7 exactly same blowouts in 7 tubes in 2 weeks

[Woodn88s]

Can anyone figure out this problem Im having with tube blowouts. 7 tubes in 2 weeks , exact same blow out in the same place. See the 2 pimple type blowouts ½” on either side of the valve stem……I rode all last summer and through the winter on this exact rim and tube and tire with no problems. This spring this problem showed up. I’ve been to 4 local bike shops and nobody has an answer, they love selling me tubes though. It seems to me as if the tube is stretching and this is the weak point in the tube. But I haven’t got the answer yet….help Its spring and I want to ride…….

Tire: Schwalbe 47-622 28x1.75

Rim: Weinmann 700 x 18c / 23c new rim tape

All tubes were : Specialized 700 x 32-50

 

[Lonestar]

What about a picture of the wheel in the same place? Dunno if it will help but worth a look.Cheers.

 

[mickle]

What Adrian said. Also, find yourself a different bike shop.

 

[Deleted member 1258]

Replace rim tape, whilst doing that give the edge of the valve hole a rub with a piece of wet and dry and check for any debris that might be around there.

 

[Elybazza61]

Deffo looks like something in the rim or your bike shop are offloading a dodgy batch of Spech tubes.

 

[Yellow Saddle]

Judging from the pimples, it is something NOT in your rim. In other words, a void of sorts. The tube gets compressed into that void and stretches too thin and pops. I doubt it is spoke holes underneath the rim tape in those positions unless it is a 48-spoke wheel. But take a look and examine the rim tape. Plastic rim tapes split over holes but the splits are not visible.

 

[raleighnut]

Dodgy Spesh tubes, I've had a couple like that, one as a 'had a puncture need a new tube' fitting whilst on a ride that didn't even get me a mile.
Don't buy Spesh tubes now.

 

[lpretro1]

looks like rim tape is weak and under pressure the tube is getting pulled down through spoke holes causing it to burst. Fit a more robust rim tape

 

[Woodn88s]

thanks for all the replies, Ive taken a few more pics .....rim with tape off, rim with tape on, and a pic of the tape pulled back. there is nothing under the tape. I believe as one person said, that the tube is being stretched beyond it's capacity causing it to weaken at this point and pop the tube, perhaps while hitting a bump or something on the road, but Im careful about that. I dont jump curbs, and really try to take my weight off the seat if I see a speed bump or something in the road.
I thought at first it might be because I was tightening the valve ring down to tight against the rim, causing the tube to distort before inflating, but the last tube I installed I only barely had the ring fingers tight.......perhaps I'll try not installing the ring, perhaps it's the valve ring not allowing the tube to seat correctly.

rim tape installed on wheel, the black line on rim tape is approx where the pimple on the tube is.

this pic is underside of rim tape pealed back

 

[Woodn88s]

looks like rim tape is weak and under pressure the tube is getting pulled down through spoke holes causing it to burst. Fit a more robust rim tape

that was my first thought also but the spot where the tube is bursting is not near any of the spoke holes........thanks

 

[Woodn88s]

Dodgy Spesh tubes, I've had a couple like that, one as a 'had a puncture need a new tube' fitting whilst on a ride that didn't even get me a mile.
Don't buy Spesh tubes now.

I'm beginning to think these tubes are crap. I ordered a couple Continental tubes that are supposed to be of a thicker quality. I'm going to try some different tubes.
thanks for replying

 

[Woodn88s]

Judging from the pimples, it is something NOT in your rim. In other words, a void of sorts. The tube gets compressed into that void and stretches too thin and pops. I doubt it is spoke holes underneath the rim tape in those positions unless it is a 48-spoke wheel. But take a look and examine the rim tape. Plastic rim tapes split over holes but the splits are not visible.

thanks for replying, I have posted more pics and examined the rim and tape, also have pulled back the tape. there is nothing there. I also believe, as you said, that the tube is being stretched and this is the weak point. I am going to install the next tube and leave off the metal ring that is on the valve stem. I'm thinking perhaps this is the problem, when I hit a bump the ring tightened against the rim is causing the problem.
I appreciate your reply

 

[Woodn88s]

Deffo looks like something in the rim or your bike shop are offloading a dodgy batch of Spech tubes.

I think you may be right about the cheap tubes, I ordered a better brand
thanks for reply

 

[Deleted member 1258]

thanks for all the replies, Ive taken a few more pics .....rim with tape off, rim with tape on, and a pic of the tape pulled back. there is nothing under the tape. I believe as one person said, that the tube is being stretched beyond it's capacity causing it to weaken at this point and pop the tube, perhaps while hitting a bump or something on the road, but Im careful about that. I dont jump curbs, and really try to take my weight off the seat if I see a speed bump or something in the road.
I thought at first it might be because I was tightening the valve ring down to tight against the rim, causing the tube to distort before inflating, but the last tube I installed I only barely had the ring fingers tight.......perhaps I'll try not installing the ring, perhaps it's the valve ring not allowing the tube to seat correctly.
View attachment 128110
rim tape installed on wheel, the black line on rim tape is approx where the pimple on the tube is.
View attachment 128111
this pic is underside of rim tape pealed back
View attachment 128112

Have you run your finger round the valve hole? Its difficult to tell from your pictures but it looks like you've got some excess material round the valve hole. If you're fitting crap tubes thats not going to help the situation, you could try some better rim tape as well.

 

[Tojo]

You could try putting an O-ring on the base of the valve stem before putting the inner tube in to give a bit of a buffer and stop the tube around the base of the valve pushing into the valve hole......