Fat Rider and Tubes Blowing Weekly

Elisa Francesca Roselli said:

The inner tubes on Flyzipper keep blowing. I've had one blow-out on
the rear wheel and two on the front wheel in the space of less than a
month! The tyres are inflated to about 5 bar - it says minimum 4.5
and maximum
6.5. I've checked and checked on the inside of the tyres and rims and
can find nothing sharp or outstanding that could cause this. The tubes
always blow AT A STANDSTILL, generally when I have just finished
riding or when the bike is parked, so it's not the typical visit from
the puncture fairy.

All tubes can stand high pressure and heavy weight so something else is
going on.

What does the damage to the blown tubes look like?....

Long jagged rip = tyre & tube not fitted properly (tube got trapped under
bead), or tyre too loose a fit on the rim. Test by overinflating and
leaving to stand for a number of hours. Note that heat from extreme
braking or the sun will increase the pressure a bit -- might explain the
timing if the bike is parked in a hot place. But you should have a margin
of error to cope with that anyway.

Hole = rim tape not good enough to stop tube pressing down into the spoke
hole recesses. Velox rim tape is good.

~PB

Pete Biggs said:

Elisa Francesca Roselli wrote:

Quoted message said:

Hole = rim tape not good enough to stop tube pressing down into the spoke
hole recesses. Velox rim tape is good.

No rim tape in there as far as I know. I'll go get some and see if it helps.

There certainly is some hard braking on this commute, but the weather
has not yet been brutally hot.

Thanks for the tip.

EFR
Ile de France

Elisa Francesca Roselli said:

The inner tubes on Flyzipper keep blowing. I've had one blow-out on the
rear wheel and two on the front wheel in the space of less than a month!
The tyres are inflated to about 5 bar - it says minimum 4.5 and maximum
6.5. I've checked and checked on the inside of the tyres and rims and
can find nothing sharp or outstanding that could cause this. The tubes
always blow AT A STANDSTILL, generally when I have just finished riding
or when the bike is parked, so it's not the typical visit from the
puncture fairy.

So I'm thinking, is this about rider weight? The limit on a Dahon is 105
kg. Fully dressed, with bags, water and some groceries, I'm well over
that. Moreover the trips I'm taking include some nasty offroad sections
with mud, gravel and pointy stones that I cannot always avoid. I would
of course rather the tubes blew than the frame break!

First, I would very strongy suggest that it's time to learn to fix
your own flats; even after you solve your current problem, there will
still be flat tires to deal with in the future.

Second, some additional information would help to suggest the cause(s)
and solution(s) for your flats. Are the punctures on the part of the
tube that faced the road, or the part that faced the spokes, or more
toward the sides? By any chance, are they at the base of the valve
stem? This latter type of failure is difficult to patch, and further,
it usually indicates that either the rube was not properly seated in
the rim when the tire was inflated, or that tire has been creeping
around the rim (usually due to significant underinflation) and
stressing the tube at the valve.

Third, given that you are aware that you're riding the bike at or
above its load limit, it would probably be prudent to run the air
pressure as close to the maximum rated for the tires as is practical.

The Dahon may not be the best choice to ride overloaded, but sometimes
one must employ that which one has at hand.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
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Werehatrack said:

First, I would very strongy suggest that it's time to learn to fix
your own flats; even after you solve your current problem, there will
still be flat tires to deal with in the future.

Well, I think I managed the front wheel OK yesterday. We'll see how it
fares on the road. I'm not ready to mess with the back wheel yet because
of all that SRAM Dual-Drive stuff that is on it. I just don't want to
mess up something delicate and complicated irretrievably.

Quoted message said:

Second, some additional information would help to suggest the cause(s)
and solution(s) for your flats. Are the punctures on the part of the
tube that faced the road, or the part that faced the spokes, or more
toward the sides?

The last one was a tear of about half an inch, on the inside (spoke
side) of the tube and about 8" away from the valve. The other
front-wheel was also about half an inch long, also on the inside, and
diametrically opposite the valve.

Quoted message said:

Third, given that you are aware that you're riding the bike at or
above its load limit, it would probably be prudent to run the air
pressure as close to the maximum rated for the tires as is practical.

That's interesting and counter-intuitive. I was afraid to run the
air-pressure so high because I thought that would _encourage_ bursting.

