View Full Version : Help: Repeat Flats, same position on the tube
kppolich
04-08-2017, 07:20 PM
Rims: Stans Alpha 340 with standard tape that comes on them.
Tubes:Vittora Latex 700x25/28
Tires: Challenge Almanzo
PSI: 50psi
So about every 3 days I notice tire is flat and today I was looking at my wheel before I went out for a long ride and all of a sudden. PSHHHHHH. it went flat. First I thought, man! what powerful eyes I have. Then i was like, crap.... what the hell is going on. So i yanked the tube out. Same story, different tube. I've used latex and butyl and the flats keep happening in the same spot.
Near the value stem but outside of the black part that is built up there is a 2mm slit that leaks air quickly.
Could this be the tape? or the stem pushing through the hole on the rim?
dustyrider
04-08-2017, 07:26 PM
Sounds like you line up your tire labels to the valve stem and you've checked all the surfaces. Bulk tube purchase? Maybe a bad batch...
kppolich
04-08-2017, 07:40 PM
1st tube was the 25/28mm
2nd tube was from a different order and was the 19/24mm
dustyrider
04-08-2017, 07:47 PM
Can you take a picture of where the leak is happening on the tube? When I read your description, it makes me think the valve stem hole is cutting the tube around the valve stem.
Matthew
04-08-2017, 07:47 PM
How long have you had the wheel? Maybe a burr or something sharp on the rims surface not covered by the tape? Rim tape hole a bit too large allowing the sharp edges of the hole to rub the tube?
kppolich
04-08-2017, 07:51 PM
Can you take a picture of where the leak is happening on the tube? When I read your description, it makes me think the valve stem hole is cutting the tube around the valve stem.
can have a picture tomorrow. the rim "tape" is the stock synthetic stuff but I haven't had trouble with the front.
kppolich
04-08-2017, 07:52 PM
How long have you had the wheel? Maybe a burr or something sharp on the rims surface not covered by the tape? Rim tape hole a bit too large allowing the sharp edges of the hole to rub the tube?
I've had the wheel for a year or so. Raced a season of cross on it and a bunch of gravel. 2 flats now in less than a week has me looking for answers.
thwart
04-08-2017, 07:53 PM
Sharp edge at/near valve hole? This has happened to someone I know. Smoothing the edge a bit with a rat tail file, and using cloth rim tape (Velox) in the area worked.
kppolich
04-08-2017, 07:55 PM
Can you take a picture of where the leak is happening on the tube? When I read your description, it makes me think the valve stem hole is cutting the tube around the valve stem.
slit has happened near where the joint is, in the circled area here:
https://c1.staticflickr.com/3/2887/33880324886_bbfdf192c4_b.jpg
dustyrider
04-08-2017, 07:59 PM
Are the rims setup with tubeless tape or the plastic rimstrips? The latter can create extremely sharp edges at hardened creases. But you should feel something like that immediately. Since all the tubes have split along that mold seam, I'd tend to think it's the tube.
kppolich
04-08-2017, 08:05 PM
Are the rims setup with tubeless tape or the plastic rimstrips? The latter can create extremely sharp edges at hardened creases. But you should feel something like that immediately. Since all the tubes have split along that mold seam, I'd tend to think it's the tube.
Mine have the plastic rim strips. Just order some 16mm velox cloth tape and I'll try that without using the value hole i'll just poke a small hole through the tape to see if that helps from the edges possibly causing the puncture. I've briefly inspected the value hole and I couldn't feel anything out of the ordinary.
biker72
04-08-2017, 08:24 PM
I've had pretty good luck using a 3"-4" strip of electrical tape across the suspect area.
I was going to recommend lowering the air pressure but I see you're already at 50 psi. That shouldn't be the problem.
Mine have the plastic rim strips. Just order some 16mm velox cloth tape and I'll try that without using the value hole i'll just poke a small hole through the tape to see if that helps from the edges possibly causing the puncture. I've briefly inspected the value hole and I couldn't feel anything out of the ordinary.
You can actually create more of an issue if the hole is blocked just a bit and the valve stem doesn't want to settle down properly.
I didn't see that you indicated where the hole was around the circumference of the tire. Is it actually on the inside?
kppolich
04-08-2017, 08:57 PM
You can actually create more of an issue if the hole is blocked just a bit and the valve stem doesn't want to settle down properly.
I didn't see that you indicated where the hole was around the circumference of the tire. Is it actually on the inside?
hole is on the inside "Rim Side" and not the tire side each time. super annoying but I'll just patch these tubes for now.
For what it's worth, I've had runs like that as well. My most recent one was with HED Belgium rims, equipped with Challenge Strada Bianca tires. I went through four butyl tires, three Challenge latex tires, and even after changing tire sizes i had problems. I switched to other wheels. Six months later I pulled those same wheels out, threw on the same tires and tubes, and never had a problem. There's something basically unfair in the universe.
cmbicycles
04-08-2017, 09:37 PM
I had a run of valve stems pulling out of the tube, right where the two attach. It's like the glue just didn't hold on half the diameter of the valve stem. They would kind of hold air when sitting, but woukd leak when id air up tires before riding. Multiple brands of tube, smooth or threaded stem, happened 4-5 times over a month or two. I attribute it to my specialized pump, as since I've been using my compressor and older joe blow pump I have had no issues.
Tandem Rider
04-08-2017, 09:38 PM
hole is on the inside "Rim Side" and not the tire side each time. super annoying but I'll just patch these tubes for now.
Well, if it's rim side, then it's either something on the rim, rim tape, or bad tubes. I would try a new rim tape first. Personally, I would pay the price of new rim tape to NOT be fixing a flat in 50 deg rain on Tri County Bridge Road sometime, DAMHIKT.
ripvanrando
04-09-2017, 07:22 AM
Rims: Stans Alpha 340 with standard tape that comes on them.
Tubes:Vittora Latex 700x25/28
Tires: Challenge Almanzo
PSI: 50psi
So about every 3 days I notice tire is flat and today I was looking at my wheel before I went out for a long ride and all of a sudden. PSHHHHHH. it went flat. First I thought, man! what powerful eyes I have. Then i was like, crap.... what the hell is going on. So i yanked the tube out. Same story, different tube. I've used latex and butyl and the flats keep happening in the same spot.
Near the value stem but outside of the black part that is built up there is a 2mm slit that leaks air quickly.
Could this be the tape? or the stem pushing through the hole on the rim?
Its the tape.
Tube is punctured but the rim nipple hole. My guess. I went thru this with latex tubes. Two layers of Scotch strapping tape and you should be good
kppolich
04-09-2017, 09:27 AM
Thanks all, have some 16mm Velox on the way, Might put some strapping tape around the problem area to double down.
Velox hasn't always been that useful for me. I've found Stans and with a couple very thin layers, it works really well.
MikeD
04-14-2017, 01:39 PM
I wouldn't use any type of plastic tape as a rimstrip, unless you have disc brakes. I have had plastic rim strips melt and the tube blow through a spoke hole. Velox worked best for me.
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