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Show HN: I Designed and Built an eBike
This post shows and explains the design of the eBike I built myself. I decided to post it on this specific forum because this is where it all started, by stumbling on another post, as mentioned in my entry.
- kumarvvr 5y agoRefreshing to see an old school forum format. Such nostalgia, and a better user experience than sites like Reddit.
- 2muchcoffeeman 5y agoIs it weather proof? I guess not since the motor windings are exposed? Where did you get the sheet metal fabricated? Otherwise looks good! When I got a 3D printer it was amazing to be able to make my own designs, but I wish I had the capability to work with more durable materials.
- holoduke 5y agoDid you try to print with nylons and carbons? I am currently in the progress of designing a fast robust RC car. I am very pleased with the durability of it. With standard pla/abs and pet I kept getting broken suspension parts. With nylon I haven't had a single failure during testing (+100mph). You have to design your stuff with plastic in mind, but you can make strong parts for sure. No doubt metal is better for most applications, but still it is doable.
- gkasev 5y agoI used PETG. I’m happy that I tried it, but it is hard to make 3d parts work, when they are subject to loads.
- usrusr 5y agoSpeaking of (hobby) 3d printing and loads, why don't I see printed parts combined with extruded aluminium profiles (rectangular tubes or T-shaped), threaded steel rods and some nuts+washers more often? Those reinforcement elements are cheap as dirt and should be almost as easy to work with as legos when you can guide all the difficult connections with bespoke printed adapters. What am I missing? (I have zero experience with 3d printing, I barely get beyond kneading a pack of Sugru...)
- johnwalkr 5y agoI work in robotics and this is very common for prototyping and also common for grad student projects. Here in Japan, Misumi will machine things like that to length and add whatever features you need, or even configure an entire assembly (eg a 6 sided box) and get all the parts delivered. I don’t recall the name of similar sites in other countries but they exist. Other easy things to get a good result is use nuts or inserts instead of threaded holes when you can, and try to keep printed plastic parts in compression, not tension. I think not enough people use sheet metal. Doing as you described plus sheet metal to put some material on the outside of the cross section not only looks professional, it adds a lot of stiffness. And for aluminum sheet 0.5mm or 1.0mm thick you can literally cut it with a knife and straight edge, and use a couple of pieces of wood or even books to make surprisingly nice bends. For thicker or more complex parts, it’s pretty easy/cheap to make or buy a decent brake, and also pretty cheap to get parts made from sites like I described above.
- 2muchcoffeeman 5y agoI think a lot of 3D printer hobbyists turned to 3D printing once it got good enough because we don't have space or easy access to even cut things or have a stash of parts. You're right, I can get a M6 x 1200mm stainless steel rod for AUD$5. But then to cut it accurately would need a few more tools. So you kinda try and limit things to what you have. And you can do quite a few useful things with just 3D printed piece and the odd screw here and there.
- 2muchcoffeeman 5y agoYeah, I think the thing with the more exotic filaments is that it's a more specialized used case for when you still need to retain the lightness of plastic. With something like this, the weight doesn't really matter and you want the big increase in strength or durability that you get with metal. Otherwise I find that correct design in your parts provides enough strength in most 3D printed parts to just use PLA or PETG. Nylon is quite a bit stronger but not worth the effort to try and print. I also think the carbon filaments are BS. I've seen several tests like this one: https://www.matterhackers.com/news/filament-strength-testing https://www.matterhackers.com/news/filament-strength-testing The carbon fibre nylon is worse than the plain nylon in terms of strength. Which makes sense to me. If you grind up carbon and put that into your filament why would that make it stronger? Maybe for compression forces?
- gkasev 5y agoIt’s not waterproof. I got the sheet metal parts from Schaeffer AG [1]. Thanks! 3d printing is here to stay, but load bearing parts are problematic. I had to change some of them to metal. [1] https://www.schaeffer-ag.de/ https://www.schaeffer-ag.de/
- bigiain 5y agoHow thick and what material is the sheet metal? Is it something that fit and be machinable on a cheap 3018 CNC mill? (Sorry if that's answered in your linked post, I skimmed it perhaps a little too quickly...)
- gkasev 5y agoI used 4mm thick, black anodized aluminum plates. I'm not a machinist and do not know the specifics of your CNC machine, but you will most probably have no problems machining these plates.
- bigiain 5y agoThanks! (I'd be able to make those, I would probably need to do it in a few passes though.)
- jstanley 5y agoYou mention a throttle - I had a skim but couldn't find anything, I wonder if you considered adding a pedal-assist system of some sort? I suppose a throttle is a much more direct connection between your mind and the motor control, unfortunately they are illegal in my country.
