Exploding Inner Tube Replacement

[AndyBSG]

OK, couple of questions here.

I got myself a nice shiny pair of slicks and took them into my local cycle shop to get a full service and the new tyres fitted to replace the bobbly ones that were on there.

Got the bike back and less than 10 minutes after riding it the rear inner tube 'exploded'. There was a loud pop and it went completely flat in about 3 seconds. I've not had a chance to look at it properly yet but have a some questions

- Does this sound like it's the actual repair shops fault (felt very overinflated with no give in it at all so I suspect the psi was too high) and should they be responsible for replacing it?

- Although I bought new tyres, I used the old inner tube. Should I have got a different size inner tube just moving from a bobbly tyre to a slick and could this be the problem?

- If so, is it the cycle shops fault for not advising me I needed different inner tubes when they swapped the tyres over?

Either way, I can't get down the bike shop until Saturday and they don't do repairs at weekends, meaning i'll have to leave it there until the following Saturday. I've already lost a few days riding when it was in getting serviced and I need to get training so i'm going to try and replace the inner tube myself with a spare I have and need some advice.

It's a quick release rear wheel with hydraulic disc brakes. I'm more than comfortable replacing the inner tube but a little unsure if there's anything special I need to do with the brakes... Last time I repaired a puncture my bike had old fashioned pad brakes.

From looking online it seems the main difference is that I don't have to release the brakes and as long as I don't accidentally pull the brake lever i'll be fine. Is that correct?

[thirdcrank]

An innertube will only explode if part of it gets outside the tyre - usually by being nipped under the bead when it's fitted. The "explosion" is caused by that small part of the innertube expanding and bursting like a balloon.

[AndyBSG]

An innertube will only explode if part of it gets outside the tyre - usually by being nipped under the bead when it's fitted. The "explosion" is caused by that small part of the innertube expanding and bursting like a balloon.

That sounds exactly like what has happened because it was right on the side of the inner tube near where the tyre and wheel meet.

CBA to actually complain to the shop and get them to sort it out for the sake of a £5 inner tube but I certainly won't be using them again!

Now just need to see if I can replace it tonight without ballsing my breaks up in the process.

[cycleruk]

From looking online it seems the main difference is that I don't have to release the brakes and as long as I don't accidentally pull the brake lever i'll be fine. Is that correct?

That is the main thing. It may be wise to slide something temporarily in place of the disc to stop accidental closure of the brake pads.

Regarding the blowout, slicks tend to be smaller area so will feel harder when inflated. (The max' advised pressure is usually stated on the tyre wall.) Maybe the shop has done something wrong but it will be hard to prove and is it worth the hassle for the price of a tube?
Do a very careful internal check of the new tyre and check that a spoke isn't poking through the rim tape and the tape is positioned correctly.

It is feasible, if the tyre was pumped up hard and then out in the sun, that the extra heat could explode a tube.
I have seen it happen a few times.

[Brucey]

- Although I bought new tyres, I used the old inner tube. Should I have got a different size inner tube just moving from a bobbly tyre to a slick and could this be the problem?....

it isn't a bad idea to get a narrow tube to match narrower tyres; if the tube is wider than the tyre is, it is very easy to trap part of it beneath the tyre bead when fitting with the consequences you have seen.

You may be able to tell if the failed tube was trapped beneath the tyre bead by seeing where the hole was in the old tube, and the shape of the hole.

Being able to fit tyres and tubes is a good thing to be able to do; I am quite sure I would have given up riding a bike years ago if I couldn't do this kind of thing. Once you have done this OK you will wonder why you paid someone else to do it for you.

BTW when the tyre is just rounded out ( < 5psi or so), you can push the bead away from the rim all round, and look in the gap between the tyre and rim to check that the tube isn't trapped in there. This can save a lot of problems with blown tubes if they are a little wide for the tyre.

