1000 pound frame load?

by Larry
(Denver CO. USA)

I'm just opening communications with your Company to make custom blue prints.

Reading through more of the products literature you offer, I ran across the term Frame load. You were describing the weight of the engine plus the weight of the rider should not exceed total frame load weight.

That information helped me formulate my question. Q. I need to build new frames with a frame load of 1,000 lbs. Weight of engine is 150 lbs plus the weight of the rider 230 lbs or a total of 380 lbs.

Q If I use 1.25 X .120 DOM tubing on the new frames will that give me the specs. I'm looking for?

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Mar 21, 2015
Bike frames to build more specifically.....
by: bikerzz007

The only thing is that if you make a bike frames in any sizes you wanted to build it for yourself is that you will have to know what is the high tensile strength is like....and that is a very important steps to know that you must take a high tensile strength for that bike frames as well as for the pound per stresses or pound per strengthen is like all welds must be a better penetrations on every sizes of DOM tubings to suits you a better shapes to verified the CWB (Canadian Welding Bureau) or AWB (American Welding Bureau) to be told to be checking all the welds before installing anything else to be provided by the welding inspectors has to be certified all kinds of bike frames made after welding more specifically.....and that is a very serious reputations for that bike frames BEFORE installing engines and trannies and wheels and batteries and lightings and wirings and fuel tanks and oil tanks and other things on that bike frames as well.....but it MUST be check by the welding inspectors to see IF that bike frames is in excellent shape to suited for everyone else without any accidents required as well....:)) and that is the law we all have to do it anyway....:)

Feb 12, 2013
by: Anonymous

There is so much to take in count to figure out frame load such as COG/Weight distribution, keeping in mind of all your rolling masses and oscillations such as wheels,engine balance factors and steering dampening. most formulas want info on size of rider and steering structure of frame to figure out percentage of upper body steering etc. Frame conditioning by adding gussets and triangulation is also discussed, I found a program that I use and figures this out in detail @Tony Foale Designs.

Aug 23, 2011
Additional weight calculation
by: Cracker

I am an engineer and work for a large "automation and test machine company" that
supplies “automation and test equipment” for many automotive companies including Harley Davidson.

Anyway, for your FEA question: you need to include the "weight of the frame" tires and wheels also. When the bike leaves the ground (like over a moderate bump in the road) this creates inertia of all the weight... and this total weight puts stress on the frame.

I design frames for my builds and I calculate a total weight of 1000 pounds for everything including the riders. The proper placement of the weight in the stress analyst is critical. Using G is ok, but can be misleading. The "rate" of the G force is unknown and can produce a large variable in your equation.

I use total stress and then add a safety factor of 10x. Especially on a ridged frame, this is even more critical. The only thing you need to look at next (which is almost a black art) is the “fatigue factor”. This will somewhat predict "life" of the frame before fatiguing and stress cracking (hence the 10x to 1 safety factor).
This sounds somewhat complicated but it really not that bad. Keep good notes … collect imperial data like life of the frame and look for stress cracks (learn to use processes like Magnaflux, pressure testing and penetrate dyes to check for cracks) to back up your analytical data.

Good luck

May 06, 2011
Heavy Loads and Finite Element Analysis!
by: Custom Choppers Guide

This is a fairly complex question to answer safely since there are so many unknown factors. But here goes...

We came up with the term "frame load" to describe the loads that will be applied to the frame. The major components that will be included in this load are the weight of the engine/transmission, weight of the rider, and any other "heavy" loads that would be added to the bike. We can even include the gas tank with a full tank of gas including the weight of the steel tank as well. We expect this to be much less than the other loads, but just to make sure the analysis is accurate.

The next step is to create an Finite Element Analysis model or FEA model. This would primarily be the Frame and all of these various loads attached to the frame. We usually run 3G or 3 x gravity load case in the vertical, for - aft and side to side cases. This simulates the various road conditions of bouncing off a pot hole, accelerating and braking as well as turning sharply.

The frames that we design usually have a safety factor of 3 or more. This means that if the max load we see on any of my tests is 1000 lbs, then I design the frame to withstand 3000 lbs before failure. This is done very tediously with adding gussets, bars and other components as needed to make the frame strong enough to withstand the forces.

This can be accomplished with 1" tubing all the way up to 2" or even 3" tubing based on the aesthetic look the builder is going for. Obviously the wall thickness and the amount of supports, gussets will change based on the size of the tube. It is not as clear cut as using a single diameter tube and having a specific load case. The design of the frame really makes a huge difference on how strong the frame is. I hope this helps. Feel free to let me know with any other questions.

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