On 2018-05-08 03:18, John B. wrote:
On Mon, 7 May 2018 18:28:44 -0700 (PDT), jbeattie
wrote:

On Monday, May 7, 2018 at 4:39:31 PM UTC-7, Joerg wrote:
On 2018-05-07 14:03, jbeattie wrote:
On Monday, May 7, 2018 at 12:50:15 PM UTC-7, Joerg wrote:
snip

Re-shaping knobbies can be ok but people use these to deepen
the valleys as well. Also, take a closer look at the video
and you can see how he damages the "meat" next to the
knobbies. That can trigger a progressing hair fracture in the
rubber next to the knobbies and then somewhere in the boonies
... *POOF* ... tire is gone. I won't likely cause injury but
a non-rideable dirt bike 50mi from anywhere can be very
unpleasant.

Tread cutting is done regularly by MTB racers.
https://www.bicycling.com/training/a...-to-cut-tires/
And, of course, motorcycle racers. It doesn't lead to a failure
unless you penetrate the casing, and then you get a flat -- and
not some massive, tire-ending failure. The tire is not gone.
I've booted innumerable casing cuts and ridden home.



I also don't see how putting some shoe goo-ish substance
on a scuffed sidewall is so dangerous. I've ridden plenty
of tires with scuffed sidewalls with no patch at all. I
just wore them out. It's not like Doug is patching some
gash, and in fact, looking at the tire, it's hard to see
the scuff.



Pictures Doug posted earlier clearly showed compromised and
frayed threads. These do not re-gain any strength whatsoever
from such a cosmetic "repair". It's like smearing Bondo over
a structural crack on a vehicle. We all know what can happen
if the front road bike tire blows on a fast downhill section
of road.

Doug says it was minor and nothing in the pictures indicates a
serious problem.


Not serious? Put on your glasses and look again at the left side
he

https://www.dropbox.com/s/1z270cz94b...30730.jpg?dl=0



Even here you can see the thread starting to fray and fail almost
everywhere along a sort of "equator line":

https://www.dropbox.com/s/ao5r35u5y7...30742.jpg?dl=0



That tire belongs on the trash heep and that's where mine went.

I didn't see the first one, but I'm still not concerned. It's not
bulging, and if I were worried and didn't want to trash the tire
(they're not cheap), I'd put a patch behind the scuff and throw
some Shoe Goo on it.

Assuming his casing scuff developed into a casing failure
(which I doubt), he would get a rear blow-out -- or just a rear
flat if the resulting hole were small. He could fold-over a
dollar bill, boot the tire, put in a spare tube and ride home.
Yawn. None of this will or could happen if he just kept an eye
on the tire, which he is doing. Bad casings will bulge long
before they burst, if they every burst.


And what do you do for the front? Bikes have two wheels. Call
your wife from the hospital that dinner is off tonight, and the
next 10-20 days?

Wow, you're a nervous nelly. And what about the front? We're
talking about a rear wheel and a casing scuff. If it were on the
front tire, I'd keep an eye on it. I've ridden front tires booted
with a $1 bill for many, many miles.



But things are different out in the wild west Jay. Imagine
a blowout when the mountain lions are circling. ...


I had cattle around me when that happened last time. The
kaboom made them run away. Luckily that didn't cause a
stampede of the rest of the herd. Strangely, while I was
cleaning up the pieces that had flown off the bike they came
back. Probably curious enough to see what's going on.

Pieces flying off the bike? What? Do you run your tires at
1,000 PSI? Are you using your wheels for shotgun target
practice?


No, 55-60psi, gnarly section with loose rocks. Rear came off the
ground, landed ... *KABOOM* ... thwock. A chunk of tire flew off
and smashed the rear light off of the bike. The remnants of the
light were found in numerous pieces in a 10ft radius around where
the kaboom happened (took a while to get the MTB to a stop,
downhill). It also took out a charge controller circuit board for
the Li-Ion lighting battery. Then some metal pieces. Plus a hole
in the trunk bag.

I learned my lesson from that. Now anything electronic is in ABS
and cast aluminum enclosures. That and the upper trunk are
protected by an aluminum strut that is shaped as a U-profile. The
top trunk now rides on a plywood plate which also allows me to
quickly move it between MTB and road bike or use the bare plate
to faster larger loads.

http://www.analogconsultants.com/ng/bike/Muddy4.JPG

The bike still looks the same except now it has 8" rotors front
and back.

There is also a third protection layer in the shape of a thick
aluminum false bottom below, mainly to catch rocks, mud and
stuff:

http://www.analogconsultants.com/ng/bike/Rack1.JPG

This has turned out to be almost indestructible but you have to
make such stuff yourself. The industry doesn't get it.

Once again, we're talking about a scuffed road tire and not some
epic smashing rof a MTB tire on rocks. You're talking about riding
a scuffed tire as terribly dangerous, yet every story is about
exploding tires on gnarly trails and physical conditions that tax
ordinary bicycles. For you, maybe a scuff is fatal. On a normal
road bike not so much.

-- Jay Beattie.

One of the many things that one might speculate on is that MTB
professionals do not seem have the same, or even similar, tire
problems as reported here. And by professional I'm talking about
people who do things for a living.

We read that the only possible way for an amateur to complete a ride
on a single set of tires is to use the cheapest Thai made tires that
can be found and super thick inner tubes. 'Cause if you don't the
side walls blow out.

Are people who ride mountain bikes for a living running the cheapest
available Thai made tires? Are professional riders crippled with
side wall blow outs?

Of course, I'm not a professional but I can't even remember a side
wall blowing out, snakebite flats, yes, but seriously, I don't
believe I ever had a side "blow" out, an explosive event that
destroyed the side wall of the tire.

But Perhaps I'm doing something wrong. Lets see, Left foot on the
pedal, right leg over the frame, right, left, right, left...


https://www.youtube.com/watch?v=PUoCSzVmhhQ
https://www.youtube.com/watch?v=vnf7VdofZF0


--
Regards, Joerg

http://www.analogconsultants.com/