How To Build An Ebike From Scratch: Assembly Day 1

The first day of assembly is laid out here item by item. By end of day we’ll have a roller we can sit on and push around, not a box of parts we have to carry.

Step 1: Planning
Step 2: Hunting
Step 3: Tinkering
Step 4: Buying
Step 5: Assembling
Build Day 1 (you are here)
Final Motor Installation
Rear Shock
Cut The Steering Tube?
Crown Race and Star Nut
Build Day 2
Build Day 3
Step 6: Perfecting
Tools List

The Build Finally Begins

It is Day 1 of our build. Coming into today as we saw earlier in Tinkering, I did a preliminary install of the BBSHD motor to the frame. This let me figure out the spacers needed to get chainline right.

That preliminary installation consisted of bolting the motor into the bottom bracket. The torque on the bolts was kept fairly low: Just enough for the motor to sit in place without moving. I think I used 40 ft lbs (which is just about what Bafang recommends as the factory-tight setting… thats nonsense but we’ll get into that later).

While I eyeballed what was needed to route the wires coming out of the motor, I did not finalize this process to see EXACTLY what was needed to make everything fit right, without wires dangling anywhere. That is our first in a long list of jobs.

Attachment To The Workstand

Before we do anything though, we have to fit the bike into the workstand, where it will stay for much of the build. A workstand is not required, but lets assume you have decided not to make yourself miserable and use one.

There is a right and a wrong way to hang a bike in a workstand. The wrong way is to clamp the bike in by the top tube. The right way is to clamp onto the seatpost.

So our for-reals first job is to attach the seatpost to the frame.

Seatpost Installation

Grease the seatpost lightly
I know… this sounds wrong. You want the seatpost clamped down so it won’t move. Doesn’t grease make it slip? Yes, but only in a good way. You want the unclamped post to slide relatively easily into the seat tube, marring its finish as little as possible. The clamp will work just fine holding a lightly greased post. Honest.

Since the fit into the tube will be snug, there is no need to grease the bejesus out of it. Just smear a light film on with your finger.

I use Mobilgrease 28 as a nearly all-purpose lube for pretty much everything, including as an assembly lube. This is because I have a big tube that will take years to use up. Its overkill but so what I have plenty.

Make a pass through the frame’s seat tube with some kind of abrasive material to ensure it is clear of obstruction
This can be as simple as a wooden dowel with some sandpaper stapled onto it, followed by a pass with a cloth towel. Or a stiff bottlebrush, or a brass or steel gun cleaning brush. You get the idea here. This does not have to be complicated or lots of work. You are just making a quick scrub to help ensure seatpost insertion goes smoothly.

Sometimes frames are manufactured but the frame interior is not deburred (or its covered with sandy crap), leaving it to you to find this out on your own when you jam the post in. Taking a moment to ensure the frame is smooth inside is a smart preparatory step.

Slip on the seatpost clamp
In this case as you can see in the pics below, we are still using the quick release seatpost clamp that came with the frame. The bolt-on clamp specified in the parts list came later (and is discussed in the Perfecting chapter). That makes attachment tool-free for now. Attach the clamp and leave it loose.

Slide in the seatpost
The grease simplifies this by-necessity snug fit. You do not have to position the post precisely. However, I know from building other bikes that I can measure 28″ from my seatpost rails to the center of my bottom bracket axle. If I position my post at that spot, I am within 1/4″ of perfect seat placement on any bike. If you have another bike, measure between those two points and save yourself some farting around later on trying to get the post just right.

Lock down the seatpost clamp
For the pictured QR clamp, this is as simple as flipping the lever and job done. HOWEVER, if you have a bolt-on seatpost clamp, it is critical to NOT overdo the torque on the clamp’s bolt. Sheared seatpost bolts are not uncommon if attention is not paid here. Most posts will have the torque specification printed plainly on the clamp itself. If they don’t, use 5 Nm. And yes thats right it sure didn’t take long until we needed a torque wrench. Keep it handy.

Now Into The Workstand

You can set your frame onto a table like this one (two folding work tables pushed together) but your upper body will be doing a lot of extended reaches and bending over, and for many tasks you won’t be able to sit down and work on a shop stool.

