Build your dream bike (Part I: Getting started)

Someone commented on Reddit, “Wish there was an IKEA for bikes. Go in, grab all stuff, assemble.”

Why? Because there’s nothing like building the bike of your dreams–the bike you’ve always wanted, if only the bike manufacturers thought like you did. But for some, assembling a bike from scratch feels like a bit of a dark art (a dork art?), practiced only by those professionally trained in such techy things.

trying to reach a goal
Without a little boost, that fabulous goal is just out of reach.

It doesn’t have to be. As long as you are aware of a few standards and know when some selective tools apply, assembling your own bike is almost as easy as assembling Legos.

So today, we’re going to virtually build a dream bike, starting with a CHANGE folding frame. That frame will allow your completed bike to fit conveniently inside any car, instead of riding outside in the rain, road grit, and bug juice. Goodbye car racks; hello, biking freedom!

bike components ready for assembly

Start with a great bike frame.

What makes a great frame? Light weight is good, although as you move into carbon frames, you start paying by the ounce. How much money are you willing to part with to save one pound? A folding aluminum frame, on the other hand, is light yet folds in half for much easier transportation.

Flatbike sells two folding frames–one for road use and up to 28mm tires, and one for all-terrain use and up to 2 1/4 inch tires. (Right up front, there’s one of those cycle world anomalies; road bike stuff like tires, wheels, and frame sizes tend to be measured in millimeters, while the identical mountain bike features are usually measured in inches. Rather than explaining that history in this article, we’re just going to roll with it.)


The aluminum CHANGE 833 folding all-terrain frame folds in half in seconds and is the frame used for both the CHANGE 811 all-terrain rugged hybrid and the CHANGE 812 off-road MTB.

Change 833 frame unfolded
Change 833 frame folded

The CHANGE 833 frame is available in three sizes, for riders from 5’1″ to 6’6″ (See the size chart on the order page), is disc-brake ready, and weighs 5.5 lbs. Currently available from Flatbike in Pine Green, it can also be special-ordered at no additional cost in Matte Black or Arctic Blue.

The aluminum CHANGE 733 folding road frame also folds in half in seconds and is the frame used in the CHANGE 702 street hybrid as well as the Flatbike Century folding road bike.

Change 733 frame unfolded

The CHANGE 833 frame is available in four sizes, for riders from 5’0″ to 6’7″ (See the size chart on the order page), is rim-brake ready, and weighs 4.5 lbs. Available in White or Black.

Learn the lingo.

There’s a Chinese saying, “First, call things by their right names.” And with bikes, Aaron Kuehn’s typograph of a classic bicycle is still the best way to do that, decades after he first drew it. About the only thing that dates this image is the location of the shifters, which have now moved to the handlebars.

We’ll be starting with the pink part–the frame and fork.

Aaron Kuehn's bike typography
To order a t-shirt of this fabulous artwork, visit Aaron’s website

Now that we’ve got the right words, the actual measurement in a frame size is the distance between the center of the crank and the top of the seat tube. MTB riders need more room to maneuver on twisting, bumpy trails, so the same size rider will have a smaller frame size for an all-terrain bike than for a road bike.

Key frame specs in four areas to get you started.

As you start to build up your frame, the first steps are the trickiest. Here are the four touchpoints of a frame that require special consideration. After you get past this thinking stage, the whole process gets way easier.

  • The seatpost. Older seatposts are often 1 inch (and a boatload of other random variations), but a more reliable standard is 31.6mm (1 1/4 inch). Both CHANGE frames use the newer 31.6mm standard.
  • The bottom bracket. Behind the crank is the hole it goes into, and the device that allows the crank to turn easily–the Bottom Bracket, where there are two considerations:
    1. Threaded or press-fit? CHANGE frames use a threaded bottom bracket.
    2. Width? Bottom brackets get wider and wider to accommodate wider wheels.

The CHANGE 833 frame is compatible with the Shimano SMBB52 Bottom Bracket (73mm). The CHANGE 733 frame is compatible with the Shimano SM-BBR60 Bottom Bracket (68mm).

  • Fork. The fork goes into the head tube, and there are three standards to be aware of:
    • Steerer tube diameter?  This is the part of the fork that goes into the head tube. One diameter indicates a straight tube, usually 1 1/8″; two diameters indicate a tapered steerer tube.
    • Length? Road bike forks are fairly standard for a 700c wheel; mountain bike forks or “rigid forks” the same size as an MTB fork are longer to accommodate different wheel sizes and often the travel of shock suspension.
    • QR or thru-axle? At the hub, the fork can use either a quick-release axle (as shown in the drawing above) or a thru-axle with a round hole

The CHANGE 833 frame uses a tapered MTB fork (1 1/8″ top and 1.5″ bottom) for a 27.5″ wheel. The CHANGE 733 frame uses a straight road fork of 1 1/8″. (You can use either a quick-release or a thru-axle, but a quick-release axle won’t need to be removed when you fold the bike.)