Quoted message said:

The Dahon may not be the best choice to ride overloaded, but sometimes
one must employ that which one has at hand.

I solemnly swear to ride it stark nekkid from now on. ;°>

EFR
Ile de France

Elisa Francesca Roselli said:

Pete Biggs said:

Hole = rim tape not good enough to stop tube pressing down into the spoke
hole recesses. Velox rim tape is good.

No rim tape in there as far as I know. I'll go get some and see if it helps.

No rim tape => inners go pop very rapidly in my experience! Those
screws on the end of the spokes tend to have sharp edges & the inner
squirms around over them with inevitable results...

Phil

--
http://www.kantaka.co.uk/ .oOo. public key: http://www.kantaka.co.uk/gpg.txt

Elisa Francesca Roselli said:

Werehatrack wrote:

Quoted message said:

Quoted message said:

Third, given that you are aware that you're riding the bike at or
above its load limit, it would probably be prudent to run the air
pressure as close to the maximum rated for the tires as is practical.

That's interesting and counter-intuitive. I was afraid to run the
air-pressure so high because I thought that would _encourage_
bursting.

It will encourage bursting when there's some problem with rim or tyre, but
normally it will prevent pinch flats aka snake bite punctures by
preventing the tyre compressing too far.

~PB

Phil Armstrong said:

Elisa Francesca Roselli <[email hidden]> wrote:

Quoted message said:

No rim tape => inners go pop very rapidly in my experience! Those
screws on the end of the spokes tend to have sharp edges & the inner
squirms around over them with inevitable results...

OK, so now I know I need rim tape. I learn the French, ruban de fond de
jante. But I also learn that it comes in different sizes.

So how do I know what size to get? Given that the inner tubes are not
readily available here, will I have the same kind of problem finding rim
tape?

EFR
Ile de France

Elisa Francesca Roselli said:

No rim tape in there as far as I know. I'll go get some and see if it
helps.

That's shocking if there is none at all. Some special rims don't need any
but you're unlikely to have one of those.

What seems smooth enough to fingers isn't necessarily to an inner tube,
and recesses must be covered as well.

/Rubber/ tape is only OK for rims without recesses and when pressure is
low.

~PB

Elisa Francesca Roselli said:

Werehatrack said:

Second, some additional information would help to suggest the cause(s)
and solution(s) for your flats. Are the punctures on the part of the
tube that faced the road, or the part that faced the spokes, or more
toward the sides?

The last one was a tear of about half an inch, on the inside (spoke
side) of the tube and about 8" away from the valve. The other
front-wheel was also about half an inch long, also on the inside, and
diametrically opposite the valve.

That sounds like the sort of thing that occurs when the tire is
incautiously mounted, leaving a small bit of the tube caught between
the tire's bead and the rim. The size of the rupture is inconsistent
with anything else that I can think of at the moment. I would
recommend extra care when putting the tire on the rim, and I would
also advise inflating the tube just slightly, barely enough to make it
round in profile, before starting to slip the tire bead over the rim
flange to complete the installation process.

Quoted message said:

Quoted message said:

Third, given that you are aware that you're riding the bike at or
above its load limit, it would probably be prudent to run the air
pressure as close to the maximum rated for the tires as is practical.

That's interesting and counter-intuitive. I was afraid to run the
air-pressure so high because I thought that would _encourage_ bursting.

Higher pressure will increase the chances of a blowout only if there's
something wrong; when everything is set up correctly, it will not. As
another respondent correctly stated, running the pressure higher will
help to prevent or reduce the incidence of what is known as "pinch
flats", which are apparently not what you have been experiencing.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Elisa Francesca Roselli said:

OK, so now I know I need rim tape. I learn the French, ruban de fond
de jante. But I also learn that it comes in different sizes.

So how do I know what size to get? Given that the inner tubes are not
readily available here, will I have the same kind of problem finding
rim tape?

Hopefully someone will know your Dahon to advise on exact width required.
Wheel diameter is not an issue for self adhesive cloth tape like Velox:
just cut to length. All half decent bike shops in your part of the world
should stock it! best of luck.

~PB

Werehatrack said:

On Sun, 14 May 2006 17:36:39 +0200, Elisa Francesca Roselli wrote:

Quoted message said:

Quoted message said:

The last one was a tear of about half an inch, on the inside (spoke
side) of the tube and about 8" away from the valve. The other
front-wheel was also about half an inch long, also on the inside, and
diametrically opposite the valve.