Now the seatpost is inserted and clamped into the bike, you can clamp the bike into the workstand. This is where it will stay for most of the build.

You can sit down in front of a bike fixed into a workstand. If your seat has wheels its double-plus-good.

Final Motor Installation

The first thing we will do is loosen the bolts that were partially tightened in the provisional installation during Tinkering. This lets the motor hang free loosely, but still remain safely connected to the bike. We can now start figuring out the cable routing.

Cable Routing

As seen in the above picture, The motor wires are hanging straight down and that just won’t do. Its best to run them up somehow, but whats the best way to do it? The right answer will vary from one frame to another. But after some trial and error it turned out these three wires are best handled as follows: The power wire and main wiring harness wire loop straight up and forward of the bottom bracket, coming up and out on the non drive side and angling back. This means they tuck in and run up over the motor. They can never present a loop dangling under the bike. This also means they can be made essentially invisible.

Jump into a time machine to the finished bike, present day: The main wiring harness and (unused) gear sensor wires come up from underneath, and move forward under the down tube. The speed sensor wire runs back along the chainstay. That stealthy matching red zip tie is loose on purpose thanks to the suspension articulation.

The speed sensor wire does the same thing, also coming up on the non-drive side. This is NOT the way it was initially attempted and you may see pictures that show different routing. There were at least three separate configs tried during the day. The speed sensor is particularly problematic as it is manufactured to a specific length, and it may take some work to get it to run back to the sensor without creating and hiding any loops of excess cable.

Those multiple routing attempts meant I had to completely redo the motor mounting more than once. Remove the loosened bolts and lock rings, then the mounting plate, then pull the motor clean off the bike, thread the wires through so they go in as desired and then put the motor back. Once that is done you have to tighten the motor back down again, making the needed spacers on the drive side remain in place and don’t get dropped on the ground and forgotten after all this fiddling.

This illustrates a great point: In a couple of short paragraphs I just described two or three hours’ worth of work. That is because this process also bled into the placement of the speed sensor itself on the chainstay. And to get everything just right, I ended up with a lot of trial and error and installing and uninstalling of the motor as I jiggered the wires around, realized I could improve somehow and had a do-over.

I will say this was probably the most fiddly motor fitment I have ever had to do. So I have had seven other motors go in with one hell of a lot less effort. Lets not forget when I say ‘go in’ I mean go in cleanly and with as neat of a look as possible while being long-term survivable and functional. Remember the mantra: DIY does not have to mean half assed. I could have half-assed it and had the motor up and running in minutes if I wanted to use tape and zip ties to just git’r’done.

Clamping on the Motor

Your typical BBSHD installation uses the recommended Bafang inner clamping ring and the outer – largely cosmetic – trim ring. The inner ring provides the torque to hold the motor immobile on the bottom bracket. The outer ring provides modest pressure to act as a jam nut, and look nice (its thin, polished metal).

Tool Tip:
Before you begin this step, make sure your largest torque wrench with the attached Bafang inner lock ring socket you chose to buy is literally within reach. You’ll need to be able to not move and reach out and grab it. Set the torque wrench to 90 ft lbs.

Fig. 1 – Rear: Two BBSHD outer trim rings. Foreground: BBSHD triangle mounting plate showing the ‘teeth’ it uses to dig into your bottom bracket.

Well, forget using that outer ring. We are going to stack up two inner lock rings, instead.

BBSHD installations (mostly by beginners who don’t fully appreciate their inexperience, especially when posting on the internet) are infamous for coming loose and shifting. This is easily fixed, and we’ll install this motor so it will never, ever move.

The Hose Clamp Trick

We are also going to use a supplemental clamp: Two hose clamps to physically lock the motor in its position relative to the frame. Ordinarily, if using the double-inner-ring method described below, the hose clamp trick is not necessary.

But if you are building a bike that is going to take a beating (a mountain bike, in other words) this is the absolute fail-safe: The lowest-key, easiest, cheapest and most unobtrusive way to permanently solidify the motor’s position on the frame… no matter what.

Even if you use no lock rings at all, the hose clamp trick will hold the motor in position (do not try this).

