Basically everyone wants to own a unique bike. This requires many requirements. You need Tools, installation experience, routine, enough freetime, money etc.
As a novice cyclist you will encounter with puncture repair. You can’t really avoid that. Sooner or later you will face this problem. You need a couple of tools to successfully remove/change your inner tube.
Hand pump, tire lever set, patch, vulcanic adhesive, spare innter tube, and Allen-key or wrench for removing the wheel if you don’t have a quick-realase wheel. A regular pump and cleaning kit is also basic, if you don’t want to visit the gas station nearby. A multi tool on-the-fly can save your life and nerves, if some bolts came loose during the training. If you are not particularry interested in bike assembly, this set will be enough for a couple of years.
If you wash your bike often and you want to learn how to adjust the brakes/shifting you can buy a stand. This can be expensive, but your back and waist will be grateful. After that you will notice that you can clean the parts easier after dismounting. You will buy your first bike specific toolkit. You can remove a cassette, chainring, chain, and look after the bearings. An iron saw also comes handy. If you have some rusty bolts, you can remove them with a left-threaded tool. If you work with small bearings, a set of pliers can increase your precision. These tools are basically rarely needed for hobby cyclists. If you sum up everything, you could probably buy a new bike for the price of the tools. And you can’t really avoid the purchase of these specialized tools, if you want to repair the bike all by yourself.
If you sink down deeper in the sea of bicycle parts, you will see the reigning chaos.
There are so many different standards, diameters, bearings, you will face compatiblity problems all the time. This is really deep water. If someone knows/understands everything in the bicycle industry, she/he must be an excellent mechanic.
I wanted to build my own bike for a while, but my resourches were limited. And it didn’t make any sense, because second hand bike were cheaper. Obviously risks are involved. Since the person don’t have X-ray eyes, and you can not check everything on the bike before you buy it. One big disadvantage is that your height will reduce the market. And it is not guaranteed that you will get a bike with your favorite color. The advantage: you can buy a similar equipped bike for half price, or buy a much better bike for the same price.
Beyond the tools, I got more and more parts over time. Like saddle, handlebar, seatpost, wheelset, fork, bowden cables, brakes etc. So basically I could use my parts to build up a whole bike. And in Covid times I could sell this bike for more money. My next motivation came from Stuttgart, where I rode a pedelec city bike. I don’t think that pedelecs are good for training, but if someone is not in shape, the bike can offer much more joy.
I made a quick research on the market and I looked around what kind of frames are available. New frames are out of question. There were a couple of older modells, but they weren’t 29er and Boost compatible. I only had such parts, so it seemed logical to buy such a frame. Ont he second hand market I found interesting things. One store offered a 29er fully frame and a 29er E-bike frame. Both had 100 mm travel. Well, I was looking for an interesting challenge. I made a list about neccesary e-bike parts to see how much it would cost. Is it possible afterall?
The short answer is: no, you officially can not build up your own bike with Shimano Steps motor. The long answer is: it might be possible. E-bikes has a decent history, but I didn’t know anything about them. I looked after how the Cannondale Trail was assembled in 2018. It had an E-8000 Series motor with 70 Nm torque. I found an used (but basically new) E8000 motor with battery, buti t was way too expensive. I chose a different path instead. I looked around and I found a motor not far from me. It had a much better price, but the E6000 Series motor only has 50 Nm. Does it matter? Probaply not. The battery comes from Croatia. My next problem: I could not find used parts for this system, so I ordered them from a webshop. I chose bike24.com, because they had the best prices. The fork isn’t an easy one, because I damaged the steering tube (bad assembly/too little fat?). Btw. the steering tube was too short for the E-bike frame. I needed professional help in this case. I found on Testbike.hu used 11 Shifters for good price. The brakes will come from my hardtail. Shimano M506 brakes were so weak, I would not recommand them. I don’t know what the are doing on a mtb. Finally I can swap them after 2-3 years. They kill your fingers in longer descents. The break swap is more tricky than it looks, because the frame has hidden cables.