How To Build An Ebike From Scratch: Planning

We’re building a bike! Lets do it smart though. We’ll see a simple project management framework. There’s even a complete parts list here.

Introduction
Step 1: Planning (you are here)
Step 2: Hunting
Step 3: Tinkering
Step 4: Buying
Step 5: Assembling
Build Day 1
Build Day 2
Build Day 3
Step 6: Perfecting
Tools List

Throughout this article, I will discuss whatever concept I am going over in general terms, and then I will answer the question “What Did I Decide?” (or “Do”). The context for this will be the test subject for this series: The Apostate. We will be walking step by step through an actual ebike build.

Be aware, though… this Planning stuff is pretty dry. Not so many pretty pictures in this installment.

Speaking of pretty pictures…

Preparation is Everything

So you’ve decided to build an ebike. You’ve got enough basic mechanical ability (and/or the gumption) to tackle the task from the ground up. Great. Before you start, you want to sit down with a piece of paper and plan out your build. BUT before the on-paper part starts, lets start inside of your head and think out some things:

How Do You Want To Ride (what is the bike’s job)?

Before you decide anything about the bike, first decide what the bike is going to do. Is it a commuter? A cargo carrier? A beachfront cruiser? A singletrack mountain bike? Does it need to be multipurpose and straddle a few categories? If you don’t know already, this is the time to look at bikes that do the thing(s) you want to do. Once you know those things, you can look at the parts available in the marketplace (starting with the frame) to make your bike come to life.

What Did I Decide?  
I needed a relatively small bike that could be stuffed into and hauled out of the back of a station wagon.  Something reasonably light weight.  So easy portage (not riding criteria) was my first requirement.  Next, I needed this bike to be good for relatively short street runs.  My primary use-case was a quick jet to the office after dropping my car off at the repair shop, and a run back to that shop from home the next morning when the car was done (stuffing the bike back into the car and driving to work from there).  

So... in its primary job, the bike needs to be comfortable for 4-5 mile trips, not 20 mile, afternoon-long rides.

Next, since the bike can be stuffed into my car, a secondary use-case was to take it on vacations or work trips and have it for general light-to-medium ride duty on streets and trails.  Singletrack not so much.  Dirt and gravel roads: yes please.
Look closely. On top of all that camping gear is an ebike, with just the front wheel off and the handlebars laying flat.

Factor In Your Terrain

At this planning stage, you also want to pick your chosen assist method… the motor. The motor is integral to the bike and you want to figure out what its going to be – at least conceptually – sooner and not later. If you end up deciding you need a mid drive for instance, that is going to have a major influence on your frame choice since you have to install the motor directly to the frame… so that chosen frame has to be able to accept that motor.

Integral to the motor decision is expected terrain: If you are going to be riding on table-flat land (or, at the most, rolling hills) then a geared hub motor could be a viable option. A direct drive hub motor could also be a workable choice. If you need the versatility to tackle hills – even steep ones – then a mid drive of some kind is a must. It helps to have an understanding of the strengths and weaknesses of the various ebike motor types, so look here for specific discussion on them.

What Did I Decide?
I needed to be able to tackle any kind of terrain.  Using a mid drive as the assist motor was a no-brainer, since they can tackle anything a bike can ride over.  Having several of them and being very comfortable with building them to last, without any wear and tear issues, made the decision all the more easy.

Additionally, I had a 68-73mm BBSHD sitting on a shelf as a spare in case of emergency (both of my daily drivers - the Bullitt and the Envoy - use that motor).  So to keep out-of-pocket costs down I wanted to use that extra motor in this build.  So this all told me I need a frame that works well with a BBSHD.

Decide What Kind of Bike You Want

So far, you have figured out what job your bike needs to do, the kind of terrain it needs to live in and as a result of those things, what kind of motor it needs. Now figure out what kind of bike fits those goals (or throw all that out and pick what looks cool). You probably don’t need to look at electrified bikes when going through this step. Just look at bikes, period… with an eye toward being able to slap a motor onto whatever ends up looking good to you.

Once you have settled onto the style of bike you want to build, your next step in planning is to set up a build sheet.

What Did I Decide?
Knowing I needed a smaller bike for relatively short jaunts, the bike type that sort of jumped out at me was a 'mountain bike'. Further, since I wanted to achieve a fully functional bike yet stay at a diminutive size (without going overboard and doing a 20" BMX kind of thing) I knew I wanted a frame that used smaller-sized 26" wheels.  Those are no longer commonly in use - so I'll probably be looking at an older, used frame.