The hose clamps are shown already installed as B in Figure 3 below. We will first wrap the frame where the hose clamp contacts it with red silicone tape as seen in Figure 2 (use whatever color is closest to your frame. This is the first of several places we will use color-matched silicone tape in this build). Additionally, each hose clamp is itself sheathed in color-matched 1/2″ 2:1 heatshrink (found on the project parts list as a ‘maybe’ item).

Since we have not yet mounted the motor completely, don’t fully clamp down the hose clamps. Do a test mount to figure out where the protective silicone tape is needed to protect the frame and wrap with, say, three layers of this tape around the frame.

Next, place the two hose clamps loosely around both the frame and the not-yet-clamped-in motor, so they are interlocked with one another but not yet tightened down. Once the hose clamps are in place like this, you can proceed with the rest of the motor mounting as described below.

Fig. 2: Protective tape wrap applied to cushion the frame where the hose clamp comes into contact with it.

Don’t even buy an outer trim ring
Check the parts list. Its not there. What is there are two inner lock rings.

Attach the Triangle Plate
Make sure the teeth shown above in Figure 1 are facing the frame so they can dig into the bottom bracket. This is crucial to a stable motor. Align the mounting plate so its two bolt holes line up with the holes on the motor. You will need spacers under the plate and between the motor. Because this frame uses a 68mm bottom bracket, I only needed to stack a couple washers under the plate (A in Figure 3 below) to get the clamp to bolt down evenly. For wider motors you may want to buy dedicated M6 spacers which are sold in different lengths by the millimeter at McMaster-Carr. Hold the motor up in its final position while you do the following – I use my knee while sitting on my wheeled shop stool. Using an M6 bolt and tighten to Bafang’s recommended value of 10 Nm (I strongly recommend you go to your local hardware store and buy replacement socket cap bolts made of stainless steel).

Tighten your first inner lock ring
While still holding the motor up with your knee, small child etc., thread on the first inner lock ring. Figure 3 below shows that first lock ring halfway to its destination, which will be jammed up against the mounting plate.

Figure 3. Click to Embiggen

Once the first inner lock ring is hand tight against the mounting plate, reach over for the torque wrench with the Bafang socket you kept handy for this moment. Since you are in a relatively awkward position, holding the motor in place with one knee, use the torque wrench to put just enough torque onto the lock ring so the motor won’t move.

Tighten up the hose clamps
You actually want to work this closer and closer to final-tight simultaneously with the previous step, as once that first lock ring becomes provisionally, fully tight you may not be able to adjust the hose clamps’ position any more.

Tighten the hose clamps so they are tight, but not so tight you will damage the frame. If you added enough layers of silicone tape, you can see them squishing and, when that starts its probably close to the time to stop tightening. Notice in Figure 3 above that on both hose clamps, I tightened them such that as each one’s excess strap length increased, turn by turn, I tucked it into the heat shrink so it stays neat – and a sharp bit of metal is not waiting to cut you while you are building this bike.

You can do this tightening process with a screwdriver but the process will be less annoying if you use a small box end wrench instead.

Remove the bike from the bike stand
You cannot put final torque onto the lock ring while the bike is being held by its seatpost in a work stand. Something will bend or break. Maybe the stand. Maybe the seatpost or frame. Take the bike off the stand. You can set it on the floor, or up on a work table… somewhere that it is self-braced so what you are about to do does not break something.

Apply final torque to the inner lock ring
An install video from Luna Cycle years ago told the world they used 100 ft lbs (136 Nm) and a big 1/2″ wrench on the finished bikes they build (which only used one inner lock ring to do the heavy lifting). So I started doing that. But I’m not going to sugar coat it… 100 ft lbs is a little scary. I have gone to 90 ft lbs (122 Nm) on my last couple of builds with no ill effects. Bafang specifies 50 Nm, which is only 36 ft lbs and ridiculous. Don’t do that. 90 ft lbs on each of two lock rings seems to be the secret sauce for a street bike. Add the hose clamp trick for a bike that is shown no mercy (or you just feel like applying a little overkill).

Thread on and torque down the second inner lock ring
It turns out the inner lock ring and outer trim ring appear to use roughly the same number of threads. Putting on this second, strong inner lock ring with its rough, parkerized sort of finish versus the decorative, polished outer trim ring makes for a really solid jam nut. It also doesn’t seem to make it any more difficult to get full thread engagement.

