ewelljer

Not sure if this is where to post this at as I am new to the forum thing. I have been on a weight loss journey and was at 353#s and now at 300#s. I have tried to start riding bikes for cardio since it is easier on my knees but every time I ride my tube blows out. I have tried 3 standard tubes, one slime tube and one presta tube and they all blew. I have a 700x32 tire and the tire is rated at 65psi so I ordered new Maxxis Columbiere 700x32c/100psi tires and put a new standard tube in it also. Before I installed it I looked and felt all around the rim for anything but could not find any rough areas. This tire blew over night and didn't even ride it. This bike is not a high quality but it is a brand new Kent road bike. Thanks for you help.

DiabloScott

When you say "blow" you mean it actually popped and the tire is off the rim? Or does it just go flat? What is the condition of the tube afterwards?

berner

I've had several tube failures near the stem when my bike was newish. After the second failure, I inspected the rim carefully and found the drilled holes for the stem had very sharp edges. I used 120 grit sandpaper to chamfer those edges and the problem disappeared. This is easy to check but you need to remove the tire, tube and rim tape.

cny-bikeman

Most failures are due to incorrect mounting - usually a portion of tube underneath the tire bead. You need to inspect all around the tire as you are inflating (after about 40lbs, and every 10 lbs or so after. There is typically a raised ridge/line of rubber near the rim edge, which I call a bead line. It should be an equal distance away from the rim at all points. If you find a spot where it is further away deflate the tire and look for a problem at that point. It is unlikely but possible that the tire is defective.

ewelljer

No it has not blown off the rim but the tube pops and it usually has a hole in it about and 1/8" long on the rim side right on the center of the tube so I figured a spoke maybe I marked the orientation to check the rim but I can't seem to feel any sharp edges.

ewelljer

Do I need a special type tube for this or is a standard valve ok for this pressure?

DiabloScott

If all your tubes have the same hole in the same place - you've got a rim problem.

Try wiping the area with a cotton ball to see if you can find a snag.

If all your tubes have holes in different places, you're either very unlucky or you're installing improperly.


No need for any kind of special tube; Schrader valves are not your problem. Get the cheapest ones you can find at least until you figure this out. And learn how to patch.

ewelljer

Thanks I will try this

dabac

Tubes and valves have no objection to any realistically achieved pressure - as long as they are appropriately contained.
Meaning no rim defects, correct installation etc.
Tires - and sometimes rims - will have a max pressure rating.
Production flaws in tubes do happen, but they are rare.
If you replace your own tubes its quite easy to diagnose.
Cut tube apart, at damage and some other places. Check rubber thickness. If visibly different, there's your problem.
Not a likely candidate for your issue, since you've tried different tubes.
I'd suspect a rim/rim strip issue. Rim strips have been known to squirm and expose enough of a spoke hole to let the tube fail there.

Carbonfiberboy 

I'll assume that when you remove the tire and take out the blown tube, it has a long rent in it. True? If this is the case, there are really only three causes:

1) You damaged the tube with a tire lever when you installed the tire. The solution is to partially inflate the tube, just enough so that it's round before you install it. Tighten the Presta valve. Put the 1st tire bead back on the rim, insert the valve into the valve hole, then work the round tube back into the tire and into the hollow in the center of them. When done, the tube should be completely invisible, hidden by the 2nd tire bead. Then push the valve up and put the 2nd tire bead over the rim where the valve is. Then, working with your thumbs, push the rest of the bead over the rim. When you get to the last bit and can't get anymore bead over the rim with your thumbs, with the valve toward you, place your right thumb on the tire and while pushing down hard, drag your thumb up to where the tire isn't over the rim yet. Doing thing drags some more tire up to where you need it. Then work a little more tire over the edge. Repeat with the left thumb and so on until it pops over the rim. Doing this without levers prevents the lever from damaging the tube, which is another big reason tubes blow shortly after installation.

2) When you installed the tire, you trapped a bit of the tube under the tire bead. When you inflate the tube, this section of it eventually works it's way up and pushed the tire bead up and over the rim and . . . BLAM. See installation procedure under #1.

