i am in the process in making a aluminum valve extender....i found that using a regular length stem in my ksyriums that about 3/8 " of the valve would stick out even though it was enough to get a pump on more an extender was needed but i hate having 2inches of extender sticking out of my rim and i dont like the longer length stem for the same reason, so i though being a machinst i would make a short one out of aluminm (about 1in. long) i could stick it in my seat bag and use it when i needed it, just screw it on pump up take it off and pu ti back....so is there a market for this? i am thinking the price would be obout 2 bucks a piece.....so let me know what you think.

thanks

You mean like these?

http://www.probikekit.com/display.php?code=A7450

same basic thing only mine are aluminum and mine dont have the stopper in it.

iam just saying that i dodnt like having a 50 - 60mm stem sticking out of my rims.
its mostly just an aid....like i said on my ksyrium with a reg. stem there is just a nub sticking out and this you can screw on pump up take off and close your valve....its just an idea i had.

iam just saying that i dodnt like having a 50 - 60mm stem sticking out of my rims.
Wow, how long are your valve stems to begin with? Perhaps you need shorter ones. ~20mm of exposed stem should be enough to accomodate most pumps. (ie: 42mm valve on a 20mm deep rim)

Look at tubes: Buy tubes with a 40 or 50mm stem in the fisrt place.

Schwalbe has popular sized tubes available in a range of stem sizes so you could drop the whole extention thing. 40/60/80mm.