Punctures

For discussions about bikes and equipment.
cyclop
Posts: 449
Joined: 3 Oct 2013, 7:49am

Re: Punctures

Postby cyclop » 25 Dec 2014, 9:13am

I use a small local wood for some easy offroad when its icy or too windy for the road.Unfortunately,gorse has taken hold,notoriously difficult to eradicate.Vicious spines caused a spate of punctures so I injected tyres with "slime" and havn,t had any since.I even did my wheelbarrow as I collect "sticks"(as they call logs in this part of the country).Road tyres would be rather heavy after such treatment however.

User avatar
hondated
Posts: 2430
Joined: 27 Mar 2008, 7:59am
Location: Eastbourne

Re: Punctures

Postby hondated » 25 Dec 2014, 10:28am

Boy some great information there.I need to get into the habit of checking my tyres more as advised.
That's the first resolution for 2015 then. Have a good day everyone whatever religion you believe in.

mercalia
Posts: 14578
Joined: 22 Sep 2013, 10:03pm
Location: london South

Re: Punctures

Postby mercalia » 25 Dec 2014, 11:54am

if things are that bad get a) slime tubes b) tyre liners. If the flints/ thorns still get thru it then give up cycling and walk :evil:

User avatar
NATURAL ANKLING
Posts: 12518
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Punctures

Postby NATURAL ANKLING » 25 Dec 2014, 12:51pm

Hi,
I greenlaned on motorcycles for 15 years or more and went where 4 X 4's couldn't......................

If you did not dig out the thorns, just plain old bramble type you'd be a fool.............they will get through any thing.
Motorcycle tyres are a darn site thicker than any cycle, puncture protection or no...................
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

User avatar
CREPELLO
Posts: 5558
Joined: 29 Nov 2008, 12:55am

Re: Punctures

Postby CREPELLO » 26 Dec 2014, 12:17am

I would like to know if there is a good technique for inspecting the rear tyre on the road, when the bike has full length mudguards. Without turning the bike upside down, I find this procedure very awkward. Front tyre - no problem.

reohn2
Posts: 40711
Joined: 26 Jun 2009, 8:21pm

Re: Punctures

Postby reohn2 » 26 Dec 2014, 12:58am

CREPELLO wrote:I would like to know if there is a good technique for inspecting the rear tyre on the road, when the bike has full length mudguards. Without turning the bike upside down, I find this procedure very awkward. Front tyre - no problem.


With the front wheel laid flat,the rear of the bike can be lifted up with a seatstay so the steering is at 90%,and the rear of the bike balanced with the rear wheel at eye level.
A foot may need to be placed on the front tyre,whilst lifting the rear of the bike.
It's easier to do than explain.
-----------------------------------------------------------

aljohn
Posts: 59
Joined: 7 Sep 2012, 9:39pm

Re: Punctures

Postby aljohn » 26 Dec 2014, 8:30am

I used to ride (many years ago...) a Carlton track bike, just front brake and flint catchers 'cos I had sprints and tubs and thought it was worth it. Riding in Spain and Britain on my road Somec with sprints and tubs (bike came with them) I have been off road, tow paths and trails and never used flint catchers and never had a puncture. Then again, even with cheap training tubs, they were probably better made than cheap clinchers (hate that word but it's shorter than "wired ons").
I have to admit that "cheap" is my middle name - as an aside, I looked at the price of sending tubulars for repair, cost more than the tyres I used. So I repaired my own but my wife took over the sewing back up :D

User avatar
CREPELLO
Posts: 5558
Joined: 29 Nov 2008, 12:55am

Re: Punctures

Postby CREPELLO » 26 Dec 2014, 5:55pm

reohn2 wrote:
CREPELLO wrote:I would like to know if there is a good technique for inspecting the rear tyre on the road, when the bike has full length mudguards. Without turning the bike upside down, I find this procedure very awkward. Front tyre - no problem.


With the front wheel laid flat,the rear of the bike can be lifted up with a seatstay so the steering is at 90%,and the rear of the bike balanced with the rear wheel at eye level.
A foot may need to be placed on the front tyre,whilst lifting the rear of the bike.
It's easier to do than explain.
Thanks R2. Makes sense - I'll give that a go.