Next, I wanted it to be full suspension and not a hardtail. By that I mean I want a live rear triangle suspended by a cushioning rear shock, and a suspension fork for the front wheel.

Because I have decided to use a BBSHD mid drive, I knew they fit better on older, more traditional frame triangles where the down tube runs straight down, directly into the bottom bracket at a sharp angle. This sharp angle gives plenty of room for the mid drive motor to tuck itself up towards the frame and away from the ground, yielding minimal lost ground clearance.  And also, sharp angled-straight down tubes are a feature of older frames.  Newer designs use curved tubes, like the one below.  A BBSHD on this kind of frame would cause the motor to hang straight down.





Also, since I have built several BBSHD'd bikes and I know their installation ins-and-outs, I know an English (threaded) bottom bracket is going to be the best style of bottom bracket to easily accept a mid drive motor (other types require adapters).

Lastly, the modern trend on quality bikes is to use carbon fiber for the frame.  But I know the torque stresses that come with a mid drive ebike introduce long term survivability issues with carbon fiber bottom brackets. As the saying goes, 'steel is real'.  Carbon fiber in DIY builds is known to pose a failure risk.  Also c/f bottom brackets have to be built thicker, and this makes a motor like a BBSHD unlikely to fit.

Ideally, I wanted a chromoly frame.  Next in order of preference would be an overbuilt alloy, followed by titanium (which is very bendy) with my very last choice being carbon fiber.





These features above, all together, are much more common on older frames, so everything above further reinforced the likelihood I'm going vintage.

What Is our net end result?

The ideal frame that I’m going to be looking for on this project is as follows:

  • Full suspension mountain bike frame.
  • Not a Large size because it has to fit easily in the car. Not a Small because of my anatomy. Somewhere in the range of a Medium (17-18″ seat tube), then. I can get one of those to fit me with a longer post and a longer stem.
  • Able to be set up as a street machine (high seatpost config in particular)
  • 26″ wheel size.
  • Chromoly steel or aluminum construction.
  • English-threaded bottom bracket with chainstays that can handle (i.e. fit the secondary gear housing) of a BBSHD without chainline drama.
  • Straight down tube into the bottom bracket, old-school style.

And of course add in that I want it to be in good condition, so I’m going to be looking at condition and possible flaws very closely.

The Build Sheet (your project bible)

A Build Sheet is essentially a list of everything you need (EVERY Thing) to build a bike. Initially, your build sheet won’t list every single part your build will actually use. At this stage, you put in a wish list and see what happens when the bottom line adds up.

Why not be precise? Well, you want to be as accurate as possible. However the purpose of this initial exercise is to give a cost estimate. Its entirely possible you will see that price at the bottom of the list and realize its too much. At that point the build sheet becomes a tool to adjust your component list to get the budget under control by choosing different parts.

This is just an image of the sheet. Click below to get yourself a live look at the real thing.

Here is a sample build sheet for the bike build that is our example for this series.

What Did I Do?
I used this exact example sheet for this project, and you are looking at a copy of it - made at the end when all the lines are green- with the costs snipped out to try and make me forget how much I spent.  I did add some notes and urls after the fact but otherwise this is the exact sheet used to manage the project.

Making Your Own Copy

NO I will not grant edit access to this sheet… If you want to make a copy for yourself, do this:

  1. Open up the Build Sheet via the link above
  2. From the sheet’s menu choose File –> Download
  3. Save the sheet to your local disk in Excel format.

From there you can either use the copy directly in your favorite spreadsheet program, copy it back up to a new Google Sheets spreadsheet etc. etc.

Why this Sample is such a big deal

This is every part on the project bike. All of them, right down to the cable ferrules, the decals… even the tape. And since this is a more or less ‘generic’ bike, this supplied parts list will be almost identical to what you need. You just substitute in your derailleur in place of mine. Your frame in place of mine and so on. If you were overwhelmed by the thought of figuring out all the parts needed to make a bike… this is your cheat sheet listing everything you need.

How it Works (project management)

First of all, note the color-key at bottom-left. According to the table, every single line item on the list is in-hand (colored light green) except a couple, which I have categorized as maybe not being needed. This is what a sheet looks like at about the end of the project.

At the project’s beginning, each of these line items is likely to be in red: “Need to Buy”. As your project matures, the red lines individually turn to blue (ordered and being shipped) and then to light green for ‘I got it’. If you have to send a part away for refinishing or something similar, the line turns dark green while the part is away at the shop.

If you buy something and it turns out to not work, or in particular to suck for some reason, switch it to blood red “Tried and failed” so when you build your next bike you have a record of your mistakes.