Figure 4 – The second lock ring has been tightened, jam-nut fashion, and we still have two threads to spare.

Pro Tip:
If you trust yourself to remember to do it later, wait to put the final torque on the lock rings (plural) until after you put the wheels on and have the bike on the ground. Of the Seven BBSHDs I have built for myself… I remembered to do this, um… six times. It took a few weeks for the motor to loosen on the one I forgot, and then I had to pull the cranks off so I could tighten the motor. So, yeah. Don’t forget.

Shrink up the Heat Shrink (later)
I’m putting this step here, now because its part of this assembly, but really you want to wait on this until later in Day 1 when you know motor placement really is final. Use a heat gun or borrow a hair dryer. Apply heat to the heat shrink to shrink it up and give a more polished appearance. When doing this, be mindful of the fact you are directing superheated air near to other wires that don’t like to have someone try to melt them. You won’t… but be careful nonetheless.

Make a Registration Mark (later)
I’ll just show a picture right away, and then explain it. As you can see from the paint color, this is a different bike that uses the same doubled lock rings.

What I want you to see is the black line that crosses the frame and the two lockrings, top-center.

Why make this mark? As time goes on, you can just routinely glance down as you are mounting the bike and, seeing the straight line, know nothing has shifted. If you are using the interlocking hose clamps as we are here, this mark is less important. Do it anyway as its really handy.

Wait until the very end to do the marks. That way if you have to pull the motor back off (like I had to) you don’t have the issue of mismatched marks for reasons other than the motor loosening up on its own.

Today we are only mounting the motor. The speed sensor install and cockpit/wiring harness stuff is going to happen later on in the build.

Mount The Rear Shock

I tried to refurb the vintage shock that was on the bike, but it was not meant to be. Thankfully a quality, compatible shock with a matching eye-to-eye and stroke length was readily available.

This is one job that requires tools and mounting hardware so specialized that, if you don’t have the gear and experience to do this already, your life will be longer and happier if you just take it to your Local Bike Shop. Have them do it for literally only a few bucks worth of parts and labor.

Rear shock installation is something of a black art. Its at least a little different for every shock and every frame combination. There’s no way I can do a tutorial on this that is even remotely comprehensive for a variety of shocks and frames that are out there. This video does a fantastic job of literally going over everything you could ever need or want to know on this subject. If you decide to go it alone, it will tell you what you need to know and where to go to buy what you need.

Should You Cut The Fork Steering Tube?

I almost never do. First of all, I am a physically large person and I am usually buying L and XL bike frames. For frames like that there often isn’t all that much excess steering tube length to worry about. Next, if I ever want to move a fork from one bike to another, an uncut steering tube makes that move a lot more likely to be trouble-free since I won’t end up trying to install a fork to a bike that needs more tube than I have left after cutting it down.

If you don’t cut the tube, what you do instead is use spacers below the handlebars to raise them up, and maybe put a small spacer on top. It depends on the individual job.

An uncut steering tube let me do something funky and practical with my Surly BFD‘s basket handlebars, that are capable of bolting to a stem at two different places. This Size M frame had lots of extra steering tube to work with.

Cutting the steerer is not a procedure used for this build (the tube was already cut on the vintage used fork I bought), but for the sake of being complete I’m including mention of it and the tools needed here on this page.

You need a pipe cutter and reamer. I have my ratcheting pipe cutter and my pipe reamer left over from when I built my Surly Big Fat Dummy Wideloaders. A ratcheting pipe cutter puts you on easy street. However its a little more expensive.

You can get a cheapie 1 1/8″ capable pipe cutter for around US$11. Or get this combo deal of a quality cutter and reamer together for about US$32.

You could use a hacksaw and a guide to cut your tube. You will do a MUCH cleaner job if you use a pipe cutter and clean up your edges with a reamer.

It took awhile to find a video where someone wised up and used a pipe cutter instead of a hacksaw…

Add Crown Race AND STAR NUT To Fork

This step may seem out of order, but life is a little easier if you have the fork ready to go before you undertake the step we’ll get to after this one.

