Rear Tire Number 5

Marian said:

I've had my new road bike for a bit under five months and a bit over
five thousand kilometers now. And, as of yesterday, I graduated to
rear tire number five.

I think you're just unlucky. I've seen three sidewall failures in
total; two were caused by flints and one was caused by a piece of broken
bottle.

On 26 Feb 2006 07:12:35 -0800, "Marian" <[email hidden]>

Quoted message said:

I've had my new road bike for a bit under five months and a bit over
five thousand kilometers now. And, as of yesterday, I graduated to
rear tire number five.

[long tale of serial tire failures snipped]

Quoted message said:

What the hell am I doing?

Sounds like you're having pinch flat problems. Pothole flats in
particular are almost always due to a pinch.

Quoted message said:

I haven't even taken my road bike offroad at all or through any
potholes or done anything particularly rough to it during the _three_
weeks I had tire four. And I don't believe that I'm "too heavy" (which
was the theory put forth by two of the guys I was riding with). 87
kilo makes me one of the heaviest bicycle people on the island but my
body weight is nothing compared to the weights some people do on loaded
tours.

You're lighter than I am, for that matter.

Questions:

What's the pressure you've been running in your tires?

What's the exact size of the tire? 700x23? 700x25?

What's the rim width, if you know?

--
Typoes are a feature, not a bug.
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Werehatrack said:

On 26 Feb 2006 07:12:35 -0800, "Marian" <[email hidden]>

Quoted message said:

I've had my new road bike for a bit under five months and a bit over
five thousand kilometers now. And, as of yesterday, I graduated to
rear tire number five.

[long tale of serial tire failures snipped]

Quoted message said:

What the hell am I doing?

Sounds like you're having pinch flat problems. Pothole flats in
particular are almost always due to a pinch.

Quoted message said:

Quoted message said:

I haven't even taken my road bike offroad at all or through any
potholes or done anything particularly rough to it during the _three_
weeks I had tire four. And I don't believe that I'm "too heavy" (which
was the theory put forth by two of the guys I was riding with). 87
kilo makes me one of the heaviest bicycle people on the island but my
body weight is nothing compared to the weights some people do on loaded
tours.

You're lighter than I am, for that matter.

Questions:

What's the pressure you've been running in your tires?

100 psi +. Depends on what the numbers say on the sidewall; the first
time I inflate a new tire (as opposed to the first time the shop does
it) I try to get my gauge to match the recommended tire pressure and
afterwards I try to keep it similarly hard. The current 30rmb tire is
rated for a max of 100psi and feels pretty hard at that, whereas the
140rmb tire said something like recommended 116 psi and didn't really
feel hard until my gauge said 120psi.

Quoted message said:

What's the exact size of the tire? 700x23? 700x25?

I'd have to go take a look to confirm but I think 700x23.

Quoted message said:

What's the rim width, if you know?

Not a clue.

A recipe for tire health if you're getting too many pinch flats on the rear :

(1) Only buy tires 25mm or larger.
(2) Buy normal japanese tires, e.g. Panaracer, not exotic $$$ tires.
(3) Convert to butyl tubes to maintain air pressure for longer.
(4) Check inflation by hand before every ride. Make sure the rear
tire is rock-hard to your fingers.
(5) Use tires at least 270 grams, anything lighter will likely wear
through too soon.
(6) Learn to ride through potholes and rough spots by "jumping" which
is putting pedals at 3 o'clock and 9'oclock and springing up in
the air slightly so that only 25 lbs (10 kg) of bike goes through
the pothole or rough spot, rather than 200 (90 kg) lbs of bike.

- Don Gillies
San Diego, CA

Marian said:

1400 km after that it was time for tire number three to go. This one
was a 100rmb Michelin. I was at the other bike shop when I bought it
so my choices were this or something lightweight and imported at the
kind of prices that reflect being made somewhere other than China. The
probably cause was a small unadvoidable pothole the evening before but
I'm not real sure. Basically, with no real warning, I got a blowout.

