Inner tube scare

[DaveP]

I've just been out for a shakedown cruise (errands ) on a freshly rebuilt bike and got a scare from one of the few bits I hadnt meddled with this time round.
I rode along a main road and executed a right turn in traffic into a private car park. I was inside for no more than five minutes and came out to find my front tyre completely flat. Upon examination I discovered that it was not a puncture in the usual sense
The rims are box section with a rubber rim tape, which was in place. I found that there were little oval marks along the inner face of the tube, presumably where it had bulged slightly into the spoke access holes. Along one of these "creases" there was a 2mm split, and this was the leak site.
It's scary because it was a very fast leak that occured with no prior warning and if it had happened a couple of minutes earlier than it did I could have been in a lot of trouble. I feel a need to understand what has happened in order to try and avoid a recurrence and this seems to have generated several questions.
I normally run these wheels at 50psi but they are rated to 80. During the rebuild I decided to try the higher pressure and pumped them up. They have been at this pressure for a couple of weeks but this is their first outing. Could it be a problem with my rimtape, Do I need something stronger now that I've left mtb pressures behind?
The tube in question was a Continental that came free with my Travel Contacts a couple of years ago. Looking at its markings, it could have been manufactured in 2004. It appears to be sound and supple but could it be an age related problem? How long does a modern inner tube last anyway? Do I need to retube all the family bikes as a matter of urgency?
I did try to patch it but I found that the patch just lifted off on inflation. I then found out that the rubber cement didnt really bite on the surface and could be rubbed off with a finger tip when dry. I havent come across this before - I thought the one kit repaired all punctures - is there something I should know?
Sorry its so many questions in one go, please dont feel inhibited - if you want to comment on just one I'd be glad to hear from you!

[reohn2]

It sounds as if the rim tape is at fault,I'd swap it for the sticky cloth type Janotex(I think) its always served me well on solos and tandems alike.

PS I also have found Schwalbe innertubes to be good consistent quality.

[JohnW]

Hmm - my guess is that the inner tube is faulty.

Why not put a questioning thread onto the site asking for members' experiences with the Continental freebie regime?

I have inner tubes which are over 25 years old - they have been patched so many times that trhey look like they've got measles. Most of them are Michelin, and I ride 21mm up to 28mm tyres.

It is possible that current inner tubes are not as good as older ones - I've had problems with new tubes, recently, coming apart where the valve is connected to the tube, and I had a tube which failed time and again in the way that DaveP's has failed - little unexplained splits. Currently I'm riding tyres which should take up to 105psi, although I inflate them to about 90psi. No trouble with my older tubes, repaired ad infinitum as they may be.

JohnW

[thirdcrank]

I would have thought that if the impressions of the spokeholes were visible on the tube, that would be the cause, as mentioned by r2. Some modern factory-fitted rim tapes are not much better than 'sticky-backed plastic' of Blue Peter fame. Something that looks OK can still be capable of damaging a tube at even only 4 bar. I have seen a tube go flat in about five seconds flat caused by this.

I also agree with r2 that adhesive cloth rimtapes are best.

(Linguistic note for r2 'jante' is French for rim so it's Jantex )

[reohn2]

Thank you T/C for the linguistical correction,once more I bow to the superior being.

[meic]

I had exactly the same sort of puncture repeatedly (around every 70 miles!) until I got rid of the rubber rim tape. It was quite a thick one with a rectangular section. I keep it for use as washers or spacers! I used insulation tape after that with no problems at 60psi. A different story at 95psi when I had to buy the proper cloth tape.
I stopped to help a kid with a puncture and I recognised the same type of puncture. After a little chatting we discovered the shop who had just replaced his tyres (and tapes) for him was the same one who supplied me.
I hope he took my advice and ditched the tapes too.
The bike shop in question is a good guy but he did not want to believe his rim tapes were to blame, if I was the first/only one to have a problem then I cant really blame him.

[meic]

The life of the inner tube will be severly reduced if it was exposed to the light while it was being stored. The light will make it perish just like an old tyre does.

