Motorcycle Frame Tubing
Motorcycle Frame Tubing And Tubing Size!
We get lots of questions on chopper frame tubing, and questions on how to build a frame so I thought we could answer a few common frame tubing questions here on this lens.
Many of the common questions are what size tubing can you use, what types of tubing, and if you can use pipe. I think you'll find the questions are good and the answers very helpful or informative. At least I hope so!
Question 1: Is 1 1/4 inch tube the standard size for most chopper frames? Or are there other sizes?
Answer To Frame Tubing Question 1:
Motorcycle frame tubing sizes are dependent on the style and aesthetic taste of the builder. Some prefer really small tubes so that the focus is on the components such as the engine, wheels, handle bars and fuel tank.
Others prefer to have solid heavy lines showing the frame and even painting the frame so that it is very visible.
Frame tubes vary from as small as 1" all the way up to 1.5". Some of the frame drawings we sell use 1.5" tubes. The most important factor is that strength should be maintained. A smaller tube generally uses a thicker tube wall for added strength.
A larger tube requires less wall thickness for the same strength. This helps to optimize weight of the frame. Another important factor is the type of tube as well. We always recommend using DOM tubing. Feel free to let us know with any additional questions or concerns.
Question 2: Is the 1 1/4 or 1 1/2 tube size referring to the inside diameter or outside?
Answer To Chopper Frame Tubing Question 2:
Good question. Usually tube sizes are outside diameter (OD) with a wall thickness for steel tubing that is used for manufacturing frames.
The only time inside diameter (ID) is used is on plumbing and other tubes where something is flowing through the pipe.
Couple questions regarding your softail sportster plans:
- Can your Sportser plans be modified to fit the stock Harley wheel tire size?
- Can the stock shocks that are on the 2004 sportster be used for the rear suspension as laid out in the plans?
We have sportster plans available that uses the stock Harley dimensions and wheelbase. You can use this frame and DOM or possibly ERW motorcycle frame tubing and use the same Harley tires (see plans for specifics). The design of most of the frames is for a 26" diameter wheel. The width of the wheel is dependent on the bike you have or are building. Most wheels are 8" wide and then there are the wider ones that go 10" and even up to 12".
Shocks need to be close to the size indicated on the drawing...
The spacing between the links is specified on the drawing. Each drawing is different so I cannot give you an exact value. Usually the common size is around 12". This can shrink or grow by a little bit but is really dependent on the frame. If your shocks pulled from the existing Harley are close to this size, then they should be easily swappable.
The motorcycle frame tubing used is shown in the plans. I've attached some photo renderings of a softtail sportster frame that we have. It is very similar to what you described in your last question with the shock built into the rear wishbone. Take a look at these photos and let us know if this is what you are interested in. The plans for building this are on our website and are downloadable. Feel free to let us know with any other questions or concerns.
Types Of Tubing:
Do you know the difference between DOM and ERW tubing? Do you know what kind of tube bender you'll need? If you don't you need to know. Get to the resource links below for quality information on these areas.