[JJ Dunnit]

Is there any good reason that I cannot run a straight valve stem on my wing? Seems they would be easier to get the air hose and gauge on compared to the 90* stems that are installed at the factory. Any comments or thoughts would be appreciated. Thanks.

 

[MichaelB]

I can not think of a single reason that you should not have a straight valve stem on OEM Honda GL1800 wheels.

 

[#1Blackbetty]

I prefer a straight on the front and 90* on the rear. Never had an issue with a straight but, have had issues with the 90* unless using metal stems.

 

[JW.]

Well the theory is that the valve core on a straight valve can leak air at high speed because centrifugal force lifts it off its seat.

 

[JJ Dunnit]

reply

Well the theory is that the valve core on a straight valve can leak air at high speed because centrifugal force lifts it off its seat.

That is interesting... I never would have thought about that possibility. Note to self: valve stems on cars and trucks are not straight up and down nor in center of rim like the bike. Maybe there is a good reason for that.

 

[MichaelB]

I have never heard that theory. I wonder how fast that wheel needs to turn in order for the valve stem to stretch from centrifugal force enough to let it leak air.

 

[Zee Fifty]

Lots truck stops have straight type air chucks for tires on their compressors. I don’t think you could air up a motorcycle tire with a straight stem.

 

[MichaelB]

Lots truck stops have straight type air chucks for tires on their compressors. I don’t think you could air up a motorcycle tire with a straight stem.

You may be correct but I have never tried to air up a tire at a truck stop, on any vehicle.

 

[JW.]

I have never heard that theory. I wonder how fast that wheel needs to turn in order for the valve stem to stretch from centrifugal force enough to let it leak air.

My understanding is that the valve stem doesn't stretch, the core throws outwards and overcomes the inward pressure holding it closed. I've no idea how fast it would need to be but it could be calculated easily enough if the weight of the active part of the core is known. It'll depend on the core weight, tyre pressure, active x-sectional area of the core, wheel rim diameter and bike speed. Google likely knows!.... :smile2:

 

[MichaelB]

I find it a bit hard to believe that the valve stem can overcome the 40 psig that is in the tire no matter how fast that wheel is turning. But hey, a theory is just a theory until it is a proven fact I guess. Now all we need is for someone to prove the theory.

 

[tamathumper]

In a Porsche, rubber valve stems can fail at speed without metal supports. Tiny little metal ramps that are stuck onto the rim.

 

[MichaelB]

In a Porsche, rubber valve stems can fail at speed without metal supports. Tiny little metal ramps that are stuck onto the rim.

I'm not familiar with Porsche wheels. Where does the metal ramps go? Are the stems straight? Are the stems vertical?


By the same token, the rubber stems on the Gold Wings can fail too without that little plastic support. That is why I use the all metal stems. No support needed. Besides, those little rubber stems are difficult to install and I always have to cut them to remove them. Metal ones are so much easier and less prone to failure.

 

[Slybones]

I switched both the front and the rear to metal stems that are straight. Then I have a 90* valve stem extender that I screw on for checking / adding air when needed. Takes a little more effort, but I am ok with it. Its not that much. I like the metal straight as I added tire guard TPMS and have them caps installed. Seems like reports here are them caps installed on the rubber 90* stems can add stress and cause stem to crack. Not sure root cause, but he also has aftermarket TPMS on stock valve stems and in July on a 4 day ride had his front tire go flat. Checked for nails, etc. could not find anything. And it would hold air stationary. But start moving and with in 10min it was flat again.

 

[MichaelB]

I switched both the front and the rear to metal stems that are straight. Then I have a 90* valve stem extender that I screw on for checking / adding air when needed. Takes a little more effort, but I am ok with it. Its not that much. I like the metal straight as I added tire guard TPMS and have them caps installed. Seems like reports here are them caps installed on the rubber 90* stems can add stress and cause stem to crack. Not sure root cause, but he also has aftermarket TPMS on stock valve stems and in July on a 4 day ride had his front tire go flat. Checked for nails, etc. could not find anything. And it would hold air stationary. But start moving and with in 10min it was flat again.

The T-Valve Stems work quite well for that on the GL1800. Not so much with the GL1500.

 

[Snowmoer]

Yes, it will work, but why? Putting a straight valve stem on would make it harder, not easier to add air or to check pressure. On the front, the disk rotors will be in the way and the center hub of the rear rim would be in the way. You would need a very low profile air chuck or gauge to get it in there for a tight seal. My ST 1300 had straight valve stems. I switched them out the first tire change to 90 degree stems.

 

[MichaelB]

One reason for a straight valve stem is to install a TPMS sensor. But, seeing as how the valve stem is going to be replaced anyway and you want to use a TPMS sensor, why not use a T-Valve stem.


If a T-Valve stem is not to your liking, use the 90 degree all metal valve stem.


If you just want a straight valve stem for no particular reason, that's cool to.

To fill a tire with a straight stem, this on your air hose works very well:

 

[JW.]

I find it a bit hard to believe that the valve stem can overcome the 40 psig that is in the tire no matter how fast that wheel is turning. But hey, a theory is just a theory until it is a proven fact I guess. Now all we need is for someone to prove the theory.

Yeh, at first thought you might think so but that pressure is 40 lbs per square inch. I don't know the x-sectional area of the air seal part of a valve core but I'd be surprised if it's as much as 1/20th of a square inch so that would only require 2lbs to open it. For interest sake, I'll measure one tomorrow. OCD... Nah?...:wink2:

 

[dduelin]

Billet or cast aluminum 83 degree stems look good, make checking and filling easy, and last 100,000 miles or more.


https://www.amazon.com/BikeMaster-Valve-Stems-CHROME/dp/B004RALY72

 

[tamathumper]

I'm not familiar with Porsche wheels. Where does the metal ramps go? Are the stems straight? Are the stems vertical?


By the same token, the rubber stems on the Gold Wings can fail too without that little plastic support. That is why I use the all metal stems. No support needed. Besides, those little rubber stems are difficult to install and I always have to cut them to remove them. Metal ones are so much easier and less prone to failure.

Porsche stems tend to extend from the rim at a 30-45 degree angle, and the ramps are curled metal supports that stuck to the rim under the stem and support them at speed. Here's a picture from Automotion showing a typical one.

 

[tamathumper]

I switched both the front and the rear to metal stems that are straight. Then I have a 90* valve stem extender that I screw on for checking / adding air when needed. Takes a little more effort, but I am ok with it. Its not that much. I like the metal straight as I added tire guard TPMS and have them caps installed. Seems like reports here are them caps installed on the rubber 90* stems can add stress and cause stem to crack. Not sure root cause, but he also has aftermarket TPMS on stock valve stems and in July on a 4 day ride had his front tire go flat. Checked for nails, etc. could not find anything. And it would hold air stationary. But start moving and with in 10min it was flat again.

Same for me, I just bought these on Amazon.

https://smile.amazon.com/gp/product/B072WMZDFF/ref=oh_aui_detailpage_o03_s01?ie=UTF8&psc=1