[DaveP]

Ok and Thanks. I'm going to blame the rimtape!
Its obviously wrong for the tube to be extruding itself through little holes. Funny thing is, these wheels are about 10 years old and I havent had this problem before. It does look as if the rubber type arent up to higher pressures.
Note to self: phone lbs in morning and find out when the kettle goes on...

I'll e mail Continental about the tubes. The markings are clear and complete so they should be able to tell me if there's something "odd" about them that would make them unglueable.

[thirdcrank]

Funny thing is, these wheels are about 10 years old and I havent had this problem before.

Ithink that would be completely normal - the rim-tape will have gradually failed over time.

As for sticking the patches, I hesitate to ask but did you roughen the surface before trying to stick the patch? Butyl tubes are notorious for the surface being 'non-stick' I think it is something to do with the chemical used to ensure they do not stick in the mould. The whole area where you intend to glue has to be well-rubbed with abrasive - there is usually something to do it in a repair outfit. Sorry if you knew that.

r2

[DaveP]

Age related deterioration?
Alas, who can deny it?
But I suspect that it is a case of a cheapo rim tape that was ok for mtb knobbly tyre pressures and was probably never up to anything more. With all the posts you see about fitting slicks to mtbs I'm surprised never to have come across a cautionary note about it!
The nice man in the shop sold me some Kore tapes. They're still stretch over(just) not adhesive but they do have a fabric base and they have been successfully fitting them under high pressure tyres for some time. Thats the sort of reassurance you go to a proper bike shop for!

I'm still puzzled about the glue failure. Butyl tubes have been the norm for quite a while now but I've never experienced a problem like this before. I did indeed wield the emery at the first attempt, and later at home I gave it a real drubbing with no greater success.
I have contacted Continental for advice. As I told them, the tubes were fine, but if they aren't patchable I wont be buying - when I think of the times I've cycled in the last couple of years with only a repair kit to hand I come out in a cold sweat. I hate walking home

[reohn2]

Dave P
You've started something off now,we had a puncture today on the tandem only the third one in 10years and we ride about 5,000miles a year on the tandem.
I was doing some reckoning and I think its only the 7th one all told in that time (annual mileage is 7,000 to 8,000miles).

I wondered how often others puncture.

[atoz]

You're not the only one. I have Mavic 221 rims on my ancient Claud Butler Dalesman. The first set of (adhesive type) rim tapes gave up the ghost after about 1 year of residence in Manchester- they came with the rims, I think. I replaced them with standard rubber stretch dark ones- they did 4 years, and then the front one punctured. Mind you, I had just come back from the Lake District, and there had been significant offroad use- the "Old Coach Road" from Ullswater to Keswick amongst other things. This bike gets used a lot in winter on CTC runs.

To get me home after such a puncture, I inserted an old piece of rubber tread from old outer cover (kept in toolbag) sandwiched between spare tube and rim tape failure point. Got me up a 1 in 7 hill and 2 miles home- can't be bad. Mind you, the tyres are the well known rather solid Vittoria Randonneurs- nuff said.

I've now replaced rubber tape with adhesive Zefal tape. This rim has deep wells for spoke holes- like the narrow section ones of course. Don't remember problems on old style rims eg Wolber Modele 58 Super Champion- c'est la vie, peut-etre?

[thirdcrank]

I think the difference between rims of the Super Champion type and box section ones is the sharp edges of the spoke holes in the latter type if they do not have ferrules. With older rims, a problem only really occurred if a spoke end was unprotected, especially if it was adjusted with the tyre on. That was all pretty rare.

A well-inflated tube will tend to push its way into modern spoke holes and sooner or later will be punctured by the pastry-cutter effect. As already pointed out by r2, a decent cloth rim tape is the best protection agains this happening. The thick sellotape sort, which are presumably used for ease of production are chocolate teapot IMO because when they do begin to fail, they produce their own sharp edges.

[reohn2]

I believe Continental introduced some plastic selotape type rim tape about two to three years ago but it didn't last long, apparently it was withdrawn (wonder why ).Its the edges you see,damn those edges .