Rear wheel 'too small'

[Pete Biggs]

Nat wrote:
> I wonder if any of you have ever encountered this problem. Every time
> I try to change the back wheel, I have some inner tube left over which
> causes a bump. It is almost as though the wheel is just a bit too
> small. I've been changing my own inners for years so I know all the
> 'tips and tricks' but this darn thing won't blooming go in!

The tube could be too big. One that is too fat will effectively be too long
as well. A fold shouldn't cause a bump, though. Try a different tube
anyway.

I'll say this even though you say you know the tricks: Make sure the tube
is tucked in before you fit the tyre bead. Push the valve up into the tyre
before inflation (do this without valve lockring).

> The bike is an old ammaco sport 6000 if it helps!

No.

~PB

 

[Pete Biggs]

Nat wrote:

> I've tried a range of sizes so I don't think this is the problem.

If you have tried a tube that is definitely not too big, then the problem is
to do with the wheel or tyre, and nothing to do with the tube at all.

The tyre may not be fitted properly, or the wheel rim or tyre is faulty. I
would try another tyre first.

~PB

 

[Nat]

I wonder if any of you have ever encountered this problem. Every time
I try to change the back wheel, I have some inner tube left over which
causes a bump. It is almost as though the wheel is just a bit too
small. I've been changing my own inners for years so I know all the
'tips and tricks' but this darn thing won't blooming go in!
The bike is an old ammaco sport 6000 if it helps!
Thanks

 

[Nat]

On 20 Jun, 09:59, "Pete Biggs"
<[email protected]> wrote:
> Nat wrote:
> > I wonder if any of you have ever encountered this problem. Every time
> > I try to change the back wheel, I have some inner tube left over which
> > causes a bump. It is almost as though the wheel is just a bit too
> > small. I've been changing my own inners for years so I know all the
> > 'tips and tricks' but this darn thing won't blooming go in!
>
> The tube could be too big. One that is too fat will effectively be too long
> as well. A fold shouldn't cause a bump, though. Try a different tube
> anyway.
>
> I'll say this even though you say you know the tricks: Make sure the tube
> is tucked in before you fit the tyre bead. Push the valve up into the tyre
> before inflation (do this without valve lockring).
>
> > The bike is an old ammaco sport 6000 if it helps!
>
> No.
>
> ~PB
I've tried a range of sizes so I don't think this is the problem.
Thanks anyway.

 

[Ben C]

On 2008-06-20, Nat <[email protected]> wrote:
> I wonder if any of you have ever encountered this problem. Every time
> I try to change the back wheel, I have some inner tube left over which
> causes a bump. It is almost as though the wheel is just a bit too
> small. I've been changing my own inners for years so I know all the
> 'tips and tricks' but this darn thing won't blooming go in!
> The bike is an old ammaco sport 6000 if it helps!

I have experienced them sometimes appearing to be a bit too big when
they're definitely supposed to be the right size (700C is just 700C).

If you try pumping up an inner tube which is not inside an outer tube,
its radius quickly becomes enormous.

Maybe it gets some permanent stretch when you do that, so if you ever
pumped one up a bit to find where the puncture was perhaps that could be
the cause of the elongation.

Anyway it doesn't matter. Just stuff it in and pump it up. If the tyre
then looks like a python that's swallowed a rabbit, let it down again,
squish it about a bit, and try again.

 

[Roger Thorpe]

Nat wrote:

> I wonder if any of you have ever encountered this problem. Every time
> I try to change the back wheel, I have some inner tube left over which
> causes a bump. It is almost as though the wheel is just a bit too
> small. I've been changing my own inners for years so I know all the
> 'tips and tricks' but this darn thing won't blooming go in!
> The bike is an old ammaco sport 6000 if it helps!
> Thanks
I hope that this isn't one of the "tips & tricks" that you've tried...
Ignore it if it is!
I prefer to partially inflate the tube, put it in the tyre (while it's
not on the rim) and bounce the tyre on the road to allow the tube to
distribute itself evenly, especially the extra bit that I'd crammed in last.
Then put one bead of the tyre on with the tube in place (after locating
the valve). and so on....
Works for me.
Roger Thorpe

 

[Nat]

On 20 Jun, 11:57, Roger Thorpe <[email protected]>
wrote:
> Nat wrote:
> > I wonder if any of you have ever encountered this problem. Every time
> > I try to change the back wheel, I have some inner tube left over which
> > causes a bump. It is almost as though the wheel is just a bit too
> > small. I've been changing my own inners for years so I know all the
> > 'tips and tricks' but this darn thing won't blooming go in!
> > The bike is an old ammaco sport 6000 if it helps!
> > Thanks
>
> I hope that this isn't one of the "tips & tricks" that you've tried...
> Ignore it if it is!
> I prefer to partially inflate the tube, put it in the tyre (while it's
> not on the rim) and bounce the tyre on the road to allow the tube to
> distribute itself evenly, especially the extra bit that I'd crammed in last.
> Then put one bead of the tyre on with the tube in place (after locating
> the valve). and so on....
> Works for me.
> Roger Thorpe

Thanks Roger, but like I said, I am used to changing a tyre and what
you mentioned are fairly standard in my tyre changing. But thanks
anyway.It is always nice to know that people do the same things I do
when chaning an inner.
I am thinking there is more than just tyre changing issues here. I
think it may be a problem with the actual wheel and so far there seems
to be no magic answer.
Thanks anway.

