tube rotation
 

So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. Schraeder valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

tube rotation
 

On Apr 14, 11:30*am, raging raven wrote:
So what causes the tube to rotate inside a clincher tire? *Under-
inflation? *I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. *Schraeder valves/26x1.95 city bike tires if that makes any
difference. *Thanks in advance.

Underinflation and hard braking will do it.

tube rotation
 

On 4/14/2010 9:44 AM landotter wrote:

On Apr 14, 11:30�am, raging wrote:
So what causes the tube to rotate inside a clincher tire? �Under-
inflation? �I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. �Schraeder valves/26x1.95 city bike tires if that makes any
difference. �Thanks in advance.

Underinflation and hard braking will do it.

I never ride on underinflated tires, and I have also see the rotation. I
personally think it's related to

http://en.wikipedia.org/wiki/Sailing_stones

--
Mike "Rocket J Squirrel"
Bend, Oregon

tube rotation
 

On 14/04/10 9:30 AM, raging raven wrote:
So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. Schraeder valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

There's a tendency to use cheap tubes that cover too wide a range of
tire sizes. These tubes are too small for the larger tire sizes of the
range specified on the box. When inflated, the rubber is stretched and
there is insufficient friction between the tube and the outside of the
tire, or the tube and the rim tape/strip.

I've seen 18-28mm tubes from one manufacturer while a competing
manufacturer will have an 18-23mm, a 23-28mm, and a 25-32mm. Always
choose the largest size possible. Never use a tube with more than a 7mm
range from smallest to largest, with a tire at the large end of the range.

If you're buying tubes at Wal-Mart or Target, they have limited sizes.

In Presta, Performance has 700c x 19-26, 700c x 28-32, 700c x 35-38,
700c x 48-52.

tube rotation
 

On Apr 14, 12:13*pm, Mike Elliott
wrote:
On 4/14/2010 9:44 AM landotter wrote:

On Apr 14, 11:30 am, raging *wrote:
So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. Schraeder valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

Underinflation and hard braking will do it.

I never ride on underinflated tires, and I have also see the rotation. I
personally think it's related to

http://en.wikipedia.org/wiki/Sailing_stones

A completely different species of gnome pushes those around.

tube rotation
 

On 4/14/2010 1:54 PM SMS wrote:

On 14/04/10 9:30 AM, raging raven wrote:
So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. Schraeder valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

There's a tendency to use cheap tubes that cover too wide a range of
tire sizes. These tubes are too small for the larger tire sizes of the
range specified on the box. When inflated, the rubber is stretched and
there is insufficient friction between the tube and the outside of the
tire, or the tube and the rim tape/strip.

I've seen 18-28mm tubes from one manufacturer while a competing
manufacturer will have an 18-23mm, a 23-28mm, and a 25-32mm. Always
choose the largest size possible. Never use a tube with more than a 7mm
range from smallest to largest, with a tire at the large end of the range.

If you're buying tubes at Wal-Mart or Target, they have limited sizes.

In Presta, Performance has 700c x 19-26, 700c x 28-32, 700c x 35-38,
700c x 48-52.

What? Are you trying to say that the tube cannot stretch enough to press
firmly enough against the inside of the casing and the rim to avoid
slithering about, while at the same time it manages to provide enough
internal pressure to keep the tire sufficiently inflated and the rims off
the pavement?

On the face of it, that seems a stretch (heh).

I'm not saying you're wrong, I'm saying I don't see it.

--
Mike "Rocket J Squirrel"
Bend, Oregon

tube rotation
 

On 15 Apr, 01:40, Mike Elliott
wrote:
On 4/14/2010 1:54 PM SMS wrote:



On 14/04/10 9:30 AM, raging raven wrote:
So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time the
tubes have moved until the valve stem is skewed at a significant
angle. Schraeder valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

There's a tendency to use cheap tubes that cover too wide a range of
tire sizes. These tubes are too small for the larger tire sizes of the
range specified on the box. When inflated, the rubber is stretched and
there is insufficient friction between the tube and the outside of the
tire, or the tube and the rim tape/strip.

I've seen 18-28mm tubes from one manufacturer while a competing
manufacturer will have an 18-23mm, a 23-28mm, and a 25-32mm. Always
choose the largest size possible. Never use a tube with more than a 7mm
range from smallest to largest, with a tire at the large end of the range.

If you're buying tubes at Wal-Mart or Target, they have limited sizes.

In Presta, Performance has 700c x 19-26, 700c x 28-32, 700c x 35-38,
700c x 48-52.

What? Are you trying to say that the tube cannot stretch enough to press
firmly enough against the inside of the casing and the rim to avoid
slithering about, while at the same time it manages to provide enough
internal pressure to keep the tire sufficiently inflated and the rims off
the pavement?

On the face of it, that seems a stretch (heh).

I'm not saying you're wrong, I'm saying I don't see it.

it's a cover - up.

tube rotation
 

Jobst Brandt wrote:
someone wrote:

So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time
the tubes have moved until the valve stem is skewed at a significant
angle. Schrader valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

How else can you give thanks when asking a question? Tubes, with
their large contact area with the tire cannot slide, considering their
elastic ability to yield to any deformation of the tire. The skewed
stem comes from tire creep and that means the tire does not seat well
on the rim and the rim has some lubricious stuff on it, that could be
wax that flows with brake heat.

How about a control experiment marking the tire sidewall at the stem
and noting whether there is any change in relative position of stem to
tire. I'm sure you will see that the whole tore is moving.


The tire slides in the rim? I-I never even thought that could happen.
Has this been documented? Oh wait, I'm sure it has been, and probably in
1893. Carl?

--
Mike "Rocket J Squirrel"
Bend, Oregon

tube rotation
 

On Wed, 14 Apr 2010 20:37:18 -0700, Mike Elliott
wrote:

Jobst Brandt wrote:
someone wrote:

So what causes the tube to rotate inside a clincher tire? Under-
inflation? I frequently service a friends bicycle and every time
the tubes have moved until the valve stem is skewed at a significant
angle. Schrader valves/26x1.95 city bike tires if that makes any
difference. Thanks in advance.

How else can you give thanks when asking a question? Tubes, with
their large contact area with the tire cannot slide, considering their
elastic ability to yield to any deformation of the tire. The skewed
stem comes from tire creep and that means the tire does not seat well
on the rim and the rim has some lubricious stuff on it, that could be
wax that flows with brake heat.

How about a control experiment marking the tire sidewall at the stem
and noting whether there is any change in relative position of stem to
tire. I'm sure you will see that the whole tore is moving.


The tire slides in the rim? I-I never even thought that could happen.
Has this been documented? Oh wait, I'm sure it has been, and probably in
1893. Carl?

Dear Mike,

Heck, the rear tire on my old Schwinn 5-speed slipped when I was a
boy, probably because of low tire pressure and constant kicking from a
standstill in low gear to pop the front wheel up for wheelstands.

Cheers,

Carl Fogel

tube rotation
 

On Apr 14, 8:35*pm, Jobst Brandt wrote:
someone wrote:
So what causes the tube to rotate inside a clincher tire? *Under-
inflation? *I frequently service a friends bicycle and every time
the tubes have moved until the valve stem is skewed at a significant
angle. *Schrader valves/26x1.95 city bike tires if that makes any
difference. *Thanks in advance.

How else can you give thanks when asking a question?

[snip]

Dear Jobst,

The phrase "You're welcome" works better than nit-picking.

Cheers,

Carl Fogel