I definitely agree not to go with the qs273 (mine actually had an axle for 150mm dropout. 200 amps is not even close to enough amps for that motor. The winding on my motor was 3.5t which got me to 60mph but not very quickly. I would definitely spring for torque over top speed. It makes for a much more useful and fun bike. It was never fun to be going anywhere over 45mph for me with simple brakes and the small ebb frame with mtb suspension. I rode motorcycles and from that learned that speed isn’t what makes riding fun. I definitely wish I had gotten a 4t winding or even 5t. However if this is your first build you will pretty much be blown away by any turn motor you choose. I know I was, but after a while of riding through the city I realized all of my riding was only up to 30mph and it made me wish I had more power down low. 4t is a great choice for a mostly on road semi off road bike.
I don’t have any experience with the savaton controllers, but I do know that there are fakes out there especially from Alibaba. I would highly recommend the power velocity controllers. They are probably a little more expensive. For $500 you get 200amp and 450 phase amps but the important thing for a beginner it’s super easy to program through the Bluetooth app from your phone. There might be slightly fewer parameters you can set, but everything you need is there and very user friendly. 200amp is a lot and will definitely be satisfactory for a long time.
For the frame, nothing beats the eeb frame when it comes to price. However, the quality is definitely the lowest. Comparing it to my new vortex frame is night and day in quality and design. The eeb side panels are thin plastic that won’t hold up to a crash compared to the vortex which is plastic double the thickness sandwiched in between two layers of thin aluminum. The eeb frame is also nowhere near waterproof with a huge hole in the bottom and openings all around where the vector is totally sealed. The battery mounting In the web is a challenge. There is no real battery box. The enduro seat was what I disliked most about the frame. It really was poorly designed and really uncomfortable. It didn’t fit snug which bugged me and it was tilted so far forward that I would slide down and be sitting on the frame while riding. I also wouldn’t consider the seat made for 2 people. Me and my girlfriend are both under 150lb and although we ride it together all the time, it was very uncomfortable and she was half way off the back of the seat at all times. I know I probably scared you off of this frame, and I think that may good thing, but I would say definitely no if you plan to ride with a passenger comfortably. The vortex frame is $899 which does seem really pricey but it is much better quality all around. If riding with a passenger is an important goal this is the best frame as it also allows for passenger foot pegs which were an oversight for me. When riding the eeb with my girlfriend, she put her feet on the pedals and I put my feet on top of hers. There was not any room for any passenger pegs and believe me I tried to install some. The bike was just to small. If riding with a passenger isn’t a main goal vector also makes the typhoon frame which is similar to the eeb in design but is more expensive. The difference in these is very large as well. They look similar but are very different. I’m not sure if I think the typhoon is worth the extra cash though. I think I would recommend getting a vortex if you can fit it into your budget. Also I would recommend stretching that budget a little further than you would like. It will be worth it in the end and makes the difference between a bike that will last you years and one that only lasts some months. My eeb bike failed 6 months after building because of water. An extra $600 will get you a completely different bike and is definitely worth it considering your large investment thus far. Vector vortex frame I would definitely put at the top of your priority list. Watch the cyber bike videos on YouTube where a guy builds this frame up and is selling them.
I can’t say much on the alibaba battery from experience but I would recommend against. For the price of the batteries, you can guarantee that the cells are not genuine, meaning that the rated power in almost definitely overstated. This means a wasted investment on all your other parts if the battery can only put out say 100amp max. I know this will sound daunting, but your best bet is a homemade pack. You can buy 18650 lithium cells and know they are genuine. You should look into diy bike batteries as it is pretty much the only option when it comes to this power of ebike. You can easily build your own for under $1500 and have a higher performance pack. But good legitimate cells and use the vruzund.com battery connectors. They don’t require spot welding or soldering. With this, a bms, some foam wrapped around, and some heat shrink you now have a Bluetooth enabled high performance pack that will perform amazing for less than $1500. I would recommend a Bluetooth 300amp 20s ant bms. They are $100 on Alibaba.
Add all you need up and it isn’t too much more then a surron, but it is way better in performance.
$1400 vortex frame, rear wheel, shipping
$500 power velocity controller
$350 motor
$1200 for the battery($800 for 200 cells, $100 for bms, $300 for vruzund battery holders)
$500 if you get the dnm downhill mountain bike suspension.
$100 front wheel(many options)
$??? Brakes. You can spend a lot or a little on these and upgrade later or not. I always buy cheap telling myself I’ll upgrade if I need it but never upgrade. Brakes are important for having fun on the bike.
So, for somewhere around $4500 you will have an amazing bike that will last you much longer than an eeb with alibaba battery. Like I said the extra $600 makes all the difference. You could have a surron for $3900 all in or you could triple that power and double the battery life for $600 (not to mention you will have a sick looking bike that can also carry a passenger). Save up a little bit more and spend a little more than you like and you will end up being very happy you did. I had the same idea and budget as you and saw that the minimum price to build one of these bike was around $3500 but I didn’t know how much better it could be to not buy the cheapest. Don’t sell yourself short. Once you build one, there is no turning back. Feel free to ask any more questions.