Valve stem questions and problems show up in the forum occasionally, and I wonder if some folks know the differences and why chose one style over another. Or don't even think about it, and just put tire after tire on and keep the original stem.

This is for tubeless applications, of course. For tubes, I just use metal stems I can anchor in place with a nut. There are different opinions of riding with them nutted down, but you can always take the nut back off when the tire/tube is mounted and aired up.

Hopefully nobody is putting a new tire with a stem like this. I've seen stems that look like this. This is the all rubber snap in type, common on automotive, and I've replaced several on bikes. I'd never use a rubber snap in, it's a failure waiting to happen, in my opinion. A straight one is bad enough, but angled, it's going to be subjected to twisting with every acceleration and deceleration. Eventually it will harden and snap off. I got lucky with the one that broke off on me, did it while trying to put air in it in my garage. Was so brittle you could rub flakes off the broken end. Was on a 10 or 11 year old bike I'd just bought, tire wasn't original, but the stem probably was.



You can get a metal stem on a rubber snap in, but it's still subject to the same twisting forces and aging failure as an all rubber - even worse, an angled metal stem is heavier and will twist against the base more. I've seen few Harleys with rubber snap in stems, a good thing in my opinion.




I like this style best, as long as you have room to reach the nuts - even though not pictured with one, I'd use a second jam nut. On stems with nuts, I always use a little blue loctite, too. Apply the loctite at the threads on the stem where the nut will be; putting it at the top of the stem, or on the nut threads, and you'll just wipe most of it off threading the nut down the stem. If the nut did come loose, or the stem seal start leaking on a trip, you can at least tighten it easily from the outside.



This style looks best on a fancy wheel, probably quite reliable with a jam nut as pictured, but I just feel more comfortable being able to check the nuts on the outside of the rim. If it does get loose, the only fix is to at least break the bead of the tire, if not remove it all the way, for access. Some wheels have recesses the valve stem sits into, that make it difficult if not impossible to tighten a nut on the outside (as in the first, all rubber, picture); this style would my choice in that situation.




Even with all metal stems, I'd still use the same rule for replacement as tires, every 5 or 6 years for age. The seal material (probably rubber most of the time) will harden, and eventually develop a slow leak. Stems aren't that expensive to risk having to pull a wheel to replace one before the tire wears out.

Just my experience and opinion. If you have more, or different, thoughts, please post, might help someone down the road.
.

 

I currently have what you have there as picture 3. I had the rubber stem but when I got the Zumo 390 I busted the rear stem when I added the TPMS cap. Next tire change I'm going to switch to a T stem system
http://advrider.com/index.php?thread...n-tpms.991661/

 

Already learned something, wasn't aware of T stem systems. Sounds like a good idea when you're adding something like that to the stem, won't risk damaging the threads or breaking it as much. Thanks for adding that.

 

We replace valve stems every time we do a tire change at our shop. 95% of people get the standard/factory rubber stems in lieu of opting for the higher price metal valve stems (rubber stem included in price of tire change, metal at retail price). I the 8+ years we have been doing tires we generally see valve stem failures are with the schrader valve rather than the stem seal to the wheel. It is scary and not uncommon to see valve stems that look like the first picture roll in here though...