Is repairing tubes dangerous?

synchronicity

I had a Dutch client tell me the other day that "repairing tubes is dangerous".

Now I basically don't agree with a 'throwaway culture' so I openly admit that I repair tubes where possible. I see a fair few punctured tubes as I have a fleet of rental bikes out there. I usually fix 5 at a time - but I always supply 2 new replacement tubes with a bike and leave the others as 'backups'.

I think it's a little sad that nobody can be bothered fixing them and I even wrote this blog article on my technique:

http://www.tenerife-training.net/Teneri ... right-way/

ANYWAY, so I basically gave him my side of the story... that it's more environmentally friendly, not to mention cheaper and that I honestly didn't think it was at all dangerous if the repair was done properly.

And I added that I reckon most new cyclists attempt to repair tubes, make a right mess of it, the patch doesn't even stick & that initial experience mars their opinion of repairing tubes forever after... now obviously I agree that some punctures simply can't be repaired (one's that are close to the valve hole for instance) and that's when I throw a tube in the bin (or when the valve itself fails or looks dodgey).

Out of probably 50 or so repairs in the last year or two using my new method, I've not had one fail yet. I even told him that I have no hesitation in riding a bike with repaired tubes. And I do.

His case was more along the lines of "do you know what can happen if this explodes?" and I was like "well did the patch actually fail?". No.

The only thing that I can think of is that the glue might deteriorate if the rim gets hot during an extremely steep descent. Just wondering what you all think about this. Surely if it was that bloody dangerous they wouldn't sell patches, but I never bothered pointing that out to him.

Sometimes I feel like pumping up a few repaired innertubes to destruction to see where abouts they actually fail... then making a video of it.

crankycrank

Well call me a terrorist because I'm running 6 patches between my front and rear tyres right now. I've seen plently of poorly applied patches leak but I can't remember any exploding. In any case it's the tyres carcass that actually restricts the air so as not to destroy any buildings if a patch were to fail. Now of course if you overinflate a tyre or hit it with a massive impact the tyre can sort of explode. Never had any problems with deterioration. I've had some repaired tubes sitting around for a few years that I put back into service and no problems. Not to worry, patch away!!

Ash_

I think the kind of accident / impact / misfourtune required to make a tyre 'explode' would do for your inner tube whether it was brand spanking new or more patches than rubber.

Surely the pressure of the tube against the tyre carcass keeps all but the shoddiest of repairs functioning? Remember those 'Leeches' patches? They were just like bits of sellotape, but they'd work to get you home (not at 120 p.s.i, though).

I just kind of assumed everyone repaired inner tubes and re-used them. Guess I'm wrong.

Repairing tubs though, now that's a dark art I wouldn't go anywhere near...

markos1963

If I replaced a tube every time I got a puncture I would be a very poor man! The amount of c%£p on the roads around here at the moment means I'm getting a puncture at least once a week. All the years I have been riding i have never had a repeat puncture in the same place as the old so I can see no justification for chucking old tubes away.

SBezza

If repaired properly they are unlikely to fail, and I would guess very unlikely to explode, because it has been repaired.

The glue isn't a normal glue, all it does is soften the rubber of the tube, and when you put the repair patch it self amalgamates with the tube, and thus if repair properly you shouldn't be able to remove the patch without ripping the actual tube.

As mentioned above if the repair is on the outer wall of the tube, the patch isn't going anywhere, as it is sandwiched between the tube and the tyre.

redddraggon

synchronicity

You mention that the glue "might" melt on a long descent but isn't the "glue" a cross linking agent for the rubber? I don't know, but I always thought it was. So it couldn't melt could it?

cee

there was a post on here a while back about this....

nothing wrong with repairing tubes if it is done correctly....

remember the glue actually vulcanises the rubber together (a process where the micorscopic rubber strands are melded together....not just stuck with glue.) which outside of a lab is a pretty much irreversible process, meaning the 'glue' will not come apart if it was applied and set correctly.

Like you say, twice the rubber....anyone ever had to patch a patch? I haven't.

iain_j

In the days when I only carried a repair kit, not spare tubes, I was quite good at patching up punctures. Since I started carrying spare tubes, when it comes to repairing the punctured ones they never stick. I've lost the knack.

