Flat tires / rim cutting valve stem

lordlewis said:

I have been getting flat tires over and over. My rim seems to be
cutting the edge of my valve stem. I was using a rim that
accommodated a tube with a Schrader style valve and then went to a
tube using a Presta valve with a brass adapter. Every time I ride my
bike I get a flat. I have checked the rim for sharp edges and can't
find any. Can anybody help me?

By brass adaptor do you mean to /inflate/ the tube, or to keep it from
"rattling around" in the too-big hole? (Those "donuts" are usually made of
rubber.)

Regardless, just changing to presta shouldn't cause all the problems you're
having; I bet your rim has a tiny burr somewhere in or near the hole, and
the slender valve is allowing some tube rubber to snag it.

Bill "file it away" S.

lordlewis said:

I have been getting flat tires over and over. My rim seems to be
cutting the edge of my valve stem. I was using a rim that accommodated
a tube with a Schrader style valve and then went to a tube using a
Presta valve with a brass adapter. Every time I ride my bike I get a
flat. I have checked the rim for sharp edges and can't find any. Can
anybody help me?

If you've been using the nut that screws down the valve stem to the
rim, you might try just leaving that off.

I once bought what I thought would be a 3 year supply of Specialized
tubes at a great price, only to find that they frequently failed at
the base of the valve stem. Throwing away those nuts made the problem
go away. I now don't bother using the nuts at all, on any brand of
tube. I don't miss their presence (I've heard the purpose of the nut
is to hold the valve stem in place to make it easier to pump, but I've
had no problem at all inflating tires without it) and haven't had a tube
rip at the base of the stem for a long time.

Dennis Ferguson

In article <[email hidden]>,

lordlewis said:

I have been getting flat tires over and over. My rim seems to be
cutting the edge of my valve stem. I was using a rim that accommodated
a tube with a Schrader style valve and then went to a tube using a
Presta valve with a brass adapter. Every time I ride my bike I get a
flat. I have checked the rim for sharp edges and can't find any. Can
anybody help me?

I had a similar problem, although the hole in my rim isn't
Schrader-sized. I got the following explanation from the LBS:

With a hole that is too big for the stem, the high pressure in the tube
tends to push the stem too far through the hole, tearing it off. Their
suggestion was to put an extra layer of Velox with a hole just big
enough for the stem over it. This will help keep the stem from pushing
through the hole and tearing off.

I haven't had any more failures since I tried that, but it's only been a
couple months.

Mark said:

In article <[email hidden]>,

lordlewis said:

I have been getting flat tires over and over. My rim seems to be
cutting the edge of my valve stem. I was using a rim that accommodated
a tube with a Schrader style valve and then went to a tube using a
Presta valve with a brass adapter. Every time I ride my bike I get a
flat. I have checked the rim for sharp edges and can't find any. Can
anybody help me?

I had a similar problem, although the hole in my rim isn't
Schrader-sized. I got the following explanation from the LBS:

With a hole that is too big for the stem, the high pressure in the tube
tends to push the stem too far through the hole, tearing it off. Their
suggestion was to put an extra layer of Velox with a hole just big
enough for the stem over it. This will help keep the stem from pushing
through the hole and tearing off.

I haven't had any more failures since I tried that, but it's only been a
couple months.

I was just into my LBS. the bike mechanic there told me that my valve
stem getting cut was due to the fact I used electrical tape and not
proper rim tape.
I did notice that my rim size is 26 x 1.50 and my tire and tube is 26 x
1.92/2.0. Any thoughts?

In article <[email hidden]>,

lordlewis said:

Mark said:

In article <[email hidden]>,

lordlewis said:

I have been getting flat tires over and over. My rim seems to be
cutting the edge of my valve stem. I was using a rim that accommodated
a tube with a Schrader style valve and then went to a tube using a
Presta valve with a brass adapter. Every time I ride my bike I get a
flat. I have checked the rim for sharp edges and can't find any. Can
anybody help me?

