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London Rider
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Postby London Rider » 29 Oct 2009, 5:03pm

Hi All

Complete Newbie question here, sorry if it's painful to read and I'm just being ignorant :roll:

But..... I got my MTB in July and I'm learning as I go. It was a cheap entry level bike from Halfords (118.00 in a sale) Here's the facts.

--> 1.95" tyres
--> Commuting to work only, just using roads, careful (I think) no ramming it up kerbs
--> Average of 40 miles per week at an average speed of about 10mph

Now the sting in the tail, I've had 5 puncture's in the last 6 weeks. I'm just putting it down to bad luck. When changing the inner tube (been a new inner tube each time as I've been so lazy and have not got round to repairing the old ones, but have kept them) I always check inside and outside of tyre for offending objects before I put new tube in.

It's also always the back tyre

I would say on half the punctures I've found something like a nail or a thorn and half the punctures nothing.

I can't seem to go longer than 7-10 days without a puncture now.

I think I'm just unlucky, but friends are telling me that it's just because my bike is cheap and cr*p basically :shock: I'm far from an expert but the tubes I'm buying from Halfords seem fine and I can't see anything wrong with the wheel rim.

I view it as just a tyre/inner tube issue whereas friends whom have ridden and owned bikes but are not currently involved in bicycling seem sure it's the bike as a "whole" issue, but unable to say specifically (i.e. in technical terms).

I'm a bit stumped and don't want to be ignorant of any technical issue and just be changing my innuer tube every week for next few months if there's another way! :shock:

Any advice appreciated, even if it's just to say "just unlucky, thats the way it goes!"
Last edited by London Rider on 15 Nov 2009, 10:55am, edited 2 times in total.

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Re: Constant Puncture's

Postby cycleruk » 29 Oct 2009, 5:16pm

No matter how inexpensive the bike is, that's nothing to do with punctures.
Cheap tire maybe but not the bike.
Assuming the puncture is always on the outside (tire side) then it's not the rim.
You must make sure though that the tire is inflated properly.
If it's soft then there is more rubber in contact with the ground and you can also get a pinch puncture.
A pinch puncture usually shows up with 2 holes in the tube.
This is caused by the tube being squashed between the tire carcass and the rim edges.
You may have been just plain unlucky though with 5 in 6 weeks.
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Re: Constant Puncture's

Postby thirdcrank » 29 Oct 2009, 5:20pm

London Rider wrote:...
It's also always the back tyre

I would say on half the punctures I've found something like a nail or a thorn and half the punctures nothing.

I can't seem to go longer than 7-10 days without a puncture now. ...

It must me something - the problem is finding it. Make sure that the rim tape is properly protecting the spokes. Try to ensure that when you replace the tyre, that the label is by the valve. If you forget to do this, when you do puncture, mark the position of the valve on the tyre. Then, when you have found the puncture, it's just a question of measuring the distance from the valve on the inner tube to see where the foreign body is in the tyre casing. The tiniest of glass shards can cause a puncture and these can be difficult to detect. Open every cut in the outer casing e.g by folding it. and search right down at the bottom.

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Re: Constant Puncture's

Postby Gearoidmuar » 29 Oct 2009, 5:56pm

I seldom find nothing. Occasionally I find nothing with a very small puncture.

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Re: Constant Puncture's

Postby reohn2 » 29 Oct 2009, 6:07pm

Follow the above advice,which is good.
Also you say half the flats are foriegn bodies (nail,thorn,etc) and half "nothing",it must be something, so as you have kept the old tubes I say check the nothing ones by trying to put some air in them then putting them in water to find out where the punctures are,if they all p/tured in the same place then there is something either in the tyre(and still could be,ie a small shard of glass etc)or something on the rim(a spoke end poking through the rim tape or sharp edge where the rim is jointed,or rough edge around the valve hole,which need "softening" with abrasive paper) causing the problem.
If I were getting punctures at that rate I'd be tempted to buy a new tyre if I couldn't prove it was the rim causing the problem.
Check this thread out for a little more info:- viewtopic.php?f=1&t=30506
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London Rider
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Re: Constant Puncture's

Postby London Rider » 29 Oct 2009, 6:20pm

Thanks for your help guys. I'm at work. Will read this in more detail later and post. Thanks for taking the time.

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Re: Constant Puncture's

Postby Oak Hill Cyclists » 29 Oct 2009, 9:53pm

I've been using thorn-resistant tubes like Avenir or Kenda for 30+ years on my single commuter (before I was retired) and on our tandem. Not a single flat - ever. Downside is that these tubes are almost 1/2 kilogram in weight and makes your bike seem a little sluggish in acceleration. But NO flats.
The older I get, the better I was.

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Re: Constant Puncture's

Postby thirdcrank » 29 Oct 2009, 10:11pm

There is just the possibility if you are cycling to work and always finding the punctures there, that somebody with a sense of humour is indulging themselves at your expense, especially if you spend any time bemoaning punctures. (Human intestines make poor innertubes but don't let that deter you from trying the idea :twisted: )

Otherwise, I'd just reiterate what I said about fragments of glass which are everywhere on today's roads. Modern butyl tubes are rather inelastic when compared with the older latex type. This means that a minute speck of glass can be lodged in the tyre and be almost invisible and not obvious to the touch if a hand is run round the inside. Once the tyre is pumped up hard, the tube is forced against this glass. The tiny movements of the tube inside the tyre as the bike is ridden cause abrasion and eventually it's another puncture. If you failed to remove something sharp like a thorn the next puncture would be almost immediate, but with a bit of glass it can be days later, deflecting suspicion from something left behind from last time. I once had this happen to me and only eventually spotted the glass when I held the tyre up to the light and looked from the inside - there was a tiny pin-prick of sparkling light where the glass was letting it shine through.