- gkasev 5y agoI‘m using a Domino throttle grip [1]. I thought about a pedal assist system, but decided to go with throttle, because it’s simpler to execute. [1] https://hubsink.com/products/high-performance-domino-twist-grip-throttle-with-microswitch https://hubsink.com/products/high-performance-domino-twist-g...
- slingnow 5y agoCool build, but it doesn't look like it would actually stand up to the typical stresses of mountain biking (rock strikes, water, mud, debris, etc). On super smooth singletrack I could see it being fun though.
- bri3d 5y agoA few ideas: * A VESC based ESC instead of the HobbyWing one will give a lot more control and telemetry, including a phone app and detailed current use logging. I know from RC planes that HobbyWing ESCs are very high quality, but VESC is specifically written for drive systems and has a lot of features. * LiIon or LiFePO4 round cells are safer and more energy dense than LiPo pouch cells, at the expense of current sink capacity you don't need. They're also cheaper.
- gkasev 5y agoThank you, those are great suggestions. The ECU selection was primarily budget driven. I need to have a look at those VESC. Battery selection was again budget driven. The also hat to have certain dimensions to fit inside the kit.
- vosper 5y agoIt's a conversion of an existing bike to be electric, right? Or did you design and build the frame, too? Either way, nice work! I think we're about to see a lot of innovation in scooter- and bike-adjacent mobility things - I don't mean the motors, but the frames etc... eg we might see more cargo e-tricycles?
- mft_ 5y agoHow are the mounting brackets made (or obtained)? You said you didn’t want to CNC anything, but they look CNC or laser cut? Any estimates of your expected range?
- Hextinium 5y agoLooks like they are router'ed, which while technically being a CNC machine is usually a order of magnitude cheaper than a CNC lathe or mill.
- gkasev 5y agoYes, this is exactly how they are manufactured. I got them from Schaeffer AG [1] and the three plates cost approximately 300€. [1] https://www.schaeffer-ag.de/ https://www.schaeffer-ag.de/
- convolvatron 5y agothat is _really_ high. I can get those 3 water jet cut for ~$100 at a commercial shop down the street, alot less in volume
- c22 5y agoAre you including the cost of materials? (And in this case shipping) I could cut these out on the plasma table in my garage for free, but that looks like at least 150 bucks worth of metal.
- convolvatron 5y agoreally? steel for me is $0.80/lb, and Al is around $4
- VectorLock 5y agoWhere?
- ghostly_s 5y agoSo it drives the pedal shaft? Isn't that a safety hazard?
- KennyBlanken 5y agoIt looks like it has a chainring clutch, though without a chainguard cover, you have the risk of clothing, body parts, shoelaces, etc getting sucked into the chain, yeah. The motor sticks out uncomfortably close to the pedals and particularly on a MTB I could see a rider accidentally stepping on it...and it looks like an outrunner, so that would also be quite bad, as the foot would get launched backwards pretty violently. This is a lot of effort compared to just bolting on a Baofang mid-drive motor. The components are also placed such that unless you have a pretty good front fender, they'll be covered in crap in no time.
- ghostly_s 5y agoI was more concerned about the pedals being spun about by a high-torque motor and banging into your shins...
- VectorLock 5y agoThere is a freewheel on there, it doesn't talk about how its implemented though and I'm interested in it as well.
- gkasev 5y agoThe basic idea for the freewheeling chainring comes from tandem bikes, where one person should be able to pedal, while the second one doesn't do anything. I have never ridden a tandem bike, but this is where I got the idea. There is also another detail, that you need to know, in order to understand how it all works. Trial bikes (not trail bikes) usually have a special kind of drivetrain, where the freewheel is mounted on the crank and not the rear wheel. This allows for a very small rear wheel sprocket and extremely high gear ratios. So to make this work, I used a trial bike crank [1] on which I'm mounting a special purpose freewheel [2]. The chainrings are mounted to the freewheel using this adapter [3]. [1] https://sickbikeparts.com/cranks-freewheel-isis-crank-set/ https://sickbikeparts.com/cranks-freewheel-isis-crank-set/ [2] https://sickbikeparts.com/front-freewheel-heavy-duty/ https://sickbikeparts.com/front-freewheel-heavy-duty/ [3] https://sickbikeparts.com/freewheel-spider-4-arm-104-mm/ https://sickbikeparts.com/freewheel-spider-4-arm-104-mm/
- mdoms 5y agoWhy the no welding requirement?
- Hextinium 5y agoThey probably don't have access to a welder and so they can't weld. It looks like they have a router table and a sheet metal bender so that's what they used to make it.