That sounds like the sort of thing that occurs when the tire is
incautiously mounted, leaving a small bit of the tube caught between
the tire's bead and the rim. The size of the rupture is inconsistent
with anything else that I can think of at the moment.

0.5" might be a bit long but still I would've thought it could be caused
by the tube being forced down a recess (?). Not a bad idea to ensure rim
tape is good, anyway, even if current problem is something else.

~PB

I cannot believe there is no rim tape.A layer of insulating tape over
the top of what tape there is can be a quick fix for any tiny
defects.Half inch gash does not sound like a spoke end puncture.
I did once get a hole like that when a pinch defect suddenly burst ,
but that is easily cured by keeping your tyre pressures at or near max.

If you watch club riders changing tubes the older they are the longer
they spend half inflating then massaging the tyre all the way round to
get the tube definitely out from under the tyre hoop edge.Also I wonder
if you could be trapping the tube with the levers creating a similar
defect that ruptures later.Put enough air in the tube to shape it
before getting the tyre on.
If you don't fancy spending an hour practicing getting the rear wheel
on and off( which is the best idea) you might consider getting a
marathon plus tyre for it or putting in a lot of slime.The slime can
occasiionally cause valve probs and needs putting in, so the marathon
plus is probably the better idea.If your lbs will not get one and fit
it then perhaps you could get one on the web and pay them to fit it.
TerryJ

Elisa Francesca Roselli said:

OK, so now I know I need rim tape. I learn the French, ruban de fond de
jante. But I also learn that it comes in different sizes.

This problem cannot be due to the utter lack of rim tape. That would
cause the tubes to blow when you inflate the tire, or shortly thereafter,
every single time.

Perhaps the rim tapes are inadequate (many plastic ones are) or cracked.
Or possibly something is wrong with the tires, or the rims. We can't
really diagnose this from here.

Quoted message said:

So how do I know what size to get? Given that the inner tubes are not
readily available here, will I have the same kind of problem finding rim
tape?

Not at all. Rim tape can be cut to size. I do second the recommendation
for Velox rim tape. Being French, it should be easy to find.

--

David L. Johnson

__o | Some people used to claim that, if enough monkeys sat in front
_`\(,_ | of enough typewriters and typed long enough, eventually one of
(_)/ (_) | them would reproduce the collected works of Shakespeare. The
internet has proven this not to be the case.

I can't believe it. Got up early this morning all rearing to cycle into
work after having successfully changed my inner tube on Saturday. THE
TUBE WAS BLOWN AGAIN! And I hadn't even RIDDEN the bike since I put it
away, all preened and ready - only for about 2 minutes round the
underground parking just to check that the settings were correct.

When I changed the tube on Saturday, I did what people are saying about
slightly inflating it so that it becomes properly wheel-shaped. Simon
showed me this in Czech Republic. He also recommended to use some talcum
powder as dry lubricant inside the tyre, to prevent pinching, and this
too I did with my rose-scented Marks and Sparks talc. I was careful
about not letting any part get caught in the rim.

I'm also skeptical that I was just sold a rum lot of inner tubes because
the 4 tubes that have blown over the past month come from two different
sources and are of two different makes. As to my storing them, they have
been kept in total darkness, in a cupboard in the garage, and at
moderate temperature, since last Autumn.

I have not yet had time to examine the shape and position of the most
recent blow-out. I'll let you know as soon as I see it. I'm really
miffed as this pretty much undoes my cycling plans for the week. It will
be many days before I have access to any rim tape and I'm not changing
any more tubes until I do.

A propos of rim tape, what width should I look for with the inner tube
spec at 35-406 20*1.351 HS341? (I think that means 35mm by 406mm or 20
inches by 1.351 inches - a weird size that is not supported in France
except by special order).

Thanks to all,

Elisa Francesca Roselli
Distressed in Ile de France

Artemisia came up with the following;:

Quoted message said:

I can't believe it. Got up early this morning all rearing to cycle into
work after having successfully changed my inner tube on Saturday. THE
TUBE WAS BLOWN AGAIN! And I hadn't even RIDDEN the bike since I put it
away, all preened and ready - only for about 2 minutes round the
underground parking just to check that the settings were correct.