I had a similar problem, although the hole in my rim isn't
Schrader-sized. I got the following explanation from the LBS:

With a hole that is too big for the stem, the high pressure in the tube
tends to push the stem too far through the hole, tearing it off. Their
suggestion was to put an extra layer of Velox with a hole just big
enough for the stem over it. This will help keep the stem from pushing
through the hole and tearing off.

I haven't had any more failures since I tried that, but it's only been a
couple months.

I was just into my LBS. the bike mechanic there told me that my valve
stem getting cut was due to the fact I used electrical tape and not
proper rim tape.
I did notice that my rim size is 26 x 1.50 and my tire and tube is 26 x
1.92/2.0. Any thoughts?

I've always used Velox, I don't think electrical tape would be a very
good barrier between the tube and spokes. I would think you would be
getting a lot of flats from spokes.

I have no idea of the tube is too big for the rim.

lordlewis said:

I was just into my LBS. the bike mechanic there told me that my valve
stem getting cut was due to the fact I used electrical tape and not
proper rim tape.

There's no difference between the effectiveness of electrical tape and
rim tape in regards to "cutting a valve stem", since regular rim tape
has a pre-formed hole bigger than the one in the rim anyway. The tape
doesn't end up between the stem and rim no matter what type you use.

Quoted message said:

I did notice that my rim size is 26 x 1.50 and my tire and tube is 26 x
1.92/2.0. Any thoughts?

The only down side is that it will be more difficult to get the tube
fully inside the tire before inflation, and a bit of extra weight.
The up side is that the tube will be effectively thicker and harder to
puncture as a result.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame

I always understood that if the spokes penetrated into the slot in the back
of the nipple, the spoke was too long. The rim tape was there to 1.
protect the tube from the nipple slot edges, 2. to provide a smooth surface
to allow the tube to adjust itself as it inflates (if all is "powdered"😉.

Many years ago I had a problem with damaged valve stems. I very lightly
sanded the inside edge of the hole (use your finger, not a hard object - too
easy to go to far and make a sharp edge), and then took a bit of tube, made
a small hole in it, and forced it over the stem before putting the stem
through the rim. A small hole forces the bit of rubber to form a collar
that extends a little down the stem, and effectively makes a thicker rubber
around the join between the stem and the tube.

Bruce Nelson

"Mark" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In article <[email hidden]>,

lordlewis said:

Mark said:

In article <[email hidden]>,
"lordlewis" <[email hidden]> wrote:

> I have been getting flat tires over and over. My rim seems to be
> cutting the edge of my valve stem. I was using a rim that

accommodated

Quoted message said:

Quoted message said:

Quoted message said:

> a tube with a Schrader style valve and then went to a tube using a
> Presta valve with a brass adapter. Every time I ride my bike I get

a

Quoted message said:

Quoted message said:

Quoted message said:

> flat. I have checked the rim for sharp edges and can't find any.

Can

Quoted message said:

Quoted message said:

Quoted message said:

> anybody help me?

I had a similar problem, although the hole in my rim isn't
Schrader-sized. I got the following explanation from the LBS:

With a hole that is too big for the stem, the high pressure in the

tube

Quoted message said:

Quoted message said:

Quoted message said:

tends to push the stem too far through the hole, tearing it off. Their
suggestion was to put an extra layer of Velox with a hole just big
enough for the stem over it. This will help keep the stem from

pushing

Quoted message said:

Quoted message said:

Quoted message said:

through the hole and tearing off.

I haven't had any more failures since I tried that, but it's only been

a

Quoted message said:

Quoted message said:

Quoted message said:

couple months.

I was just into my LBS. the bike mechanic there told me that my valve
stem getting cut was due to the fact I used electrical tape and not
proper rim tape.
I did notice that my rim size is 26 x 1.50 and my tire and tube is 26 x
1.92/2.0. Any thoughts?

I've always used Velox, I don't think electrical tape would be a very
good barrier between the tube and spokes. I would think you would be
getting a lot of flats from spokes.

I have no idea of the tube is too big for the rim.