I bought a used bike today and one wheel has a Presta valve and the other has a Schrader. All my bikes have Schrader. Sould I just deal with this one wheel needing an adapter? Swap it for a tube with Schrader and then have no worries if I have my adapter with me? Should I convert the old Schrader to a Presta tube so I can move into the 21st century? :-)

Opinions?

If the valve hole in the wheel will take a schraeder. put one in. Otherwise only switch it if it is super narrow where the hole enlargement would weaken the wheel. I prefer Presta valves but outside the realm of v narrow rims, these valves are just different, and one is no better than the other.

The cheap way to go would be getting an adapter. However, if you have the $ then get a good pump with a pressure gauge that fits both presta and schrader.

I have Presta but don't like them a whole lot. I've already managed to bend the threaded post the lock nut rides on (taking a frame pump off the valve) and as I very gently tried to straighten it a bit, it broke (very fragile). I also find that even when I am being VERY careful and deliberate, one loses pressure every time one takes a pump off the valve. And if you have to fuss a bit to be extra careful to remove the pump and not bend that threaded post, you can lose even more pressure.

And in general I am not all that fumble fingered, nor prone to impatrience.

You do make a good point about the diameter of the valve and the wheel... I have a hybrid so it's about half way from road to mountain. BUT, I'm not so sure a Shrader that was narrower wouldn't be an answer.

Thanks guys! I visited REI. The bike guy was very nice to explain and show. I purchased n adapter and he installed it on the Presta and we left I there. He pumped both tires to 90 lbs. So I'm all set tomorrow.

I also purchased two 27 x 1" schrader tubes because the REI bike guy showed me that the holes were big enough for the valve. So I'm all set for flats Shh ...

I think once this single Presta tube wears out or whatever I will just toss it so all my tires and pumps can remain consistent. Until the next bike I buy!!!! ;-)

Does this adapter to change Presta to Schrader fit all the way down to the locknut on the outside of the valve (i.e. almost alll the way down to the rim)?

I think I've seen the negatives in Presta valves, but what are the negatives in Scraders?

Some negatives are the larger hole required for the valve which weakens the rim some. Although I have never seen a rim fail at the valve hole that would not have otherwise failed, ie an impact or crash.

Schraders bike tubes don't come in valve lengths long enough for aero rims. Although I don't know any aero rims that are drilled for schrader.

There are not any schraders tubes built for the racing crowd that I know of (lightweight, narrow).

There is a little more aero penalty for schrader valves compared to a presta valve of equal height. I'm not sure which valve weighs more though.

As usual Sheldon covers almost everything

The negatives on Schraeders are bigger holes in the rims and loss of air from the tire as you remove the pump (both negligible). The air you hear coming out when you remove a Presta pump is from the pump and not from the tire. Valve damage with prestas can be eliminated if you use pumps with hoses - floor pump or Road Morph.

Ah, thanks guys for the input, I appreciate it as I am trying to understand the issues!

It seems to me that once the lock nut is all the way out, the slightest side deflection will allow air to escape from the tire. Is this not true?

As for said lock nut, is my "screw it all the way out" the right way to do it?

the adapter is a little tubular collar kind of thing that is only about 1/4' long. so it sits at the top of the valve stem, furthest from the rim.