Torellian

I’m experiencing a problem with an inner tube I’ve never had to deal with before. I had a slow leak on the tire facing side of the tube and I patched it. That patch is holding fine and not causing any problems. But after not riding that bike for about a week, I noticed that the tire had suddenly gone flat again. At first, I assumed that the patch had come off, but after taking it all apart and checking the tube, I discovered that there was a new puncture, and it was located on the side of the tube facing the rim. I inspected the rim carefully and couldn’t find any sharp edges.

The puncture is located right above one of the spokes, so I thought maybe a spoke was protruding. That didn’t seem to be the case. I even took it to the bike shop to have them look at it. They couldn’t find the cause either and said it all looked fine. I put a patch on the hole and put it all back together. After about 4 hours, it suddenly went flat again. For some reason, the patch was being pushed from the sides so that the patch formed a wrinkle in the middle, exposing the puncture. I tried the whole thing twice again using larger patches and got the same results. This is getting very frustrating!

The only other thing to try is a new inner tube. But without knowing what caused the puncture in the first place, I’m afraid it will just go to waste if it goes flat right away. After all, I hadn’t ridden the bike for about a week before the tire suddenly went flat. Why would that happen? And why aren’t the patches working? Can they not be used on the rim facing side of the tube for some reason?

bikeman715

Are you sure your rimtape is covering the spokes in the rim ? Is it a deep well rim ?, about the spokes' nipples , any sharp corners ?

blamp28

What type of rim tape?

Retro Grouch 

What kind of rim?

Double wall rims have the spokes recessed into little holes. A rim strip or rim tape covers those holes. Now think what happens if the rim strip migrates a bit to the side and uncovers a portion of a spoke hole. As you inflate your inner tube the air pressure forces the inner tube against the unprotected edge of the spoke hole. Can you say pssssst? That's actually more common than I think should be allowed with brand new bikes.

Ideally the rim strip should completely cover the rim from flange to flange. If it's a little shy of doing that, at least make sure that every tiny little bit of spoke hole arc is completely covered. Velox 17mm rim tape is my personal favorite for the majority of rims.

Steve530

Replace the rim tape. It may not be the problem, but it's cheap and you probably need to replace it anyway.

relyt

Maybe the type of rim tape is to blame. I have the best results with cloth Velox rim tape. Fewer flats than with the plastic stuff which can harden over time.

Torellian

To answer everyone's questions: The rim tape is covering the spokes and is in good condition, according to the bike shop attendant. I don't know if the rim wells are deep, but they are in my own opinion. The spokes don't seem to have any sharp corners.

I don't know what kind of rim tape it is. It was what was installed by the manufacturer when it was made by Specialized.

The bike is a Specialized Hardrock, so it's not one of their high end models, so I doubt that it has double rim walls, although I could be wrong. The bike is a few years old, so it's not totally new. If the rim was the problem, I assume this would have happened back in its first days. As it happened, it went flat at a time when I wasn't even riding it for about a week prior. Just went flat suddenly.

I'm going to put in a new inner tube and see what happens. I've been reluctant to do that until I got some advise considering how expensive tubes have gotten lately. I can't believe their prices have risen so much!

blamp28

Looking here:
https://www.bikepedia.com/quickbike/BikeSpecs.aspx?Year=2006&Brand=Specialized&Model=HardrockSport&Type=bike
I find that the 2006 model year did use Alex HR 26 double walled rims so it would not be a surprise for yours also to use these or similar rims. Often, the factory original rim tape on an entry level bike is just enough to work reasonably well but can be improved upon. The rub is (pun intended) that the pressure of the inflated tube can push on it and allow chafing against the edge of the spoke hole. As suggested above, a high quality Velox tape or similar product can be bought for a few dollars and will prevent this type of interaction. I use the Velox 17mm and am very pleased with it.

