Rear inner tube valve failure at speed

[sdcr]

   First off, I feel very fortunate to have survived this with myself and the bike unscathed.

   Last Saturday, heading west on Rt, 78 near Clinton NJ, my rear tire rapidly deflated, in about 10 seconds. I was able slow the bike down and control the wobble, and get to the shoulder. Trailered it home, and discovered that the valve core was not holding air. Took the tire back to the  Multi brand dealer in Montgomery county Pa, where the tire and tube where purchased and installed 11 months ago. They researched the original install, and said the tube was a Bikemaster brand. The only markings on the failed tube are a size number, 375/400/425-18 and M11 under the size. I do not see any manufacture name. They put in a different brand( STI) and chalked the incident up to " using high pressure air machines, �r the tire hit a bump, to cause the failure" .

   In 40+ years and over 500,000 miles of riding, I've never seen, nor heard of something like this.

  Again, I am feeling lucky that this did not turn out worse than a tow and buying a new tube.

[yogidozer]

If I am understanding you correctly, the valve stem was bad? Was there a cap on the valve stem, if so, I don't see how it could deflate that fast?
Or was it where the valve attaches to the tube, more likely to lose air quickly. Never seen that, but could be a manufacturing defect, or damaged sometime over a years time

[yogidozer]

picture popped up when I reloaded the post. Looks like the stem detached from the tube

[sdcr]

picture popped up when I reloaded the post. Looks like the stem detached from the tube

    To answer your question, yes, it had a cap on it.

   The motorcycle shop tech cut the entire stem off for some reason.

    The failure, as it was explained to me, was internally in the core, the valve itself. They could not say whether the threads gave way, or the o ring failed, etc.  Just that the valve failed.

[Mike Tashjian]

Did you check your air pressure before you rode?  I know many people do not. I have experienced that type of failure on my old dirt bikes when the tires are running low air pressures and the rim locks fail to keep the tire from moving.  Another scenerio is that the tube was not put in correctly and it finally failed.  High pressure air machine sounds rediculous.  Mike

[Groover]

That's scary stuff. Glad you are OK.

[Wayne Orwig]

Been there, done that, on dirt bikes. At the lower pressure, the tire slips on the rim and rips the valve stem out. That is why rim locks are/where popular.

I would suspect you had low air pressure, maybe a slow leak, and the tire slipped on the rim. The shop also may have used a tire lube that didn't evaporate and the tire rim may have still been slick.

[Antietam Classic Cycle]

IMO, that size tube (375/400/425) is a bit undersize for the rear. Could have been a factor in the failure.

[Triple Jim]

Been there, done that, on dirt bikes. At the lower pressure, the tire slips on the rim and rips the valve stem out. That is why rim locks are/where popular.

John said that the failure was in the valve core, and the photo shows the valve stem after it was intentionally cut off the rest of the tube.

I'm still confused about how a failure of the valve core could cause a deflation if there was a valve cap in place.

[Groover]

I think sdcr said a valve failure, not the actual tube. Anyway, I think Michelins are the only tubes to use IMO.

[Antietam Classic Cycle]

I think sdcr said a valve failure, not the actual tube. Anyway, I think Michelins are the only tubes to use IMO.

IRC tubes are also excellent quality, wider selection of sizes, cost less. Made in Japan.

[Penderic]

Does not look like they "cut" the stem off to me. More like someone ripped it out. Or maybe it was half off when they pulled the tube out when removing the tire.

I just installed a new tube and front tire, a couple of days ago, on my V7Classic. I was never sure about those inner tube valve stem nuts.

Why are there two nuts provided on the valve stem of a new tube taken out of the box? I usually see just one used.

Checking it out, I found out that the cupped washer goes on the inside and the two stem nuts ARE used together, on the outside, to lock up against the rim, under a slight compression.

I turned the first stem nut up against the rim, a little more than finger tight.

The idea is to avoid squeezing the rubber too tight between the stem's wide bottom flange and the cupped washer.


VIP road service.

[rodekyll]

It could surely have been worse.  I don't see how 'using high pressure air machines' relates.  Did the guy explain how the high pressure machine messed up the valve threads?  Was English his first language?  How high does the pressure have to be to blow the air out through the sealed cap in 10sec?  It sounds like a phrase you'd randomly assemble on the refrigerator door. 

If pressure was a factor, I'd go with the comment about LOW pressure -- tire slipping on the rim due to low pressure/bad locks/inappropriate assembly lube shears the valve.  I'm more inclined to suspect a mechanic got a rattle gun for his birthday and used it to install your tire valve.  That would be 'using high pressure air machine'.

[Wayne Orwig]

I think sdcr said a valve failure, not the actual tube. Anyway, I think Michelins are the only tubes to use IMO.

Doesn't matter if the valve fails. The CAP is the primary air seal so the CAP would have prevented any air loss while under way. So the air loss must have been the valve stem ripped out of the rubber, as the picture shows.

[John A]

I also think the stem must have torn, unless the valve was improperly installed but with a cap on it shouldn't have rapidly deflated. in '78 I was going over the bridge from Marysville to Yuba city on a '71 Ambassador with a guy nearly my size on the back when the rear deflated suddenly. I kept it upright and we spent the rest of that Sunday repairing a damaged tube so we could get back to base. since then I've taken better care of my tires and mount them myself. 

