Pinch p*nct*res and tyres



T

Tim Downie

Guest
It struck me that all my recent p*nct*res have been pinch p*nct*res in my
rear tyre caused by hitting rocks or pot-holes on a forest road that I like
to ride along.

Short of making sure that my tyres are well pumped up before I set off
(90-100 psi), is there anything else I can do to reduce their likelihood?
Are any tyres less prone to them than others or is it simple a function of
tyre width and pressure?

Tim
 
Tim Downie wrote:
> It struck me that all my recent p*nct*res have been pinch p*nct*res
> in my rear tyre caused by hitting rocks or pot-holes on a forest road
> that I like to ride along.
>
> Short of making sure that my tyres are well pumped up before I set off
> (90-100 psi), is there anything else I can do to reduce their
> likelihood? Are any tyres less prone to them than others or is it
> simple a function of tyre width and pressure?


As long as there's nothing sharp in the rim and the rim tape is working,
it does all come down to having adequate pressure for the tyre width and
the load on it. Maybe 100 psi is not enough for you and your tyres. What
size tyres?

~PB
 
"Pete Biggs" <[email protected]>typed

> As long as there's nothing sharp in the rim and the rim tape is working,
> it does all come down to having adequate pressure for the tyre width and
> the load on it. Maybe 100 psi is not enough for you and your tyres. What
> size tyres?


> ~PB



What weight rider?

--
Helen D. Vecht: [email protected]
Edgware.
 
Tim Downie wrote:
> It struck me that all my recent p*nct*res have been pinch p*nct*res in my
> rear tyre caused by hitting rocks or pot-holes on a forest road that I like
> to ride along.
>
> Short of making sure that my tyres are well pumped up before I set off
> (90-100 psi), is there anything else I can do to reduce their likelihood?
> Are any tyres less prone to them than others or is it simple a function of
> tyre width and pressure?
>


100psi sounds very high for avoiding pinch punctures. My mtb tyres are
around 35-40psi and cover really rough ground without pinch puncturing.

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham
 
Tony Raven wrote:
> Tim Downie wrote:
>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>> in my rear tyre caused by hitting rocks or pot-holes on a forest
>> road that I like to ride along.
>>
>> Short of making sure that my tyres are well pumped up before I set
>> off (90-100 psi), is there anything else I can do to reduce their
>> likelihood? Are any tyres less prone to them than others or is it
>> simple a function of tyre width and pressure?

>
> 100psi sounds very high for avoiding pinch punctures. My mtb tyres
> are around 35-40psi and cover really rough ground without pinch
> puncturing.


I'm not sure 100psi would be enough for a 20mm tyre + 15 stone rider
versus atrocious potholes, for example.

~PB
 
Tim Downie wrote:
> It struck me that all my recent p*nct*res have been pinch p*nct*res
> in my rear tyre caused by hitting rocks or pot-holes on a forest road
> that I like to ride along.


This is unlikley if you've had lots, but there's a chance you had an
ordinary slow p*ncture shortly before each pinch p*ncture and didn't
realise the pressure had dropped.

~PB
 
Tim Downie wrote:
> It struck me that all my recent p*nct*res have been pinch p*nct*res in my
> rear tyre caused by hitting rocks or pot-holes on a forest road that I like
> to ride along.
>
> Short of making sure that my tyres are well pumped up before I set off
> (90-100 psi), is there anything else I can do to reduce their likelihood?
> Are any tyres less prone to them than others or is it simple a function of
> tyre width and pressure?

I've been riding Tufo clincher tubulars for some time now. They can't
pinch and as pressure stays up well (120 back 110 front) I don't think
I've had a p*nct*re in 7,000 miles although they have a sealant to stop
air escaping.
All the best
Dan Gregory
 
Pete Biggs wrote:
> Tim Downie wrote:
>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>> in my rear tyre caused by hitting rocks or pot-holes on a forest road
>> that I like to ride along.
>>
>> Short of making sure that my tyres are well pumped up before I set
>> off (90-100 psi), is there anything else I can do to reduce their
>> likelihood? Are any tyres less prone to them than others or is it
>> simple a function of tyre width and pressure?

>
> As long as there's nothing sharp in the rim and the rim tape is
> working, it does all come down to having adequate pressure for the
> tyre width and the load on it. Maybe 100 psi is not enough for you
> and your tyres. What size tyres?


700c x 28.

Tim
 
Helen Deborah Vecht wrote:
> "Pete Biggs" <[email protected]>typed
>
>> As long as there's nothing sharp in the rim and the rim tape is
>> working, it does all come down to having adequate pressure for the
>> tyre width and the load on it. Maybe 100 psi is not enough for you
>> and your tyres. What size tyres?