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Re: Constant Puncture's

Postby bensonboo » 29 Oct 2009, 10:18pm

Another option to check whether it's the rim or tyre causing problems is to swap the tyres front to back, if you keep getting front tyre punctures afterwards then it would indicate something in the tyre, if the back still keeps going, then check the rim for sharp edges or spokes sticking through.

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Re: Constant Puncture's

Postby Swizz69 » 29 Oct 2009, 10:53pm

Its also worth taking care fitting a new tube. Stick some air in it first, so that when fitting inside the tyre & over the rim, there will be no snags.

Also, where on the road are you riding? If in or too near to the gutter, then you will be riding through all the bits of debris thrown over from car tyres. Thats a good reason why cycle-lanes aren't such a good idea :shock:

And ditto 'cycleruk' s advice re: tyre pressures. It'll speed up your commute too :wink:

London Rider
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Re: Constant Puncture's

Postby London Rider » 29 Oct 2009, 11:25pm

Thanks for all these problem solving suggestions guy's. I can confirm that the tape going over the spokes on the inside of the rim seems to be fine as it all seems pretty smooth and I can't see any sharpe parts on the inside of the rim at all.

I think the issue about small bits of glass are very crucial and I think I will not pay a lot more attention to type examination upon a puncture. It's possible I've been too carefree with this aspect and paying the price. I'm so fed up that I actually spent a good 20 minutes under a strong light examining the tyre now that I have fitted yet another new tube on it. I was running my fingers all over the inside and outside of the tyre, willing to run the risk of injury so I could find the damn culprit if there was one in the tyre that I have missed previously.

I like the idea of swapping the tyres (back to front) and seeing what happens, although I really wish I don't have to. I'm going to see how long the new back inner tube lasts. If I get another flat on the back anytime soon I'm going to have to try something different other than just putting in a new inner tube.

I really do hope I haven't missed anything with the rim, as this is the first bike I've had so I know nothing about what a rim SHOULD look like inside. It seems fine, but maybe I need a second opinion.

I can live with getting a new tyre as I want to upgrade from these 1.95" tyres and get something slightly less bulky, as all my riding is commuting on the road so I don't know if I really need this size tyre!

Thanks again for the feedback. I really am learning from scratch here.

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Re: Constant Puncture's

Postby quiksilver » 30 Oct 2009, 4:32am

It could be to do with your road position? New or inexperienced riders oftern tend to hug the kerb area. A lot of crap on our roads ends up here. I ride a road bike running 120 psi tyres and avoid the edge of the road, along with puncture proof tyres has given me 18 months flat free riding in London.

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Re: Constant Puncture's

Postby fatboy » 30 Oct 2009, 7:36am

Your tyre could just be worn out. When you get lots of punctures it can be a sign that it's all got a bit thin. Given that you are changing inner tubes at a seemingly alaming rate the cost of a new tyre might be a good investment. Look to get a good tyre with some form of puncture protection. Schwalbe Marathons are popular and whilst they don't completely stop punctures they do help.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

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Re: Constant Puncture's

Postby niggle » 30 Oct 2009, 9:18am

My commuter bike has Continental Sport Contacts (26"x1.6", 60-65psi) and has never had a puncture, despite this year doing around 50 miles per week, and my weekend/folder/distance bike had issues with the original inner tubes which were something Far Eastern and quite flimsy and tore at the valve base, but since replacing with Schwalbe tubes I have had no problems and never had a puncture (26mm Primo Comet tyres with fairly high pressures).

OTOH I have had no end of punctures riding off road on my (cheapish) MTB this year, practically every other ride it seems, always long hawthorn type thorns, 50:50 front or rear. I put it down to the Cheng Shin tyres which had big knobs all round with even bigger gaps between them where the tyre wall seemed very thin. I have just replaced them with Schwalbe Landcruiser tyres as they are a good brand with puncture protection and a solid centre section to the tread that should roll smooth on tarmac sections as well as be quite protective against punctures due to being quite thick. All that for a little over £8 each from Wiggle (now still only £9.44 ... 360042609/ ) but I have only had one ride on these so too early to recommend.

If after thorough checking for hidden causes lurking in the tyres, rims and making the other changes re. road position and pressures if necessary, the punctures persist, then IMO the OP should consider changing tyres for something with puncture protection. For never, or only rarely, riding off road then he would be better off with something slick and fast rolling (you don't need tread on tarmac even when its wet) like the Conti Sport Contacts or I see Schwalbe City Jets are a lot cheaper from Wiggle, though I have no experience of these ... 300003750/ . For a bit on tracks etc. on a regular basis where there is wet mud at times then the Schwalbe Marathons already mentioned would be ideal, though I have had perfectly OK experience with the cheaper Continental City Rides ... 360008049/. If on a lot of off road sections, deep mud etc. the Landcruisers could be a good, reasonably priced upgrade IMO.

So to summarise, a pair of puncture resistant tyres could be installed for around £19-£27 for a pair, whatever the usage.

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Re: Constant Puncture's

Postby thirdcrank » 30 Oct 2009, 9:43am

I'm sure you are right that avoiding puctures is better than mending them, and that the right tyres ridden in a way that avoids as many of the threats as possible will go a long way to achieve that. OTOH, in spite of what we read on here about fairies, repeated unexplained punctures in the same wheel suggests to me that the cause has not been identified and eliminated.