Newb questions about fixing flats.

[lordofthemark]

I am a bit embarrassed to show what a mtnce newb I am, but embarrassment keeps people from learning, so here goes.

I had a flat over a month ago, someone lent me a tube, I am now trying to fix the flat so I can return the tube (my old tube is a schrader, and the borrowed one a presta, so they are not interchangeable) and because I need to learn to do this.

I managed to find the puncture, and there were two holes near each other (which I guess means it was a pinch flat?)

I used the little roughening tool that I found in my bike room toolkit, some glue (from my own flat fixing kit, some swag I got on BTWD I think) and the little patches. I think I did one of the patches too quickly (and had glue on my fingers and was generally messy about it) and didn’t quite get it down smoothly on the tube surface – anyway, when I came back to look at the tube a day later (I did not put the tube in the tire yet) it had lost most of the air I had filled the tube with. This weekend I tried again, putting a third patch on top of the patch that seemed to have been put down wrong, filled the tire again, and rode off (on the borrowed presta tube – I wanted to make sure the fix was holding) When I came back a few hours later, the tube had lost the air again.

So question 1 – does this show I patched improperly – or is there something about inner tubes that they will not hold air if outside a bike tire? (Remember there is NO SUCH THING AS A DUMB QUESTION).

If the latter, I guess I should fill the tire, and then put it in the tire right away.

If the former, do I need to remove the patches I have put on and start from scratch?

Your assistance is appreciated.

Topic

[mello yello]

Was the hole on the inside or outside of the tire? I just had two tubes rupture there… on the inside, at apparent weak spots in the rubber material. It had nothing to do with the tire, or the perfectly smooth rim-strip. I also had trouble getting my patches to hold in that particular location.

Of note, if you want to add sealant inside the tube on a Presta-valved tube, you need to cut it open, add the slime, and then patch it. I’m not comfortable enough to do that. A schrader you can take the valve out with the attachment on a can of slime.
Edit: maybe this was just how my old scout leaders did it back in the 90’s… I’m reading some of the previous posts and it looks like this is not true. You learn something new every day.

[bentbike33]

@mello yello 145746 wrote:

Of note, if you want to add sealant inside the tube on a Presta-valved tube, you need to cut it open, add the slime, and then patch it.

Some presta tubes now have removable valve cores. Stan’s NoTubes makes a tool for that, or you could use a small adjustable wrench.

[hozn]

Some presta tubes have removable valve cores, which should allow you to inject sealant. (Most don’t, though.)

[huskerdont]

As Mellow Yellow (quite rightly) implies, tubes that flat right by the valve stem might not have flatted from foreign object debris. I’ve had a few go there over the years. Sometimes it’s a weak spot in material, and sometimes it’s just from extra stress in that area. Still worth it to inspect the tires though, even if you can no longer line up the tube to see where on the tire the hole was.

[bentbike33]

In my experience…

@huskerdont 145752 wrote:

… tubes that flat right by the valve stem …

… were due to the advanced age of the tube, or tightening the little round presta valve-stem nut too much. Best to be a weight-weenie and recycle those things.

[Author]

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