Moodyman1

Punctures

Postby Moodyman1 » 26 Dec 2014, 10:49pm

I'm with Reohn.
Mid range puncture protection tyres are good enough ie Gatorskin/ marathon greenguard level

chech tyres weekly for embedded objects be careful Turing away from the kerb

i ride about 130 commuting miles per week and get 1 or 2 punctures per year.

ukdodger
Posts: 2992
Joined: 18 Aug 2007, 5:32pm
Location: Sunny Surrey

Re: Punctures

Postby ukdodger » 29 Dec 2014, 11:45pm

jb wrote:Punctures are a thing of the past with modern tyres, Unless I deliberately ride over a barb wire fence I fully expect never to get another one , ever.
:twisted:


Hmmm. I've had a Marathon Plus Kevlar 'puncture proof tyre' where the wire bead broke and went straight through the tube. Dont count yer chickens..

Image

jb
Posts: 1045
Joined: 6 Jan 2007, 12:17pm
Location: Clitheroe

Re: Punctures

Postby jb » 30 Dec 2014, 12:52am

Is that not classed as a tyre defect rather than a failure to stop road debris ingressing the carcass? and as of yet I've counted my chickens out and counted them all back
Cheers
J Bro

Brucey
Posts: 42986
Joined: 4 Jan 2012, 6:25pm

Re: Punctures

Postby Brucey » 30 Dec 2014, 8:33am

ukdodger wrote:
jb wrote:Punctures are a thing of the past with modern tyres, Unless I deliberately ride over a barb wire fence I fully expect never to get another one , ever.
:twisted:


Hmmm. I've had a Marathon Plus Kevlar 'puncture proof tyre' where the wire bead broke and went straight through the tube. Dont count yer chickens..

Image


That might be a result of underinflation but I think it is just as likely to be a result of defective manufacturing. The wire bead doesn't have to break to come out like that; tyres are made with two or three turns of thin wire in the bead (with two free ends) and they are held to the correct diameter by a combination of rubber moulded in the carcass and simple friction. The friction arises as a consequence of air pressure. This section;

Image

has a larger rubber fillet in with the bead wire, extended up the sidewall, meant to give some snake-bite protection. But most tyres have a similar (but smaller) rubber infill in the with the bead, designed to cushion it and make it secure.

In recent times Schwalbe have (accidentally or deliberately) deleted the rubber from the wire region; such tyres 'creak' when the beads are flexed. The tyre sections that they supply to their dealers still have the rubber in with the wires (like they should do) so when you are shown these you are being shown a lie; that is not the same as the tyre you will be buying in many cases. I've seen a few such tyres fail because the wires started to move around, but I think they were all underinflated to some extent. I do think that leaving the rubber out from that region is a pretty dumb idea though; it is bound to increase the risk of tyre failure.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

ukdodger
Posts: 2992
Joined: 18 Aug 2007, 5:32pm
Location: Sunny Surrey

Re: Punctures

Postby ukdodger » 30 Dec 2014, 11:10am

That sounds right Brucey. The end of the tyre bead didnt have the look of a break. If you notice to the left in the picture the rubber appears to have worn away releasing one end of the bead. I run on 55-65lbs which is within Schwalbe's limits because I like a soft ride (though if you get any sidewall cracking Schwalbe will claim their limit is only a 'guide' and 55-65lbs is too soft to prevent it). However this occurred after doing the Trans Pennine way which is seriously rocky in places and no doubt explains it

Question: What is the measure of tyre suppleness? I once had a pair of tyres made but Hutchinson that were wonderfully comfortable to ride but werent 'soft'. They dont make them anymore but knowing what to look for would help. Thanks.

Brucey
Posts: 42986
Joined: 4 Jan 2012, 6:25pm

Re: Punctures

Postby Brucey » 30 Dec 2014, 1:34pm

ukdodger wrote:..... I run on 55-65lbs which is within Schwalbe's limits because I like a soft ride (though if you get any sidewall cracking Schwalbe will claim their limit is only a 'guide' and 55-65lbs is too soft to prevent it)....


this is another case of weaselry IMHO. Tyres that are underinflated typically suffer the consequences of the sidewall flexing excessively, which normally results in the casing failing in some way (including the wire bead failing in some types of tyre). But the sidewall is made of rubber, and should flex repeatedly without issue. Were it not so, you would see cracking on (say) rear tyres and not fronts; but you normally see cracking on both.