 

[Nat]

On 20 Jun, 11:57, Roger Thorpe <[email protected]>
wrote:
> Nat wrote:
> > I wonder if any of you have ever encountered this problem. Every time
> > I try to change the back wheel, I have some inner tube left over which
> > causes a bump. It is almost as though the wheel is just a bit too
> > small. I've been changing my own inners for years so I know all the
> > 'tips and tricks' but this darn thing won't blooming go in!
> > The bike is an old ammaco sport 6000 if it helps!
> > Thanks
>
> I hope that this isn't one of the "tips & tricks" that you've tried...
> Ignore it if it is!
> I prefer to partially inflate the tube, put it in the tyre (while it's
> not on the rim) and bounce the tyre on the road to allow the tube to
> distribute itself evenly, especially the extra bit that I'd crammed in last.
> Then put one bead of the tyre on with the tube in place (after locating
> the valve). and so on....
> Works for me.
> Roger Thorpe

Thanks Roger, but like I said, I am used to changing an inner and what
you mentioned are fairly standard in my tyre changing. But thanks
anyway.It is always nice to know that people do the same things I do
when chaning an inner.
I am thinking there is more than just tyre changing issues here. I
think it may be a problem with the actual wheel and so far there seems
to be no magic answer.
Thanks anway.

 

[Pete Biggs]

I wrote:
> Nat wrote:
>
>> I've tried a range of sizes so I don't think this is the problem.
>
> If you have tried a tube that is definitely not too big, then the
> problem is to do with the wheel or tyre, and nothing to do with the
> tube at all.
> The tyre may not be fitted properly, or the wheel rim or tyre is
> faulty. I would try another tyre first.

Sorry, ignore all that above.

Reading the original message again, it's clear that the inner tube size is
incompatible if there is some "inner tube left over" and the "darn thing
won't blooming go in".

Nat, What make, model and size is the tyre, and what size and make tubes
have you tried?

I still suspect that the tubes you have tried so far are too large for the
tyre size. Perhaps you have misunderstood the size required, or the tube is
badly manufactured. If it could be the latter then try another brand.

It is ulikely to be anything to do with the wheel. Some tyres are actually
different in size than what is on the label, so that could be the problem.

~PB

 

[Nat]

On 20 Jun, 13:49, "Pete Biggs"
<[email protected]> wrote:
> I wrote:
> > Nat wrote:
>
> >> I've tried a range of sizes so I don't think this is the problem.
>
> > If you have tried a tube that is definitely not too big, then the
> > problem is to do with the wheel or tyre, and nothing to do with the
> > tube at all.
> > The tyre may not be fitted properly, or the wheel rim or tyre is
> > faulty.  I would try another tyre first.
>
> Sorry, ignore all that above.
>
> Reading the original message again, it's clear that the inner tube size is
> incompatible if there is some "inner tube left over" and the "darn thing
> won't blooming go in".
>
> Nat, What make, model and size is the tyre, and what size and make tubes
> have you tried?
>
> I still suspect that the tubes you have tried so far are too large for the
> tyre size.  Perhaps you have misunderstood the size required, or the tube is
> badly manufactured.  If it could be the latter then try another brand.
>
> It is ulikely to be anything to do with the wheel.  Some tyres are actually
> different in size than what is on the label, so that could be the problem..
>
> ~PB

Hi,
Sorry to do the 'teaching granny to suck eggs' thing again, but the
wheel is definitly a 700c x23. Thus far I have tried four different
inners of that size and a few others of different widths. Most, as you
know, have a broad range (eg 18-23) and I have tried the smallest I
can find. The wheel is the factory one so I think my solution is to
get another. I am wondering if the previous owner had an accident on
it and the damage is not noticable.

 

[Pete Biggs]

Nat wrote:
> Hi,
> Sorry to do the 'teaching granny to suck eggs' thing again, but the
> wheel is definitly a 700c x23.

You mean the *tyre*, I suppose.

> Thus far I have tried four different
> inners of that size and a few others of different widths. Most, as you
> know, have a broad range (eg 18-23) and I have tried the smallest I
> can find.

Ok, I'll accept that now. Sorry to doubt you, but had to make sure the most
likely cause was eleminated.

> The wheel is the factory one so I think my solution is to
> get another. I am wondering if the previous owner had an accident on
> it and the damage is not noticable.

