Auto-inflating motorcycle tires?

[richar18]

AloRaptor - try carrying your air compressor with you and plugging it into a cactus on the side of the road in the middle of Arizona, after you run over a nail... It might be nice to have this device then.

How do you guys feel about Tire Pressure Monitoring systems? just curious.

[teufulhunden07]

come on now, no harm intended. I never said it wouldn't work. You just didn't have to talk about it like we are a bunch of stupid biker idiots with no intelligence and our only goals in life are to ride and procreate...

Personally, I like the idea. I posted a reply in your other forum thread. I also seriously took your survey. Is there any way to see a few concept drawings or photos? If you could make it functional, compact, safe, and appealing to the eye... then I'd really be interested.

[teufulhunden07]

Tire pressure monitoring... sounds expensive.

[tallannie]

Richar...
you have been treated to a very mild form of the kind of play our regulars on this forum can dish out.
We live to spin humor for our buddies off of innocent posts...especially from people who dont participate in the forum for more than some very personal gain.
We hope you make money....and we intend to to have fun at your expense if we can... until and unless you become a regular, at which point it might get worse !...



"Stanford Graduates are like milkshakes.... Thick and rich !"

[DrBob]

Peristaltic-pump action self inflation systems for tires are already available for cycles, and have been patented for motorcycles- there are a couple companies working to bring them to market, the potential for tens or even hundreds of millions of dollars worth of liability being one fo the big stumbling blocks. They attach to the hub, which is a better idea than the valve stem, which could have clearance issues, plus the issues of attaching weight that causes ever increasing lateral forces on the stem as rpm increases. Valve stems simply are not designed to carry the extra weight.
Other companies are developing self-inflation systems like the ones on cars, which have a sensor on the rim and a valve in the hub to add air from a central source.
So while you might have an idea, consider the competition, and the legal risks to you should you start selling them. As I always say, dream big, but consult a lawyer.

[richar18]

tallannie, thanks for that. I need to grow some thicker skin . It really just caught me off guard, but I can appreciate it now.

And teufulhunden07 - I totally apologize if I came off as condescending, or in any way insinuated that you guys were stupid - that was DEFINITELY not my intent, and I had no idea I gave that impression. I really do respect all of you guys' viewpoints, and will work to understand and cater to as many of these viewpoints as I can, as I move forward in the development process.

I appreciate your interest (even more so, since you gave me such a hard time before lol), and will keep you updated as to when I can released a sketch or something to illustrate it's likely form. I am at the very beginning phases of the development process, and haven't nailed down enough specifics about packaging/peripherals/extra functionality yet. This is another reason for the survey.

[richar18]

Hi DrBob - I know of the Peristaltic pump based design you mentioned - it was invented by Coda development in the UK, and needs to be nested between the tire and rim. It is a good idea, but the main drawbacks are that the wheel/tire must be removed for installation and it does not produce electrical energy so it must use a battery if a pressure monitor is to be used.

The hub-mounted system was introduced by Pirelli in 2004, and requires a special rim. It is not as good a retrofit product, due to its cost (you have to buy the rim). It also must use batteries to power the pressure sensor and radio transceiver.

The device I am working on produces electrical energy, so the pressure sensor and transceiver will be battery-less which reduces cost and required packaging space.

About the valve stem load issue - I have done some testing, and have figured out how to solve the problem. The secret is to make centripetal force work for you, instead of against you. All you need to do is support the centripetal load with the device geometry instead of the valve stem - the system is designed such that centripetal force causes the load to be transferred to compression of the device geometry surrounding the valve stem. The added benefit (how you get the load to work for you) is that any moments that occur due to bumps are transferred to negative axial load on the device geometry, which is then cancelled out by the positive axial load generated by centripetal force. Provided the axial force caused by the transfer of the bending moment is lower than centripetal force, all bending load is removed from the valve stem, in addition to centripetal load. There is the equivalent of over 18 g's of centripetal force at 25 mph, and 90 g's at 55 mph, so it would require HUGE bumps to completely overcome centripetal force and cause the valve stem to bend.

