terrymorse 

No, it's definitely not rocket science. Or aerospace engineering. Or mechanical engineering. Or any other engineering discipline.

It's bicycle lore, where the standard engineering practices don't apply.

cycling2012

cycling2012

cycling2012

Is that normal after I wash bike with low pressure water gun,but I don't wash hard bearings or not wash it .

cycling2012

This pressure gun

cycling2012

indyfabz

And the award for the largest photos goes to....

cxwrench

Just guessing here but you're neither an engineer (in the bicycle industry, not that it matters) nor a mechanic. Correct?

terrymorse 

Incorrect on both counts, but why does that matter to you? I don't like to go on about my qualifications, as that falls towards an "appeal to authority".

FWIW, I was doing mechanic work after school and on the weekends in my dad's bike shop before I was able to ride a bicycle. I continued to work there through college.

I was educated in Mechanical Engineering (BSc, MSc), with most of my professional experience on spacecraft designs.

I worked on the support systems of this one, before it had a name:




Recently, one of my Hubble units was on display at the National Air and Space Museum:



Hubble Space Telescope Power Control Unit (PCU) - astronaut trainer unit

This unit got replaced on the third Hubble servicing mission, in 2002. Since it was the power control for the whole spacecraft, Hubble had to be fully powered down to permit replacement.

I had my hand in many other spacecraft designs, but most of them were proprietary.

I hope that satisfies your curiosity.

cycling2012

Is it normal?

colnago62

I live in a city where every other person is an engineer of some sort. I have heard engineers say a lot of things that just were plain wrong. They always justify their position by saying, “I am an engineer at Boeing.” I played in an orchestra with tuba player who was a Boeing engineer. He spent 20 minutes explaining his reasoning for keeping a chromatic tuner attached to his horn. Problem was he didn't account for the fact that pitch rises in orchestras and so was always out of tune. Drove me crazy playing with him.

cxwrench

Very cool. But...it doesn't mean you know any more about bicycles and how to clean them properly than I do. There are tons of shop mechanics that don't understand how nor believe it's possible to clean a bike with a bunch of soap and pressurized water. I have done it for years and as others have said it's pretty easy to avoid ruining things. Just because you can't wrap your head around doesn't mean it's a bad idea. I can't even begin to fathom how to design and build a space telescope but that doesn't mean I'm gonna tell you it'll never work because you've done it. You just have to understand that lots of things are possible even if your highly educated and trained self don't think they are.

terrymorse 

I never wrote that power washing wouldn't work. I wrote that it was risky, which is why I banned its use (and the use of a garden hose with a nozzle) in my shop.

If a technology relies on the skill and caution of the operator, or acquired methods passed down from one mechanic to another, it will eventually produce failures.

Some mechanics can get by without using a torque wrench. It's still a bad idea.

cxwrench

Pretty much all that we do relies on this. Do you have a better method?

terrymorse 

Yes, absolutely: Written procedures for the job, based on maintenance instructions from the manufacturer, documentation of what work was performed, signed off by the mechanic.

An aircraft mechanic doesn't touch a plane without a job card with detailed instructions. The plane doesn't fly until the mechanic has completed the work and signed off the job card, and someone else has checked the job card for completeness.

In my shop, mechanics worked from iPads that provided step-by-step instructions on the job to perform, one task per screen, with the instructions usually copied directly from the manufacturers, and they had to check off each task as they went. Mechanics initially balked at the idea, thinking they were far too skilled to submit to such baby sitting. But quality, reliability, and efficiency all improved.

cxwrench

Not a bad idea. It also provides a higher level of professionalism for the customer to see this kind of thing.

KJ43

There is no problem washing your bike with a hose or a pressure washer as long as you pay attention to the stream and where it's aimed. I've been washing my bikes for over 30 years and not once have I ever had any issues from doing it.

popeye

You don't really know how many bearing you have killed. That is just lazy. Those baby bike seals are easily breached with pressure.
“Avoid using the high-pressure sprayers you find at pay car washes to clean your bike. The soaps can be corrosive, and the high pressure forces water into bearings, pivots, and frame tubes, causing extensive damage over time.

Many more on uboob.

cxwrench

Uhmmm...yes, I actually do. You have absolutely no idea what you're talking about here, and it's obvious.

colnago62

This is how driver’s education is taught. a torque wrench is not absolutely needed in every situation, it depends on the application. I don't use a torque wrench when adjusting the aluminum seat post on a steel frame bike. I doubt anybody used a torque wrench prior to carbon parts. I have seen people, shops, pro mechanics, myself all use a sprayer on bikes with no negative impact.

terrymorse 

Here's a little secret:

Torque recommendations for bike bits aren't typically set according to the application.

They're set according to the fastener. Here are the rated fastener maximums:

M5: 7 N-m
M6: 11.8 N-m
M8: 28.8 N-m
M10: 57.3 N-m

Bike manufacturers universally seem to pick torques approaching but slightly below these fastener maximums.

Atlas Shrugged

With respect, no reputable school instructs it’s mechanic trainees not to use a torque wrench under all reasonable situations. I assume you feel the same way about the aircraft mechanics servicing any plane you are on. The same goes for using a pressure washer around bearings sealed or not, it’s not a good idea.

colnago62

Maybe true, May not be true. There is this fact that many, many cyclists in the days of steel bikes never used a torgue wrench to tighten anything on their bike with zero disaster. The same applies to cleaning bikes.

cycling2012

could you guys tell me is it normal?

Sy Reene

But can you show us that the bike you've been powerwashing for 30 years still works?