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  #291  
Old January 21st 17, 04:49 PM posted to rec.bicycles.tech
JBeattie
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Posts: 5,870
Default Stronger rubber cement?

On Saturday, January 21, 2017 at 3:56:44 AM UTC-8, DATAKOLL MARINE RESEARCH wrote:
JB. .... are discs easier adjusting to 'just right max stop max control' than rim brakes ?


There is no adjusting hydraulic brakes -- apart from lever travel and changing pads. Cable discs are more like rim brakes in that you can adjust the pads closer or farther from the rotor. Assuming you have a super straight rotor, you can set the pads too close, and they can wear to the point where you run out of lever travel before the bike stops. Cable discs are more fussy than rim brakes, but I still prefer them for wet weather riding.

-- Jay Beattie.
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  #292  
Old January 21st 17, 04:59 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Stronger rubber cement?

On 2017-01-20 18:08, John B. wrote:
On Fri, 20 Jan 2017 16:13:02 -0800, Joerg
wrote:

On 2017-01-20 15:53, John B. wrote:



[...]

... Given that
the usual sped of professional MTB racers is in the 18 mph range for
average courses and in fact one site discussing professional racers
states that, " An impressive pace for a pro mountain biker, on
average, could be around 15 mph, or a 4-minute mile."

^^^^^^^^



Do you, like some here, not understand the difference between average
speed and top speed? Nobody can hold 20mph on a MTB for three hours but
it is easy to do that on a flat section for a limited time. It is by
nature limited because the terrain on other sections would make 20mph
almost a suicide ride.

My point back then was not to brag about me being a super action hero
because I am not. The point was that I believe MTBs must be capable of
sustaining regular 20mph episodes on a raggedy trail where everything
rattles.


You are unbelievable! First you say that "Nobody can hold 20mph on a
MTB for three hours" and then you say "MTBs must be capable of
sustaining regular 20mph episodes on a raggedy trail".

So tell us, how long is an "episode"? Are you talking about an hour?
20 minutes? 5 seconds?


sigh

It depends on the trail. Typically 10-15 minutes if there is sufficient
flat stretch. Usually there will be brief interruptions for bends or
when you don't want to chance it bombing through a creek.

I cannot hold that sort of speed for much longer and never said so. I am
sure my bike dealer could hold that speed and more for a long time on
his MTB.


As I said before, I can't understand why you aren't riding for a pro
team, after all the average for the tour de France, on super light
weight bicycles, on paved roads, with nearly constant care and feeding
by a team, is only 24 mph.



So you do seem to be one of those here who cannot grasp the difference
between average speed and top speed?

Besides, if I went 20mph average (which I can't and never claimed) I
would not even remotely stand a chance in any bike race. Bike races are
for others, not for me and I never had any ambition to particpate in one.


... But you do 83% of that speed on a heavy
clunky mountain bike through the mud so think that you have to poke it
off with a special stick that you carry.


We do happen to have summers out here where there is no mud. Is it so
hard to understand that there are _seasons_ even on singletrack? The
weather does not miraculously run a circle around the area.


Incredible!


How fast do you go on your road bike? For how long? I can hold 22mph for
half an hour. A friend goes 25mph and when I follow him I am totally
bushed, so I don't know what you find miraculous. A MTB is just a little
heavier and has higher rolling resistance but not a lot. Going 20mph on
one of those is something every somewhat fit rider should do. If you
can't and you are not grossly overweight I suggest to see a
cardiovascular specialist. Of course, this assumes that one does not
ride with minimum pressure in the tires like many mountain bikers do. I
keep them above 50 psi.

BTW when is the last time you rode a decent mountain bike? 20 years ago?
Fast forward to this century. On modern MTB such as mine you can lock
out both front and read suspension _while_ riding. For the rear with the
flick of a switch, on the front by turning a dial. I can even fine-tune
the response of the fork while riding, making it harder or softer
depending on trail conditions. So far for "clunky".

[...]

--
Regards, Joerg

http://www.analogconsultants.com/
  #293  
Old January 21st 17, 05:32 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Stronger rubber cement?

