90 Degree Angled Aluminum Valve Stems


S

SlowBoyRacing

Vendor
Hey everybody, here is a great product for the lowest price available on the internet, for you fellow FZ6R Forum members.

90 Degree (83 degree to be exact) Drop Forged Aluminum Angled Tire Valve Stems in various colors...

Available in:

-Black
-Red
-Silver
-Gold
-Blue



Available in both 11.3mm and 8.3mm
For our bikes and most Japanese bikes you will need the 11.3mm but if you have Carrozzeria, Galespeed, OZ, Marchesini, Marvic and BST you will need the 8.3mm ones.

These are the same valve stems which come from the factory on the fancy italian bikes (ducati, aprillia, etc) and area standard equipment on MotoGP bikes as well...
They are made in Italy and are the same valves which are sold under the Ariete brand.

What they do?

-Easier to check pressure and fill tires (specially on the front)
-Lighter than rubber stems- they weigh in at 12 grams each
-They are reusable, no need to replace them like rubber valves with each tire change
-Fixed to the wheel with a locking nut, can't bend, or be expelled from the wheel
-The angled quill reduces the effect of centrifugal force, which tends to fling the valve coire outwards in a conventional valve, leading to loss of pressure in tires.


Installation

Torque the locking nut to 7-10 Nm

How much?

$25 shipped for the pair! within US and Canada. For people outside North America it will be an extra $3 for shipping, please PM me for PayPal information.

How to purchase?

Use the specific buy now button that corresponds to the size/color of the stem you would like.


11.3mm Black - Pair



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11.3mm Silver - Pair



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11.3mm Gold - Pair



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11.3mm Red - Pair



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11.3mm Blue - Pair



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8.3mm Black - Pair



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8.3mm Silver - Pair



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8.3mm Gold - Pair



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8.3mm Red - Pair



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8.3mm Blue - Pair

 
N

Nastybutler

Cynical Member
Elite Member
I just installed these when my dad and I changed my tires to the Pilot Road 3's. Installed nice and easy, and look and work great so far. I love not having vertical stems for a couple of reasons: A) Easier to check/fill, and B) Tire pressure shouldn't drop as fast.

With my vertical stems I'd lose a couple of PSI per month, which I'm sure was due to the centripetal force pushing the bleeder valve inward as the tire spins. As a comparison, over the winter (aprox 5 months) my tires lost only 1-2 PSI. With angled valve stems I predict I'll have significantly less pressure loss. I'll let you all know if these do indeed make a difference in pressure loss.
 
P

Perdurable

Teeker!!!
Elite Member
Nastybutler said:
I just installed these when my dad and I changed my tires to the Pilot Road 3's. Installed nice and easy, and look and work great so far. I love not having vertical stems for a couple of reasons: A) Easier to check/fill, and B) Tire pressure shouldn't drop as fast.

With my vertical stems I'd lose a couple of PSI per month, which I'm sure was due to the centripetal force pushing the bleeder valve inward as the tire spins. As a comparison, over the winter (aprox 5 months) my tires lost only 1-2 PSI. With angled valve stems I predict I'll have significantly less pressure loss. I'll let you all know if these do indeed make a difference in pressure loss.
Click to expand...

oh man these look awesome!!! im going to pick up a few for the next changeover!!!!
 
M

MiltonDorkenhoff

Search, THEN post.
Elite Member
Nastybutler said:
I just installed these when my dad and I changed my tires to the Pilot Road 3's. Installed nice and easy, and look and work great so far. I love not having vertical stems for a couple of reasons: A) Easier to check/fill, and B) Tire pressure shouldn't drop as fast.

With my vertical stems I'd lose a couple of PSI per month, which I'm sure was due to the centripetal force pushing the bleeder valve inward as the tire spins. As a comparison, over the winter (aprox 5 months) my tires lost only 1-2 PSI. With angled valve stems I predict I'll have significantly less pressure loss. I'll let you all know if these do indeed make a difference in pressure loss.
Click to expand...
Isn't "inward" the way the spring in the valve already pushes it, to seal the valve?
 
N

Nastybutler

Cynical Member
Elite Member
MiltonDorkenhoff said:
Isn't "inward" the way the spring in the valve already pushes it, to seal the valve?
Click to expand...
Nope. Notice in this diagram that where the valve is placed as the tire spins the force of the rotating tire will push the valve in the stem to the outside of the tire. Which is the same direction you'd push it if you were going to bleed off air pressure if they were too full, right?

 
M

MiltonDorkenhoff

Search, THEN post.
Elite Member
Nastybutler said:
Nope. Notice in this diagram that where the valve is placed as the tire spins the force of the rotating tire will push the valve in the stem to the outside of the tire. Which is the same direction you'd push it if you were going to bleed off air pressure if they were too full, right?
Click to expand...