Schwalbe tyres have gone through a very bad patch where they suffer sidewall cracking even when they are not used at all. You can park the bike with clean tyres in a cool dark shed and come back and find the tyres perished. This is nothing to do with underinflation whatsoever; it is just substandard manufacturing of some kind.

Question: What is the measure of tyre suppleness? I once had a pair of tyres made but Hutchinson that were wonderfully comfortable to ride but werent 'soft'. They dont make them anymore but knowing what to look for would help. Thanks.


Obviously if you can obtain meaningful CRR data that will help, but do bear in mind that real roads are nothing like the rollers they usually use to measure such things. For ad-hoc techniques;

1) if you can see a pair on the rim, correctly inflated, flick them with the end of your finger. Listen to the noise; if it is a resonant noise then the tyre may roll a whole lot easier than a tyre where flicking it produces a dull thud instead.

2) If you are able to take a bare wheel with the tyre fitted, and simply drop it (on smooth concrete) so that it bounces up again, then look at how high the wheel bounces. You will need other wheels/tyres to compare, and you will have to practice nice straight drops. Good tyres will cause a bare wheel to bounce up to 60-70% or so, and it will likely sound resonant; bad tyres won't bounce so high and the noise will be duller.

3) Handle the carcass of the tyre. To a good approximation there are three things that create rolling resistance; a) the tread squishing vertically when loaded (so soft rubber and a heavy tread pattern count against you here), b) the bending properties of the tread (the circumference of the contact patch is flexed at any one time) and c) the stiffness of the sidewalls. Typically if you have a light racing tyre you can get all three to be good but any amount of puncture protection tends to add to b) at least. [It isn't clear to me which of a) b) c) is most important; it may vary with the tyre.]

If you look at easy rolling tyres they usually have a vertically firm tread that usually isn't very thick; this is built on a carcass that is made very supple by having very little rubber in it and lots of fine cords (high tpi). The reason high tpi works well is that you can make the sidewall (say) half as thick. If you do this (which might require four times as many threads in the same material, each half as thick, to get the same strength) then the bending strains in the sidewall (and therefore the hysteresis) is very greatly reduced; half as thick potentially means 1/8th the strain in the sidewall. [BTW That isn't a reduction of 1/8th, that is a reduction of 7/8...! It really can be a powerful effect!]

So I hope this helps, anyway. You clearly don't get owt for nowt here; if you insist on tough rubbery sidewalls, a heavy tread, and good puncture protection, you had better get used to the idea of relatively sluggish tyres.

BTW the marathon 'greenguard' tyres are quite clever because the puncture resistant layer is made in highly elastic rubber that cannot squirm excessively; this means that the CRR is nothing like as bad as it would be if you had a tread that was as thick as all the layers put together. It isn't a quick tyre like this, but it is nothing like as slow as it might be otherwise.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Bikefayre
Posts: 176
Joined: 1 Dec 2014, 3:36pm

Re: Punctures

Postby Bikefayre » 30 Dec 2014, 3:57pm

So far have just had my fourth puncture in over ten years. The tyre is a useless Cyclo-Cross Michelin with toilet paper thin rubber and no puncture protection so took a deep breath and with the magic of Amazon ordered a super thick Raleigh tube, about the thickness of a pound coin. Relax... Now have a puncture proof tube fitted, no slime, so instead of the tyre having a layer have done it the old fashioned way using a tube! Stilll think there's nothing to beat Plus tyres from Schwalbe and have some Samura ones as well. Continental, Halo [Duro] and Panaracer all do Plus tyres. My own bikes are getting the Schwalbe Energizer, Marathon Plus Evo and Durano Plus Tyres. The secret is to keep your tyres as like cheese they harden with age so puncture less the more you keep them so do not use them till the smell is gone, have been ding this since the mid 'eighties and works a treat. Raleigh puncture proof tubes are a good solution though they do make the wheel feel heavy unlike Plus tyre which do not. Also have noticed people who fit directional and dynamic tyres the wrong way have the most punctures. In normal directional tyre the tread pushes everything forwards and out wards not into the middle as would happen if the tread is pointing backwards. Also let it be noted do not read endless tyre articles in cycling magazines as these specialise in mainly unaffordable, unattainable expensive Kevlar beaded tyres whereas I specialise in wire bead tyres and all the makes no-one uses on this forum.