Does Punctured Tyre Need Replacement?

Artemisia

Hi all,

I'm getting ready to take Widders on his first big tour. We leave Friday.

Today I was practising the folding and unfolding and unmounting of the
trike, and noticed, as Sod's law would have it, that one of the wheels
was already flat. It hadn't been flat the last time I stored the bike, a
few days ago, and the bike is flaming new.

Upon examination, I found a small, almost invisible puncture in the
inner tube, opposite the valve. Checking the inside of the tyre, I found
that a small wooden thorn or splinter had clear gone through both tyre
and tube, at the same place. This is relatively comforting, as I feared
a repetition of the Flyzipper scenario - 11 exploding tubes with no
visible cause.

I have a replacement tube. But do I need to replace the tyre? I need to
know this fast as that would mean combing all of Paris to get the same
spec of tyre by this afternoon, since tomorrow is bank holiday and I'm
off before dawn on Friday.

Thanks

EFR
Ile de France

Mark T

Artemisia writtificated [some stuff snipped]

> Upon examination, I found a small, almost invisible puncture in the
> inner tube, opposite the valve. Checking the inside of the tyre, I found
> that a small wooden thorn or splinter had clear gone through both tyre
> and tube, at the same place.

> I have a replacement tube. But do I need to replace the tyre?

No, though make sure you've removed all of the thorn.

I only replace tyres if there is a cut/tear in the rubber that exposes the
inner tube or the canvas stuff under the rubber. This is quite rare.

Artemisia

Mark T wrote:

> No, though make sure you've removed all of the thorn.
>
> I only replace tyres if there is a cut/tear in the rubber that exposes the
> inner tube or the canvas stuff under the rubber. This is quite rare.


Thanks, that saves me a lot of precious time.

Cheers,

EFR

Pete Biggs

Artemisia wrote:
> Hi all,
>
> I'm getting ready to take Widders on his first big tour. We leave
> Friday.
> Today I was practising the folding and unfolding and unmounting of the
> trike, and noticed, as Sod's law would have it, that one of the wheels
> was already flat. It hadn't been flat the last time I stored the
> bike, a few days ago, and the bike is flaming new.
>
> Upon examination, I found a small, almost invisible puncture in the
> inner tube, opposite the valve. Checking the inside of the tyre, I
> found that a small wooden thorn or splinter had clear gone through
> both tyre and tube, at the same place.

At risk of stating the obvious, that is how punctures usually happen:
something goes straight through the tyre and tube - a thorn, or shard of
glass or stone or metal.

> This is relatively comforting,
> as I feared a repetition of the Flyzipper scenario - 11 exploding
> tubes with no visible cause.
>
> I have a replacement tube. But do I need to replace the tyre? I need
> to know this fast as that would mean combing all of Paris to get the
> same spec of tyre by this afternoon, since tomorrow is bank holiday
> and I'm off before dawn on Friday.

Few cyclists replace a tyre after *every* puncture. It would be a waste of
money and materials. In my opinion, a tyre does not need need replacing or
repairing if the hole or cut is so small that it doesn't cause the tyre to
bulge when inflated.

~PB

Ian Smith

["Followup-To:" header set to uk.rec.cycling.]
On Wed, 30 Apr 2008 14:15:24 +0200, Artemisia <nospam@free.fr> wrote:
>
> I have a replacement tube. But do I need to replace the tyre? I need to
> know this fast as that would mean combing all of Paris to get the same
> spec of tyre by this afternoon, since tomorrow is bank holiday and I'm
> off before dawn on Friday.

Normally not.

I replace a tyre if the puncture is so big that it has cut the
threads in the tyre, or if it is the third puncture in unusually
rapid succession (since that indicates that the tyre is worn out,
aged, or otherwise deficient).

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Peter Clinch

Artemisia wrote:

> I have a replacement tube. But do I need to replace the tyre?

As has already been said, no. But one thing to consider for the future
is a tougher tyre, which makes a puncture less likely in the first place
with associated faff fixing it. The Marathons that (IIRC) are standard
on the Scorpion are pretty tough, but there is a "Plus" version which is
about as close to bombproof as pneumatic tyres get.

However, they do weigh more than what you've got already, and the
rolling resistance is a bit higher, so you choose, you lose. It's also
worth considering that the front wheels don't have to come off to fix a
puncture, which makes the whole exercise a lot less painful.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/

PoB

"Peter Clinch" <p.j.clinch@dundee.ac.uk> wrote in message
news:67r9e7F2q45tcU1@mid.individual.net...

| However, they do weigh more than what you've got already, and the
| rolling resistance is a bit higher, so you choose, you lose.

Relative to the weight of a Scorpion?

I was swithering about pluses on my GT because of the weight penalty, I then
thought that a couple of ounces in 40lbs (and yes, I know the double penalty
for wheels) - I'd leave out a Mars bar or two....more room for the now
(almost) redundant puncture kit...

pOB

DougC

PoB wrote:
> "Peter Clinch" <p.j.clinch@dundee.ac.uk> wrote in message
> news:67r9e7F2q45tcU1@mid.individual.net...
>
> | However, they do weigh more than what you've got already, and the
> | rolling resistance is a bit higher, so you choose, you lose.
>
> Relative to the weight of a Scorpion?
>
> I was swithering about pluses on my GT because of the weight penalty, I then
> thought that a couple of ounces in 40lbs (and yes, I know the double penalty
> for wheels) - I'd leave out a Mars bar or two....more room for the now
> (almost) redundant puncture kit...
>
> pOB
>
>

In my experience the Marathon Plus do have higher rolling resistance.

I have a bike that came new with Primo Comets, which were fairly light
(for their 1.5" width) and rolled easily. After a few flats in a few
weeks I decided to switch to the Marathon Plus 1.75's, which have not
flatted once despite my general ignorance of what my tires are rolling
over... but the Marathon+'s do not coast like the Comets did.

This bike is my urban/commuting ride, so I will accept the sloggier
tires for the lack of punctures but I decided against putting the M-P's
on my longer-distance bike.
~