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From: Catrike Ryder <Soloman@old.bikers.org>
Newsgroups: rec.bicycles.tech
Subject: Re: Extensive article on Rivendell and Grant Petersen
Date: Wed, 25 Sep 2024 05:39:01 -0400
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On Wed, 25 Sep 2024 09:05:25 GMT, Roger Merriman <roger@sarlet.com>
wrote:

>Frank Krygowski <frkrygow@sbcglobal.net> wrote:
>> On 9/24/2024 3:17 PM, Catrike Ryder wrote:
>>> On Tue, 24 Sep 2024 14:14:41 -0400, Frank Krygowski
>>> <frkrygow@sbcglobal.net> wrote:
>>> 
>>>> You might do well to read some of the archives of this group. There have
>>>> always been people posting opinions that were factually wrong, and there
>>>> have always been people pointing out those mistakes. As I've noted
>>>> earlier, having mistakes pointed out is a necessary part of the process
>>>> of education.
>>> 
>>> That's fine of the person being corrected understands that the
>>> corrector is qualified to do so and is truly interested in making
>>> things better. In my opinion, you fall far short of both those
>>> standards.
>> 
>> Your opinion on that matter is worthless. You don't have anywhere near 
>> the background needed to judge technical proficiency. Professional 
>> Engineering licensing boards of two different states have disagreed with 
>> you, not to mention those conferring my engineering degrees and those 
>> institutions for whom I've worked.
>> 
>>>> There are many examples of ideas that were posted frequently, and noted
>>>> as wrong. Most of them seldom pop up any more - and not only, I think,
>>>> just because there are fewer posts. I think people actually learned things.
>>>> 
>>>> Examples of mistaken claims? Chains wear by stretching the metal. Old
>>>> frames get "soft." Increasing spoke tension makes a wheel more rigid.
>>>> Tying and soldering spokes makes a wheel stronger. Headsets fail by true
>>>> brinelling due to impact loads. Hanging a bike by the front wheel makes
>>>> the spokes stretch... and many more.
>>>> 
>>>> BTW, what was that stopping distance from 20 mph again?  ;-)
>>> 
>>> 20 MPH would be maybe 9/10 feet if I didn't concern myself with
>>> slamming the chain rings into the ground or doing a face plant on the
>>> ground in front of the bike. 30 MPH would be a little further. Two
>>> front brakes work better than one, especially when the rider's weight
>>> is already more over the front wheels before he applies the brakes.
>> 
>> Right, good one. There is no way you can stop your tricycle in 10 feet 
>> from 20 miles per hour. That would require a deceleration of 43 ft/s^2 
>> or 1.34 times the acceleration of gravity. IOW you'd need tires with a 
>> static coefficient of friction at least 1.34, plus absolutely perfect 
>> application of both brakes so that both wheels were at the absolute 
>> limit of traction but not skidding. And you'd have to be in a "nose 
>> wheelie" all the while, with your rear tire up in the air so every bit 
>> of your weight was on the front wheels. It's essentially impossible.
>> 
>> For 9 feet, your acceleration would have to be nearly 48 ft/s^2, and 
>> besides absolutely perfect braking reflexes, you'd need tires with a 
>> static coefficient of friction at least 1.48.
>> 
>> And 30 mph would be _much_ farther, not "a little." The velocity term 
>> gets squared in the relevant calculation, much as it does when 
>> calculating kinetic energy.
>> 
>> I'm sure you don't know what a lot of that means. But what you're 
>> claiming is practically impossible. Feel free to prove me wrong by doing 
>> what you claim and posting video evidence.
>> 
>> 
>Even if he means without thinking time 

Yes, I know I'm going to stop and my fingers are already on the brake
levers.

>20mph is 6 meters or 20ft for a car,
>which almost certainly can out brake the trike.

I doubt that.

>If a planned braking action on the MTB probably could reduce that a touch
>as it has huge amounts of grip and braking force, and frame allows one to
>get behind the rear wheel.
>
>Other bikes at best would equal, the old commute bike as it has weight to
>the rear is surprisingly effective at emergency stops or just using the
>rear brake hard, but even that will during a emergency start to lock the
>rear.
>
>Neither of the road/gravel bikes would do well at emergency stops as your
>in the wrong position ie far too forward.
>
>Roger Merriman
>

A few weeks ago, after posting about braking, I tested the Catrike's
brakes at 15 MPH. I stopped at about 6 feet, keeping the chain rings
off the ground. 

--
C'est bon
Soloman