Sorry, physics was never one of my favorite things. Maybe I should have paid better attention in school. What I remember was this:

  • Centripetal Force - this is going to cause the valve to pull inward, toward the axle
  • Centrifugal Force - this doesn't exist, so it can be safely ignored
  • Inertia - this is going to cause anything spinning to want to continue onward on a path tangential to its path

But you're saying that the valve is going to spin outward. I think physics disagrees with you; it's going to be heading towards the axle (centripetal force) and tangentially to its path (inertia). Inertia is sort of outward, so I'll give you that, but it's not "whooosh, shooting straight out, perpendicular to the tangent to the surface of the tire" outward (visualized in my mind, that'd be kind of cool though)..

I found this picture of a valve online - no guarantees that that's what yours look like:



I'm pretty sure when I press the tiny middle/top piece down, the silver piece below the red rubber piece moves downward, which lets the air escape. So the goal would be to have a valve where the lower silver piece (below the red rubber piece) does not move outward. Since centripetal force pulls it inward, I think we're set, no?

As far as the angled valve stems go, I'm pretty sure they're not permitted in the AMA (older rules), and if we go back to the physics thing, in the case of a vertically oriented valve stem, centripetal force is acting on everything linearly, radially outward from the axle, which seems like a good idea. In contrast, with an angled valve stem, the valve itself is laid out horizontally, which I would expect would cause the differnt forces to act on its different parts differently (the pieces with more mass being subject to more inertia than those with less, so the tiny center pin doesn't have as much force acting on it as, for example, the large silver thing at the "bottom" that is hopefully pressing really hard up on the red rubber piece.

Or, if you're up for some empirical evidence, I have straight valve stems on my bike, my wife has right angle ones (I was jealous of hers for a while). Yesterday I checked the air in our tires and all four were low. :)
 
N

Nastybutler

Cynical Member
Elite Member
Not to belabor the point, but take a bucket and put some water in it. Now grab the handle of the bucket and swing it around. Where does the water go? How is a motorcycle wheel and tire any different?
 
D

dart1963

Super Moderator
Elite Member
  • Centripetal Force - this is going to cause the valve to pull inward, toward the axle
so far as I know, this is what is needed to be applied to keep the tire spinning,


  • Centrifugal Force - this doesn't exist, so it can be safely ignored
this is the force the object feel in a direct equal but opposite direction... e.g. you are pulling on the bucket handle, but the bucket and water inside water is pulling away from you


do not know how fast the tire spins at 120mph, and how much force the spring on the pin is set to withstand...

and I'm in no ways a physics major...


to me, it's the ease of use that makes this worth it... not the effects of air loss due to rotation (if any;))
 
M

MiltonDorkenhoff

Search, THEN post.
Elite Member
Nastybutler said:
Not to belabor the point, but take a bucket and put some water in it. Now grab the handle of the bucket and swing it around. Where does the water go? How is a motorcycle wheel and tire any different?
Click to expand...
Great example. The water goes around and around. If the bucket wasn't there, the water would want to go shooting off in the direction tangential to the circle. Thankfully there is a bucket there.

Now apply that same analogy to the valve. Hold the bucket sideways (because the valve in sideways). Where does the water go when you spin it?

dart1963 said:
this is the force the object feel in a direct equal but opposite direction... e.g. you are pulling on the bucket handle, but the bucket and water inside water is pulling away from you
Click to expand...
Centrifugal force.

dart1963 said:
to me, it's the ease of use that makes this worth it... not the effects of air loss due to rotation (if any;))
Click to expand...
I agree completely - they're much easier to use. I was disagreeing with NB's earlier suggestion that angled valves would prevent air loss (or maybe it was that vertical valves speed up air loss), which came from this part of the original post I guess:

The angled quill reduces the effect of centrifugal force, which tends to fling the valve coire outwards in a conventional valve, leading to loss of pressure in tires.​
 
alaskanflyboy

alaskanflyboy

Premium Member
Centrifugal force exists, just not in the context of our wheels. Centrifugal force is a draw towards the center of rotation where as centripetal is a force away from the center of rotation. I'm not sure how you get that force is inward toward the axle on a bike. Inertia will cause that valve core to want to go out and away from the bike. The only time you see centrifugal force (movement toward the center of rotation) is with satellites and anything going down a drain.
 
P

Perdurable

Teeker!!!
Elite Member
alaskanflyboy said:
Centrifugal force exists, just not in the context of our wheels. Centrifugal force is a draw towards the center of rotation where as centripetal is a force away from the center of rotation. I'm not sure how you get that force is inward toward the axle on a bike. Inertia will cause that valve core to want to go out and away from the bike. The only time you see centrifugal force (movement toward the center of rotation) is with satellites and anything going down a drain.
Click to expand...
stock stems go from the rim out into the center and to release air you push the center of the stem inward to the rim.... soo ya cent force could potentially cause you to loose air
 
M

MiltonDorkenhoff

Search, THEN post.
Elite Member
Deanohh said:
If knowledge of dynamics was rocket fuel, you guys couldn't launch a ping pong ball.
Click to expand...
Good thing we're not trying to. But you seem to know what's going on, so please, by all means, fill us in. Pictures are appreciated, real simple ones, drawn in crayon if possible.
 
D

DakinechicK

Active Member
I'm not smart enough for this thread. :tard:
 

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