Which is the same way tire four died. No warning and a blowout.

When you say you had a blowout, what do you mean? A cut
developed in the tire and the tube burst through the cut? Was
the failure in the tread or sidewall? Generally, hitting potholes
does not cause a failure of the tire casing.

If the tire bead lifts away from the rim, the tube can blow out,
i.e. the tire blows off, so to speak. This is usually a sign of
improper tire mounting, or occasionally an undersize rim,
though I think I had one case where I hit a pothole and the
tire became dislodged enough to blow off several blocks later.
But a blow-off is not a tire failure and the tire is still usable.
You imply that the tires are unusable, that's why we need more
details about the failures to understand what is happening.

Quoted message said:

You [Marian] imply that the tires are unusable, that's why we need
more details about the failures to understand what is happening.

I agree... there's not enough info here. If the sidewalls of 4 tyres
have blown, I suspect something like a brake pad chafing the sidewall.
Potholes, improper installation, and the reported misadventures of
Marian don't sound like they're tyre killers.

--
Dave
dvt at psu dot edu

not only that butbutbut after reading various complaints on ruining the
FI running across the dry lake bed
i went to the tire ads and found, in general, manufacturers with a
broad rubber line tend to state the applications fairly
and that in general, complaining tire users not only had the wrong tire
but were insisting the wrong tire was the dammit the right tire and the
hell with the manufacturers clams

Donald Gillies said:

A recipe for tire health if you're getting too many pinch flats on the rear :

(1) Only buy tires 25mm or larger.
(2) Buy normal japanese tires, e.g. Panaracer, not exotic $$$ tires.

Normal _Chinese_ tires, you mean. Japanese tires _are_ exotic $$$
tires.

Quoted message said:

(3) Convert to butyl tubes to maintain air pressure for longer.
(4) Check inflation by hand before every ride. Make sure the rear
tire is rock-hard to your fingers.
(5) Use tires at least 270 grams, anything lighter will likely wear
through too soon.
(6) Learn to ride through potholes and rough spots by "jumping" which
is putting pedals at 3 o'clock and 9'oclock and springing up in
the air slightly so that only 25 lbs (10 kg) of bike goes through
the pothole or rough spot, rather than 200 (90 kg) lbs of bike.

They've been promising to teach me how to jump for a while now but
still haven't. I do "post" over rough spots by standing up and lifting
my weight off the saddle and rear tire.

-M

Quoted message said:

Marian said:

1400 km after that it was time for tire number three to go. This one
was a 100rmb Michelin. I was at the other bike shop when I bought it
so my choices were this or something lightweight and imported at the
kind of prices that reflect being made somewhere other than China. The
probably cause was a small unadvoidable pothole the evening before but
I'm not real sure. Basically, with no real warning, I got a blowout.

Which is the same way tire four died. No warning and a blowout.

Definitely 700 x 23cc. I'm in the other bike shop as I write this.
However, I can't figure out how to ask questions about size/depth/etc
of the rim and there is no useful information written on the rim.

Quoted message said:

When you say you had a blowout, what do you mean? A cut
developed in the tire and the tube burst through the cut? Was
the failure in the tread or sidewall? Generally, hitting potholes
does not cause a failure of the tire casing.

A cut developed in the tire and the tube burst through the cut with a
loud POP noise after which point the tube had a big hole in it.

Quoted message said:

If the tire bead lifts away from the rim, the tube can blow out,
i.e. the tire blows off, so to speak. This is usually a sign of
improper tire mounting, or occasionally an undersize rim,
though I think I had one case where I hit a pothole and the
tire became dislodged enough to blow off several blocks later.
But a blow-off is not a tire failure and the tire is still usable.
You imply that the tires are unusable, that's why we need more
details about the failures to understand what is happening.

For tire one I hit a pothole HARD. Got my tube patched and reinflated
at the shop. Tire damage was commented on but it wasn't one of the
clueful doing the work and it wasn't until the next day with the tube
trying to poke it's way through that I went back and got my new tire.

