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Project "Firebolt"

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Hello everybody!
I was unsure weather or not take part in this year build-off, since honestly this year is tough with free time and resources. However i came up with an idea to finish one project i was planning and preparing for a while ago.
I am going to build an electric bike. Mid motor, with TSDZ2 750w and a Nuvinci hub. I actually bought all the electric components like one and a half years ago, and even made a test-build on alu Electra Rat Fink frame. However i quickly found out that a factory made frame just won't satisfy my needs for an electric bike, even though my daily bike which i find very practical is built around an Electra Ghostrider.
The general input is that i probably will use an ebike often, in different weather conditions, for long rides and as well to carry my trailer around. So it should be very practical, with the option to attach a trailer, a luggage rack and the side bags if needed. The rack should be pretty sturdy, so here comes my first inspiration: Columbia Firebolt. I really like the smart and stylish way they incorporate the rack into the frame design.
FireboltRed-1.jpg


I have made a few sketches and renders of the frame i wish to make, but then i happened to buy an 2011 Basman bike quite cheaply. I was offered a leftovers from a bike that was taken out of the fire (just realized how it goes together with the firebolt on the top). Here how it looked like when i got it:
IMG_4569.jpg


It doesn't seem to be very infuenced by heat, so i don't worry about the steel loosing its strength. The paint had burn, but there are even some plastic parts on the lamp and headset that were molten, but not completely burn. That means the bike was heated up to around 120 - 150' C, and it takes around 600' to start changing the steel microstructure. So anyway, after some time i have realized that my sketches of the frame i want are kind of similar in shape to Basman, so instead of building a frame ground-up i can just cut up a Basman and remake it. So that is what i am here to do! :)
Here is a little render i have made:
basman_alt2.jpg


So i have basically raised the belly of the frame so i have more clearance to ride in terrain, got rid of the famous Basman BB plate and found a place for an Euro-style threaded BB instead. That solves me three problems at once: the electric engine mounts to a threaded BB, by this modification i will make the connection stronger since Basman bikes are famous for twisting the plate off sometimes, and also by doing so i am extending the frame size to fit my height. Then instead of the original mid tube i am going to have the double bars i can continue as a rack. I can attach my side bags to it and make a detachable rear rack to be mounted there. I feel a potential for a nice design here.

I think this all makes a good starting point :)
 
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Here is a photo of my engine together with the 52v 17.5ah battery:
IMG_6151.JPG


I didn't charge it in a year until yesterday, but i hope it is still okay :) I don't know how far it could take me, but i am really hoping for a great result. If it won't do what i expect from it i may as well get a second one and switch them during the ride if needed. The plan is to put that big boy down in the belly if i would have enough space for it. Even though it won't look as cool as hidden in the tank, it would ensure the lower mass center.

Here is a frame waiting to be chopped apart:
IMG_6150.JPG
 

kingfish254

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Oh Yeah!!!! I always like the idea of blending the old and new together. Your idea is quite unique for a Basman. I also like your vision of lowering the rack below the top of the rear tire. This is gonna be fun!!
 
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Oh Yeah!!!! I always like the idea of blending the old and new together. Your idea is quite unique for a Basman. I also like your vision of lowering the rack below the top of the rear tire. This is gonna be fun!!
Just like on your last years bike :D
I have actually tried to find an alternative line for it so it would have a functional surface, but it all just looked too much, and i didn't want to loose the smoothness of the lines. Here is one of the earlier renders:
basman_alt.jpg

Therefore i have decided to make a rack with the surface detachable, and leave the side tubes below the tire. Still good for the side bags and to put the rear lights in the end of the bars maybe :)
 
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Like the first drawing, interesting combination. How is the TSDZ2 750w in general, speed and torque wise. I have been looking into one.
Torque is very good, i was even afraid to get mad with it sometimes, i totally feel the engine could have done even more if it won't be a test build and i'd dare to let it show all its power :) About the speed i really don't know, since the speed sensor that came stock with it had a cable that is too short to reach the wheel on a stretched cruiser. I guess it was around 50kmph or so, but then again, if i would push it to the limit and spend some time adjusting it, it probably would let me have more speed out of it.
Overall i have a feeling that it is very balanced and easy to handle, especially with the Nuvinci hub that can shift under load. It has a quick response so it's a good choice.
 
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Torque is very good, i was even afraid to get mad with it sometimes, i totally feel the engine could have done even more if it won't be a test build and i'd dare to let it show all its power :) About the speed i really don't know, since the speed sensor that came stock with it had a cable that is too short to reach the wheel on a stretched cruiser. I guess it was around 50kmph or so, but then again, if i would push it to the limit and spend some time adjusting it, it probably would let me have more speed out of it.
Overall i have a feeling that it is very balanced and easy to handle, especially with the Nuvinci hub that can shift under load. It has a quick response so it's a good choice.
I heard they were not bad, did not know they could take a 52v. Cheaper than the bafang(not by much) but looks more clean and smaller.Plugs look like the higo, you could prob purchase a cable extender. Might have to invest in one...
 