I prefer tubes that have to stretch slightly to fit inside the cover, simply because they are much less likely to be trapped when fitting. Tyre manufacturers usually size their tubes this way too, i.e. a tube that is a perfect fit in a 28mm tyre will also stretch to fit a 35mm tyre, but the converse is not usually recommended.

cheers

[531colin]

An innertube will only explode if part of it gets outside the tyre - usually by being nipped under the bead when it's fitted. The "explosion" is caused by that small part of the innertube expanding and bursting like a balloon.

That's not quite true.....if manufacturing tolerances for tyres and rims mean the new tyres are very slack on the rims, it is possible for normal inflation pressure to lift the tyre off the rim at one point, letting the tube burst. Uncommon, but it can happen.

[geomannie]

My view is that this is up to you. Tubes are expendable items. Its likely that the shop fitted the tube incorrectly, but its almost impossible to say one way or the other. A new tube is <£5 so IMHO its hardly worth the fight. Look at You tube for instructions on hydraulic disc brake.

Cheers

geomannie

[AndyBSG]

Managed to replace the inner tube with no problem so got my first bit of bike maintenance out of the way.

The explosion was caused by the shop because when I removed it, as someone mentioned above, there was a piece of the inner tube pinched between the rim and tyre where the puncture happened.

One question I do have as a follow up, are there any tips for actually putting the new inner tube on?

I had a problem where I got the tube in the tyre then tried to put the tyre onto the wheel but towards the end of pushing the tyre on I found the last bit of the inner tube was 'twisting'. Ended up having to try about 4 or 5 times before I managed to finally get it on OK.

[meic]

Inflate the inner tube enough for it to take shape before putting it in then keep deflating it bit by bit as you put the tyre's second bead back on the rim.

You have to avoid pressure in the tube from keeping the tyre from going into the "well" as you want the part that is already on to go into the "well" which gives the bit you are still trying to get on an extra bit of temporary length.

[531colin]

Theres a video at the end of this page...http://www.spacycles.co.uk/index.php
The straps aren't normally needed, but they can help somebody inexperienced to mount a stiff/difficult tyre.

[Gearoidmuar]

Theres a video at the end of this page...http://www.spacycles.co.uk/index.php
The straps aren't normally needed, but they can help somebody inexperienced to mount a stiff/difficult tyre.

if you start with a completely airless tube and work the bit of the tyre rim into the centre of the well, before working the last bit on, you will not need straps. I can do nearly every tyre by hand. Occasionally I may need one lever. I regard this video as nonsense! I've never had to do it.

[531colin]

Theres a video at the end of this page...http://www.spacycles.co.uk/index.php
The straps aren't normally needed, but they can help somebody inexperienced to mount a stiff/difficult tyre.

if you start with a completely airless tube and work the bit of the tyre rim into the centre of the well, before working the last bit on, you will not need straps. I can do nearly every tyre by hand. Occasionally I may need one lever. I regard this video as nonsense! I've never had to do it.

Just look here http://www.youtube.com/watch?v=-XUFVrl0UT4 and see what people say.
Even better, try it yourself.
Theres loads of ways to put tyres on, just do what suits you, theres no call at all to rubbish somebody elses way. Ten years in the bike trade, and I saw a way of putting tyres on that was news to me only a week or so ago.
In my opinion the 2 best ways to pinch a new tube are fitting it with no air in, so it can get trapped under the tyre bead, and fitting the tyre with a lever, so you can pinch the tube with a lever....but if it works, it works.

[Brucey]

...Ten years in the bike trade, and I saw a way of putting tyres on that was news to me only a week or so ago.
In my opinion the 2 best ways to pinch a new tube are fitting it with no air in, so it can get trapped under the tyre bead, and fitting the tyre with a lever, so you can pinch the tube with a lever....but if it works, it works.

I agree re the tube pinching risks that way.

What was the 'new way' of fitting BTW?

cheers

[531colin]

Tyre right off....bit of air in tube......fit tube inside tyre.....fit first bead manually, putting valve in hole.....lever the first bit of second bead on, and run the lever round the rim, the bead slots in as you go.
He made it look very easy, I'm going to try it!

[Brucey]

hmm, I can't see what will pull the bead into the rim well with that technique.

I can see it working with some tyres on (say) an open pro rim, but not some other combinations, no....

cheers