>
>> ~PB

>
>
> What weight rider?


About 11st (on 700c x28 tyres)


Tim
 
Pete Biggs wrote:
> Tim Downie wrote:
>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>> in my rear tyre caused by hitting rocks or pot-holes on a forest road
>> that I like to ride along.

>
> This is unlikley if you've had lots, but there's a chance you had an
> ordinary slow p*ncture shortly before each pinch p*ncture and didn't
> realise the pressure had dropped.


Don't think so. I've checked both tubes carefully and the only leaks have
been from the new pinch punctures.

Tim
 
Dan Gregory wrote:
> Tim Downie wrote:
>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>> in my rear tyre caused by hitting rocks or pot-holes on a forest
>> road that I like to ride along.
>>
>> Short of making sure that my tyres are well pumped up before I set
>> off (90-100 psi), is there anything else I can do to reduce their
>> likelihood? Are any tyres less prone to them than others or is it
>> simple a function of tyre width and pressure?

> I've been riding Tufo clincher tubulars for some time now. They can't
> pinch and as pressure stays up well (120 back 110 front) I don't think
> I've had a p*nct*re in 7,000 miles although they have a sealant to
> stop air escaping.
> All the best
> Dan Gregory


Thanks, they look interesting. I'd hate to give up on this forest road as
it's a nice route. These could be the answer. Know of any good deals for
theses tyres?

Tim
 
in message <[email protected]>, Tim Downie
('[email protected]') wrote:

> Pete Biggs wrote:
>> Tim Downie wrote:
>>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>>> in my rear tyre caused by hitting rocks or pot-holes on a forest road
>>> that I like to ride along.
>>>
>>> Short of making sure that my tyres are well pumped up before I set
>>> off (90-100 psi), is there anything else I can do to reduce their
>>> likelihood? Are any tyres less prone to them than others or is it
>>> simple a function of tyre width and pressure?

>>
>> As long as there's nothing sharp in the rim and the rim tape is
>> working, it does all come down to having adequate pressure for the
>> tyre width and the load on it. Maybe 100 psi is not enough for you
>> and your tyres. What size tyres?

>
> 700c x 28.


I'm surprised 100psi isn't enough for 28mm tyres with an 11 stone rider,
but if you're getting pinch flats then it isn't - end of story. Or else
your pressure gauge is under-reading. Either way, pump 'em up harder.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Men never do evil so completely and cheerfully as when they
;; do it from  religious conviction."          -- Pascal
 
"Tim Downie" <[email protected]>typed


> Helen Deborah Vecht wrote:
> > "Pete Biggs" <[email protected]>typed
> >
> >> As long as there's nothing sharp in the rim and the rim tape is
> >> working, it does all come down to having adequate pressure for the
> >> tyre width and the load on it. Maybe 100 psi is not enough for you
> >> and your tyres. What size tyres?

> >
> >> ~PB

> >
> >
> > What weight rider?


> About 11st (on 700c x28 tyres)



> Tim



100 psi should be ample, but get your butt off the saddle for any
obvious forthcoming blips.

--
Helen D. Vecht: [email protected]
Edgware.
 
Tim Downie wrote:
> Dan Gregory wrote:
>> Tim Downie wrote:
>>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>>> in my rear tyre caused by hitting rocks or pot-holes on a forest
>>> road that I like to ride along.
>>>
>>> Short of making sure that my tyres are well pumped up before I set
>>> off (90-100 psi), is there anything else I can do to reduce their
>>> likelihood? Are any tyres less prone to them than others or is it
>>> simple a function of tyre width and pressure?

>> I've been riding Tufo clincher tubulars for some time now. They can't
>> pinch and as pressure stays up well (120 back 110 front) I don't
>> think I've had a p*nct*re in 7,000 miles although they have a
>> sealant to
>> stop air escaping.
>> All the best
>> Dan Gregory

>
> Thanks, they look interesting. I'd hate to give up on this forest
> road as it's a nice route. These could be the answer. Know of any
> good deals for theses tyres?


Special tyres aren't necessary. Any normal 28mm tyre + 100psi* + 11st
should not compress all the way to the rim, whatever you hit. There's
something funny going on.

Rim tape is No. 1 suspect if puncture isn't actually caused by tube
getting pinched between rim and road.

* consider trying 110psi in rear if tyre is actually more like 25mm than
28mm.

~PB
 
Tim Downie wrote:

>> This is unlikley if you've had lots, but there's a chance you had an
>> ordinary slow p*ncture shortly before each pinch p*ncture and didn't
>> realise the pressure had dropped.