On 2017-01-20 17:51, John B. wrote:
On Fri, 20 Jan 2017 16:01:23 -0800, Joerg
wrote:

On 2017-01-20 15:38, John B. wrote:
On Fri, 20 Jan 2017 07:43:20 -0800, Joerg
wrote:

On 2017-01-19 19:00, John B. wrote:
On Thu, 19 Jan 2017 14:57:42 -0800, Joerg
wrote:

On 2017-01-19 14:39, Doug Landau wrote:

On road bikes it usually happens when hitting a rock "just so". Like
when the rock gets under the tire off center and flies off to the side
with gusto.

Haha and makes a loud CRACK as it hits the passenger door or window of the car to your left :-)


No kidding, that has happend. Also, drivers give me extra wide margin
when I just came off a dirt path in bad weather and all sorts of gunk
flies off my rear wheel.

I am beginning to wonder.

You have repeatedly stated that your usual speed is 20 MPH. Now, a 26
x 3.0 tire will be spinning at about 250 RPM at that speed..... But
this speeding tire accumulates "all kind of gunk"?


As explained many times 20mph is the speed on flat sections of trail or
slightly higher when downsloping a little. My average trail speed is
more around 10-12mph depending on turf unless I want to push it. Meaning
there are murky or gnarly stretches in the low single digit mph. There
are people on this NG who do not understand the difference between top
speed and average speed.

On such trails I often slow down to enjoy the scenery, animals, and so
on. Something that the "bicycles belong on road" people will likely
never understand.

Then I ride on 29" wheels. A usual scenario is that I come back on
singletrack from Placerville and the last section before entering a
regular road is this:

http://www.analogconsultants.com/ng/bike/Chapparal2.jpg

Imagine that after three days of rain. Also, on rainy days my average
speed on the "real" trail can drop substantially because the rear wheel
becomes stuck several times. Big clump of mud caked up near the BB,
wheel will hardly turn even in granny gear, have to stop, look around
for a sturdy branch piece of manzanita, poke the mud out of there,
continue the ride. Until it gets stuck again a few miles later.
Sometimes it's so bad that I strap that piece of manzanita onto the rack.


I ask as my road bike, who's wheels are spinning at only about 157 RPM
don't seem to accumulate any junk at all.


Well, do your road bike tires have knobbies? BTW, my road bike does
fling dirt off the wheels after a muddy stretch of "bush road" and I
have caked up its BB area with mud. Usually purposely rolling through
some water puddles washes the mud off the tires, something that does not
work for the MTB tires.

You are almost unbelievable. You have a double handful of mud lodged
on the bottom bracket and you need to run about and find a stick to
dislodge it.

Why can't you just grab a handful and throw it on the ground... oh, of
course you'd get your fingers dirty, wouldn't you.


Can you possibly imagine that there are occasions where one wants to
arrive at a destination without dirty hands? Even when ... gasp ...
using a bicycle for transportation in ... oh horror! ... non-ideal
weather along less than stellar paths?


Sure I can, but you say that are riding through the woods at speeds
not obtainable by professional MTB racers ...



This statement makes me sure that you have no clue about mountain
biking. Pros will leave me in the dust (and have) because a rider doing
20mph on a flat stretch of trail is something they consider a slowpoke.


... and you don't want to get
your hands dirty. But you are talking about California, where. if I
remember, it gets hot. You mean after your 20 MPH trip through 50
miles of "pristine wilderness" I believe you called it, you are not
covered with sweat and stinking like a goat?


In the summer I am totally drenched. Which is why I sometimes carry a
2nd T-shirt and a small towel in the panniers depending on where I go.
Other times I dunk it in a creek and also splash water over myself.

And where did I ever write about 20mph over 50 miles? Don't make stuff
up and falsely claim people wrote that. Because I didn't. Leave that
sort of stuff to the media, they are good at fake news lately :-)

https://www.youtube.com/watch?v=L_DETYq4WoE

Do you think these are all Tour de France riders? They are going around
20mph (speedometer shows km/h), they aren't breaking much of a sweat and
they are even chatting at times. It doesn't make much difference whether
you ride on a road or on a flat section of trail. You just have to watch
out for ruts and rocks on the trail.

