There are a growing number of materials and methods used to build bicycle frames. This instructable is specifically about building steel bicycles frames. MIG, TIG, Lugged and Fillet Brazing are all common methods for joining steel bicycle tubing. The steps leading up to the actual joining of the tubing are very similar for these methods so that is what I will be covering in this instructable. It would be very difficult and beyond my abilities as a builder to try and describe how to effectively weld or braze. I recommend you learn to weld or braze from someone face to face and then practice (a lot). I personally learned to build bicycles through the United Bicycle Institute frame building class. Most of the information I give in this instructable I learned through the class and the literature they provided. They offer a really great way to learn frame building, I highly recommend you take one of their classes.

Here are some common acronyms I will likely use in this instructable:

HT - Head Tube
ST - Seat Tube
TT - Top Tube
DT - Down Tube
BB - Bottom Bracket
CS - Chain Stay
SS - Seat Stay

MTB - Mountain Bike

Step 1: Design

The first step in building a frame is to design the frame you intend to build. There are lots of different opinions, techniques and algorithms to sizing a bike frame to a specific rider. I will not go in to detail about bike fit.
There are many ways to draw your frame. You can use any old CAD software, bike specific CAD or a drafting table. Doing it on a drafting table is convenient because you get a full scale 2-D model of the frame before you build it. You can use this model to lay actual tubing down on to see how things are shaping up.
However you decide to do it, you want an accurate drawing of your bike frame. You will be using this drawing to take dimensions and angles from so make sure it is accurate!

I will be breaking most of the parameters used in frame design in to two categories fit and feel.
The fit parameters are determined based on the body of the individual the frame will be for. The feel parameters influence how the bike will feel or perform. If you want to learn more than I discuss about how these effect the feel of a bike take the UBI class or do some research.

Fit parameters (basically, what size bike are you building):
ST length (measured center of BB to where the center line of the TT intersects the centerline of the ST)
TT Length (measured from the ST TT centerlines intersection to the TT HT centerlines intersection)

Feel parameters (affects the comfort vs. efficiency of the bike):
BB drop (how far the center of the BB is below the axle line); influences frame stiffness, less drop = stiffer but less comfortable.
ST angle (measured clockwise from horizontal); affects weight distribution, shallow angle = more comfort but less efficiency.
HT angle (measured clockwise from horizontal); influences steering quickness and shock absorption, steeper angle = faster handling at the cost of shock absorption
CS length; also affects shock absorption as well as tire/fender clearance, longer stays means more shock absorption and more clearance for bigger tires at the cost of efficiency.
Rear axle over lock dimension (how wide the rear axle is going to be)

The best way for someone new to frame building to determine these fit and feel parameters (unless you have a fit bike at your disposal) is to take measurements of the bike you ride that fits you the best. Because you have ridden it you know what feels good about it and what you may want to change, starting with your current bikes geometry is a good way to go.
Another option is to look up different bike geometries online. Most bicycle frame manufacturers give frame dimensions on their website.

Other parameters important to your drawing/design
Wheel size; What size wheels are you going to use? (the important quantity is the bead seat diameter (BSD) or the diameter of the bead of the tire)
Common BSDs:
26” (MTB) 559mm
700c (road) 622mm
27” (old road) 630mm
29” (29er) 622mm
Tire Profile (this is the diameter of the tire profile i.e. the distance the tire extends beyond the BSD)
This quantity is usually given the by the tire manufacturer. For example 700 x 23 tires have a tire profile of 23mm.
Front tire clearance (how much room the front tire will have, bead seat to the bottom of fork crown)
Lower headset stack (how much room do you need for the lower headset bearings default dimension is 13mm)
Fork height (I am not going in to how to build a fork so you will get this number from the mfg of the fork you are going to be using. It is the distance from the center of the front axle to the base of the crown race seat (also called “axle-to-crown”).

Now time to pick your tubing dimensions:
Bicycle tubing can be bought from a variety of distributers. I personally have bought and built with True Temper tubing from Henry James. A great way to go for your first frame is to buy a kit that includes all the tubing for a frame. UBI sells Kasai tubing kits here (click the steel tubing tab). The numbers refer to the alloy type. Oversize and Standard refer to common tubing diameters.

Standard Road/Track Frame Oversized Road Frame
TT 25.4 mm 28.6 mm
DT 28.6 mm 31.8 mm
ST 28.6 mm (27.2mm seat post) 28.6 mm (27.2mm seat post)

Head tube diameter is determined by the size of steerer you want. 1" threaded steerers are the older standard, 1 1/8" threadless steerers are the more common modern standard. The steerer you choose influences the internal diameter of the head tube but the outer diameter is determined by the wall thickness of the head tube. They make thin walled head tubes for bikes being built with the added support of lugs thicker ones for luggless bikes.

