On Thu, 16 Nov 2017 16:19:43 -0800, Joerg
wrote:

On 2017-11-16 15:41, John B. wrote:
On Thu, 16 Nov 2017 10:37:16 -0800, Joerg
wrote:

On 2017-11-15 16:45, John B. wrote:

On Wed, 15 Nov 2017 15:17:28 -0800, Joerg
wrote:

On 2017-11-14 17:31, John B. wrote:


[...]

Anyhow, there are numerous issues here, not the least being that it is
tough to mount a thick rotor so it still lines up correctly. It may be
possible to machine a part to adapt a motorcycle caliper and I have had
parts machined for my MTB. Requires time though. As I said, first I am
going to see if the 8" rotors are good enough which they very well may
be. 6" in back was clearly not adequate.

Good Lord! A disc is just about the simplest thing that you could
design - two circles one inside the other - and almost the simplest
thing to manufacturer. Even in the wilds of California you should be
able to find either a "home machinist" or a commercial shop to make
them to your specifications.


Take a look at a modern MTB, how much available clearance there is and
then think again about your statement.

I do take a look. Just about every time I visit my LBS, and I see no
problems with installing a disc, or a bracket for the caliper for that
matter.


Check again, this time with glasses and measuring calipers. Between
rotor and fork there is about 1/20th of an inch on my MTB. A 3mm rotor
would barely squeeze in, a 4mm rotor would not. It would scrape.


But I do notice that both bicycles and small motorcycles have the
caliper mounted on the back side of the front fork tubes and I have
read your posts about how that is the wrong side. Which makes one
wonder.... are all the two wheel vehicle designers in the world wrong?


Often they are. Just because everybody does it a certain way does not
make it right. It's not a problem with a through-axle and certainly not
with motorcycles. There, it has the advantage that a caliper behind the
fork runs less of a chance of being hit with debris kicked up by a rider
up front. Where it is clearly the wrong design is with QR axles.

But really, is there a real reason to run quick release axles on
bicycles?

If memory serves I have had two flats this year with one month to go
to make 12. The old "coaster brake" bicycles that were the only thing
available when I was a kid had conventional axles with nuts. The first
"Mountain Bikes" had solid axles.
https://mmbhof.org/mtn-bike-hall-of-fame/history/


Or...

One way to do it is to machine out some material in the center. And that
requires ... a machine. As I wrote several times now, if the 8" rotors
are good enough then they are good enough. I shall see.

But they are relatively small, compared to a proper "SRAM Guide
Ultimate Disc Brake" which has a 1,000 mm disc.


Huh?


But perhaps the Ultimate is designed for the really fast riders?


Fast doesn't matter much, weight, cargo and long hills do.

[...]


Assuming a normal healthy individual you should be able to march (even
with a can of beer in your pocket) at about 3 miles per hour - about 5
kph - for hours on end.

I can assure you that a 5 Km stroll is far more invigorating then a 5
Km ride on a bicycle.


However, walking is boring and sometimes dangerous. There are no
sidewalks out here. Also, I can net 25km or so during the same time I
walk 5km and see a lot more interesting stuff while doing that.

How so? After all most people can walk and chew gum at the same time
and being on foot one is far more agile then when mounted on some sort
of wheeled device.


I could chew gum on my bikes. I just don't like chewing gum. If eating
counts then yes, I have done that while cycling. Even riding at a good
clip can be so boring at times that I turn on the MP-3 player. Once as a
kid on the way to school I even fell asleep while pedaling.

The saying is/was "He is too stupid to walk and chew gum" as a
description of someone who is really, really, dumb. In other words,
most "normal" people CAN walk and chew gum at the same time :-)


Some folks multi-task:

https://www.youtube.com/watch?v=x4nxylN4InE


BTW, that thought has crossed my mind as well. Some day when I am almost
competely retired I want to walk some of the singletrack I ride around
here. It's much slower but one hears more where there is none of the din
of a mountain bike. Occasionally I already do it and push my MTB for a
few miles, watching birds and such. You can't do that when having to
concentrate on ruts and stuff.

True walking/running speed is much slower then riding a bicycle but
the level of intensity is much higher. Try running, oh say 26 miles
(43 Km), again lets say, two and a quarter hours and then do the same
thing on a bicycle.

More bang for a buck so to speak.


Except those bucks eventually get slurped out of your bank account by
the bucket load when the hip gives out. That is what happened to a
former co-worker who used to run a lot. The doctor told him that it'll
ruin his hips. And then it did. The doctor's advice to him (besides hip
surgery): Consider cycling.
--
Cheers,

John B.