I have probably said too much... but to address your concerns yes I have done my research! This device offers a cheap solution that can be installed by ANYONE without tools in minutes, and it provides a display to let you know of a puncture (the peristaltic pump design likely will not, since it is alot more difficult to incorporate this technology with that design).

The big boys don't scare me . And yes, product liability must be dealt with; however it can be done safely, and I intend to show them how.

[tj1964]

Ummmm.... I know how to tie my own shoes!

[DrBob]

I see what you are saying about the load issues, but I think that is where your basing your design on your individual experience with motorcycles may be limiting you. Out in my driveway right now there are 6 bikes, and all six have different valve stem designs. On one the valve stems are on center, between the spokes, and only as long as the cap- from the way you describe your device it sounds like it would not fit between the spokes. On another, the valve stem comes out then takes a 90-degree turn, so it is parallel to the surface of the rim. On another the valve stem has a 45-degree angle to it and is almost 2 inches long. On another the valve stem comes out well off center from the centerline of the rim. While the thread size is standard, there are 16 different designs of valve stem available for my Harley alone, in various lengths, shapes, sizes, and angle. Something to consider: do you want to try and develop 16 differnet versions of you product, or keep production costs minimal and just hit the 3 or 4 most popular types? Or will you be able to design a series of adapters to make the same basic product fit all the non-angles ones, and include the adapters with each product? Are there liability issues with adapters and the change people will choose the wrong one? And what about tubes- have you studied the interactions and implication of the device being supperted by the rim if the tire valve is not? All questions you need to have answers to, better sooner than later.

[frostbitevinnie]

Originally Posted by tj1964

Ummmm.... I know how to tie my own shoes!

Ha!! Bet they are Velcro!

This sounds like a decent product but for me tire inspection and maintenance are performed weekly. I do have a slime tire pump, I think most of us that ride a lot have some sort of pump or plugs along, that is compact enough for me. I guess my issue with such a product would be that folks would have a "set it and forget" it mentality which can be disastrous in itself. This sport is dangerous enough and IMO regular tire maintenance and especially inspection are critical.

[AloRaptor]

Originally Posted by richar18

AloRaptor - try carrying your air compressor with you and plugging it into a cactus on the side of the road in the middle of Arizona, after you run over a nail... It might be nice to have this device then.

How do you guys feel about Tire Pressure Monitoring systems? just curious.

Oh man, I really am in trouble, we don't have cactus in Arkansas.

[richar18]

Thanks for the words of wisdom DrBob - good insight. I have been thinking about how universal the product might really be, and so far it appears that I can cover most bikes and user tastes by offering three components with the device:

1) a telescoping screw adapter, that is essentially just a tube that acts to surround a rubber valve stem. Just twist, and it lengthens or shortens so that it is the right length to transfer the load of the device to the rim. Note that this is only required for rubber valve stems that do not bolt to the rim; metal valve stems that clamp to the rim WILL support the load of the device even at high speeds.

2) a new valve stem designed to fit as many rims and rim holes as possible, that is gauranteed to work with the device

3) an adapter for the new valve stem that allows the user to install the device INSIDE the rim instead of outside

This might allow me to tap into as many demographics as possible - however, the option to buy the "one sized fits all" kit (which includes the extra valve stem/stems and inner wheel adapter) may need to be offered separately from the generic version, for a premium. Based on what I have seen so far, the generic version (that includes the telescoping adapter) would fit almost all straight valve stems.

I want to emphasize that a straight metal valve stem that bolts to the rim will not need any adapter (not even the telescoping tube). It is robust enough to support the mass of the device at high speeds.