Torellian

Interesting! Well, I know exactly where the offending spoke would be if it was the spoke that caused the problem. If I want to be "lazy" and just tape a piece of cloth over that area before installing the new tube, should that work? Or would that cause some other problem?

blamp28

I really doubt it has anything to do with a spoke. It is probably weak tape allowing the tube to push it against the sharp edge of the hole. If your spoke is loos enough to do this damage, you have other problems comming up soon. You could test the theory by putting some good cloth tape over the suspected site but whty waste the time? just put some decent tape over EVERY hole as in rim tape. This will give you a far better chance at not having to repeat the job.

Steve530

I've had tape split at the hole. Barely perceptible. Under pressure, the tube would get a puncture over that hole. I don't know ifn the tube was being cut by the edges of the hole or the tape itself. Anyway, Velox solved that problem.

Maybe you just had a bad tube, but for a few bucks and few minutes, you can be sure it's not the rim tape.

Torellian

Well, I tried something a little out of the ordinary and I'm hoping you can give me your opinion about it. I patched the hole again, but this time I rolled up a small paper towel in the channel of the inside of the rim. It seems that my patches kept coming off before because of the way the tube folded into that channel as it inflated and that made the patch fold and crease, causing it to let the air out. With the channel stuffed with the towel, I finally have had success with the patch since it keeps the tube "flat" at that location! It has kept the same pressure all night long. So now I'm wondering if by stuffing the paper towel into the rim channel, could I be courting disaster when I ride with it that way? I mean, the rim was designed the way it is to probably keep the inner tube in place, right? I only have it stuffed at the location of the patch, not the entire rim.

So what do you all think? Is this safe practice, or will the tube and tire come off while I'm riding?

blamp28

Is there some reason that you will not simply put a new round of rim tape on this thing? I mean really. If you even value your time at minimum wage, you have allready cost yourself more than the cost of a role of tape just messing around with these potential solutions. If you don't really place a value on the answers you get here, why ask?

Torellian

I'm not all that familiar with bike mechanics and am trying to learn how to make improvised fixes. When I first got the puncture, everyone told me, "just buy a new tube". But I like trying to fix things when possible instead of just throwing out what I have and buying more. Patching doesn't take much more time to do and is much less costly. I do value the advice I'm getting here. That's why I'm asking about what you think of the fix I just made and if it's safe. As far as my time goes, I'm not placing a dollar value on it. I'm placing more of a value on what I'm learning by trying new ways of fixing it. If I can come up with a way to patch my tube and do it successfully, then I feel I've accomplished something. But now that I've tried something unconventional that appears to have patched the hole and is allowing the tube to maintain pressure, I'd just like to know if the way I went about it is safe for when I actually ride it.

blamp28

Good answer. I like the desire to learn. First off. The patch should not come off under any circumstances when applied correctly so there should be no need for anything to hold the patch in place. Do you have a photo of the channel you describe? This channel should be covered by a decent rim tape that spans the width of the rim at the bottom. The high quality tape provided by Velox and competitive brands is sold by most bike shops and will last years. I regularly use it on all my bikes and always have extra in my supplies. My road tires are inflated to 120psi for every ride and this tape has kept the tubes from this sort of chafing for many miles. I did patch a tube on the rear a couple of weeks ago and again, nothing other than the glue and patch itself are needed to keep it on. So my answer is that while your unconventional approach with this paper towel may help, it is only temporary and the repeated aggravation, or the avoidance of it, is worth the effort and a few dollars to do the job right.

I prefer to be on my bike rather than working on them so I place a very high value on doing things once and that means the right tools, parts and approach. You can learn about all of them here and the faster you do, the more time you will be able to spend enjoying the bike(s)

Torellian

I'm not at home so I can't take a picture of the "channel" in the rim I'm talking about. I don't even know if channel is the right word, but I'm referring to the space in the interior of the rim where the tube inflates into. It's not like a "U" shape, so I thought maybe the patch was getting gripped against the side and slid over a bit as the tire inflated. That's what it looked like by looking at the patch and how you can see where the adhesive was originally, and how the patch was wrinkled up in the middle. Here's a web picture of the shape of the "channel" inside my rim: https://rpmedia.ask.com/ts?u=/wikiped...agrams_03_.png

The lowest part of this is what I rolled up a paper towel into (about 2" length where the patch would be over) to keep the tube from inflating in deeper and causing the tube to "pucker" where the patch is on the tube, which seemed to be what made the patch flex and shift as the tube inflated. In other words, the tube would now be flat against the paper towel in there rather than puckering up into an "A" shape with a flattened top. (It's so hard to use words to draw a picture!)