Figure 5 – Left: Star Nut Setting tool. Center-Top: Crown race. Right: Star nuts (you only need one)

Add the Star Nut
The Star Nut is a little doodad that you literally smash into the steering tube of your fork. Don’t worry… its meant to be smashed in, but you really (REALLY) want to use the proper tool to get it in there.

See the little threaded hole in the center of the star nut? See how the ears of the star nut sort of angle upwards if you hold it right-side up?

  • Fit it upward-angle-first inside of the star nut setting tool.
  • Now set the tool with the star nut inside on top of your fork’s steering tube. On the inexpensive tool I am linking to use here, that black bit is what you are going to use your hammer on. Give it a couple of bashes and the tool/guide will ensure your star nut is seated to the correct depth and it goes in nice and straight.
Figure 6 – Star nut installed!

Set the Crown Race
Figure 5 above shows a Crown Race… thats the lower bearing race that interfaces directly with the bearings in the bottom half of your headset that we have yet to install into our frame. Its not the race that I used – I picked a durable steel race made by Cane Creek. Unfortunately the only pic I took of that race is in Figure 6 above… see that blurry blue ring in the background at the base of the steerer? Thats it. Oops. So I am going to be describing its simple installation without any pictures (you can watch one being installed in the fork installation video above if you like).

What you do is grease the base of your steering tube, where the crown race will be installed. The steering tube is flared just a bit at this base so the race will sit above the bottom by about 5mm. The grease will let it easily install in our next move, which is to drop the crown race onto the steering tube and let it sit where it lands near the bottom. Now take your installation tool (which is just a hunk of 1.25″ PVC tubing; not the US$90 crown race setting tool) and slip it over the steering tube so it touches the race.

Can you guess what happens next? Holding the fork in one hand and the tube in the other. Bashbashbash the tube down onto the crown race. After a couple-three bashes, take a look and oh wow look we’re done. Its that easy (or at least it should be). The bearing race should now be fully seated with its base flush with the crown of the fork. If its not anywhere along its diameter, give it a couple more bashes. Job done.

Figure 7 – At left: A length of 1.25″ PVC – a ten-cent tool versus a $90 one.

Your fork is now ready for installation to the frame. But before we can do that, we have to …

Install the Headset

This is one of those jobs that requires a dedicated tool. Your headset is a pair of bearings – one on the top, the other on the bottom of your frame’s head tube – that your fork sits inside of. These bearings let the fork and thus the handlebars turn smoothly. The bearing races for the headset need to be press-fit into the frame. There are many types of headsets. For this vintage build we are using a Cane Creek 40 external cup headset.

Figure 8 – Our Cane Creek 40 steel-race headset. Top left: The upper cup and dust cap. Top Right: The lower cup. Bottom Center: The steering tube cap (with star nut).

Once again this is a very simple process – assuming you have the right tools. Its certainly possible to use some assembly lube and gently tap in the cups top and bottom, being careful to not get impatient and keep them straight. However, its dirt-simple and not really possible to screw up if you just use the right tool for the job. In this case I used a $28 tool and it was worth every penny (also I did find the $17 version I already owned … after assembly was complete, of course).

Figure 9 – the headset press

Installation is as follows:

  • Separate your headset parts keeping in mind the order the parts go in so you can put them back together (take a picture!)
  • Set aside the upper and lower headset cups – those are the only pieces you will stick in the press.
  • Take apart the headset press so one end has a bare bolt end. Thats the left side in Figure 9 above.
  • Lube the head tube’s upper and lower portions where the headset cups will be pressed in. Do the same to the upper and lower cup, where they will insert into the frame. Set the upper cup on top of the headset tube. Make sure its really the upper cup as your life will suck if you put the bottom one in the top (there are tools to remove the cups but lets agree you won’t make the mistake in the first place).
  • With the upper cup in place, set the headset press into the frame head tube, bare-bolt-side-down (thats left side down per Figure 9).
  • Thread the lower cup thru the open end of the press bolt. Reattach the lower portion of the press so the lower cup is captured in the press. Tighten gently (!) until the press is almost snug to the cups. Take care that the cups are facing the head tube of the frame straight in. You can just use your fingers to do this final alignment.
  • Slowly, carefully tighten the headset press. With every gentle turn ensure the cups are going in smooth and straight. Stop when the two both bottom out for a snug fit. You should know you are done when the smooth turns suddenly get tight. There is no need to clamp the headset in hard. Just stop when top and bottom pieces are visibly bottomed into the frame and the press is no longer turning easily.
  • Grease the top and bottom bearing races, regardless of whether or not your headset uses sealed bearings. Insert the bearings and any spacers or covers that go with the headset.