  • Rear hub. This is where the rear axle connects, and five variables are important as you choose a wheelset:
    • Maximum wheel size? The CHANGE 833 frame is designed for a 27.5″ wheel but can also do 700c. The CHANGE 733 frame is designed for 700c. (Yes, 27.5 and 700c are strangely different measurement systems, but we’ll save that anomaly for a later article all its own. For now, we’ll just roll with the weirdness.)
    • Maximum tire width? The CHANGE 833 frame is designed for tires up to 2 1/4″ wide. The CHANGE 733 frame is designed for 25mm tires, but works well with up to 28mm.
    • Rear hub spacing? This is the distance between the two parts of the frame where the rear axle fits. It has been getting wider with more gears and wider tires, but there are still two well-defined standards at 135mm (MTB) and 130mm (road). The CHANGE 833 frame has 135mm spacing. The CHANGE 733 frame has 130mm spacing.
    • Quick-release or thru-axle? Both frames are designed for quick-release.

Whew! That’s a lot of stuff. But the end result is really simple. You’ve bought a seat post, bottom bracket, fork, and a set of wheels that all fit. You’re well on your way.

Tools of the trade

Who knew that a hacksaw was standard bike shop equipment?

Below are the tools needed to assemble a bike from scratch. You don’t need to own all of them–you can borrow from a bike geek friend or visit the local bike shop for assistance, but most of them are good to have. Let’s go through them one-by-one

tools needed for bike building

Clockwise from upper left:

  • A hacksaw is a good general-purpose tool anyway, but in this specific case, you’ll be using it to cut the steerer tube of your fork to the right size for your frame. Measure twice, cut once!
  • Everyone needs a good rubber mallet so you can pound on things without denting them! In this case, you’ll be using it twice–once to prepare the frame for the fork, and once to gently tap your crank into place.
  • Cable housing cutters give you clean cuts for your cable housing, your cables, and even crimp those little aluminum thingies on the ends of the cable. These will be useful for years.
  • A chain tool does only one thing; it connects and disconnects the master link in your chain. But, if you ever need to replace your chain anytime in the future as regular maintenance, you could pay someone to do it for you or just use your handy chain tool to do it for free.
  • Every bike owner needs a good hex wrench set. Flatbike customers who buy a full-size folding bike get one for free.
  • A bottom bracket tool. It’s hard to make a case for owning this one. Bottom brackets are usually “set it and forget it” as long as you do it right and use enough grease. And naturally, these are different for every bottom bracket. So maybe this is a bike shop thing.
  • A cassette installer. This is for installing a specific set of rear gearing on the rear wheel. Which is super-portable anyway. It’s easy to take a wheel into a bike shop and have them do it.

Finally…let’s start building our bike!

Both the CHANGE 833 and CHANGE 733 frames come with press-fit a headset…uninstalled. A headset consists of two cups–top and bottom–that need to be set with a rubber mallet, along with some sealed bearing rings and washers that need to stay in the same order. When you order a frame, let us know if you’d like the cups set, and we’ll do it for free before shipping.

installing the headset cups
This looks like a mess of washers, but they’re carefully laid out in order.

Next, you’ll want to cut the fork’s steerer tube to the right length for your frame (or if it’s a steel fork, you may have bought it the right length). A fork is held to the frame by two actions:

  1. First, a top cap presses down on the stem and whatever spacers are underneath, compressing the stack. With a steel fork, the top cap pulls against a “star nut” pounded into the top of the steerer tube (Remember your mallet?). With a carbon fork, the top cap pulls against an expansion plug screwed into the same place.
  2. Second, the screws on the back of the stem keep the step tight so it doesn’t swivel side to side. You now have a secure fork.

To get that compression going, once you’ve inserted the steer tube in your head tube, you need to have the stem set at your maximum preferred height, with as many spacers as needed below it. Every bit of the steerer tube above the top of your stem needs to go, along with enough spare room for the top cap to get pulled down.

calibrating the steerer tube cut
This top cap needs to pull down on the top of the stem, once the steerer tube is cut.
installed compression plug
This expansion plug is now set low enough in a cut steerer tube for its cap to compress the stack.

And now it’s time for special tools.

installing the bottom bracket
Actually, before you start using your bottom bracket tool, spend some time gently getting the threading exactly right. This will keep you from accidentally mashing the threading.
installing the cassette
Your sprocket tool (or the bike shop’s) needs just a moment to get your cassette securely installed.

You now have a frame with all four frame touch points fully addressed, and all you need to do is assemble, cable, and tune it.

We’ll cover that next week in Build your dream bike: (Part II: Assembly and tuning).

Anything we glossed over in this part?

Bob Forgrave,
President, Flatbike

Biking made easier.


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