3) The tire and rim aren't of the same type. Older rims are smooth on the inside. Modern rims are "hooked", and have a raised bead at the top of the brake track. Older tires have a smooth bead. Modern tires are also "hooked", having a raised bit on the outside of each edge of the tire. A cross section of a hooked rim and tire:

wphamilton

Possibly the rim tape. The cloth type works better than the thin rubber one that comes with some wheels.

Wheever

Yeah, OP, Check that the rim tape is correctly installed. (Or that there even IS rim tape.) It looks something like THIS (Just a random pic.)

andr0id

This is the next thing I'd be checking replacing.

79pmooney

You say you have tried both "standard" tubes and Presta. So your rims are drilled for those big "standard" (Schraeder) valves? If so, using Prestas will give you problems in the form of flats right at the valve stem where it is impossible to repair them. A thin washer over the Presta valve to cover the hole will improve the odds, but that is still not ideal.

I am a big fan of Presta, but they do need the smaller valve holes. I bet that thin washer and a nice, neat piece of tent repair tape or the like cut in a larger circle with a neat valve sized hole over the washer would make a good "permanent" repair though I haven't tried it.

One of the posters above talks of putting some air in the tube before inserting into the tire. If you are using Presta, getting the right amount is easy. Inflate the tube by mouth. Hard. The perfect level of air. Easy. Fast. I learned this from a pro.

Ben

noglider 

Are you getting one hole in the tube or two? If two, we call that a snake bite puncture, and it comes from pinching the tube between the rim and a road obstacle. If this is happening, you need to add more pressure to the tire. You can overinflate your tires above the rating safely, and you probably should, too.

Jon T

You shouldn't need to use a tool to remount the tire. Tools are for unmounting tires.
Jon

maddog34

EXCELLENT POST! i agree completely...

1: i also, after getting the tire on the rim, inflate the tube to about 10 lbs., then grab the tire, and first push, then pull, the tire to makecertain no tube wall is trapped under the bead of the tire...

2: this can also cause the bead to pinch the tube and cause a failure similar to the OP's... see #1 to prevent this, ewelljer.

3: The Kent bikes have modern, standard beads on the rims/tires they install at the factory.... like in the diagram in your post.... and Kent bikes tend to have multiple issues, "Brand new"... very low quality control at the factory NEEDS to be changed. i've seen extremely tight or loose axle bearing settings, cables bent during installation, brake pads that nearly fall of, poor shifting, etc.... and then, there is that Kent chain thread... i've replaced about 5 "brand new" chains on Kents... they were "worn out" before installation... and the scrapper just hauled away a 7 speed freewheel from a Kent that was so worn after about 50 miles that the bike was jumping teeth already... the cog material was never hardened, from the looks of things.... nice even impact flare burrs on the teeth... that was Kent's fault for penny pinching, i'd think.

maddog34

yes, but not everyone knows what we do.

and rims/tires vary some between different manufacturers, eh? valley depth and nipple band thickness plays into this...

the Kent rims/tires are loose enough, that's for sure... a quick wiggle after unseating both beads all the way around, and they can be easily removed.... if you've done hundreds of tire swaps.

ewelljer

Thanks for all the input I will update with status

ewelljer

Thanks for all the input I will update with status

cny-bikeman

When you update, if you have not resolved the issue we need the following info:
1. Are you sure there is only a single puncture each time, and do they all look similar?
2. Is the puncture always the same distance from the valve stem and next to the rim (if not give details)?
3. Are you using a tire lever (or worse, a screwdriver) to remount the tire?
4. Do you know what the original puncture looked like and where it was on the tube? (presumably you had a flat that caused the 1st replacement)
4. Are you using a gauge to make sure you have proper tire pressure?

ewelljer

Thanks I got it. When I removed the rim tape there was several jagged holes from the spoke holes and especially the valve stem. I sanded the rim down good and replaced the tape. Rode the bike and tire is good. Thanks