This video is for a vintage road bike, but I chose it to illustrate an external cup headset install like the one I am doing here. The headset tool in the video is the really expensive kind you don’t need to buy 🙂

Install The Fork

This is why we prepped the fork first, before we installed the headset… because we are immediately ready to install the fork, and in fact we want to do so to ensure various bits of the headset don’t go rolling off and under something; never to be seen again.

Top Tip:
If not installing the fork immediately, run a zip tie (or two of them zipped together to make a longer one) thru the open headset, top to bottom, and out the other side. Zip it together gently. This will temporarily capture all the headset parts in their proper order and make sure nothing can go AWOL.

Clamp it Snug
This is the first of many times you will be happy the bike is held in place on a bike stand. Slide the fork up inside the head tube. It will bottom out with the crown race in direct contact with the bottom half of the headset. With the Cane Creek headset, fitment out thru the top is a bit fiddly as the dust cap fits tightly to the fork’s steering tube. It will take a bit of a push to get it up and thru and you will need both hands to hold the top of the headset in place while you fit the steerer thru the hole in the cap, and then make sure everything is fit together.

When the steerer is up thru the headset, reach out and grab the handlebar stem that you kept handy. Thread the stem over the steerer all the way down so it bottoms out to the base of the headset and clamp it down. Stems typically use either M5 or M6 bolts and require 5-6Nm of torque for final tightening.

You just want to do a quick-and-dirty tightening right now to keep the fork in place, so some gentle turns on the wrench until the fork is snugly held is plenty. There’s not even any need to make sure the stem is properly aligned. Just get that fork on so it stays in place while sitting in the bike stand and doesn’t fall off. Don’t worry about the star nut or the headset cap with its M6 hex bolt for now.

Figure Out The Spacers Needed
You now have a stem that is clamped all the way down onto a bare steerer. The next step is to figure out how many spacers we need. In the parts list I specified a steering tube spacer assortment. However for this build I used my parts pile, which in this case is an absolutely accurate description.

Bare alloy, anodized alloy, matte carbon fiber, glossy carbon fiber. Thick and thin. This is my spacer pile after I completed the build, so I had more than this to start with.

On the excess steering tube length that is sticking up and over your stem, drop a combination of spacers over top of the stem until the spacers that are stacked up are a little taller (maybe 2-3mm, tops) than your steering tube. Now is the time to test-fit your headset cap with its M6 bolt. If you can tighten the cap onto the spacers and the spacers are no longer loose and spinnable on the steerer, then you have enough extra spacer height. If not, find some combination of spacers that give you just enough extra height to let the cap clamp the spacers (not the tube!).

Once you have found the quantity of spacers needed, decide how you will organize them. Maybe you want your handlebars up as high as possible, so you will put all but the smallest spacer under the bars and that small one goes on top – in fact thats probably the best way to start. recognize that down the road you may want to switch things up and perhaps lower the bars by 1 cm, or similar. You might also want to change the spacers you use so – if you needed a slew of them – maybe you use different spacers so you only need one or two.

Present Day pic: Different and longer 45-degree, 120mm stem installed. I only needed one spacer and could put the clamping headset cap directly onto the stem with no small spacer on top.

With the spacer mystery solved, its time to unbolt the stem, support the fork in place (I stick my knee into it while sitting next to the bike), remove the stem, add the spacers, replace the stem and add the headset cap. This is the final setup (until later on when you ride the bike and decide to fiddle with it some more). Once again we go snug on the bolts and not whole hog. We’ve got to get thru the next step before we start getting serious about the torque wrench.

Install Day pic: My original stem had a different ‘stack height’ – thats how tall the stem is on the steering tube. I needed a short spacer on top of the handlebars. Both stems are made by Ritchey. Stack height varies by stem.

