Aluminum Valve Stem Maintenance

Ashley

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I emailed Bridgrport Sri, in Italy and Bridgeport USA. Here are the answers I received:


Hello, I would like some info on your angled metal motorcycle valve stem part number 40-450-2579, What is the life expectancy of the stem? Is the seal designed to last the life of the stem or should it be replaced at certain intervals? What is the seal made from and what is the temperature it is designed to handle?

Thank You, Ashley Horn


Good morning Ashley,



Thank you very much for your interest in Bridgeport products. Please see below our answers to your questions (in bold italics below):



· What is the life expectancy of the stem? The valves are warranted for defects of workmanship for a period of three (3) years. The life expectancy is not possible to predict due to variability of environmental and use factors.

· Is the seal designed to last the life of the stem or should it be replaced at certain intervals? Bridgeport srl (our parent company, and the manufacturer of the valves) recommends that in the event the seal no longer functions, that the valve should be replaced, rather than just the seal.

· What is the seal made from and what is the temperature it is designed to handle? The seal is made of EPDM, and generally has a temperature range of -30 degrees C to + 135 degrees C.



For your information, Bridgeport USA provides Bridgeport tire and air conditioning valves to the North American market via our network of distributors… We would be happy to provide you the contact information of a distributor from which you can obtain Bridgeport products.



Sincerely,



Customer Service

Bridgeport USA, LLC


___________________________

Dear Mrs. Horn,



the valve stem has a guarantee of 5 years in normal usage condition. We suggest to check the valve's gasket every tire change, if the gasket has been damaged we suggest to change the whole valve.

The valve is designed to work between -40°C and +135°C.


Kind regards.



Castelli Ing. Giulio
 

SupraSabre

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I guess I'm just one of those that throws them on and forgets about them. After 6 tire changes on the 2010, and probably 15+ tire changes on the '05 before sending it off north, I really haven't given them much thought!

I have also put them on both 04's and the 2012. I haven't had any issues from any of them.

Maybe I'll get a couple of spares so just in case I do need to replace one, so I don't have to wait for it to arrive. :D
 

SteveST1300

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I have checked the nut on the inside to make sure it was torqued properly but as long as they are holding air I am leaving them alone.
 

Ashley

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Igofar
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That may be a way to identify the ones from China. The cheap knock off ones I have seen had cheap o rings like an air pressure gauge where the hose attaches to the body.
Thanks for the email and sharing the info
 
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Re: ST 1300 Tire Recomendations...

If it wasn't already mentioned in this thread the bridgeport/ariete seal is epdm which has good resistance to ozone, brake fluid, antifreeze, isopropol, silicone grease, and doesn't play well with grease, motor oil, gasoline.
 
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Ashley

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Re: ST 1300 Tire Recomendations...

If it wasn't already mentioned in this thread the bridgestone/ariete seal is epdm which has good resistance to ozone, brake fluid, antifreeze, isopropol, silicone grease, and doesn't play well with grease, motor oil, gasoline.
It's Bridgeport. Also, EPDM is good for temps up to 135 degrees C or 275 F
 

Blrfl

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(Started writing this earlier, so there's some redundant material...)

Haven't had a chance to mention it until now, but I got the same reply from Italy. I did write them back and let them know their distributors (Areiete in particular) were telling their customers something different.

I'd swear the stems on my bike have O-rings on them, but it's been a decade, and I guess you forget stuff like that over time. :) I do know the current stems are a different design than the older ones, so maybe mine do.

The EPDM rings seem to have established a decent track record for not causing trouble, which is good. The shelf life of EPDM is 5-10 years (less in service), so mine are quite clearly in need of replacement. That may be why Bridgeport recommends such frequent changes: "tire change" isn't a unit of time, and if it was, it would vary with every rider.

EPDM has fair resistance to compression setting, which is where it assumes the shape of whatever it's sealing over time. That's not necessarily a bad thing, because it often provides a better seal. Its big weak spot is that it doesn't get along with hydrocarbons (fuels, oils, etc.). We're certainly not dousing them in the stuff, but they do feature on our list of nasty substances found out in the air on the road.

