Presta valve issues
 

Wednesday after I got to work I did my usual once over and when I squeezed the rear tire it felt kinda low, naturally I pumped it back to pressure and at my break I checked it again,drat it was low so at lunch time I put in a new tube. That tube also did a slow realease of pressure so I figured if I pumped it up just befoer I left work I would make it home ok and I did. I used my Topeak road morph and had never had any trouble with this pump but this time I ended up bending the brass core on both the first and second tube. These tubes had the 48mm long stems and I think that was part of the problem, (ie) not getting the head of the pump in straight. I don't seem to have that problem with the shorter stem Presta valves. I'm also thinking maybe the plastic innards of the pumphead on the Topeak are partly to blame. I may be all wrong but I just wondered if anyone else has had this problem. I don't have a problem with my floor pump at all. Is there a good pump out there that has at least some metal parts in the pumphead?

You just have to be very careful when pumping, not to bent the valve back and forth.

Topeak pumps are fine. That they are small, holding the wheel and pumping simultaneously can be a challenge, particularly when it takes a couple hundred pumps to fill a tire completely. Yah... I've bent the stem too. Just gotta be careful.

I had a different presta issue the other day; I had been dealing w/ a very slow leak on my front tire (very slow, just pump it up every week or so), and then Thursday, after I pumped it up that morning, it was flat by lunchtime. I had a crappy floorpump at the office that required a presta-schrader adapter (that's not the crappy part of that pump), so I put it on, pumped it up, and then, when I was taking it off, the core of the presta valve, w/ the adapter attached, shot across the room like an airgun pellet.

Apparently the threads holding the core into the valve had been loose, and I was maybe loosening it more as I was pumping it up, and then I loosened it a lot while removing that adapter. Anyway, I was glad I could thread the core back in, pump it up again, and ride home (and it's still holding pressure now).

Seems like you might have a pinch flat

They same guy that invented presta valves invented the low-flow toilet!

No it wasn't a pinch flat since the tire was a max pressure the night before and I even checked the first tube for a leak in a bucket of water and couldn't find one so that didn't seem to be the problem. The brass core did seem a bit fidgety so I replaced the tube and the second one was a leaker too even though it was brand new out of the box. I think I just got carried away but I am gonn look for a pump thats a bit more robust even if I have to carry it in my panniers. Do any of you know if there is a mini floor pump? that might be what I'm looking for.

I had the same issue with a new tube. After I tightened it up it's been fine.

With the road morph I use a presta to schrader adapter with the morph set up for schrader. This accomplishes two things: 1. You don't have to hold the valve on the tire while pumping to keep the head from popping off the valve. 2. You won't damage the core this way.

I just keep the adapter attached to the pumphead so it is available.

I like this idea, why didn't I think of that? DUH great tip, no pun intended