Bicycle Engineering

[EngMark]

I am working with a client that has asked me to design a bicycle component. It looks as if there will be additional bicycle component work coming from them. I am the sole engineer on this, and I have no professional bicycle specific expertise. I'm struggling with determining the appropriate loads / overloads / cycles to design to. I did some searching online and came up with a list of standards that can be boiled down to the list in the Wikipedia article,

http://en.wikipedia.org/wiki/Outline_of_bicycles#Standards

and more specifically to these few standards / specifications:

EN 14764 City and trekking bicycles - Safety requirements and test methods
EN 14765 Bicycles for young children - Safety requirements and test methods
EN 14766 Mountain-bicycles - Safety requirements and test methods
EN 14781 Racing bicycles - Safety requirements and test methods
EN 14872 Bicycles - Accessories for bicycles - Luggage carriers
EN 15496 Cycles - Requirements and test methods for cycle locks

Each of these specs costs hundreds of dollars, and I can't find any preview as to what I'd be getting. Are these useful for my situation? Are there better sources of information?

Thanks,

Mark

 

[MintJulep]

Are these useful for my situation?

How could we know? You haven't told us what "component" you are designing.

Bicycles have been around a lot longer than EN standards.

 

[EngMark]

The immediate component is a head bracket / clamp for the top of a seat post, but I'm not asking if those specifications are pertinent to that component, what I'm asking is if the CEN / EN specs in general are useful in giving loading conditions and load cycle counts to be expected for multiple components or whether they address other things. ...And whether there are better references to consult?

Mark

 

[hydtools]

http://www.bike-eu.com/public/file/archive/20081023-cen_bike_standards_en_14764_english-draft.pdf

Section 4.14 for tests that apply to saddle and seat pillar.

No?

Ted

 

[EngMark]

Ted, thank you for that. Now I see that those standards do have what I'm looking for. Do you know if the saddle requirements are the same between trekking bikes, racing bikes, and MTB? I tried to follow through the links and get to the other specs, but couldn't. I assume you have a membership of some sort that gets you in??? ...Or there ways to access the other standards online for free?

One of the comments I found in reading the spec and related links was this -
""These EN standards for bicycles have been criticized by many in the industry as inadequate. The main reason for the criticism is that fatigue tests do not apply to fully assembled bikes while the standards for sub-assemblies and components specify only very basic and minimal requirements."
Does that mean that there are tougher standards or references out there that some people / companies work to?

Thanks,

Mark

 

[hydtools]

I just googled the EN number and that site came up with the pdf file of the document.

Ted

 

[gadkinsj]

I worked at a bike shop for 8 years while I was getting my degree. If you want some information about bicycle testing, I would call up Cannondale, which is a bike manufacturer in PA. They have moved all of their production overseas but still do testing in the states. They had open tours of their plant and I spent about an hour and a half quizzing the test tech's on the testing they did on each of the components.
The company expecting you to design this thing should have given you some criteria to meet I would imagine? If they list a spec to test to, go buy the spec. If they have given you no guidance whatsoever, then go buy a few of these components and break them.
From experience, the highest force on a Seat post collar is when someone gets a few feet of air and then lands. That was actually one off the tests I saw done. They used a Loading dock and just had a guy jump off with a bunch of sensors on him and the bike.

 

[TVP]

Mark,

You can view EN 14765 and 14766 using the following links:

http://www.baltikvairas.lt/filemanager/download/28/EN 14765 .pdf

http://www.baltikvairas.lt/filemanager/download/28/EN 14766 .pdf

You are not going to find better information within the public domain than what is contained in the EN standards. In my opinion, if your customer wanted you to design something that could meet a more stringent standard developed internally by a bicycle manufacturer, etc., then they should have provided that up front.

 

[kingnero]

They both point to the EN 14765 on my computer?

 

[IRstuff]

Those are copyrighted materials, but they can be purchased:

http://webstore.ansi.org/RecordDetail.aspx?sku=BS+EN+14766:2005

http://webstore.ansi.org/RecordDetail.aspx?sku=BS+EN+14765:2005+A1:2008

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[flash3780]

Well, standards are certainly helpful, but I'd guess that the loading requirements for a specific bicycle would depend on its intended use.

Perhaps the company that produces the bicycle has some functionality range? I'm sure that a mountain bike would be required to withstand much larger dynamic loads than a racing bike. I'd start by getting some design requirements from the company to determine how harsh of an environment they would like their bicycle to survive. If their requirements are incomplete, you could propose some design requirements to them based on standards or plain old engineering judgment (i.e. what seems like reasonable use, harsh use, etc.).

I'd imagine that many bicycles out there don't conform to all industry standards (though surely many do). You may ask the company if they use industry standards in their designs, and if so, which?

At the end of the day, it's all about clearly understanding customer's expectations.

//signed//
Christopher K. Hubley
Mechanical Engineer
Sunpower Incorporated
Athens, Ohio
--

http://engineeringliberty.wordpress.com