If we were looking at regular O-ring replacement, I'd be going for a fluorine-based rubber called Viton that does fine around pretty much every substance you'll run into on a bike. It's better at resisting compression set, has a much higher maximum service temperature and the material has a 20+-year shelf life. Viton is three times more expensive than EPDM, but you'd be staring down about $7.00 (vs. EPDM at $2.50) for a bag of 25 that could be split with a friend and would last both of you 20 years.

I wasn't able to find any standard part that resembles what's on the newer Bridgeport stems, so I'm guessing they're custom and the path of least resistance is new stems. I think, based on how mine have performed, I'm going to replace them at the next tire change and at 7-year intervals thereafter. That'll more than cover valve cores, too.

--Mark

P.S.: Larry mentioned earlier that the bands for his spear guns deteriorated rather quickly. I did some poking around and found that many of them are made of latex, which is at the bottom of the longevity heap with natural rubber. Both have a shelf life of 3-5 years and don't tolerate the outdoors very long.
 
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Mark, thanks for the updated information. I've been using Viton o-ring in dive equipment for years with mixed gasses and trimix. O2 is really hard on o-rings not made of Viton. And you get all kinds of pretty colors (purple, blue, brown, etc.)
You are correct about your latex comment, however, once again, I didn't provide enough information to get the point I wanted to across. I use only the very best Latex band material. Sometimes the natural amber only, other times amber core with black outer layer to protect the latex a little better. Normally I keep the material and the bands in air tight zip lock bags or pelican boxes etc. However, even when I stored them inside my house (on the gun) and didn't seal them, the bands never changed color and die like they did in my GARAGE. I'm thinking the chemicals in the air in the garage had alot to do with it. I also noticed that my dehumidifiers just collect water in the house, however, in the garage area, the water turned dark brown/black. Again, I am thinking it was from exposure to gas, oil, carbon fumes etc.
The point I was trying to make was even though we don't see it happening, some things (chemical/ozone) can cause harm to most types of rubber or synthetic materials.
And lastly, If YOUR valve stems are the old style and do use o-rings, let me know what size/dia. and I can mail you some Viton ones if you'd like.
Larry
 
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ibike2havefun

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If we were looking at regular O-ring replacement, I'd be going for a fluorine-based rubber called Viton that does fine around pretty much every substance you'll run into on a bike. It's better at resisting compression set, has a much higher maximum service temperature and the material has a 20+-year shelf life. Viton is three times more expensive than EPDM, but you'd be staring down about $7.00 (vs. EPDM at $2.50) for a bag of 25 that could be split with a friend and would last both of you 20 years.
Based on the accelerating rate at which my rear tire has been losing pressure over this season, and on the fact that I have a set of angled stems (Ariete knock-offs), this thread has me looking in the direction of replacing the O-rings. I don't have tire changing facilities at my house, and have relied on my local independent shop to see to it for me. But if I could hand over a fresh set of O rings for every time I have tires done (for me that is roughly once a season, or at most a season and a half so far), I'd hope that the results would be salutary.

Shall I order us a bagful?
 

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Has anyone ever experienced, seen or heard of the rim seal failing on a metal valve stem? If so, what were the consequences?
 

ST Gui

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ibike2havefun said:
Shall I order us a bagful?
At $4 a pop that's going to be a pricey bag! Add $3.75 for shipping and you're at $11.75 plus applicable tax. I'd sooner change my oil at every 3,000mi! A soapy water inspection would be a good thing.

I can't complain too much as they're no doubt not available at Gaskets-R-Us. And a less than half the price of a new set of valves (which would have been the only option until now).
 

Blrfl

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At $4 a pop that's going to be a pricey bag!
Dunno where you're buying yours, but at McMaster-Carr, they're about $8.50 for a bag of 25. (Plus shipping, but I almost never order just one thing from there.)

--Mark
 
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