Here is a classic high speed MTB ride on a mostly flat trail:

https://www.youtube.com/watch?v=F5hrN8ShNeE

You may not have those trails in Thailand but we do here in the US, lots
of them. Next time you are in the US rent a MTB, hop on and ride. It'll
open your mind about MTB, what they can really do. Yes, they are a
viable transport vehicle if equipped correctly. The real fun in
bicycling is not found on roads.

--
Regards, Joerg

http://www.analogconsultants.com/
  #294  
Old January 21st 17, 06:24 PM posted to rec.bicycles.tech
DATAKOLL MARINE RESEARCH
external usenet poster
 
Posts: 2,011
Default Stronger rubber cement?

On Saturday, January 21, 2017 at 10:49:39 AM UTC-5, jbeattie wrote:
On Saturday, January 21, 2017 at 3:56:44 AM UTC-8, DATAKOLL MARINE RESEARCH wrote:
JB. .... are discs easier adjusting to 'just right max stop max control' than rim brakes ?


There is no adjusting hydraulic brakes -- apart from lever travel and changing pads. Cable discs are more like rim brakes in that you can adjust the pads closer or farther from the rotor. Assuming you have a super straight rotor, you can set the pads too close, and they can wear to the point where you run out of lever travel before the bike stops. Cable discs are more fussy than rim brakes, but I still prefer them for wet weather riding.

-- Jay Beattie.


AAA

https://groups.google.com/forum/#!topicsearchin/rec.bicycles.tech/Jay$20Beattie;context-place=topic/rec.bicycles.tech/zlhfIcRnLx4

I dunno about 'I still' but take a look thru these meanderings for a skeleton of fluent information then tack in road stories illustrating the concept as maintenance ride epic McManus failure repair and off course VICTORY AGAINST ALL ODDS ...

with some stuff abt you n the California boys down at the Mill Stream

good for a film
  #295  
Old January 21st 17, 08:32 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,345
Default Stronger rubber cement?

On Saturday, January 21, 2017 at 7:59:32 AM UTC-8, Joerg wrote:
On 2017-01-20 18:08, John B. wrote:
On Fri, 20 Jan 2017 16:13:02 -0800, Joerg
wrote:

On 2017-01-20 15:53, John B. wrote:



[...]

... Given that
the usual sped of professional MTB racers is in the 18 mph range for
average courses and in fact one site discussing professional racers
states that, " An impressive pace for a pro mountain biker, on
average, could be around 15 mph, or a 4-minute mile."
^^^^^^^^



Do you, like some here, not understand the difference between average
speed and top speed? Nobody can hold 20mph on a MTB for three hours but
it is easy to do that on a flat section for a limited time. It is by
nature limited because the terrain on other sections would make 20mph
almost a suicide ride.

My point back then was not to brag about me being a super action hero
because I am not. The point was that I believe MTBs must be capable of
sustaining regular 20mph episodes on a raggedy trail where everything
rattles.


You are unbelievable! First you say that "Nobody can hold 20mph on a
MTB for three hours" and then you say "MTBs must be capable of
sustaining regular 20mph episodes on a raggedy trail".

So tell us, how long is an "episode"? Are you talking about an hour?
20 minutes? 5 seconds?


sigh

It depends on the trail. Typically 10-15 minutes if there is sufficient
flat stretch. Usually there will be brief interruptions for bends or
when you don't want to chance it bombing through a creek.

I cannot hold that sort of speed for much longer and never said so. I am
sure my bike dealer could hold that speed and more for a long time on
his MTB.


As I said before, I can't understand why you aren't riding for a pro
team, after all the average for the tour de France, on super light
weight bicycles, on paved roads, with nearly constant care and feeding
by a team, is only 24 mph.



So you do seem to be one of those here who cannot grasp the difference
between average speed and top speed?

Besides, if I went 20mph average (which I can't and never claimed) I
would not even remotely stand a chance in any bike race. Bike races are
for others, not for me and I never had any ambition to particpate in one.


... But you do 83% of that speed on a heavy
clunky mountain bike through the mud so think that you have to poke it
off with a special stick that you carry.


We do happen to have summers out here where there is no mud. Is it so
hard to understand that there are _seasons_ even on singletrack? The
weather does not miraculously run a circle around the area.


