “aha” moments before too, and then kicked yourself when a couple of years later you see someone else bring that brilliant idea to market. Well with your help, it won't be like that this time…
When you slip a CO2 cartridge into a hollow axle, it all seems so obvious and simple. Keeping it that simple has been a lot of work.
There have been may design challenges, like how to make sure it still performs the tensioning function of the original plastic bolt? How to stop the canister rattling in the axle? How do you make it easy to tighten and remove, so it never jams? How to make sure your hands don’t freeze? How to stop the cylinder piercing while you ride? Most of all, how to do all that within the tiny space of a hollow axle? You can find details on many of these challenges in the FAQ section at the bottom.
CrankPump has gone through dozens of prototypes, trying to figure out what works well and what is strong enough.
For functional prototypes, we were fortunate that there are many CO2 pumps already around, so the basic problems of providing CO2 from a canister to a tyre are well understood. The problems of packing all that in a 20mm diameter axle were not so easy, and it has taken two years to get CrankPump to the point where it’s ready.
What we need from Kickstarter
We've been building and testing CrankPump prototypes for two years. As you can see in the video, the prototypes are working well.
Now that the patents have been filed, our next step is to prepare tooling. CrankPump uses a fibre-reinforced nylon bolt, designed so it threads accurately into the axle. Producing the mouldings to cast plastics is expensive - many thousands of pounds. If you’re spending that sort of money, you’d like to make sure a few other people want to have a CrankPump.
We need your support and orders.
Timeline / When we will deliver
CrankPump has a simple timeline: There’s a short sample run that gets tested to iron out any kinks, then production.
We’ll give you give you a regular update at each stage, on the status of everything.
CrankPump isn't just a guy in a workshop in London - CrankPump is based at the Royal College of Art’s InnovationRCA business incubator. That means there has been some serious coaching that you don’t have to pay for, so your money will be spent on making CrankPump high quality.
CrankPump will be well made - it is designed by Damon Millar, an ex-Formula 1 engineer, avid cyclist and industrial designer from London's Royal College of Art, who has started a few successful companies, but prefers to be in the workshop.
Here's how you can get involved with CrankPump:
Risks and challenges
CrankPump has no moving parts, so the risks and challenges are pretty straightforward. But if you’re risking your money, you’ll want to know that all the challenges have been considered, so read on.
First, there’s a risk that CrankPump won’t be good to use. To mitigate that risk, we’ve taken expert advice, done lots of prototype testing, and have scheduled in another round of testing for a month with the samples, when they arrive. Any issues we see with the samples will be fixed before production tooling begins.
Then, there’s a risk that some part can’t be manufactured in the way we expect. To mitigate that risk, we’ve had manufacturers quote on detailed engineering drawings and CAD files. They are happy that the parts can be made.
Finally, there’s a risk that some part won’t be made well. To mitigate this risk, we’re paying more money to deal with high-end manufacturers, and we are only using manufacturers that people we know have previously made successful products with.
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