It is worth noting at this point there are many options for BB shells. If you know all about bottom brackets, great, buy the shell you need. If you don't know much about bottom brackets get the most common 68mm bb shell.

Most bike tubing is butted. The wall thickness varies across the tube. The end of each tube has a thicker wall (stronger joints) while the center is thin (lightweight). For your first build I recommend you stick with thicker tubing like 1/.7/1 for example which has 1 mm thick butts and a .7mm thick center. (.9/.6/.9 is also a good option)
Tubing comes in different lengths and each piece can have different length butts. All this information is given by distributors and is important when selecting cutting your tubing. You want to make sure you don’t cut the butt off of one end of the tubing...

After you have selected what diameter tubing you will be using and have come up with all the necessary dimensions it is time to draw your frame. Compile the necessary parameters in to an easy to use list. This example is from the UBI frame building handbook given to me in the class.
Road bike:
Rim BSD: 622mm
Tire profile: 25mm
Tire diameter (BSD + 2 X Tire profile) 672mm
HT: 73°
ST: 73°
BB Drop: 75mm
Fork Length: 370mm
Chain stay length: 410mm
ST length: ?
TT Length: ?
Fork dimensions

Take your time and get it right. Draw a side profile and a top down view of the chain stays.
Precision is important.
<p>Nice one, nice one, nice one !!</p>
Great instructable, thank you! I'd like to make mine. Since I do not want neither cannot afford to make any mistake. Can I learn ST, TT and SS tube lengths &amp; diameters you have used.
<p>I want to build a full suspension motorized bike out of a free mongoose xr200 frame for as cheap as possible and slowly upgrade to better parts later. The starting point is with the frame. I can MIG weld steel and aluminum, notch tubing etc.. I was hoping with 2 other donor frames, to extend the rear swing arm a bit and relocate the shock from inside the frame to the rear of the bike similar to a motoped rear suspension set up to make room inside the frame for the 2 stroke engine and also so the bikes my size better.. I'm hoping I can do it without a jig and won't be wasting my time..</p>
What is the cost of making it ?
<p>WOW!!! I'm making a fatbike for a secondary 5 project and I think it's going to be very useful! </p><p>Thanks!</p>
<p>Thanks for going through the process start to finish! Inspires me towards my own tube framing projects.</p>
<p>beautiful design and making process, thanks for posting!</p>
Lovely work, very inspiring :-). I 'd love to have a go at making something like the Top and a from the early days of mountain biking.
<p>Goodwill. Habitat for Humanity. Yahoo's Freecycle groups. Craigslist Free section. Local thrift shops. Trash. Bicycles are an item often given as presents to children and youths that either never get used or have a short interest span due to changing friends. One woman gave her dad a bicycle to entice him to get some exercise, and it never was ridden. Bicycles given away often still have the rubber mold &quot;spikes&quot; on the tires. Bicycles often sell at thrift shops for less money than a set of bike brakes or a set of tires and inner tubes at a bike shop. No knock on someone wanting to build a bicycle, but if you want to ride you will spend a lot more time in the shop than on the road building rather than looking for inexpensive 2d hand bikes.</p>
<p>True, but not everyone wants to ride around on a girl's Schwinn or with an old Raleigh, they'd like to know how to hack the remains found at such shops you mention into a bike they enjoy riding, something they made themselves instead of pre-made. Not to worry, though, those old bikes will find good homes; hey aren't as perishable as a puppy in a shelter.</p>
<p>A month or so ago I bought a Trak 7200 Multitrack 21 speed hybrid with an aluminum frame and Shimano gears for $15 at a local Habitat. I had to replace the rear innertube for $5 and buy an adapter for a buck - it has the Presta or French valve. Thing retailed - MSRP - for $450. I'd never heard of a Trak, but I can recognize quality when I see it.</p>
<p>Good find, if you like hybrid bikes, the comfortable, granny-style, the Jack-of-all-trades/master-of-none bike. You prefer to buy, nothing wrong with that. Some also prefer to make their own; I also prefer presta valves, so there you go. It's what makes the world spin, other peoples warped ideas of right and wrong, I mean.</p>
<p>I have a very similar mind set Snidely70448. I have spent lots of time volunteering in bicycle co ops and fixing bikes for free. Reviving old bicycles is one of my favorite hobbies. I am an avid proponent of cycling as a primary means of transportation. </p><p>Unfortunately many of the bikes you speak of are of poor quality and improper design. A $200 department store bicycle often has full suspension (too many moving parts for something that only costs a few $100) and crap components. They are made to be ridden less than 30 miles. We need companies making and selling bicycles that are simple, functional and last so that when they inevitably reach the thrift store or dumpster they still have value. Part of my interest in frame building is producing quality bicycles that are made to serve dozens of owners.</p><p>I am also anxious to work towards building and designing frames that fit people. From non typical body geometries to people with physical disabilities, if bikes fit, people ride them more. I also hope to do some cargo bike building, designing frames that aren't commercially available that reduce dependence on motor vehicles.</p>
