Take the 2-minute tour ×
Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

I have noticed that presta tube valve stems come in various lengths. I always assumed the longer valve stems were to allow the use of deeper aero wheels. Why is it that many wheels in print ads seem to have what I would consider an excessive amount of stem exposed? Is there an advantage or disadvantage to usng a stem that is just long enough?

share|improve this question
add comment

2 Answers

up vote 4 down vote accepted

I think the valve should be as short as possible while still allowing comfortable inflation of the tire.

On the other hand, a longer valve usually "won't hurt", specially if you have more than one bike or your group of fellows use to lend spare tubes to one another during rides (happens a lot to me, but in shcraeder-equiped mountainbikes).

Hope this helps!

share|improve this answer
1  
Agree, make sure "comfortable inflation" is with all your pumps (some need more stem). Roll with a stem sized for your rim, carry a spare that will work for you and your buddy. If you are really nice, also carry a valve extender. –  Ken Hiatt Aug 10 '12 at 17:57
add comment

I'd say that ideal is about 1.25" sticking out of the rim. That's enough to accommodate most pump chucks without being so long that it increases the risk of damage.

But mostly an over-long stem just looks ugly.

I've seen a tendency in the last few years for the stems on the tubes at your LBS to get (much) longer (they generally only stock one or two lengths), presumably because of aero rims. Manufacturers make more lengths, of course, but you'd have to special-order.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.