[lawrence]

Road bike -
Does having a threaded stem where you use the nut to hold it to the rim and chews up the bushing/seal on the tire pump head better than having an unthreaded stem that doesn't chew up the pump? If you keep riding pressure in the tube, will the unthreaded stem tube move inside the rim? Isn't that what the nut is for, to prevent the tube from shifting?

I want to buy an extra tube(s), I don't know which to buy, threaded or unthreaded.

 

[TurboTurtle]

Road bike -
Does having a threaded stem where you use the nut to hold it to the rim and chews up the bushing/seal on the tire pump head better than having an unthreaded stem that doesn't chew up the pump? If you keep riding pressure in the tube, will the unthreaded stem tube move inside the rim? Isn't that what the nut is for, to prevent the tube from shifting?

I want to buy an extra tube(s), I don't know which to buy, threaded or unthreaded.

Unthreaded. The little nut does nothing but hold the stem up so that you can get the pump head on it when there is no air in the tube. You can do the same thing by pushing from the back with your thumb. Once inflated, the tube isn't going anywhere. - TF

 

[Kerry Irons]

Unthreaded

I want to buy an extra tube(s), I don't know which to buy, threaded or unthreaded.

Functionally, I cannot see any reason for threaded stems. I have been using unthreaded tubes for several years and can see no downside. For normal road usage, the ability to thread on a nut is meaningless.

 

[ergott]

I have used long threaded stems with extra nuts (I know, ha ha ) to balance out a wheel. The seam on many rims is quite heavy. Adding the weigh opposite the seam will make the wheel more balanced at high speeds. It is rumored that this is one of the reasons for Ullrichs's crash on the Tour a few years ago. I have no imperical evidence of the benefits of a balanced wheel with regards to high speed stability, but I figure, why not. Car tires are balanced for highway speeds and I've hit 60mph before.

Note the valve in this movie http://websites4ever.com/ergott//wheeltruewithtire.mov That is my own personal wheel. I have about 4 or 5 nuts on there and a valve cap (they are useful for something).

-Eric