>
> Don't think so. I've checked both tubes carefully and the only leaks
> have been from the new pinch punctures.


Have you patched the pinch punctures before looking for the tiniest of
bubbles under water?

(Worth doing for the sake of research even if you don't intend to use the
tubes again)

~PB
 
Tim Downie wrote:
>
> About 11st (on 700c x28 tyres)
>



You won't be getting normal pinch puncture then and can forget about it
being the surface you are riding on. There must be something else
causing pinch puncture like punctures. Have a look for a sharp edge on
the inside of the rim or a cheap plastic rim tape (replace with Velox
rim tape)

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham
 
"Simon Brooke" <[email protected]> wrote in message
news:eek:[email protected]...
> in message <[email protected]>, Tim Downie
> ('[email protected]') wrote:
>
>> Pete Biggs wrote:
>>> Tim Downie wrote:
>>>> It struck me that all my recent p*nct*res have been pinch p*nct*res
>>>> in my rear tyre caused by hitting rocks or pot-holes on a forest road
>>>> that I like to ride along.
>>>>
>>>> Short of making sure that my tyres are well pumped up before I set
>>>> off (90-100 psi), is there anything else I can do to reduce their
>>>> likelihood? Are any tyres less prone to them than others or is it
>>>> simple a function of tyre width and pressure?
>>>
>>> As long as there's nothing sharp in the rim and the rim tape is
>>> working, it does all come down to having adequate pressure for the
>>> tyre width and the load on it. Maybe 100 psi is not enough for you
>>> and your tyres. What size tyres?

>>
>> 700c x 28.

>
> I'm surprised 100psi isn't enough for 28mm tyres with an 11 stone rider,
> but if you're getting pinch flats then it isn't - end of story. Or else
> your pressure gauge is under-reading. Either way, pump 'em up harder.
>
>>



I have recently started cycling on the road after a break of 35 years.
Living in the Yorkshire Dales there are plenty of hills but I have got my
distance over the first month up to 12 miles.

I recently bought a nice second-hand Bianchi road bike.
Bought a new track pump for the Armadillo 700 x 23 tyres that are fitted,
currently have these at about 95 PSI.
It says on the tyre a maximum pressure of 115 to 135 PSI.

My weight is 15 stone 10lbs.
Anyone wish to comment on the Tyres and pressures.
What is the best type of Inner Tube to buy for a spare.

Rusty Spokes
 
Rusty Spokes wrote:
>
> I recently bought a nice second-hand Bianchi road bike.
> Bought a new track pump for the Armadillo 700 x 23 tyres that are fitted,
> currently have these at about 95 PSI.
> It says on the tyre a maximum pressure of 115 to 135 PSI.
>
> My weight is 15 stone 10lbs.
> Anyone wish to comment on the Tyres and pressures.
> What is the best type of Inner Tube to buy for a spare.
>


The tyres at those pressure should be just fine but I'd tend towards the
upper end if your pump will make it.


--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham
 
On Mon, 01 May 2006 17:31:55 +0100, Tim Downie wrote:
> About 11st (on 700c x28 tyres)


I'm around 11 1/2st and ride 700C x 23 Schwalbe Blizzards at 80-100psi
(Depending on whether I've remembered to pump them up). My last puncture
was a pinch pucture but that came from riding off road (Accompanying a
jogger) when the tyre pressure was already down to ~70psi.

Unless your deliberately putting all you weight on the rear as you hit
potholes I doubt that pressure is an issue.

Jon
 
Rusty Spokes wrote:

> I have recently started cycling on the road after a break of 35 years.
> Living in the Yorkshire Dales there are plenty of hills but I have
> got my distance over the first month up to 12 miles.
>
> I recently bought a nice second-hand Bianchi road bike.
> Bought a new track pump for the Armadillo 700 x 23 tyres that are
> fitted, currently have these at about 95 PSI.
> It says on the tyre a maximum pressure of 115 to 135 PSI.
>
> My weight is 15 stone 10lbs.
> Anyone wish to comment on the Tyres and pressures.


You'll probably get away without pinch punctures at that pressure but try
a few more psi in the rear tyre to reduce rolling resistance, say 110 to
125 psi, depending on how soft/harsh the ride feels with it. 95 should be
ok for the front.

Some lighter & faster tyres would be nicer and not too impractical in the
summer, eg. Vittoria Open Corsa CX EVO 23.

> What is the best type of Inner Tube to buy for a spare.


Michelin or Vittoria Ultralight 18-23, or Schwalbe SV20 Extra Light 18-25.
These are reliable enough and pack up nice and small.

~PB