[sdcr]

IMO, that size tube (375/400/425) is a bit undersize for the rear. Could have been a factor in the failure.

Charlie,

  I had not considered this. The factory tire size is 110/90-18, which is what I have on the bike. I hope that they would know enough to install the correct tube size.

   Regarding some of the other comments, I honestly don't know exactly how long the tire took to deflate, as I had my focus  on other matters at that time, like getting my Le Mans onto the shoulder of a busy highway. It did seem like a very quick deflation, in retrospect.

   Additionaly re examining the valve core, it does not show any" cut" marks. At the separation area, it is jagged, as if it was torn off.

    I specifically told the service writer that I wanted the " tube" back. When they got the tire done, he handed me the stem, saying that the tech had cut it off. I had him retrieve the tube as well as my metal cap that had been replaced with a rubber one.

    I don't want to denigrate this store, but my confidence in their abilities, as well as their candor is slipping. I have been a regular parts and service customer for many, many years there. I am disappointed in the way this was handled, but at the same time realize that the situation could have been much worse.

[rodekyll]

I think the stem was torn and they handed it back to you that way with that completely lame analysis in a CYA attempt.  The story smacks of improper installation.

[atavar]

I agree, their explanation was just to get you to pay for the tube and labor when they should have covered it.

[Triple Jim]

I think some of the confusion in this thread is due to mixing up of the terms "valve stem" and "valve core".

[sdcr]

I agree, their explanation was just to get you to pay for the tube and labor when they should have covered it.

    Not trying to beat a dead horse here, but the cost of the tube and labor isn't as important, as whether they were trying to cover up either a defective tube, or a poor installation. If they would have given me a more plausible explanation for this failure, such as I have go heard on this thread, I would have accepted that. As it is, my confidence in this company is gone.

   I have decided to find another shop to reinstall another, name brand, correct size tube in the rim.

[pat80flh]

It would be hard for me to blame a bad install 11 months after the fact.

[Fuzzy]

They overtightened the nut. Took a while, but it is bound to fail, quicker if the washer is not installed, as per Penderic. It is a weak spot on bicycle tubes as well and have to handled carefully.

[pete roper]

Umm? Why do people insist on tightening the valve stem nut against the rim?

The nut should be used as a lock nut for the cap, not against the rim. If the nut is used to clamp the stem in the rim you won't see it begin to cant over if the tyre starts to 'Creep' on the rim and the first you'll know about it is when the valve stem rips out of the tube as I suspect occurred here.

Pete

[Antietam Classic Cycle]

Umm? Why do people insist on tightening the valve stem nut against the rim?

The nut should be used as a lock nut for the cap, not against the rim. If the nut is used to clamp the stem in the rim you won't see it begin to cant over if the tyre starts to 'Creep' on the rim and the first you'll know about it is when the valve stem rips out of the tube as I suspect occurred here.

Pete

As tightly as the stem fits into the hole of the Guzzi cast rims, there's little chance of the stem "canting". It's well supported for 75% of it's length. It would be different if it was a Borrani spoke rim, but it's not. 

[Mike Tashjian]

Feeling the shop did you wrong or may be less than honest with you may be true. But really do you expect them to remember you after a few days, months or a year?  If this tube failed in an hour, day or month it would seem more plausible they may have not gotten something right.  The real question here is do you do your part and check your tire pressure often enough.  It is possible you caused this problem and it will happen again if you do not check the pressure often.  Mike

[sdcr]

It would be hard for me to blame a bad install 11 months after the fact.

Pat,  with all do respect I don't think I'm "blaming a bad install". My disappointment in the shop has more to do with them not taking the time to give me a more credible explanation as to what caused the failure. I did not ask for any monetary refund, and paid for the new tube and service.

[bigbikerrick]

 Sir, Have you considered converting your wheels to tubeless? I have done it to my 03 aluminum( same wheels as your jackal) my 73 eldo, and my sons HD street bob, its been over 5 years for the aluminum, and not a single issue. On a side note, I have witnessed a few bikemaster tubes that seemed pretty thin and flimsy. IMHO, I would only use Michelin airstop tubes if I ran tubes in my bikes.
Rick.

[sdcr]

Sir, Have you considered converting your wheels to tubeless? I have done it to my 03 aluminum( same wheels as your jackal) my 73 eldo, and my sons HD street bob, its been over 5 years for the aluminum, and not a single issue. On a side note, I have witnessed a few bikemaster tubes that seemed pretty thin and flimsy. IMHO, I would only use Michelin airstop tubes if I ran tubes in my bikes.
Rick.

Rick,

Yes I have considered doing this in the past, just never got around to it. This incident may move me in that direction. IIRC, harpers has parts that make it workable. Thanks for the reminder.

 Btw, the bike that we are talking about is a 83 Le Mans with the cast, hour glass wheels.

[Kentktk]

  Was English his first language?   

Why would that be a problem?

[rodekyll]

Why would that be a problem?

What problem are you imagining now?