I guess what I'm just trying to do now is see if I can patch this tube and make it work. As for getting new rim tape to possibly prevent another puncture--I guess that's something I'll do if I get another flat and discover that it was caused at the same point as this previous puncture. But now that I have the tube patched and reinflated and it's all back together again, my present concern is whether the type of fix I did could cause the tube to come off the rim while I'm riding since the tube is not seated as deeply into the rim because of the paper towel being in there at that one spot.

BTW, I have 2 other bikes, so I'm not being deprived of riding enjoyment. The bike we're talking about right now is the one I use for rainy/Winter conditions. (I still manage to keep it in good shape).

Retro Grouch 

"According to the bike shop attendant" Do yourself a favor, take off your tire and take a look for yourself. All that it takes is the tiniest little arc of unprotected spoke hole to cause your inner tubes to puncture repeatedly.

Torellian

I did that. In fact, the tire was off the majority of the time and I took it off 7 times to make another attempt at patching the tube. It looked fine to me. The reason I said, "According to the bike shop attendant" is to indicate that I got the advice of an expert rather than relying on my own opinion. I'm not as familiar with the way it should look as the guys at the bike shop are.

qmsdc15

Torelli, I have successfully patched many, many inner tubes in my 20+ years as a bicycle courier, but never, ever have got a patch to stay airtight on the concave surface of the tube. Nearly 100% success on the outer convex surface, 0% on the inside of the tube. Good luck, but I don't believe it can be done.

Torellian

Well then I'm happy to report that I may have had success with it and would love to share with you how I did it. It has been holding for 2 days so far at 42psi, but I haven't ridden on it yet. Here's what I did.

I applied super glue directly to the hole, then put 3 layers of duct tape over it, then overlayed that with masking tape (it's more slippery than duct tape. It appeared at the time the grippiness of the duct tape was causing the problem, but not sure). Before putting it all back together, I inlaid a rolled up paper towel into the channel of the rim to keep the tube from puckering too much into it. It appeared from my past experience that the "puckering" of the tube into that channel is what caused the patch to come off before. The paper towel in there now seems to keep the tube more flat.

If you want to try this, I hope it works for you. It gives me pride to have success at something and to be able to share it with others like this!

Also, once I start riding on it, I'll let you know if it comes apart. You might want to wait until I have success or failure before trying it.

davidad

The best material for the rim side of the tube is Velox rim tape. Put it on, forget about it. If you put paper inside the tire it will be turned into confetti by the fretting motion of the tire to the tube.

Torellian

I know. But protecting the tube from the spoke ends isn't what the paper towel is there for. I only put it there to not allow the tube to form into the deeper part of the rim and make the patch come off. I suppose a piece of cloth could be used instead. I was getting frustrated with the whole experience and just grabbed whatever happened to be nearby. Next time, I think I'd use a rolled up piece of cloth instead of paper towel.

blamp28

I just patched a tube in the same place two weeks ago - the inside convex surface - as I have many times before. This tube is inflted to 120psi with not trouble whatsoever in the first 200 miles or so. It's a matter or using good patches, doing the job right, and in this case making darn sure that you have good solid rim tape in place. If I had taken a tire off seven times to finally get it right, I would be pulling my hair out. Thats a lot of work to save $5. That was kind of my point earlier.

curbtender

I'm not sure if you stated what kind of rim tape you had? That vinyl junk will suck down to the spoke.

qmsdc15

200 miles? Exactly my point. Patch on inside surface will not hold for long.