As for what would happen if the patch blew - well, surely it would be no worse than the original puncture?

synchronicity

Thanks for the replies.

redddraggon, yes I thought the glue caused a vulcanisation process (cross linking) so melting per se isn't possible. Truth be told I'm a bit rusty with my polymer science. It's just something I thought of that could possibly cause trouble... even so, I might do a little test.

I've found that clealiness is crucial to a good patch repair. You need to start with clean hands and you need to clean the tube with alcohol (or similar) after sanding it, otherwise the rubber particles stick to the patch and not the tube.

hodsgod

I don't see how it can be dangerous. The air pressure inside the tube will maintain the position and integrity of the patch seal.

ride_whenever

As the above, the 'glue' causes the patch and the tube to form a single piece of rubber when done well. As for the using alcohol to clean the tube, i don't see how that would help, the rubber isn't soluble in alcohol so you might as well wash it with water. But putting 'glue' on both sides (ie patch and tube) and waiting till almost dry will prevent the dust stoppign the patch bonding,

balthazar

Take home, patch, leave overnight before use. I've had plenty of tubes with 6 or more patches and can't remember the last time one leaked. I replace my tubes when I replace my tyres, usually, for no reason other than a general sense of neatness.

All about patches:

http://www.sheldonbrown.com/brandt/patching.html

cee

I had a thought......

might be dangerous if you try to fix the tube whilst standing in the polar bear enclosure at the zoo...

ride_whenever

or repairing a tube using nitroglycerin in lieu of vulcanising solution.

Chaz.Harding

Personally, I don't repair patches (call me the devil if you want...)

Innertubes don't cost a fortune. More expensive than a repair kit, yes. But I can't normally be bothered, and it's so rare that I do get punctures nowadays anyway (ONE in the last 2 years)

I put it down to the fact that I ride larger tubes than the tyre suggests I should - so the rubber isn't so stretched inside the tyre itself. Weight isn't really an issue with me - I am certainly never gonna be mistaken for a racing snake :twisted:

And yes, I do ride regularly 8)

STEFANOS4784

bigchazrocks wrote:

Personally, I don't repair patches (call me the devil if you want...)

Innertubes don't cost a fortune. More expensive than a repair kit, yes. But I can't normally be bothered, and it's so rare that I do get punctures nowadays anyway (ONE in the last 2 years)

I put it down to the fact that I ride larger tubes than the tyre suggests I should - so the rubber isn't so stretched inside the tyre itself. Weight isn't really an issue with me - I am certainly never gonna be mistaken for a racing snake :twisted:

And yes, I do ride regularly 8)

Well excuse me for not being rich but a fiver(if you need one right there right now) is a lot more than a puncture kit (3quid can do about 8 repairs =£40)


Correct me if i'm wrong :P

nwallace

Think my supply of Conti's cost about £2.50 each.

Since most of my punctures have been valve failure or just plain age related degeneration I have just replaced them, carry a repair kit in the saddle bag on one bike along with tubes, never seem to manage to go as far as I intend to on it.

Tim Farr

Occasionally I have a failing repair - and it may well be, as Synchronicity says,because of dirty hands - thanks for that insight Synchron.

However like him after roughening the surface I clean the area, not with alcohol but with petrol or turps. Let it dry then I apply just one thin coat of adhesive. That works fine, IMO you don't need several coats.

Like others on this thread I am surprised that many automatically jettison a punctured tube. Perhaps it's a generation thing.

Crapaud

ride_whenever wrote:

or repairing a tube using nitroglycerin in lieu of vulcanising solution.

I'd definitely miss out step 6 then...

david 142

But even that wouldnt be as dangerous as finishing your trip without an inner tube...

brixtonbiker66

Its not glue its Vulcanising solution,

'Vulcanization, is a chemical process in which polymer molecules are linked to other polymer molecules by atomic bridges composed of sulfur atoms or carbon to carbon bonds'.

Your tyres are made using this process.

Vulcanization cannot be undone. The two bits of rubber become one..

Once done your tube is as good or better than a new one....If done correctly.

Takes only a few minutes to do, dont even have to take the tube out sometimes. Quicker than replacing a tube , My Dad showed me as a kid and since then i have always done it,quiet like doing it, its really a clever process.

better for the environment.