Author Topic: Presta inner core  (Read 182 times)

Matt2matt2002

  • Hero Member
  • *****
  • Posts: 1358
Presta inner core
« on: November 10, 2018, 11:38:13 AM »
Discovered the slow leak is from the inner core of my Presta valve.
It is removable but the bent inner core section is not accessible.
No other leak. Certainly not at the base.
I presume the bent inner core is not allowing it to sit snug and form a seal.....

I've only patched the tube x2 -(!!)- so wonder if there is a fix?
I have seen on YouTube a valve core removal tool but advice on a free fix would be handy.

Also; the Schwalbe tube I have used as a replacement, does not have a removable inner core but I can't see this referred to on the box.
Is it pot luck to get a tube with a removable inner core?
Or are codes on box an indication?
My Google searches haven't produced an answer.

Many thanks folks....
« Last Edit: November 10, 2018, 11:41:07 AM by Matt2matt2002 »
Never drink and drive. You may hit a bump  and spill your drink

John Saxby

  • Hero Member
  • *****
  • Posts: 1480
Re: Presta inner core
« Reply #1 on: November 10, 2018, 04:59:23 PM »
Hi Matt,

On the valve core tool, I bought one of these a couple of years ago:
https://www.mec.ca/en/product/5048-364/VC-1-Valve-Core-Tool?org_text=valve%20core%20removal%20tool

Works like a charm -- I've used it only on a couple of occasions, but when I needed it, there was no easy substitute.

I bought it after seeing on a thread (here, I think?) that Presta valves in Schwalbe tubes often worked loose, causing slow leaks.

I also bought myself a pkg of spare Presta cores, and these have been useful.  They weren't easy to find--most of the cores on the market were for Schrader valves.

On valves with non-removal tubes: Um, I've always assumed that all valves had removable cores -- how else would they get in there?  OTOH, I guess they could be inserted & secured with red Loctite or something similar.

Hope that's helpful, tho' it doesn't answer all your questions.

Cheers, John

Matt2matt2002

  • Hero Member
  • *****
  • Posts: 1358
Re: Presta inner core
« Reply #2 on: November 10, 2018, 08:57:46 PM »
Thanks John.
I'm pretty sure the new one i fitted didn't unscrew like the leaky one.

But having patched it twice - I guess I've had my money's worth.
I did read that a dab of glue or insulating tape can help things - but then I'd be riding with a tube awaiting to deflate.....

Another strange thing was that when I put the cap on the valve - the next day the inner had unscrewed!
I reinflated the tire - left the cap off and the next day there was hardly any air missing - but it was on it's way down for sure.
I couldn't work out how the valve came loose with the cap on.

Interesting that you have the tool and replacement inners. This is the first time I think I've experienced this issue. Maybe caused by careless inflating?

Strange goings on...
Never drink and drive. You may hit a bump  and spill your drink

mickeg

  • Hero Member
  • *****
  • Posts: 1544
Re: Presta inner core
« Reply #3 on: November 10, 2018, 09:31:56 PM »
I try to avoid getting removable valve cores on presta tubes, but quite frankly that is the last thing I think of when I am buying tubes.

My Lezyne Micro Floor Drive pump chuck threads onto the valve instead of clamping around it.  And if my valve core is not tight enough in a Presta, the valve core will come out of the valve when I remove the pump chuck.  That is a major hassle, you finish topping off the tire and suddenly ALL of the air has been let out, plus you now have to look for a pliers to tighten the valve core into the valve so that after you spend many more minutes pumping up your tire AGAIN, you do not have a re-occurrence.

Those little Shrader to Presta adapters that thread onto a Presta so you can use a Shrader pump on it - those often have an O ring that will fit snuggly on a Presta.  I usually store one of those adapters on my rear wheel Presta valve.  And a few weeks ago, same thing as my Lezyne pump, removed the adapter so I could pump up the tire with a pump configured for a Presta, and the valve core came unthreaded when I removed the adapter.

So, my luck with removable cores has not been good.  I understand why you might want to buy them if you use a sealant in your tube, that is how you get the sealant into it.  But I have not used sealant for several years, have no immediate plans to use it again.

John Saxby

  • Hero Member
  • *****
  • Posts: 1480
Re: Presta inner core
« Reply #4 on: November 10, 2018, 10:10:05 PM »
Weird stuff indeed, George -- I have the same Lezyne Micro Floor pump as you do, and it works brilliantly well...except on the occasions when it doesn't.  Shortly after buying it, I had the same problem as you did--pumped up my tire quickly & accurately, removed the chuck and of course unexpectedly removed the valve core at the same time, so that it shot upwards with all the air in the tire. 

That was one of the early opportunities to test the Park valve core tool, and to offer thanks for the little cache of spare cores.

Those Schrader/Presta adapters are handy things to have in the tool/spares kit as well.

What's the takeaway?  Maybe a preventive dab of Superglue onto any removeable cores before using them?

I'll stick with my Park Valve Tool for the time being -- but I carry superglue in my kit for sundry other things.

Danneaux

  • Administrator
  • Hero Member
  • *****
  • Posts: 7553
  • reisen statt rasen
Re: Presta inner core
« Reply #5 on: November 10, 2018, 11:15:27 PM »
Quote
What's the takeaway?  Maybe a preventive dab of Superglue onto any removeable cores before using them?
I remove the core and apply a drop of blue Loctite 242 on the threads of every new tube's valve stem. Keeps 'em in place really well but still allows removal if needed.

Best,

Dan.

mickeg

  • Hero Member
  • *****
  • Posts: 1544
Re: Presta inner core
« Reply #6 on: November 11, 2018, 01:13:22 AM »
Quote
What's the takeaway?  Maybe a preventive dab of Superglue onto any removeable cores before using them?
I remove the core and apply a drop of blue Loctite 242 on the threads of every new tube's valve stem. Keeps 'em in place really well but still allows removal if needed.

Best,

Dan.

I think a new plan is starting to take place here.  A bit of Loctite can do marvelous things.

martinf

  • Hero Member
  • *****
  • Posts: 564
Re: Presta inner core
« Reply #7 on: November 11, 2018, 08:02:13 AM »
Discovered the slow leak is from the inner core of my Presta valve.

Also had this, only with Schwalbe inner tubes, so far never with other makes.

I don't have a special tool to tighten the inner core, I just use a small adjustable spanner (adjustable end wrench in the US ?).

The first time it happened I spent a long time looking for the puncture, taking the wheel off twice. Now that I know about it, it is only a minor hassle.

mickeg

  • Hero Member
  • *****
  • Posts: 1544
Re: Presta inner core
« Reply #8 on: November 11, 2018, 04:09:56 PM »
..., I just use a small adjustable spanner (adjustable end wrench in the US ?).
...

Thank you for the translation, but I got it figured out.

Matt2matt2002

  • Hero Member
  • *****
  • Posts: 1358
Re: Presta inner core
« Reply #9 on: November 11, 2018, 05:24:38 PM »
On close examination I see that the inner part is bent. Unable to withdraw it and straighten out.
I appreciate the glue solutions ...... Many thanks.
Never drink and drive. You may hit a bump  and spill your drink

Mike Ayling

  • Full Member
  • ***
  • Posts: 152
Re: Presta inner core
« Reply #10 on: November 13, 2018, 06:54:02 AM »
H

I bought it after seeing on a thread (here, I think?) that Presta valves in Schwalbe tubes often worked loose, causing slow leaks.


Cheers, John


Yes, I have had that experience too!

Mike