Self-Inflating Commuter Tire

Aug 23, 2011 By Ted Johnson Posted in The Archives Tagged with Commute by Bike 13 Comments

You’re a bike commuter. You’re in good shape. Your risk of coronary artery disease is pretty low, so you’re not likely to be needing a peristaltic pump–one of those pumps in an open-heart bypass machine.

But would you be interested in a peristaltic pump if it was at the heart of a self-inflating commuter tire?

Will Powers and Benjamin Krempel are a couple of bike commuters who have invented a bike tire that self-inflates to the desired pressure, and keeps the tire at that pressure. As long as you don’t get a flat, you’ll be properly pumped.

The tire draws air from the environment, and a “lumen” tube on the rolling edge of the tire pushes the air into the tube.

When I saw the diagram, the first thing I thought of was a urethra. I thought I’d share that.

The system is called PumpTire, and it’s actually a system involving an integrated tire, tube, and valve. They work together, so you won’t be able to use this system with your favorite tire. PumpTire will have to be your favorite tire. The fact that Will and Ben are cyclists gives me hope that the tires will be the kind that real cyclists would want.

PumpTire Diagram — ScreenShot: PumpTire Video

Will told me that they had not given much thought to licensing this technology to other tire makers — so you could have a self-inflating version of your favorite tire. But if the product is successful, I think that’s probably inevitable.

PumpTire is a KickStarter project, looking for backing. If you want to be the first people to try this tire, you’ll need to pledge to the project. But if you do, you’ll get insider pricing when the tires are produced.

They aim to produce two models:

City Cruiser for Casual Riders

The City Cruiser is designed for the casual, urban cyclist. Its a 26 x 1.5 tire with a set pressure valve. The pumping mechanism will pump from a flat up to 65psi. It has a moderate tread design and is intended mostly for pavement.

The City Cruiser will retail for $65, but backers of the project can pre-order them for $45 or $75 for a pair.

City Pro High Performance Tire

The City Pro is a high performance tire with a 100 psi maximum pressure. Its a 700c x 28mm tire. The tire works in conjunction with a high performance user-adjustable valve which allows the user to set the pressure from 65-95psi. This tire is designed for the avid cyclist who is constantly seeking better performance from themselves and their equipment.

The City Pro will retail for $149.90 for a pair. Backers can pre-order a pair for $100.

If you are interested in backing the project, go to the PumpTire page on Kickstarter.

If you want to wait and see, you can follow the project on Facebook.

13 thoughts on “Self-Inflating Commuter Tire”

FellowRichmonder says:

August 23, 2011 at 3:25 pm

This is brilliant. I foresee some kinks in the engineering, particularly with preventing over-pumping, but I hope this gets the funding that it needs.

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Andy says:

August 23, 2011 at 5:51 pm

Here’s the math behind why this won’t sell to a typical rider: A set of tires/tubes = $130. It takes ~1 minute to top off a tube. Topping off every 2 weeks should give a reasonably small change in pressure. 6 months of riding in the year would then require ~13 fill ups, which would take about 13 minutes. So in order to save yourself 13 minutes of effort, would you really pay $130? That’s $10 per minute!

I can see this being more feasible on bike sharing programs where zero maintenance is key to keeping up a few hundred bikes, but this is just a solution to a problem that didn’t exist for regular riders. Heck, you could pay me $129 and I’ll fill your lighter tires to the desired pressure before every ride! 😀

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1. Ted Johnson says:
  
  August 23, 2011 at 9:08 pm
  
  @Andy: It probably takes more than a minute to top off a tube. And the price you need to look at is not the full price of a PumpTire system, but the difference between that and a traditional set of tires and tubes.
  
  Perhaps your idea of a typical rider is someone who knows how to pump their own tires. There are a lot of people who ride bikes, and they don’t know how to do this–and there are potential cyclists who would rather not ever learn top off a tire. This is the J.O.Y.B.A.G.™ market. I wonder if the PumpTire people are targeting J.O.Y.B.A.G’ers, or experienced, tire-pump-competent cyclists.
  
  Imagine a purchase where you would feel totally inadequate to make an informed choice. You’re a geek and a cyclist, Andy, and I don’t know you personally. So I’ll resort to stereotypes and say, imagine you have to buy a nice suit for a fancy occasion. You don’t know what to buy, and you don’t know how you’ll ever take care of it. The salesperson at the fancy suit shop says, “For an extra $40, I can give you a suit with self-folding trousers, and you’ll never have to worry if you’re doing it wrong.”
  
  Now imagine someone at a bike store, feeling just as inadequate as (my stereotyped version of) you at the fancy suit store. Let’s call him/her Shannon. Shannon is a bit overwhelmed by all this bike stuff, and intimidated by how it all is going to complicate Shannon’s life. The salesperson says, “For an extra $40, I can give you a set of tires that will always keep themselves properly inflated.”
  
