Commuting, Day rides, Audax, Incidents, etc.
Posts: 411
Joined: 23 Sep 2008, 6:50pm
Location: Telford, West Midlands


Postby Thomas125 » 23 Sep 2011, 6:59am

Cycling home from work yesterday I noticed that my front tyre looked a bit soft, wasn't bottoming out or anything just looked a bit soft.

So I gets home and looks at the sidewall of the tyre 'Inflate to 75 psi'. I hooked it up to the car compressor which showed 33 psi, bit low then, dialed in 75 psi and switched it on. Compressor cuts off at 75 psi.




The thing went of in my face like a shotgun :shock: ripped the bead off the tyre as well.

Now bearing in mind I have only owned the bike a week and done nothing to it except drop the handlebars I was a bit miffed :!:

Incidentally the tube says 700 x 47/52 and the tyre is a 700 x 45c. I think when I blew it up full it was too broad and blew the tyre off the rim!

So I took it back to Halfords for a replacement and was told it was wear and tear wasn't covered under the warranty. :!:

I had to buy a new tube, then a new tyre. (The halfords tech was going to refit the bust tyre with half the bead missing!!!)

They didn't have any 700 x 45c tyres so I had to get a 38c tyre. then as I didn't trust the frotn tube not to do the same I bought the same for the front.

I would have told then to get stuffed but it was 7pm and I needed the bike to get to work.

Come home and put the front set on, all sorted for work.

Also noticed the back wheel is out of true will have to wait until next month now to get that done at lbs I'm skint :roll:

Got up this morning and the front tube was flat, don't know yet if its defective or I've caught it trying to hurry up last night.

So stuck in a taxi this morning at more expense.

Good news is I ordered a puncture kit from wiggle yesterday to keep for emergencies so I should get it tomorrow morning lol :mrgreen:

Halfords head office can expect a strongly worded letter from me asking for a refund of tyre cost.
Was 93.4kg now 78.3kg

Next target 74.0kg

"Life is one long bike ride" :-)

Posts: 4604
Joined: 29 Jun 2010, 4:45am


Postby snibgo » 23 Sep 2011, 7:15am

I was waiting for that "BOOM", and laughed when it came. Sorry about that.

Car compressors are designed for, well, car tyres. These have much larger volumes of air than bike tyres. So compressors can pump in loads of air before checking the pressure. If they don't check sufficiently often, they can reach enormous pressures, hence "BOOM".

It's possible that this wasn't the problem. Maybe it was a defective tyre. But I wouldn't use that compressor again, if I were you.

User avatar
Posts: 1080
Joined: 19 Jul 2010, 2:51pm
Location: Swadlincote, South Derbyshire

What's wrong with a hand pump?

Postby tykeboy2003 » 23 Sep 2011, 7:51am

Its never crossed my mind to use a compressor to pump bike tyres up with. My reasons include the following:-

1. Finding it, and connecting it up to the car 12v supply
2. Its very noisy
3. The hand pump is handily located on the bike
4. I cycle partly to keep fit so why use a labour saving device when there's an opportunity to use your arms a bit?
5. A thumb pressed into the tyre is an excellent pressure gauge - been using it for 40-odd years

Posts: 28844
Joined: 9 Jan 2007, 2:44pm


Postby thirdcrank » 23 Sep 2011, 8:03am

AFAIK, if it goes bang, rather than just deflating PDQ, then a part of the innertube must have been outside the tyre casing. It wouldn't happen purely from going a few pounds or even a couple of bar over the listed pressure in a sound tyre. Without seeing the actual damage we are guessing but one possible explanation is that a brakeshoe was badly aligned and had been scoring the tyre: that would cause rapid "wear and tear." Alternatively, if the tube had been trapped under the tyre bead from new, then inflating it hard would have led to a huge bang, but without damage to the tyre.

Posts: 411
Joined: 23 Sep 2008, 6:50pm
Location: Telford, West Midlands


Postby Thomas125 » 23 Sep 2011, 8:17am

Disc brakes on bike so no rubbing on rim.

Tube or bead must have been incorrectly seated from new when it was 'checked' by halfords I did nothing to it except add more air. Bang tore the bead from the tyre over a 12" length so tyre had to be replaced as well.

As for the compressor I'm newly returning to cycling and don't have a pump yet :oops: Ordered it from Wiggle with the Park puncture repair kit on Thursday morning. Good job really should come tomorrow morning, hopefully I can get things sorted out.
Was 93.4kg now 78.3kg

Next target 74.0kg

"Life is one long bike ride" :-)

Posts: 4192
Joined: 30 Jan 2010, 9:54am


Postby Ayesha » 23 Sep 2011, 9:22am

Have a read through this..


Note especially the width vs pressure chart.

There is also this..