  • Column A “Item”: Describes the line item. A general part description like “Handlebars”.
  • Column B “Model/Item”: A more specific description of the item. If the Item is Handlebars then the Model could be something like “Jones H-Bar 660mm, black”.
  • Column C “Tracking Number”: When your line item is blue that means you ordered something and its on the way. Put your tracking numbers on this sheet so you can go down the line and click on each of them to check tracking (right click and do a google search on the number works for most shippers).
  • Column D “ETA”: While your line item is en route to you, put the estimated time of arrival date here, so you can see if something is overdue.
  • Column E “Source”: Where did you buy the item from? You might use this to identify and consolidate buying sources and shipping charges prior to making the buy. Possibly to get up to a minimum order amount for free shipping. When I already have an item in my shop and I don’t have to buy it I list that as “parts pile” and set that line to green.
  • Column F “Cost”: I use this column for items not yet purchased (red). The total at the bottom of this column is the amount I still have to spend to complete the project. When I make my own lists, I do not list costs for ‘parts pile’ items in an effort to kid myself as to how much I am spending on this bike.
  • Column G “Paid”. When an item goes from red to blue, the purchase amount goes from the Cost column to the Paid column. The total at the bottom of the Paid column tells me how much I have overspent so far on this project.
  • Column H “Notes”: If you need to write something that doesn’t fit into the other columns, it goes here. I put in some notes on this sheet not for my own benefit but for the reader looking at this list for the first time.
  • Column I “URL”: A purchase link for each item on the list. Sourcing parts can be overwhelming. This list shows sources for everything on this project. Where I list an item as ‘Parts Pile’ I went and got a link as you can’t very well pull parts off the shelves in my shop like I can. Also some unique auction items, like the frame and fork, only have a generic url those were one-of-a-kind items. If an item is no longer available from the seller I bought from, I plugged in a substitute url. Usually from Amazon. Remember: when sourcing hard to find parts, Google is your friend.

This build sheet, as-delivered here, should give you a list with purchase links to every part you could need to build an ebike. You can’t use all the parts I did, nor would you want to. But now you have a road map to all the parts needed to build a bike.

Use Your Build Sheet

OK, so you have listed all the parts you think you will need. You scoured the internet to find sellers for each item you want to use, and listed what each item is going to cost.

Thats no small job. You’re going to need a bunch of evenings or a whole Saturday (or both) to get through the exercise. But its going to be worth it. Especially for the very next step:

Go or No Go?

Look to the bottom line on the sheet. Can you afford this bike? Its entirely possible the answer is no. Running this build sheet exercise is what stopped my Bullitt project dead in its tracks. When I saw the cost of building up a frame kit and electrifying it, I bailed and built something else (a couple of years later I built it anyway).

If you have concerns about project costs, now is the time to make adjustments to make the project realistic, or chuck it out the window and start over – without having spent any real money.


Speaking of costs, its worth noting you may not end up doing a cheaper bike when going DIY. You could go cheap, or you could also go with top components that will end up being better, stronger and more reliable than any manufactured product. The Apostate is such a project.

What About Cost Of Tools?

There is a whole separate installment on tools needed to build a bike. Plenty of them are specialized. There aren’t very many that can be worked around. For my project build sheet, since I build bikes as a hobby and I’m using tools that oftentimes I’ve had for years, I do not include tools on my build sheet. That is true even if I need to buy a tool for this current build – and in fact I had to buy a headset press because I couldn’t find the other one I own.

Whether you include tools on your Build Sheet is up to you. Just make sure that, as part of your project cost assessment, you go into it with your eyes open with regard to the tools needed to build a bike.

While You’re At It

You have to have a place to work on this project. If you don’t know exactly how thats going to go down, now is the time to start figuring it out. Most likely final assembly is going to take more than a single day (for me it was a core 3-day build with numerous short afternoons and evenings going thru the Tinkering and Perfecting phases).

Start thinking now about where you are going to actually do the work here. If at all possible, make your workshop a place where you can leave everything overnight. For instance if you can, leave your car out in the driveway overnight for the weekend and do the work in your home garage.

However…

If you created the build sheet, have a list of parts to buy and you can make the numbers work, its time to move to the next step… hunting for your frame, followed by the motor. Why just those pieces, in that order? We’ll see in

Step 2: Hunting

Author: m@Robertson

I'm responsible for the day-to-day operations at my place of business: Leland-West Insurance Brokers, Inc. We do classic and exotic car insurance all across these United States. I'm also an avid auto enthusiast, a born again cyclist (i.e. an ebiker) and participate in medium and long range CMP and NRA sanctioned rifle competitions.

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