Incredible!


How fast do you go on your road bike? For how long? I can hold 22mph for
half an hour. A friend goes 25mph and when I follow him I am totally
bushed, so I don't know what you find miraculous. A MTB is just a little
heavier and has higher rolling resistance but not a lot. Going 20mph on
one of those is something every somewhat fit rider should do. If you
can't and you are not grossly overweight I suggest to see a
cardiovascular specialist. Of course, this assumes that one does not
ride with minimum pressure in the tires like many mountain bikers do. I
keep them above 50 psi.

BTW when is the last time you rode a decent mountain bike? 20 years ago?
Fast forward to this century. On modern MTB such as mine you can lock
out both front and read suspension _while_ riding. For the rear with the
flick of a switch, on the front by turning a dial. I can even fine-tune
the response of the fork while riding, making it harder or softer
depending on trail conditions. So far for "clunky".


George, it's clear these guys simply haven't ridden good full suspension bikes. The comments they make sound like they come from outer space.
  #296  
Old January 21st 17, 08:51 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Stronger rubber cement?

On 2017-01-21 11:32, wrote:
On Saturday, January 21, 2017 at 7:59:32 AM UTC-8, Joerg wrote:
On 2017-01-20 18:08, John B. wrote:


[...]


Incredible!


How fast do you go on your road bike? For how long? I can hold
22mph for half an hour. A friend goes 25mph and when I follow him I
am totally bushed, so I don't know what you find miraculous. A MTB
is just a little heavier and has higher rolling resistance but not
a lot. Going 20mph on one of those is something every somewhat fit
rider should do. If you can't and you are not grossly overweight I
suggest to see a cardiovascular specialist. Of course, this assumes
that one does not ride with minimum pressure in the tires like many
mountain bikers do. I keep them above 50 psi.

BTW when is the last time you rode a decent mountain bike? 20 years
ago? Fast forward to this century. On modern MTB such as mine you
can lock out both front and read suspension _while_ riding. For the
rear with the flick of a switch, on the front by turning a dial. I
can even fine-tune the response of the fork while riding, making it
harder or softer depending on trail conditions. So far for
"clunky".


George, it's clear these guys simply haven't ridden good full
suspension bikes. The comments they make sound like they come from
outer space.


Yeah, I am beginning to wonder :-)

http://graphics8.nytimes.com/images/...4wat-wood1.jpg

https://ixquick-proxy.com/do/show_pi...a9595a438cb381

--
Regards, Joerg

http://www.analogconsultants.com/
  #297  
Old January 21st 17, 09:29 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Stronger rubber cement?

On 2017-01-18 14:50, Phil Lee wrote:
Joerg considered Tue, 17 Jan 2017
10:56:15 -0800 the perfect time to write:

On 2017-01-17 10:36, jbeattie wrote:
On Tuesday, January 17, 2017 at 9:47:32 AM UTC-8, Joerg wrote:
On 2017-01-17 08:21, jbeattie wrote:


[...]


What I pay in car insurance annually would buy me an all new
bike every year. Skip cleaning the chain -- just put last year's
bike out with the garbage. Plus, my bikes are reliable. I
reliably change the chain when the wear indicator indicates and
change the tires when they are worn out. I fix a flat now and
then and do other routine maintenance. It's not like some
monumental inconvenience, and if flats were epidemic, then I
would switch to a hard-case tire. I would not agonize over the
fact that the 20lb tire on my Subaru goes flat less often.


My point is that when I say I am going to be there for an
important meeting at 11:30am I don't want to leave half an hour
earlier just in case I get a flat. And good luck getting that
Gatorksin tire back onto one of my rims.

If it takes you half an hour to fix a flat, you have other problems
that need to be addressed.


Yeah, I could get new rims and/or different tires. That is why finding a
suitable tire isn't easy. You are welcome to come over and try getting a
Gatorskin onto my rims.


It seems to me that the problem is with either your rims or your
technique.



The rims are shallow. The problem is that some tires run too small in
the bead.


I've changed Gatorskins without levers or difficulty, right up to the
stage where my arthritis was a serious problem for normal riding, or
even holding a pen.
Therefore I would suggest that any other tyre you try will have the
same problem.