Looks like you were a tad overpressurizing the tyre.
Also, did you spare a thought as to why the tyre was soft? There could have been a 'slow puncture' with a bit of sharp stuff through the tyre casing.

Posts: 2411
Joined: 20 Jan 2009, 4:38pm


Postby iviehoff » 23 Sep 2011, 10:18am

Those people saying he was over-pressurising the tyre, read the bit where he says "the sidewall of the tyre (read) 'Inflate to 75 psi'".

He says - "the tyre looked soft". The compressor measured the pressure at 33 psi. This does not sound like the compressor was misreading.

The Halfords person who said "wear and tear" to a one-week old bicycle, which exploded when inflated with a high quality rated inflator to its design pressure, using a reliable piece of equipment, was taking the michael. It seems clear the tyre was either faulty, or not properly mounted. This is an egregious failing and they should roll over the instant you mention "small claims court". However, do check to make sure your compressor is working properly and can be relied upon to inflate a bicycle tyre to the correct pressure...

You should also insist upon a new rear wheel, as it has been damaged by the explosion.

In fact this is in reality such an egregious failing by Halfords that you should take it up with the local trading standards office, regardless of whether they refund you. You were nearly badly injured by the faulty item they sold you.

Posts: 2244
Joined: 15 Jul 2011, 2:07pm


Postby karlt » 23 Sep 2011, 10:26am

I did read that, but I still agree with the possibility that it over inflated. Some compressors are meant to inflate car tyres, which have many times the volume of a bike tyre. They read pressure, put some air in, read pressure again... It's quite conceivable that the compressor measured 33psi, put some air in, and by the time it measured pressure again, was already well over 75psi. That's why some of them aren't meant to be used on bike tyres. Without knowing the make and model of compressor, and whether it's meant for car use only, it's impossible to rule it out.

Posts: 4604
Joined: 29 Jun 2010, 4:45am


Postby snibgo » 23 Sep 2011, 10:54am

What make/model is the tyre?

Posts: 119
Joined: 4 Sep 2009, 1:46pm


Postby Slidingpillar » 23 Sep 2011, 12:49pm

For what it is worth, I go with the theory that the tyre was incorrectly seated, and was trapping the tube. While no way would I use an electric car tyre inflater, I think it is very unlikely to be to blame for the explosion. A tyre that says 'inflate to 75lbs' correctly fitted should be safe to at least 100lbs or more as otherwise, it would go bang every time you hit a pothole.

In my opinion Halfords are talking out of their bottoms. I'd take photo's of the damaged parts and write to their customer service department at the head office. Won't cost you much and the worst that can happen is they say the same thing as the shop.
Trice Q
Longstaff Trike

Teddy Two Teas
Posts: 26
Joined: 20 Jun 2011, 6:55pm


Postby Teddy Two Teas » 23 Sep 2011, 12:54pm

I think the key phrase here is "Halfords"
Alarm bells should start ringing right there.

Posts: 411
Joined: 23 Sep 2008, 6:50pm
Location: Telford, West Midlands


Postby Thomas125 » 23 Sep 2011, 1:29pm

To answer a few q's

Tyre was a CST Traveller 700 x 45c.

New 38c Tyre will fit on the rim the rim width is ok.

Car inflator is a Michelin Brand one, came with presta, football and inflatable adapters so it is ok to use for other applications as well.

Halfords will get a written letter from me. I want a refund of the money paid for tyres and tubes as there is nothing I have done to cause the explosion. I also want them to doot the bill to have the wheel checked and trued by a good lbs as I don't trust there technicians.

Watch this space, got my puncture kit in post so I will inspect the other tube tonight.
Was 93.4kg now 78.3kg

Next target 74.0kg

"Life is one long bike ride" :-)

Posts: 4604
Joined: 29 Jun 2010, 4:45am


Postby snibgo » 23 Sep 2011, 2:53pm

A tip about tubes: when the tube and tyre are on, before blowing it up (umm, I mean, before inflating it), squeeze one side of the tyre towards the other side to check the tube isn't trapped under the tyre bead. Check all around the wheel. Then check the other side.

I note that your tube was slightly too wide for the tyre (47-52 mm is wider than 45mm). I wouldn't expect that to cause a BOOM within a few seconds of inflation, but I don't know.

Posts: 24
Joined: 5 Aug 2011, 5:14pm


Postby paulbrookes » 23 Sep 2011, 5:15pm

I am newish to cycling, but I use a home use electric car tyre inflator due to a knackered arm (i can be in pain for days if manually inflate [tyres]).

What I do is inflate to half stated max pressure, spin the tyre check seating/balance etc then once all okay take to max pressure (have a auto cut off compressor)


Posts: 196
Joined: 11 Aug 2011, 9:14pm


Postby diapason0 » 23 Sep 2011, 5:17pm

I use a track pump which I bought in Halfords half-price sale. It's been good for some years now.