How To Build An Ebike From Scratch: Hunting

We figured out what kind of bike and frame we wanted in the previous step. Now its time to hunt down that frame,

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

Find Your Frame

In the previous Planning step, we determined what kind of frame we wanted to buy:

  • Full suspension mountain bike
  • Medium-ish size along the lines of an effective 16-18″ seat tube
  • Able to be set up as a street machine (high seatpost config in particular)
  • 26″ wheel size
  • Chromoly steel or aluminum construction
  • Threaded bottom bracket
  • Straight down tube into the bottom bracket
  • Space around the chainstay root able to fit a BBSHD secondary hoursing without drama.

Now its time to go out into the market, find the frame that meets these goals, buy it, receive it…

… and stop!

At least for a bit. Once we have an actual for-reals frame in our hands, we have some work to do to make sure all of our parts assumptions still hold before we take the next step and start buying parts for it willy-nilly.

Why You Want To Wait

I had my eye on a 2000 Marzocchi Bomber X-Fly Z1 fork that looked as if it was brand new, despite its age. It was priced right at about $200 delivered and would be perfect for this build. But the seller disclosed the steering tube had been cut to “about 230 mm”.

Looking at the pictures of the frame I had bought, but not received yet, the head tube on the frame looked like a fork with a 230mm steerer would fit just fine. But until I had the frame in my hands and could measure it (and added in the length of the external headset cups), I was taking a $200 guess if I bought the fork before the frame arrived.

Likewise, my chosen frame claimed 135mm rear hub spacing. Since its a 1999 frame, that sounded right. But lots of times these older frames are being sold by pawn shops or via estate sales and the seller may be guessing, or repeating something they were told with no expertise of their own. Honest mistakes can happen across a variety of fronts that will make big differences in your parts choices.

So did I want to start a wheel build costing hundreds of dollars based on anything but total certainty? Hell no. Neither do you. Cool your jets and wait until you can verify frame measurements from the advertisement. Once you have done that, then you can go and order parts that rely on those measurements.

Cart Before The Horse!

Before we go through the learning experience of confirming measurements, we have to find and buy the frame in the first place. Chances are pretty good that process is going to entail some unexpected learning as well.

For example: Here I am hunting for an older, full-suspension MTB frame. One thing I didn’t expect (and should have, because I was riding back in that day when these frames were common) was the kind of brakes commonly used on mountain bikes back then were frame brakes – cantilevers with bosses on the frame that clamped down on the rim. I found many frames that were a great fit for my needs … but they didn’t have disc brake mounts. And I consider disc brakes to be a requirement for a modern bike (and especially an ebike).

Going hand in hand with this, cable housing in the days of yore was nowhere near as effective as it is in modern times. So bikes were designed with lots of space to stretch bare brake and shift cables. Also the functional best practice solution for braking is now hydraulic – which uses pressure hose and not cables.

Lastly, I found older frames might not use the most common rear spacing. Forget about Boost spacing. In fact, I found I needed to make sure I had at least 135mm so I could use a more or less modern 9/10/11 Shimano cassette body.

Once these things became apparent after looking at a bunch of frames, I started paying close attention to these items first. If a frame looked like a winner, I immediately looked to see if it had disc brake bosses. No bosses… instant reject and move on. I saved a lot of time that way, ignoring how nice a frame may be and instead focusing on a core list of must-haves and immediately moving on if one was missing.

I was also looking carefully at whether I could adapt the cable routing on a given frame candidate.

These were not things I had expected to care much about, but after I began shopping I came to realize they were essential.

The Marketplace

So where do we go online to look for a used bicycle frame? There are some crowd favorites

Craigslist

This venue offers great possibilities, but also carries perhaps the most personal and financial risk. Transactions are most likely going to be face-to-face handovers of cash for merchandise at a public parking lot mutually agreed-upon. It goes without saying warranties or purchase protections do not exist, and you can decide for yourself whether you want to get out of your car and walk up to a stranger who knows you have – at the least – several hundred dollars in cash in your pocket.

Thats not to say that Craigslist purchases are a bad thing. They’re popular for a reason. However, there’s a bit of the Wild West going on there with regard to unrestrained capitalism and personal responsibility.

Facebook Marketplace

I kind of put this in a similar category as Craigslist. I have friends who swear by it over Ebay, but I’ve never found it to be particularly comprehensive in terms of the products that can be found there. You’ll peruse ads and look for pictures of bicycles. There won’t be a lot if your locality is anything like mine. Facebook searches by default in a 40-mile radius around where my personal profile says I am located

Pinkbike

A great marketplace for mountain bike parts is Pinkbike. The site is largely populated by people well-experienced in the sport, and you can expect to see some pretty high end stuff for sale there. It also has a formidable database search capability. At the time of this writing, 1125 All Mountain/Enduro frames are available in North America. Within a few seconds I can refine that search:

  • Frame Material: Aluminum, Steel and Chromoly (466)
  • Frame Size: Medium (176)
  • Wheel Size: 26″ (49)

Perusing 49 frames that are pre-qualified to a significant extent will not take long. If I expand the search to include Large frames, I have 68 to look over.

Ebay

Of course we’re going to go look on Ebay! Globally, thats where all the buying eyeballs are, and that means thats where a whole lot of sellers are as well. We’ll see as wide of a selection there as we do on Pinkbike, but with much more primitive search tools.

I used “mtb frame” as a search criteria, and from there EBay let me select 26″ wheels as a filter. Since Ebay listings are notoriously bad for sellers listing specific criteria that their filters can use, I didn’t want to go any further on search filtering, and ended up with about 913 results.

So… figure if you are shopping on Ebay you need to set aside about an hour each time to go thru the list that comes up.

Others?

The above is not meant to be an all-inclusive list of places you can find a frame. They’re just the ones I used, although Craigslist or Facebook were not exactly my preference and I only mention them here to be as comprehensive as possible.

Score!

In the end, after about three weeks of poking and prodding every evening, I found a frame that seemed almost too good to be true: An Intense Tracer from (I discovered later on) the first production run in 1999. It was very reasonably priced.

Here it is, fresh out of the box! the 350mm vintage seatpost was an unexpected freebie.

This frame pretty much ticked every box and added one or two I didn’t have on my list:

  • Size Medium/Large. (effective 18.5″ seat tube length, measured Center-to-Top). Top tube config means plenty of standover height.
  • Excellent condition. On close inspection the frame had very few marks and appeared to have lived most of its life in storage.
  • Overbuilt aluminum frame with extra-strong rear triangle (important for a mid drive where the chain will be pulling stumps).
  • Disk brake bosses!
  • Rear shock is external to a rigid ‘triangle’ that has plenty of space and is almost uniquely battery-friendly. Its almost as if someone from the future went back in time to design this bike to hold a battery.
  • English-threaded 68mm bottom bracket.
  • Lots of clearance up front at the root of the chainstays to clear the motor’s secondary housing.
  • Nice straight, angled down tube so the motor will tuck up into it just fine.

SO… job done. We have a frame. Next we have to see whats up with motor fitment. The next phase of our build is to buy the motor, now that we’ve got the frame to measure it up to.


Step 3: Tinkering

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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