<p>You are much more ambitious and have much higher standards than do. I ride a couple-three times a week, a mile or two, weather permitting, but mostly to exercise my dog. I MAYBE could do 30 miles if my life depended on it, but I'd be a basket case by the end. I'm old and retired, and the joints and back just aren't up to it no matter how ergonomic the bike. As for reducing dependence on motor vehicles, it will never happen for most people, though the last time I was in New Orleans I did see a bike delivery guy with a good sized package on a unique cargo bike. I think this is the setup.</p><p></p>
<p>OOPs. The picture got lost. It showed a bike attached to about a 6' trailer.</p>
<p>I can see that you have a shop I would be envious of, LOL. As for notching tubing, I found a nice tool at Harbor Freight for that, Tubing Notcher Item # 42324. I used to work at a custom motorcycle shop and we used this tool with .125&quot; wall tubing making frames and it works really well. </p>
Very informative. Thanks for the great detailed instructions.
<p>Nice job and the most thorough instructable I have seen. Just curious.....why did you curve the top tube? For aesthetics? Wouldn't a straight TT have been more rigid, thus stronger? </p><p>Why did you braze it instead of welding with TIG or MIG? </p>
Yeah, curved the top tube for aesthetics.<br><br>I brazed it because I don't know how to weld :(
<p>...and because I really like fillet brazed bicycle frames! :)</p>
<p>Excelente instructable !</p>
<p>Great!<br>Can you give an estimate of the cost?</p><p>And maybe savings when you compare it of buying a frame ?</p><p>Thanx!</p>
<p>Thanks for the compliment sjochim.</p><p>If you went for a fairly simple, no frills frame you could buy the raw materials for around $250 (or even less if you used cheaper, heavier tubing). </p><p>Paint jobs can be expensive. You can get a cheap powder coat job for around $100 or spend over $1,000 on intricate liquid pain. </p><p>Access to a jig is helpful and you need a welder or oxy acetylene rig.</p><p>Custom hand built frames can cost more than $4,000 so compared to them it is quite the bargain. As Snidely70448 mentions above, there is no shortage of used bicycles that get no use. You can pick up frames from thrift stores or bicycle cooperatives for less than $100...</p>
<p>Good post. I disagree with your description of hand mitering as being tedious and time consuming. With sharp hacksaws and files, it can go very quickly. If you have to tram the mill and indicate the fixture, milling can be as time consuming. For one-off work, I don't see where the machines help much. </p>
Good to hear mjenk20236. I was more or less hypothesizing about hand mitering. I have had the good fortune of easy access to milling machines and I have only had good experiences with them. I am sure I will end up making some hand miters at some point. Thanks for the feedback.
<p>Awesome instructable, i love your work. All the machinery belong to the school or it's yours?</p><p>Did you use regular carbon steel tubes? </p>
<p>The machinery is actually at the instructables creative workshop in San Francisco. This project was part of my residency there.</p><p>The majority of the tubing is True Temper 4130 steel tubing. </p>
<p>Great Instructable, thanks for posting! I have a question on the brazed joints... did you grind or sand them to get them smooth looking? </p>
<p>I used a series of hand files and emory cloth strips. Some people use electric grinders but a little slip could ruin the look...</p>
<p>Awesome step by step!</p>
<p>very professional work</p><p>I think this instructable wasn't acessible to the common user</p><p>It was a pleasure to saw all the steps envolved in a building of bicycle frame</p>
<p>Beautiful bike, and great instructable. Thanks for sharing!</p>
<p>Cool. Great work. You have confirmed my notions of my caveman style of engineering my home built bikes. I think my left eye aligns things better. ;)</p>
<p>I'm amazed to see butted tubing used to reduce the weight, and a redundant top tube added to raise it. Art is cheaper in lower grade steel, and just as pretty, as well as easier to build.</p>
Hey you are officially my God! Ahaha <br>Congrats!!! You are a master!!
This bike has a bottle opener... That is genius.
<p>Wow this is beautiful. I've always wanted to build a bike and recently did by chopping up a few bikes to make one. It was hard and there are a ton of mistakes with mine but yours is wonderful.</p>
<p>Great-looking frame! Very interesting and informative instuctable. </p>

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