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I heard they were not bad, did not know they could take a 52v. Cheaper than the bafang(not by much) but looks more clean and smaller.Plugs look like the higo, you could prob purchase a cable extender. Might have to invest in one...
They take 52v and mine was set up to 850w peak power. It was slightly warm after the ride, but that's totally normal. Of course you could burn it if you put way more amps to it, but it is almost as powerful as 1kw Bafang model. I have ordered the extender from China last year but it had never arrive, so i am trying my luck again now :)
 
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I appreciate your thorough plan and detailed design. Hope you can source all the parts you want / need. Really cool ideas!

RaT oN~!
 
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Here are some things i have received by mail lately, that are related to this project!
First of all a 40mm hole saw (on the right) that is going to help me put the euro bottom bracket (on the left) into the frame.
IMG_6153.JPG


Then i bought this leftovers from what once been an electric bike. Apparently buying slightly used ebikes from Germany and parting them is a good business. I paid just 50$ for what you see.
IMG_6154.JPG


As you may have guessed, we are only going to need this monoshock fork :) Though i may find use for a great quality heavy duty semi-integrated headset for some other project. While testing the electric motor on another bike i found out, that on high speed all the bumps on the road really end up affecting your hands and wrists, so some shock absorption is what i want to have in this project.
IMG_6155.JPG


This is how they connect it. Maybe it will be cut off at the level of the thread if i decide to convert to threadless.
IMG_6156.JPG


Caution, next picture is a shock content, take the kids away from the screens. That's how it looks naked.
IMG_6157.JPG


And here it is fully disassembled. Not good that it can't be fully taken apart, that rubber damper may melt if i overheat it while welding. The design is very simple, though the feeling of it is quite smooth.
IMG_6158.JPG


As you may see it is almost in a level with the frame. But i think i'd need to attach other legs to it anyway, since this fork does not have enough space for the 80mm fender to clear it. Good thing it is steel, and the diameter of the lower crown is 40mm, just like the saw i have shown in the first picture of this comment :) So we will see what direction would i go with that fork.
IMG_6159.JPG
 

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So, on Tuesday i've got a fresh delivery of parts from Germany. Some fork bumpers, new grips for my Murray Monterey and a new BB shell. I decided i go with a new one for this build instead of cutting out one from a donor bike because of a few reasons. First is it looks neat and clear, i don't have a lathe yet to be able to clean out my cutout shells to same quality. Second reason is good thickness and absence of mounting holes, welding up which i could have destroyed the thread.
IMG_6170.jpg


The next step is marking a ground level line of the frame with some tape for the further measurements.
IMG_6171.JPG


Marking a spot for inserting a new BB now accroding to the render i've made earlier and some calculations.
IMG_6172.JPG


Using a hole saw i am making this nice hole through the frame, leaving this place hanging on what's left from original BB reinforcement plate.
IMG_6173.JPG


Test fitting the BB. Snug and tight!
IMG_6174.JPG


Then it's time to separate the belly of the frame together with the chain stays from the rest. I am leaving the mid tube on its place for now, so the frame would be more stiff and easier to work with. I am making sure the inner tensions in the material would not affect geometry, and then i remove the mid tube once the rest of the frame is welded up.
IMG_6176.jpg


Here is a magnet held mockup of how i may want to weld it back up. As you see the length of the chain stays dos not anymore allow to connect it to the dropouts in a same fashion. I have two options now, either i extend them a bit, and that shouldn't be difficult, or i just consider their new shape when designing new set of drop outs.
IMG_6177.jpg
 
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Then yesterday we had a little ride with local custom bike crew Kastom Garaż Poznan.
186987616_293345642514251_8454537578138028887_n.jpg


I would probably not mention that, if not a guy on an electric Basman we met at out towns main square at the end of our ride. Second bike from the front on this photo. His name is Kamil and he told me a little story.
186812261_293345822514233_6483827821521753073_n.jpg


He said this bike of his is made for him by a company ebiker.pl and he strongly won't recommend them to anyone. This bike of his is a second version already, since something bad have happened to the first one. While modifying the first version, the guys had their warehouse caught on fire. When he came and asked them to give the leftovers of his bike back, they said they don't know where it is and it was probably lost during the fire. He sued the company but never got any refund. Should i say the story sounded familiar to me? I have found the owner of the bike i bought. It was in my garage for 1,5 years, and week after i cut it up the original owner shows up and says it basically was stolen from him. That's a small world indeed. I've helped the guy providing all the details on how and when i bought it, so hope it helps him out to fight for his refund, he seems to be a good guy.
 
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kingfish254

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I didn't realize you were raising the bottom tube of the frame. That should give you a little more ground clearance.
 
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