As I have written that is not the case. All the tires I mounted in the
80's and 90's went one with ease.


Heck, if you think your Gatorskins are difficult, I wonder how hard
you'd find a Marathon Plus on an ISO 406 (20") rim!
I've done that too, and although I did need levers to remove the tyre,
it wasn't particularly difficult or time consuming - about 10 minutes,
mostly spent prepping the tube for patching and checking the inside of
the cover for debris and/or penetrating objects (although that was
done while waiting for the rubber cement to dry enough for the patch
to be applied). I could have halved the time by using a CO2 inflator,
at a guess - but I prefer a pump, which doesn't run out or leave
waste.


Same here. A large pump at home and a Pocket Rocket for the road.


Your half hour tube change on a road bike is about the time I'd have
expected to take to replace the tyre on the inside wheel of a pair on
the drive axle or semi-trailer of an articulated heavy truck, which
I've also had to do in the past. The tyre, not the whole wheel - that
part just takes 10 minutes. So 20 minutes for the tyre swap, although
admittedly that is with split rims (although they are in my experience
universal on wheels designed for that duty).


I helped a friend mount a motorcycle tire onto the rim. That only took
minutes. Not having a compressor with large enough volume he pushed the
bead back, spritzed starter fluid in there, lit a match ... *BAM* ...
threw a wet towel over it to douse remaining flame, aired it up, done.


Certainly, the variability in arrival time from punctures on a bicycle
is FAR less than the variability in arrival time in a car due to
traffic - that is one of the major reasons people choose to commute by
bicycle!


Not around here.

--
Regards, Joerg

http://www.analogconsultants.com/
  #298  
Old January 21st 17, 09:38 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,538
Default Stronger rubber cement?

On 1/21/2017 1:42 AM, John B. wrote:
On Fri, 20 Jan 2017 21:48:19 -0800 (PST), Frank Krygowski
wrote:

On Friday, January 20, 2017 at 9:10:34 PM UTC-5, John B. wrote:


Being a cowardly old man when it gets slippery I slow down :-)


Being a sensible, slightly younger man, I agree and do the same!

- Frank Krygowski


I also admit to deliberately running off the road to avoid being hit
by a truck :-)


So far, I haven't had to do that. But then, I've only been riding for
about 45 years - plus the riding I did as a kid or teen.


--
- Frank Krygowski
  #299  
Old January 21st 17, 09:44 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default Stronger rubber cement?

On 1/21/2017 11:32 AM, Joerg wrote:

Other times I dunk it in a creek and also splash water over myself.

And where did I ever write about 20mph over 50 miles? Don't make stuff
up and falsely claim people wrote that. Because I didn't. Leave that
sort of stuff to the media, they are good at fake news lately :-)

https://www.youtube.com/watch?v=L_DETYq4WoE

Do you think these are all Tour de France riders? They are going around
20mph (speedometer shows km/h), they aren't breaking much of a sweat and
they are even chatting at times.


There's also a lot of coasting, which makes me strongly suspect that
they're on a long, gentle downgrade.

--
- Frank Krygowski
  #300  
Old January 21st 17, 09:54 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default Stronger rubber cement?

On 1/21/2017 10:59 AM, Joerg wrote:
On 2017-01-20 18:08, John B. wrote:


... But you do 83% of that speed on a heavy
clunky mountain bike through the mud so think that you have to poke it
off with a special stick that you carry.

Incredible!


How fast do you go on your road bike? For how long? I can hold 22mph for
half an hour. A friend goes 25mph and when I follow him I am totally
bushed, so I don't know what you find miraculous. A MTB is just a little
heavier and has higher rolling resistance but not a lot. Going 20mph on
one of those is something every somewhat fit rider should do.


What mountain bike tires are you running that have just a little more
rolling resistance than road bike tires?

http://www.bicyclerollingresistance.com/ indicates roughly twice as much
CRR, and that's not including the greater losses from tossing your
body+bike mass over rough surfaces. Suspension reduces those losses
compared to a rigid mountain bike, but the losses are still much more
than a road bike on any reasonable road.


--
- Frank Krygowski
 




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