Install The Handlebars

Put simply, put the handlebars into the stem and tighten. Easy peasy. If the bars have a taper, be sure its going the right way, but other than that you just want to make sure you center the handlebars in the stem mount. Feel free to clamp down to the max amount shown on the part itself. Usually that will be 5-6 Nm. Tighten in a pattern that applies equal force top and bottom – pay attention to how the fastening plate is angled. You want it equally far from the top and bottom sides. Remember that as you tighten on the bottom, that increases tension on the top, so it is VERY important to tighten slowly and incrementally in a 4-corner pattern. Be patient.

Now that you have installed the bars, straighten them so they are perpendicular to the forks. This is why we didn’t fully tighten the stem yet. You want the stem tight enough to hold your adjustment, but not so tight you cannot make teeny-tiny adjustments.

I used the cantilever brake posts on the fork to ensure they were parallel to the stem and thus perfectly aligned. A nice little cheat you don’t get nowadays since forks don’t have those posts anymore.

This step is an inexact science and most likely you will need to revisit it. Once you get the bars aligned, cinch down and tighten the stem to finalize the fork installation. The proper amount of tightening is a process in and of itself, so here’s a 2-minute video that gets straight to the point:

Get The Wheels Ready

We have a set of professionally built wheels for this bike, but we still have work to do.

Install The Brake Rotors

Brake rotor installation is straightforward. Nowadays it seems as if button-cap bolts with T25 Torx heads are something of a standard. At least the Magura and Tektro rotors I buy all come with a set of such bolts included with the rotors. As we’ve seen in the Tools list, and in my list of tools I normally carry on the bike, I take a T25 wrench as a routine item. However since we’re doing proper bolt torqueing, a 1/4″ drive T25 bit is needed. I torque the bolts down in a star pattern to 6 Nm.

eek. You call that a brake mount for an mtb?

For the Apostate, since it is a vintage bike that dates back to the early days of disc brake usage, I decided to use discs in line with what was considered sufficient back in the day – smaller rotors. One look at the spindly (by today’s standards) brake mounts on the manufactured-in-1999 forks and I knew I didn’t want to play hardball with stopping power. Magura 4-piston calipers are so strong anyway I have not felt a need more stopping power than the 160/180mm rotors give me.

Upgrade the Rear Hub

I know from experience that you want to use a steel cassette body in conjunction with a high powered mid drive. The DT Swiss 350 Classic hub does not come with one of these. If you can find a 350 Hybrid, it does and this is the preferred ebike hub. However, if you’re like me and can’t find a 350 Hybrid, the 350 Classic with its 18-pt ratchet engagement is known as one of the few hubs that can take the punishment of a BBSHD pretty much forever. Especially if we upgrade it with an available steel cassette body option.

Remove The Cassette Body
On DT hubs, all you have to do is literally pull off the end cap on the cassette side, then grasp the cassette body firmly and pull hard on the little sucker. It will pop right off, tool-free disassembly for once.

With the cassette body removed, you can see why the DT ratchet engagement hubs are so strong. Not 3, 4 or even 5 pawls. 18 points of engagement. The Hybrid hubs have 24 points. Those points are the ridges in between the two ratchet wheels.

Install The Steel Replacement Cassette
Again, this is simple and tool-free. Just slide the new steel body over the axle, give it a push and it pops into place. Snap on the end cap and you are done. Instant indestructo hub.

Alloy on the right. Lightweight. Steel on the left. Heavyweight. After 1300 miles its surface won’t even be discolored. The alloy on the other hand after 500 miles will look like someone chewed on it.

Install The Cassette (gear cluster)
Once again, easy-peasy. The ridges on the cassette body are all uniform in width, except for one that is very narrow. This is the ‘key’ and the cassette itself has one single narrow slot.

Find the matching key slot and groove, match them up and slide the cluster down over the hub. Do the same for the remaining two individual small cogs, and then finally thread on the lock ring. Use your cassette tool to tighten the lockring down. Officially it needs 40 Nm but since its such a weird part with a weird tool that doesn’t lend itself to a torque wrench, I try and just tighten it down pretty good while staying mindful of the fact that someday I will have to get the thing back off again.

Mount The Tires and Tubes

I have nothing against tubeless installations. I have several bikes that run tubeless in fact. But this bike build is not one of them. We’re going old school and doing tubes.