Regarding rims, I haven't seen any that had spoke center-center distances of less than 1.25." This would be sufficient space to install the device.

frostbitevinnie - Thanks for the comment. I am of the same feeling as you, regarding regular checks; however I take console in the fact that I am offering the device primarily for safety, and the ability to drive for a much longer period on a punctured tire. When my warning light comes on, people will actually pay attention - it means you actually have a leak; they can then drive until the "STOP NOW" (pressure below critical) light comes on.

[richar18]

And AloRaptor - haha .

But just curious - do the safety aspects of the device appeal to you at all? or do you just feel like the added benefits are as unnecessary as adding seat belts to a motorcycle?

[AloRaptor]

Originally Posted by richar18

And AloRaptor - haha .

But just curious - do the safety aspects of the device appeal to you at all? or do you just feel like the added benefits are as unnecessary as adding seat belts to a motorcycle?

Sounds like to me cost will outway the benefit, but tell me something, where is this stop now indicator going to be located

[tallannie]

does not appeal..

Originally Posted by richar18

And AloRaptor - haha .

But just curious - do the safety aspects of the device appeal to you at all? or do you just feel like the added benefits are as unnecessary as adding seat belts to a motorcycle?

[richar18]

The costs would likely be in the $50-70 range.

At this point in time, we are thinking the stop now and leak present light will be located on the same fob, which the rider will place at the most convenient location. We need to do user testing and market studies to determine the specifics.

[DrBob]

Originally Posted by richar18

1) a telescoping screw adapter, that is essentially just a tube that acts to surround a rubber valve stem. Just twist, and it lengthens or shortens so that it is the right length to transfer the load of the device to the rim. Note that this is only required for rubber valve stems that do not bolt to the rim; metal valve stems that clamp to the rim WILL support the load of the device even at high speeds.

Sounds OK. By the way, those that that bolt onto the rims that are cabable of supporting your device are the valves used with tubes, and I really think your devise will be absolutely worthless with tubes, which fail suddenly and go flat very rapidly when punctured. I find it imposible to believe that your pint sized device can put out enough volumn of air at a high enough PSI to make any difference at all.
But probably 40% of the bikes on the road use tubeless tires, so you still have a potential market. And tubeless tire valves are fare more standard than those on tubes, eliminating parobably 12 out of the 16 different valves.

2) a new valve stem designed to fit as many rims and rim holes as possible, that is gauranteed to work with the device

The different valves are used for a reason. And if you could make a valve that fit multiple size rim holes, they would make them already. They have to fit the size fo the hole exactly to be air tight, so the best manufacturers have been able to do is narrow it down to three sizes of rubber stems. But if you focus on tubeless, three is a hell of a lot better than 18.

3) an adapter for the new valve stem that allows the user to install the device INSIDE the rim instead of outside

Hmmm...I'm guessing you have never changed a motorcyle tire. Not a good idea.

Keep working on it though...

[omegajim]

Hmmm...I'm guessing you have never changed a motorcyle tire. Not a good idea.

begging your pardon - he's never changed a tire, period.

changed a couple of tires off the rim. Yes, twice I did this insanity.

the third time will never happen.

[richar18]

DrBob - thanks again for your informative responses! I actually wasn't aware that tubed tires deflated more quickly than tubeless - testing would have revealed that, but its good to know now.

Btw, the device puts out enough volume at 40 psi keep a tire inflated above 25 psi for two hours, if a puncture occurs that would normally have caused the tire to lose 28 psi/hr. Maybe not enough for tube still... I'll have to test out some tube leak rates.

Oh, and about putting the device inside the tire - I have changed a motorcycle tire, and it should be possible (but probably exceedingly difficult), as long as the device is located as close to the rim as possible. I thought maybe people would like to have that option, even if it is a PITA to install...

Thanks again for the advice! I have a lot to learn through product research, I am really glad I decided to come here - you all are very knowledgeable.

[richar18]

OmegaJim, I have too changed a tire!

That was the first thing we learned at Stanford lol.