Hi there. I found myself wondering the other day about a fairly basic force and support question, and I realized that I don’t have the mathematical tools to answer it myself. So instead of telling me the answer, teach me to fish: what are your favorite resources for learning basic mechanical engineering principles?
I don’t expect anything bike specific, but it’d be nice to know enough to figure out basic stuff on my own, e.g. estimates for tube sizing, what is a big enough support for a rack, etc.
I thought this was going to be an easy answer, but the more I thought and researched it, the more I realized there is no good answer.
There are plenty of free online resources and youtube lectures. But putting myself in someone’s shoes, there are a few problems:
If you don’t know what to search for, you can’t find the proper resources
If you don’t understand the material, you don’t know if the material you found is difficult to understand, or just bad teaching
You need practice to truly understand something. That means self-assigned homework
This is a typical mech eng core classes (first two years)
Statics and Dynamics: Analysis of forces and motion in systems. Solid Mechanics (Strength of Materials): Stress, strain, and deformation in materials. Thermodynamics: Energy systems, heat transfer, and thermodynamic cycles. Fluid Mechanics: Behavior of fluids in motion and at rest. Heat Transfer: Conduction, convection, and radiation in engineering systems. Material Science and Engineering: Structure, properties, and applications of materials. Dynamics of Machines: Vibrations, control systems, and kinematics of mechanisms.
Framebuilding overlaps with statics and dynamics and solid mechanics, so that is a starting point!
You can also look into the structural analysis of a truss. While a true truss does not have any bending moments in the members (tubes) it can give you an idea of how forces are transferred and why some members are in tension and others in compression.
For bending moment concepts, maybe look into a “simple span” beam with a point load applied at the mid-point of the span. See what the bending moment is and how there will be compression at the top of the member and tension at the bottom of the member.
In general I agree with what Daniel said. However, in consideration of this:
I would take a look at the following books, in order. The specific editions don’t matter too much, and PDFs of these can be found for free in the wild:
Statics: Engineering Mechanics: Statics, ISBN 13 978-0133918922 Mechanics of Materials: Mechanics of Materials, ISBN 13 978-0133254426 Mechanical Engineering Design: Shigley’s Mechanical Engineering Design, ISBN 13 978-0073398204
This ordered list is how mechanical engineering design is taught in universities: each class teaches prerequisite knowledge for the next. The specific books I listed have been vetted by several years of use in ABET accredited universities, so I believe they’re worth your time and attention.
There is great educational youtube content out there too. Jeff Hanson comes to mind, I learned a lot from his channel while I was taking the courses that used the books I listed.
It’s one of the only text books I actually kept from college. I think the way information is presented is very easy to digest. It would fit along side Mechanical Engineering Design in the ordered list. It covers failure modes such as buckling or sheering which are directly related to your question.
Also, I think it’s important to note that most mechanical engineers and engineers in general are not doing heavy math or complicated equations when designing things. Engineers in research and academia like @Daniel_Y may be an exception. If you learn and understand the basic concepts of what makes things strong or what causes things to fail ect. and draw from existing designs and sprinkle in a healthy factor of safety, you can make things that are strong and work without needing to do calculus or anything fancy.
As a mechanical designer professionally, I 100% agree with Daniel’s list of issues.
My engineering degree exposed me to far too many concepts, research, and formula all the time for me to grasp much of anything in the moment. Drinking from a firehouse sorta thing.
It’s only been a career of mechanical design, in a variety of industries, that I’ve been able to make sense of most of it. And all of it will eventually break my brain if I go down too many rabbit holes.
My key takeaways for my MechE degree:
All of the concepts progressively build on each other, the curriculum is intentionally logical
Energy impacts and influences Material, MechE helps to mathematically describe these interactions
You don’t have to memorize something, only know that it exists and where to look it up again. Example - It took almost ten years to need to remember Thermodynamics again until this year.
MechE is such an incredibly broad subject that no two engineers will approach a problem in exactly the same way - it’s weirdly simultaneously an art and a science. I often call it ‘The Science of Approximations’
Sometimes you’re landing something on the moon, sometimes you’re making sheet metal boxes.
It is very similar to framebuilding - there’s a logical order to construction that is creatively variant depending on artistic expression. That’s why I gravitate.
All that said, here’s a list of resources I reference regularly:
Machinery’s Handbook - Has a ton of information, I mostly use it for pressfit class tables
Machine Design - Norton - This one has great information about component design and fatigue mechanisms
Mechanics of Materials - Hibbeler - All that beam bending goodness
Materials and Processes in Manufacturing - DeGarmo, et al.
Outside of textbooks, I generally start my topic research outside of bikes in some other further developed industry. Eg - when I was learning about bike suspension, I started in motorsports.
I have actually found ChatGPT and Bing Copilot to work pretty well for helping me learn the engineering stuff. There are a lot things my Econ education skipped over in terms of material properties and such.
I used this prompt when designing a custom oddball stem that I posted on this forum a while ago. It helped me get the basics from the example presented and then I could tweak the inputs to get a safety margin I was comfortable with.
Paste the below into chatgpt or Copilot and I think you’ll be surprised. You can add things like “explain it to me as if I was a college engineering student” or “explain it to me like i’m a 4th grader”. Have fun!
“I need to calculate the dimensions of stainless steel tube that has to support 500lbs of force. The tube will be 11 inches long and brazed on one end to a clamp. The tube will be angled at 30deg angle upward from horizontal.”
I agree, ChatGPT or other AI tools can be very valuable to quickly research a topic you’re unfamiliar with.
One thing both my engineering degree and my experience on the job has taught me though is to detect BS, an absolutely essential skill to resesarching anything on the internet. And since AI tools are essentially an amalgamation of all info to a certain topic on the web, it is even more needed here.
I’ve come across numerous topics already, where the first couple of search results in a search engine are just blatantly wrong and/or dangerous, but they would throw off an AI prompt to that particular topic. Just think about the thousands of absolutely bonkers five minute craft “hack” videos…
So I would strongly advise to use established sources for engineering concepts first, before turning to AI. Once there is a fundamental understanding of engineering, it can be a useful tool.
Search engines are based on advertising and different algorithms so you can’t really compare. AI’s accuracy is affected by the obscurity of the topic and number of sources it can draw from. I always visit the references provided. With generative AI, it’s important to have a conversation. It’s not search. I almost never use search any more.
Depending on where you’re at with maths/engineering etc, I’d start with good popular science books to get the concepts/language clear and sorted before diving into higher levels and calculations.
My own engineering curiosity was kicked off in my teens by these two books by JE Gordon which still sit on my shelves:
Great answer from @Daniel_Y . One thing to add to his advice: Before embarking on self-study of hard-core ME subjects, a good grasp of math is needed. Statics and dynamics can be handled with a really strong knowledge of geometry, trigonometry and algebra (and I mean really strong, not just “I passed it in high school 20 years ago”). But other courses like fluids, thermo, heat transfer and some sections of solid mechanics will assume you have math skills consistent with four semesters of calculus up to and including differential equations.
