3030vision

Hi,
I've been on a search for new Presta tubes: 700c, 18-23, 48mm smooth stems! You'd be surprised at how hard this has been.

Now I'm seeing that there are tubes with fixed and removable cores. Can someone help me understand why I'd want a removable core for my tubes? I assume it doesn't matter for me since I've never noticed.

Wouldn't mind recommendations for a good source for tubes either. Annoyed that tubes with smooth/unthreaded stems are so hard to find locally. Thanks!

bikinfool

Funny, when I was in Freewheel on Valencia recently I had to hunt for one with threading (I prefer them for inflation, plus they just tend to look better). Uses I can think of are for filling sealant on a mountain bike, not sure why you'd want one for a road bike unless you tend to break them and want to repair them I suppose.

jasonrobo02

They are useful for deep wheels like Zipp 404's or deeper. The tube valve stem is often too short, so you have to buy extenders. If the tubes have removable cores, you can get the better extenders that take the place of the valve core in the tube and then the valve core screws onto the end of the extender.

3030vision

So, wheels like you're referring to require stems longer than 60mm? Otherwise I'm not sure why you wouldn't just buy tubes in the appropriate length.

Also, what I'm hearing is I don't need to worry about this for me for regular (e.g. Velocity) deep V wheels.

Thanks!

ScrubJ

If you have a leaking valve you can replace it.

I think almost all the tubes my LBS stocks are the smooth type. I much prefer them over the threaded type as they tend to not eat pump heads.

Jed19

One of the advantages of removable core tubes is that you can use them on both regular rims (Open Pro, et al) and deep rims (Zipp 404, et al in conjunction with valve extenders) if you have different size wheelsets.

If you standardise, then you just buy regular size presta valve tubes with removable core.

I use and like Continental 42mm Removable Core Prestas.

3030vision

So, with removable core tubes, I'm assuming the whole valve stem is replaceable as opposed to the little metal bit that keeps the air in? Again, I've never seen/noticed this before so I'm just trying to understand.

Thanks!

ScrubJ

I wouldn't worry about the valve core.

As far as where to find nonthreaded tubes, can't help you there. My LBS is chock full of them.

bikinfool

Just the valve core, the outer portion is permanently part of the tube. Like these https://www.google.com/products?hl=en...ed=0CBcQrQQwAg

3030vision

I went to three bike shops here in San Francisco-- including the aforementioned Freewheel on Valencia-- and no threadless stems in 48mm. Weird no? Of course then I decided I had to have them and ended up ordering Michelin Airstops from eBike Stop (https://www.ebikestop.com/michelin_ai...ube-TU8135.php) and ended up with a decent deal on Conti Ultra Gatorskins too.

Had a surprisingly difficult time searching for the right tubes with a specific stem size (48-52mm) and threadless stems on a number of sites.

Thanks for your help!