When I changed the tube on Saturday, I did what people are saying about
slightly inflating it so that it becomes properly wheel-shaped. Simon
showed me this in Czech Republic. He also recommended to use some talcum
powder as dry lubricant inside the tyre, to prevent pinching, and this
too I did with my rose-scented Marks and Sparks talc. I was careful
about not letting any part get caught in the rim.

I'm also skeptical that I was just sold a rum lot of inner tubes because
the 4 tubes that have blown over the past month come from two different
sources and are of two different makes. As to my storing them, they have
been kept in total darkness, in a cupboard in the garage, and at
moderate temperature, since last Autumn.

I have not yet had time to examine the shape and position of the most
recent blow-out. I'll let you know as soon as I see it. I'm really
miffed as this pretty much undoes my cycling plans for the week. It will
be many days before I have access to any rim tape and I'm not changing
any more tubes until I do.

A propos of rim tape, what width should I look for with the inner tube
spec at 35-406 20*1.351 HS341? (I think that means 35mm by 406mm or 20
inches by 1.351 inches - a weird size that is not supported in France
except by special order).

If you have no rim tape at all, then the punctures you are experiencing are
typical. If you absolutely need to use the bike, then use electrical tape,
at least twice around and make sure the tape is put on tightly. It's not
great, but will do at a pich.

Basically rim tape needs to cover any spoke heads/holes and that's about it,
so if you have a choice of widths get a size that doesn't ride up the rim
walls. Indeed if the tape does go up the rim walls you might cause other
problems.

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

Artemisia said:

A propos of rim tape, what width should I look for with the inner tube
spec at 35-406 20*1.351 HS341? (I think that means 35mm by 406mm or 20
inches by 1.351 inches - a weird size that is not supported in France
except by special order).

try this
http://mikedyason.com/productDesc.asp?session_id=d6c802699f52861021aa9289adab00b1&text_product_id=VRT19

Measure across the rim with a ruler. You want to measure between the
inside faces of the rim.
If it is wider than 19mm then order the tape above. Otherwise order the
16mm one.

To fit it you will need a good pair of scissors in addition to the
normal tyre and wheel changing tools.

Remove the wheel from the bike, and remove tyre and tube. Clean away
any old crappy rim tape.

Locate the valve hole and the correspndign hole in the rim tape. Place
the hole in the rim tape over the hole in the rim. The tape is not
super sticky so you may need to put the valve back in at this point to
keep it located. Place the rim tape around the rim, making sure it sits
straight and covers all the spoke holes and heads. A small amount of
tension as you place it won't do any harm.

The tape will be longer than you need. Cut it so it just reaches the
valve hole (ie a few cm overlap.

Now refit tyre and tube. All should be happy.

...d

Artemisia said:

A propos of rim tape, what width should I look for with the inner tube
spec at 35-406 20*1.351 HS341? (I think that means 35mm by 406mm or 20
inches by 1.351 inches - a weird size that is not supported in France
except by special order).

Rim tape size required depends width & shape of rim, not tube or tyre.
Sorry I don't know what rims you have and probably wouldn't know what
they're like anyway. I suggest either: take bike to a shop and let them
do it, or order as many widths of Velox tape as you can find and see which
fits best.

As I mentioned in another reply, wheel diameter is irrelevant with the
type of tape that is cut to length, eg Velox.

~PB

David L. Johnson said:

This problem cannot be due to the utter lack of rim tape. That would
cause the tubes to blow when you inflate the tire, or shortly
thereafter, every single time.

Not necessarily if there were no particularly sharp or recessed bits and
the tube was tough and the pressure wasn't high. However, I do find it
incredible that anyone would supply Elisa with wheels/bike with no rim
tape.

~PB

Artemisia said:

A propos of rim tape, what width should I look for with the inner
tube spec at 35-406 20*1.351 HS341? (I think that means 35mm
by 406mm or 20 inches by 1.351 inches - a weird size that is not
supported in France except by special order).

Rim tape needs to correspond to the internal width of the *rim*, not the
tube. Adhesive cloth tapes like Velox fond de jante come on a roll like
Sellotape, and can be cut to length. The tape should cover the spoke bed of
the rim.

Narrow 406mm tubes may be a special order item in your local shop, but
shops that deal in 20" bikes - Bicloune for example - will keep them in
stock. 406 is also a common BMX size, though usually in broader widths than
those you use.

Offer of hands-on help still open, by the way, and reply-to address valid.
No pressure.

James Thomson