This is an unusual full-suspension city bike. I’m using very (very!) tough Schwalbe Pickup 26×2.35 tires which are in fact cargo bike tires. The tubes are Schwalbe AP (Air Plus) presta tubes. AP is Schwalbe’s take on a thick tube. Its not thick enough to be what you’d call thorn-resistant, but its heavier-duty than a standard tube. The rims in use are DT Swiss FR 560’s which are meant for downhill bikes (as in super strong) and most noteworthy here… they are tubeless compatible. That means our thick tire and thick tube are going to be fit onto a really, REALLY tight rim. I’ve used the FR560 on my 29er Guerilla Gravity Smash, so I knew coming into the game it was going to be a real party putting the tires onto these rims. And it was.

This 20-minute video is a bit long but the mechanic who is giving the instruction knows what he’s doing, as evidenced by his accomplishing the impossible without tools right before your very eyes. Stick with it and watch – all the way through – what he does. Hopefully your rim and tire combo will not be this difficult, but if it is, what he is showing you is the solution to the problem without losing your mind, your tire levers and your fingernails.

The example above uses a tubeless setup and an insert, but the issues I suffered thru with a tire and tube were identical thanks to the fact I was using a tubeless rim. The solution illustrated here is the same. I did not have the jig he uses in the video. Instead I used a few moving blankets on the ground in front of me to provide a pad, and worked around the wheel from above while I sat on my work stool.

Top Tip?
The newfangled Bead Bro and Bead Dropper tools from Cush Core are modern miracles. The heavy lifting is done by the Bead Bro but the Dropper lever is a nice spiff. Not cheap but a great substitute for supplementing the palm-crushing technique above. They are meant for use with the Cush Core product but they work a treat simply as a quick and dirty way to turn the arduous process of getting a super tight tire on into a 2-minute job.

Add Tube Sealant

If you are doing a tubeless install, then of course sealant happened in the previous step. As I have noted elsewhere, I use FlatOut both as a tubeless and tube sealant. The linked flat prevention article was written in 2020, and events from then to now have only reinforced that FlatOut is the best tool for the job. For this build I used 1/4 of a bottle in each tire.

Attach The Wheels

This is pretty basic stuff. I used Axlerodz for wheel skewers. I have used them on other bikes meant to be left outside where I don’t want to advertise easy wheel removal (or offer a free $40 skewer to anyone who wants to take it off my locked wheel).

They are QR skewers that need a hex wrench to loosen up the wheel. Not high security but also not a lever asking to be snitched, either.

Install The Saddle

There’s no particular reason to put the saddle on now, other than it is very satisfying to see my parts pile starting to look like a bicycle. So the saddle goes on sooner, not later.

Saddle attachment is simple: Loosen the bolt on the seatpost enough so the saddle rails can be slipped underneath the top clamp. Don’t loosen the bolt so much the top clamp comes off. Nothing good ever comes of that when trying to install a saddle. Just make it as loose as you can while keeping it captured on the bolt. Slide the rails underneath and position it in the middle of its travel area (that area is marked on one of the saddle rails… just stick it in the middle for now).

Bolt On The Derailleur

It was getting late, and I wanted the bike to look like a bike as much as possible. So I picked as the final job of the day the simple attachment of the derailleur to the frame. I greased the threads (anti seize is a better choice given the dissimilar metals – alloy frame and steel bolt) and carefully, gently tightened the bolt. This was one time I stayed away from the torque wrench and simply snugged the bolt, which is as far as I’ll go on a frame that has an integrated (irreplaceable) hanger. If I lose that hanger the frame is done for so no mistakes can be tolerated. There’s no need to heavily torque this bolt beyond being snug-tight. If I were to guess I’d say I put 3-4 Nm onto it.

Once the wheels are attached… this is the end of the first day’s work on this build. At the end of the day to help me visualize what now almost looks like a bicycle, I set the chainring and crankarm onto the motor and axle without bolting them on, and then snapped this picture

End of Day 1. I need a beer.

We Have A Roller!

On to Assembly Day 2

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.

12 thoughts on “How To Build An Ebike From Scratch: Assembly Day 1”

  1. Everyone should read this if they are considering a DIY! You’re a pro Matt. You impress the hell out of me with your professionalism. Now….build me a bike like this!😉

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