I have a mountain bike using regular 26" tires. Lately, I got a very slow leak that was causing it to lose about 6Lbs. of pressure per day. Finally, I decided to put a patch on the tube after locating the tiny leak. Well, now there's a bulge on one side of the tire that's only visible when it's inflated. The bead looks like it's starting to come off the rim. The bulge brushes past one of the break pads while I ride.

I don't know if the bulge is something caused by the inner tube or not, as I haven't taken it all apart again (I hate to do that again). But can someone please advise me what would cause this. Is it likely due to the patch I put on? It's one of those "slime" brand ones from Walmart that self-stick. I'm not losing pressure anymore, so that means it's doing its job, but could that also be a reason for the bulge?

It could just be you didn't seat the bead properly, the tube will inflate as much as it can and will squeeze out the crack.. deflate the tire and make sure the tire bead is not stripping off and reseat it (You should not need to remove the tire). The way I do it is to inflate the tube just a little to give the tire some shape then make sure all the beads are locked in place.

Also make sure you have not caught the tube in between the rim and the tire. Don't ride it till you fix it, it could explode and give you a heart attack!

What Aquakitty said.

Then next time you have to reinstall a tube/tire, make sure you just partially inflate the tire,then stop and check that the bead is seated all the way around on both sides. When you are sure it is okay, then finish pumping up the tire. This will keep you from blowing out a tube that pokes out.

I forgot to mention this, but I already took it to a gas station (for the air compressor there) and deflated the tire as much as I could, and then used a screwdriver to push in on the tire near the rim where the bulge was, but when the tire was deflated, the tire seemed to be on the rim just fine. I pushed on it anyway to make sure and didn't appear to be making any difference, so I reinflated it again and the bulge came back just like before.

I actually have been riding the bike and hope I'm not doing any damage. When riding on a smooth surface, I can feel a slight bump everytime the bulge makes contact with the ground as the tire spins. Tonight, I'll deflate again and give it another try. I only have a foot pump at home, so it's a pain to reinflate from scratch, but I guess I'll have to do that.

Is there any chance that my patch caused a problem? Those patches from Walmart were super-cheap, but seemed awfully sticky, giving me confidence that it'll stay stuck on the tire.

How old is that tire?

Maybe 4 years. It doesn't get hard use. I use it on the road, and usually within a mile from home.

It's possible the patch is pulling on the tube and creating a flat spot, I would just buy a new tube if concerned. Is the tube 4 years old as well?

You can usually see visually if it is a tire bead issue



there are marks on the tire walls to show what should be inside the rim. Just make sure the bead is not peeling off and the tire is not worn. A pic might help as well

Unable to provide a pic right now as I'm not home. The tube is the same age as the tire. What concerns me most is that this problem online popped up after I repaired the tiny puncture with a patch and put everything back together. Makes me think it was some mistake that I made rather than something wearing out.

My bet is that you have pinched the inner tube under the tire bead. That's fairly common. When that happens, the inner tube pushes the tire bead upward in that area. If it gets bad enough the inner tube will have an anurism and will blow out.

The solution is to completely deflate the tire so you can push the tire bead inward in the area that was bulged. If you can see the inner tube, work it into the tire caseing and reinflate. If I'm right, that'll fix it.

Get a floor pump, air compressors tend to inflate too fast. Bead not seated evenly.

Don't use a screwdriver on tires or tubes.

I went ahead and delated it and pried up the bead where the bulge was to see if that's where my patch job was underneath on the innertube. It wasn't. I reseated the bead back the best I could and reinflated. No more bulge! I don't know what I did differently this time, but I guess it's ok now, accept that even though I tried to make sure the valve stem was straight when when I adjusted everything, it is slightly crooked. Will that cause any problems now? I really don't want to have to deflate and do another adjustment if I don't have to.

If the angle is too extreme, it could tear the inner tube.

Remove the wheel from the bike.
Deflate it fully (but do not take the tire off.)
Place the wheel on the ground with the valve stem at the very bottom (pointing up).
Observe which way the valve stem is leaning.
Gently roll the tire for exactly one revolution in the direction that the leaning stem points.
If the stem is still leaning the same way, roll another revolution but push down slightly.
If the stem is leaning the other direction, roll the other way but push down less.
Once the stem is vertical, inflate, reinstall, and ride!

Currently, instead of being at a 90 degree angle to the rim, it's between that and 45 degrees. Is that too much?

Out of curiosity, did you happen to notice if the bulge was right on the valve? Sometimes the base of the valve won't slip up between the beads properly and thus create a nasty bulge that's easily fixable. Illustrated here (with a moto cross bike, though). I've had this issue with a couple of inner tubes.

Nope. It wasn't.

There's no reason to not have it at 90 degrees.

We don’t normally work on the bike ourselves but it’s a long weekend and we wanted to ride. The tire was low yesterday and we added more air but within the maximum PSI listed on the tire. We went on a short ride yesterday with no problems. This morning we heard a unusual noise and noticed that the tire was bulging making it look more like a snake on the part of the tire that hits the pavement. It appears fine next to the rim. We let some air out but it still has a bulge although not as pronounced. Any suggestions?

IF the bead was seated properly AND the tire didn't go flat, the cords have failed and you need a new tire.

Note you are resurrecting a 9+ year old post-

Thank you!