90 Degree stems are inherently not the best thing for a MC application. And certainly not in anything but metal. Even though they are metal, the pose other problems. Your much better served by a short and straight stem. An angled gauge and chuck such as used on trucks will work just fine to check

To say, I don't condone the use of angled valve stems on MC tires.

Dynabeads have turned gazillions of miles in tires of many applications I don't think that's your hole.

Tubes are tricky business and that is precisely why they invented tubeless tires. A good amount of the time a very very small spec of something gets trapped between the inside of the tire and the outside of the tube and over much time the force and friction between the two will in itself cause a flat from within, without you running over anything.

If you must run tubes, clean the dogsheet out of the inside of the tire with a good cleaner, dry it and blow it with air, do the same to the tube before you install it, and hope.

What's bad about 90 degree stems? Side stress?

Yeah............inquisative minds want know...what's the big deal re using 90 degree valve stems

I hope nothing, because I have a brand new one sitting here getting ready to go in my new tire next week.

moondog166 wrote:
I hope nothing, because I have a brand new one sitting here getting ready to go in my new tire next week.

No worries there is nothing wrong with 90º stems. I know that myself and many others have been using them problem free for yrs. Fact is that is what my bike had in the rear tire from OEM. Some members just have personal preferences and that is fine, but not a problem.

OK, took the tube out, I had it patched a few weeks ago and the patch didn't hold.

I reused the dyna-beads, even thou they were about 80% black from the inside of the tube. The valve stem was fine, no leak there.

I guess the black beads just made me wonder about how much of the rubber is being worn off mile after mile?

BTW, I have 90 degree stems on front and back.

Darn wrote:
What's your thought? Dyna-beads in tubed tires, yes or no?

No. There is residue in the tube from the forming process. That is what was on them.

Im not going to look this up. But, the problem on a 90 stem is inertia, Being it's a bike that could matter. On a semi truck it will not. But it is the law on a semi that they be metal thus eliminating the risk.

While your speeding around the force of inertia on a 90 degree vale stem makes the stem flex out, tipping it, as you slow it returns to where it was, over time a lot of this action causes stress cracks in the place that has been flexing and if your lucky it leaks, if your unlucky it blows all at once. (instant flat)

So when I read that information in my tire studies, I took them off my list. They said if you MUST use them use metal ones on a Motorcycle. I think that would be fine on a cruiser but i would never run them on a Crotch Rocket that goes from zero to 122 in 2 gears and a few seconds.

They did not suggest running rubber 90 degree stems on any motorcycle at all. And the metal 90 stems you would use should be all metal meaning have a nut that fits on the inside of the rim. Not just the pull through rubber type.

If I run across the info soon I will add the source, but you can better see my reasons. A straight stem is not affected my inertia at all. Inertia is the same reason you should have a cap on the stem and it should be metal period, unless you have aluminum stems or tire sensors and then the cap should be same metal as the stem or, plastic in the case of tire sensors since it will notify you of air loss.

MS1700 wrote:
Im not going to look this up. But, the problem on a 90 stem is inertia, Being it's a bike that could matter. On a semi truck it will not. But it is the law on a semi that they be metal thus eliminating the risk.

While your speeding around the force of inertia on a 90 degree vale stem makes the stem flex out, tipping it, as you slow it returns to where it was, over time a lot of this action causes stress cracks in the place that has been flexing and if your lucky it leaks, if your unlucky it blows all at once. (instant flat)

So when I read that information in my tire studies, I took them off my list. They said if you MUST use them use metal ones on a Motorcycle. I think that would be fine on a cruiser but i would never run them on a Crotch Rocket that goes from zero to 122 in 2 gears and a few seconds.

They did not suggest running rubber 90 degree stems on any motorcycle at all. And the metal 90 stems you would use should be all metal meaning have a nut that fits on the inside of the rim. Not just the pull through rubber type.

If I run across the info soon I will add the source, but you can better see my reasons. A straight stem is not affected my inertia at all. Inertia is the same reason you should have a cap on the stem and it should be metal period, unless you have aluminum stems or tire sensors and then the cap should be same metal as the stem or, plastic in the case of tire sensors since it will notify you of air loss.
Interesting. My tubes on my bike have metal 90º valve stems and they bolt to the rim.

My stems are metal, and have a steel collar inside the tire, and a nut on the outside, I always use metal caps, infact mine have the valve core tool built into them