  See what I mean?
  
  Reply
Chrehn says:

August 23, 2011 at 8:29 pm

I like it a lot.

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Will says:

August 23, 2011 at 9:05 pm

Hi, actually to be safe you should be pumping up the tires of the bike every day that you ride. I do this and so does every other rider that I know. At the very least, every 3 days. SO for people who don’t want the hassle of pumping up everyday – which is ideal – this solves that problem by pumping up the tire automatically, every time you take out the bike.

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John Romeo Alpha says:

August 24, 2011 at 6:58 am

Unless you run sealant, which means you rarely have to pump up your tires. If pumping every day is the challenge, sealant is the answer. It also performs its primary function of sealing many punctures, which I don’t think is covered by the self-pumper-uppers.

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will says:

August 24, 2011 at 8:00 am

If you wear the tyre or skid, the lumen will burst.

Also the extra rolling resistance of compressing the tube and the extra rotating weight of the larger valve is a problem.

Apart from that, it’s a great idea. It is pointless though. Pumps cost Â£2.99 so why not use one?

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Columbus commuter says:

August 24, 2011 at 8:18 am

I agree with Andy. Unless they can bring the price down more in line with traditional tires, I just do not see that there will be enough of a market of people who want to purchase and ride a bike but don’t have the skill set to pump up a tire or don’t want to learn. It is afterall pretty basic. If a person can ride the bike they can certainly fill up the tires.

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Andy says:

August 24, 2011 at 10:56 am

Ted, I certainly see what you mean. I wish that all people that get on a bike realize that it’s not just about hopping on a bike and assuming everything will always work all the time so long as you dish out tons of money. The unfortunate side affect of products like this is that they are so prohibitively expense to make cycling seem out of reach. Grab a few products like this and you’ll soon realize that you blew hundreds in extras that hardly solved a problem.

Maybe this is more of a interpersonal problem. My neighbors used to walk their bikes over once in a while and I’d gladly fill up their tires for them or do light tune ups as best as I knew how back then. These days it’s more likely that someone will throw the bike in a car, drive 20 miles to a shop, pay $30 for a shop to do 5 minutes of work, all because we’ve lost the neighborhood feel in the last few decades. It makes me sad to think that people might actually spend $150 on these tires because they are afraid to ask their neighbor for help a few times in the year.

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Lisa Black says:

August 24, 2011 at 1:10 pm

I hate pumping tyres (or ‘tires’ as you American’s spell it, which is probably better since I get ‘tired’ of pumping them). I wouldn’t dream of pumping them up every day. Or every three days.

I’d be thrilled to have have a tyre that didn’t need my attention.

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Dano says:

August 24, 2011 at 1:23 pm

I am a hard and fast work on everything myself kind of guy. Even if that means that I don’t know how to fix it… Breaking it and then going to the shop, buying the part, B.S.ing with the shop guys and then fixing what I busted is usually all the learning I need (by the way you can only do this a finite number of times until you know how to fix anything).

For me these would just be another thing on my bike that can bust. I imagine that the peristaltic pieces wear out and then it stops inflating itself. Then I have an expensive tire that I can’t fix and have to blow up “the old fashioned way” anyway. Tires are a consumable, which means for me they need to be as simple and robust as possible.

If this idea was something that bike commuters needed then why not come up with a design that stays with the bike and will inflate any tire you put on it. Many automobiles (semi’s and military vehicles) have self inflating tires that will inflate any thing you put on the rim. For the cost of 2 or 3 years worth of self inflating tires I am sure you could (if someone designed it) have a self inflating kit that was intrinsic to your bike (something that connected from the axle of the bike to the valve on the rim and was powered by the rotation of the tire). This way its not a consumable but accomplishes the same thing.

Man, if our ancestors who invented the wheel could only see us now.

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Andy says:

August 24, 2011 at 2:59 pm

@Dano, it does exist for bikes. I don’t have a link handy, but I saw it on a blog last year. To going rate was $300, and I think that was per tire. Again, a super expensive to a solution that should take 1 minute on a $5 pump.

I’m curious why a few commenters think tires need to be pumped up every 1 or 3 days. I have both racing and commuting bikes, and top off the tires one every two weeks usually, and they do just fine. Only the “ultralight” or latex tubes need to be pumped up multiple times a week.

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Chris says:

August 25, 2011 at 12:19 pm

Sounds kind of cool. I’ll tell you what – I have a Montague folding bike that I keep in my trunk. I ride it pretty regularly – I do a combination car/bike commute, and there have been times where I’ve taken my pump out of the car and forgotten to put it back in, also times when I have been in way to much of a hurry to check my tire pressure, let alone pump them up. So something like this would be pretty nice for me, even if it is a little pricey. Also makes me glad a got a folder w/standard size wheels.

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Self-Inflating Commuter Tire

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