Unpatchable hole on rim side

Question

Well, I am new to road biking and I got my first flat yesterday. I was going to go for a ride and the front tire was completely flat, so I popped it off and went to patch it. I found the hole, it was on the rim-side, and I noticed that the rim tape had slipped off a little and the spoke hole was slightly exposed, so I pushed the tape back to position, patched the hole, and pumped the tire back up.

As I was pumping it up the patch blew out. So I went back and tried to stick another patch on, and it blew out too. I ended up going through about six patches before I got one that 'worked.' I let it sit a couple hours and it was holding pressure just fine. After about 4 hours I was going to go for a bike ride and it was completely flat again.

I took the tube off again and there was a wrinkle that formed in the patch where the air is coming out. I checked the rim tape and it was fine, none of the spoke hole where sticking out. My current theory is that the tube is conforming to the shape of the rim on the inside, right where the patch is, and forcing the patch to wrinkle and inevitably blow out.

I am completely at a loss as to what to do here. I've patched tires on my mountain bikes many times and have never had this much trouble. I don't want to get a new tube, I have only like 60 miles on this tube. Should I just try slapping another patch over this patch's wrinkle and hope for the best or should I just start from scratch with a new tube and rim tape?

Thanks.

Answer 1

I'm not sure why this question needed four paragraphs to explain, but I'll indulge it. However, I want to point out that the most effective decision is whatever results in a reliable tube using the least amount of time, money, and effort to accomplish. That should be obvious and not need to be pointed out.

That said, I would personally buy a new tube and rim tape. I might even buy a new tire while I'm at it. If a tube keeps going flat, there are only two or three possible explanations.

1. The patch isn't taking
2. The rim or something in the tire (e.g. small, short piece of metal) keeps puncturing the tube
3. The tire is worn through/weak in a specific area

There is a certain level of convenience in patching a tube. If you're having to patch the same spot on a tube multiple times or keep getting multiple flats on the same tube in a day, or even a week, is it really worth your time to diagnose when you can spend ~$5 on a new tube and rule possibility out (unless you're extremely unlucky and get a defective tube, which has happened to me once)?

If you feel it is really worth your time, you can rule out the first potential cause by pumping up the patched tube outside of the tire, and putting it in a tub full of water. Watch for air bubbles.

You can try ruling out the second by running your finger through the rim and through the inside of the tire, but BE CAREFUL! You can slice your finger open if there's something sharp and big enough poking through.

The latter is something you can only determine through visual inspection. I know one of the most confounding flats I've ever had was caused by a small cut in the tire, big enough for the inflated tube to poke out of, embolize, and eventually blow out.

Answer 2

While I dont like the throw away and not repair philosophy these days, I would say that 6 patches are more expensive than a new tube. Mine, at 1.50 euro the piece, are not best quality but have been enough for thousands of kilometers. As for patching, I believe that if you patch properly no spoke should move the patch. In any case,the hole should not be unpatchable unless very big. And what about flipping the tube to avoid contact of the spoke and patch, or is it just in the opposite side of the valve? Lastly, I 've found that when patching, leaving the paste solution to dry for some 20 seconds longer than the typical recommended minute helps the patch stick and not move.

Answer 3

I always swap out the tube and do my patching at home when I'm out of spare tubes (stock up if you see them on offer). This is partly to stop the glue going off in the tube, but it means that when I do patch it's easy to do it perfectly and not rush.

My recipe: The tube is dry and slightly roughened, plenty of glue, let it go tacky (if I'm rushing I can never get a patch to take), then patch. Just enough air to get the tube to take shape and a bit more glue smeared round the edge. Then leave the tube while you do something else. It will need some chalk when you come back to it.

I've never got on with glueless patches though some people here love them. It always seems impossible to get the backing off in one go, unless it's falling off when the patch doesn't stick to the tube.

The only time I've had trouble with wrinkles forming is if I've patched over the seam in the tube. Extra glue helps then,but it takes ages with no pressure to dry.

Answer 4

1. If you can push the rim tape aside, I'm guessing it's that rubbery strip typically installed by the factory. You might consider getting better rim tape, which will have an adhesive backing and cannot be pushed aside.
2. If multiple patches are not sticking, is it possible you aren't applying them correctly? The innertube has mold-release compound on it that needs to be removed first, either by washing with soap or abrading off with the tiny path of sandpaper typically included in patch kits. Clean the patch area first, apply the vulcanizing agent, let it get tacky, then apply the patch. The patched area of the exposed tube may not hold much pressure right away, but if you've done a decent patch job, reinstall the tube in the tire—the tube + tire will hold pressure.

Answer 5

I had this happen one time on a stint down the coast. Six flats. All rim-side. Lovely. I've already seen some good solutions above, but I'll throw in my two-cents just for clarity's sake.

First, it's probably not the patch but the tube getting re-punctured/stressed in the same place - the patch just happens to be there, so I would (as someone above suggested) switch out rim-tape (that being said, try using a new tire just to take that variable out of play). Also, run your finger inside the rim to see if there are any sharp pieces sticking out either on the side or from the spoke hole. You may need to use a file to smooth them out or remove them. You didn't describe the puncture, and it may have been caused by the spoke-hole, or it could have been something else. It's worth taking a closer look - if it's a length-wise cut, rather than a puncture, the rims are biting into the tire, and the rim-strip should fix the problem - as long as it's wide enough. Also, when you see the rim tape sliding around, you have to ask 'why?'. You may have been riding on underinflated tires, or had a small collision with a curb which created the stress that caused the flat.

Answer 6

In the comments you mention that the spokes "they are all recessed quite a bit because of the rim design".

Usually the inflated tube squeezes the patch against the wheels, so even if vulcanization of the patch is not perfect while you seat the tube and the wheel, the patch is hold in place by air pressure.

In your case, instead, there is the double effect of the patch sitting on the inside of the tube, with the rim/rim tape design being nowhere close to hold in place the patch.

I see two options:

• patch the tube at home, letting it dry with a rather heavy weight on top of it, to be sure it is adhering and the vulcanization process is complete;
• cut a small section of an old tube, with a "C" shape, then use it to cover the patch on the rim and close it on the opposite side (possibly gluing them, or using another patch to close the C.

All these options are to be done considering the tube is some special tube, with a value/remaining value of more than 20$/EUR/GBP: with 6 patches you are already heavily in "sunk cost" regime ... giving up may save you some money :) !

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