I think the effective circumference would have to have been made smaller for
an inner tube not to fit, and I can't imagine what could do that without it
being extremely noticeable... and unrideable! And the tyre wouldn't fit if
the inner tube wouldn't fit.

Something very strange is going on. Sorry I can't think what it could be.

~PB

 

[Pete Biggs]

ps. Even grannies who know their eggs can make mistakes and oversights, so
no one should be offended at being asked the most basic questions. And it
may still help to answer those questions in full.

~PB

 

[Pete Biggs]

pps. It doesn't make sense that the tube doesn't fit because the wheel is
too small. If that was the case then how would the tyre fit?

Either something very, very strange is going on, or something basic is being
overlooked.

~PB

 

[Pete Biggs]

Mark T wrote:

> - I stick a bit of air in the tube, put it into the tyre, then put the
> tyre onto the rim. I will try putting the tube into the tyre *before*
> putting the bit of air in them. That would prevent any chance of
> stretching.

A *small amount* of air (barely enough to round it out) won't stretch the
tube permanently and will make it easier to fit. Too much air, though, will
make the tube too big, and that might be the OP's problem.

Replacing the wheel because the tube doesn't fit the tyre is one of the most
bonkers ideas I've ever read on this newsgroup.

~PB

 

[Mark T]

Nat writtificated

> I wonder if any of you have ever encountered this problem. Every time
> I try to change the back wheel, I have some inner tube left over which
> causes a bump. It is almost as though the wheel is just a bit too
> small. I've been changing my own inners for years so I know all the
> 'tips and tricks' but this darn thing won't blooming go in!

Firstly, I very much doubt the rim is the problem. If the circumference
had been significantly changed after an accident, or if it was
significantly undersized in some way then you'd have all sorts of major
problems (like tyres not fitting, zillions of broken spokes.

Secondly I always seem to have a bit of inner tube left over and have to
coax it into the tyre. I suspect this is because:

- Many inner tubes are designed for 622mm and 630mm rims[1]. It is
possible to buy tubes designed only for 622 rims, but I'm haven't
bothered seeking them out to use. I wouldn't trust the lack of a
"27xwhatever it is" on the packaging to indicate it's only for 622 rims.
I'm not even sure whether Continentals 630mm compatible tubes are any
bigger than their 622 only tubes. Even if they are I doubt 8mm would
make much difference on a 622 rim.

- I stick a bit of air in the tube, put it into the tyre, then put the
tyre onto the rim. I will try putting the tube into the tyre *before*
putting the bit of air in them. That would prevent any chance of
stretching. I should really fit one tyre bead onto the rim before I put
the tube in too.

I suspect our problems are due to bad technique, but I'm going to put all
the blame on some tubes being designed for rims 8mm bigger in
circumference



This lists Continental's inner tubes:
<www.conti-tyres.co.uk/conticycle/accessories.php>

This is wheely helpful for when understanding the complete mess that is
rim sizing.
<www.sheldonbrown.com/tire-sizing.html>




[1] e.g.
700x18/25 Continental Race 28 Light inner tubes are rated for 18/25-
622/630
700x18/25 Continental Race 28 Supersonic are rated for just 18/25-622

 

[vernon]

"Pete Biggs" <[email protected]> wrote in
message news:[email protected]...
> Mark T wrote:
>
>> - I stick a bit of air in the tube, put it into the tyre, then put the
>> tyre onto the rim. I will try putting the tube into the tyre *before*
>> putting the bit of air in them. That would prevent any chance of
>> stretching.
>
> A *small amount* of air (barely enough to round it out) won't stretch the
> tube permanently and will make it easier to fit. Too much air, though,
> will make the tube too big, and that might be the OP's problem.
>
> Replacing the wheel because the tube doesn't fit the tyre is one of the
> most bonkers ideas I've ever read on this newsgroup.
>
I'm surprised that the original poster has failed to notice that since the
tyre fits the wheel OK, the 'problem' lies with the tube(s) not the wheel.
Though, there again, one can get fixed on a notion that is difficult to
dislodge by others with unblinkered views - been there done that.

 

[Rob Morley]

On Fri, 20 Jun 2008 02:50:36 -0700 (PDT)
Nat <[email protected]> wrote:

> I wonder if any of you have ever encountered this problem. Every time
> I try to change the back wheel, I have some inner tube left over which
> causes a bump. It is almost as though the wheel is just a bit too
> small. I've been changing my own inners for years so I know all the
> 'tips and tricks' but this darn thing won't blooming go in!
> The bike is an old ammaco sport 6000 if it helps!
>

The tube doesn't really fit the rim, it fits the tyre and tyre fits the
rim. Also the tube can't cause a bump (unless it's trapped under the
tyre bead) - the tyre holds its own shape and the tube just holds the
air inside the tyre.