Tire two had lots and lots of flats after the Guangzhou incident. It
was fine until one day out by the volcano when I accidentally mucked up
the valve on the tube and had to take the tire off a second time and
put it back on a second time. The tube was poking through in three or
four places and two kilometers later POP.

Tire three didn't really have much warning. It was a nicer tire picked
up at the other bike shop. Rode it across Guangxi and down through
Vietnam to Hanoi. This was the fourth day of the round the island
event. The night before I'd hit a small pot-hole hard enough that I
checked tire pressure at first chance but no problems. Nor were any
problems noticed in the morning when everyone did inflating and oiling.
I spent the first part of the morning asleep on the truck (you expect
me to wake up _before_ sunrise _without_ coffee _and_ ride my bike??)
Then a lazy twenty kilometers riding next to a loaded tourist from
Guangdong. Shortly after leaving him I got a loud POP followed by more
truck time because the time it took to fix the flat made me the very
last rider. I didn't get the chance to start again until a
particularly nasty descent and while all the bikes were being checked
the bulge of tube through sidewall was noticed and ... I spent the rest
of the day on the truck.

Tire four no potholes, no rough riding, no flats, no nothing... also,
because it was tire four in such a short time the mechanic checked my
rim for burrs and spent 45 minutes sanding it down just in case. Still
on the nice semi-flat section of Haikou to Wuzhishan (210km each way,
let's make it a weekend, bloody sadists) right after it stopped raining
and POP. I caught a dbt bus to the front of the group (lets not say
anything about people who go on 400km trips without bringing their
pumps) where we discover a hole in the sidewall at which point it was
The Quest For a Bike Shop followed by Marian Takes the Bus to
Qiongzhong and the 30rmb tire.

On three of the four tires the tube has developed a hole after creeping
through a hole in the sidewall. On the first tire the tube was
creeping through a hole in the sidewall and I managed to limp first to
school then the bike shop and get a new tire before having the tube
blow.

-M

dvt said:

Quoted message said:

You [Marian] imply that the tires are unusable, that's why we need
more details about the failures to understand what is happening.

I agree... there's not enough info here. If the sidewalls of 4 tyres
have blown, I suspect something like a brake pad chafing the sidewall.
Potholes, improper installation, and the reported misadventures of
Marian don't sound like they're tyre killers.

The brake pad doesn't appear (to me) to be chafing the sidewall and
four different mechanics from three different bike shops have installed
tires for me... so one would think one of them would've noticed if it
were.

They don't sound like tire killers to me either. Even if I do do some
pretty rough stuff to my road bike ... (it's only offroad if the path
in question doesn't have milemarkers.)

In article <[email hidden]>,

Marian said:

Quoted message said:

(6) Learn to ride through potholes and rough spots by "jumping" which
is putting pedals at 3 o'clock and 9'oclock and springing up in
the air slightly so that only 25 lbs (10 kg) of bike goes through
the pothole or rough spot, rather than 200 (90 kg) lbs of bike.

They've been promising to teach me how to jump for a while now but
still haven't.

<snip>

This is easily mastered by trying. While freewheeling with the cranks
parallel to the road, just jump up on the clipless pedals (you do ride
clipless no?).

Luke

Luke said:

In article <[email hidden]>,

Marian said:

Quoted message said:

(6) Learn to ride through potholes and rough spots by "jumping" which
is putting pedals at 3 o'clock and 9'oclock and springing up in
the air slightly so that only 25 lbs (10 kg) of bike goes through
the pothole or rough spot, rather than 200 (90 kg) lbs of bike.

They've been promising to teach me how to jump for a while now but
still haven't.

<snip>

This is easily mastered by trying. While freewheeling with the cranks
parallel to the road, just jump up on the clipless pedals (you do ride
clipless no?).

I've been riding clipless for slightly more than a month.

I do admit that while the idea of jumping my bike is something I really
want to try the reality is that I'm a little bit afraid and am willing
to wait until one of the impressive people stops saying "one of these
days" and actually plays teacher at me.

-M