- frosted-flakes 5y agoThe router table breaks the "no CNC" rule though...
- earleybird 5y agoTechnically yes however home cnc's that are aluminum capable are so much more common than when I first started back around 2008. Taking inspiration from but not achieving the precision found here: http://oneoceankayaks.com/madvac/madvac_index.htm http://oneoceankayaks.com/madvac/madvac_index.htm
- 8note 5y agoWhile the capabilities have gotten cheaper, the storage space is much more expensive nowadays
- mdoms 5y agoHard to imagine a workshop with some pretty fancy sheetmetal equipment but no welding equipment. A welder is, like, the first metalwork tool you buy.
- jbay808 5y agoI think that would depend a lot on your workshop space, ventilation, available power, and the prevalence of nearby flammable surfaces.
- stavros 5y agoThis is fantastic, well done! I love the simplicity of the kit. I'm extremely surprised to hear that soldering the XT90s was hard. Even a $20 Pinecil (well, maybe I shouldn't say "even", it's a fantastic iron) can handle those no problem. Also, what cost 1200 EUR? That motor costs 30 EUR, an ESC another 40, and the batteries maybe 80 EUR for Li-Ions (less weight). Were the CNCed plates that expensive? EDIT: Added the praise I meant but realized I forgot to actually write.
- notjulianjaynes 5y agoBy chance I just soldered some 10 awg wire to an xt90 connector earlier today, using a Pinecil no less. It was super annoying to get right. Few cold joints before I got it. The problem was with the stiffness of the wire I used. It made it difficult to keep in the exact right position until the solder cooled down. Would have been easier with thinner or higher quality wire though.
- stavros 5y agoHmm, were you pressing the button to get the 400C boost? With that, first you tin the wire VERY WELL, then you put some solder in the nook of the connector (fill it about half), and then you push the wire into the nook with the iron. That will melt the solder on the wire and then the connector, and it should give you a nice even connection without any over- or underflow. Once the wire goes in, you remove the iron, hold the wire there for a second or two until the solder solidifies, and you're done. I used 12 AWG but it should be pretty close. EDIT: I just did it again, make sure you hold both the wire and the XT90 firmly with helping hands or something similar.
- m4x 5y agoSoldering heavy gauge wire is more about having thermal mass in the iron tip than high temperature. That is part of why you can buy different tips - selecting the tip with the right thermal mass will allow you to quickly get the workpiece up to temp without overheating anything nearby. You can hack it by just turning the temperature way up, but there are a number of drawbacks to doing so. It's better to use the right tip.
- initplus 5y agoCurious why there is a derailleur, but seems to be only one fixed gear at the back? Guess you trust that motor to have enough torque to not need any rear gears?
- blackth0rn 5y agoon rear suspension bikes with a changing chain length you need something to account for that change in chain length so it doesn't go floppy at certain points of the rear swingarm motion.
- etcet 5y agoIt's probably used to keep the chain under tension when the rear suspension moves around.
- gkasev 5y agoOn a full suspension bike like this, the distance between the rear wheel and bottom bracket changes when the suspension works, so you need a way to compensate for this.
- 8note 5y agoAdding to the other comments - chain tensioners look like derailleurs, but are much simpler/can't move the chain to different gears
- neilv 5y agoNeat. Has the design work yet looked at safety of how the boxy assembly and its pointy bits might interact with rider's legs in an accident?
- gkasev 5y agoThis is a good point, thank you! I take this very seriously and I'm very mindful when riding the bike.
- notjulianjaynes 5y agoCan you post a better picture of how the brackets attach to the downtube? Did you drill into the frame?
- gkasev 5y agoIt’s just a zip tie. It only needs to support part of the weight, the moment from the kit is reacted by the frame itself, e.g. the motor pushes the kit against the frame, when it drives the chain.
- jdiez17 5y agoI think you did a great job designing and implementing this. However if you are in Germany unfortunately electric bikes and other personal electric vehicles with a top speed over 15 km/h (off the top of my head) need to be registered with the traffic authority and carry a license plate. It’s basically impossible to do this for DIY builds, as far as I know.
- gkasev 5y agoI live in Germany myself. I mostly built this bike for fun.
- _ph_ 5y agoFor electric bikes, that also require the user to pedal to get propulsion, the limit is 25km/h.
- sva_ 5y agoI think it's 25 km/h + tolerance = 27.5 km/h.
- emteycz 5y agoNote that this applies on public roads/bikepaths only. You're free to ride on private property as fast as you want (and anything you want, with or without licenses).
- bigiain 5y agoI have a home-brewed eBike here in Sydney, where the rules limit you to 200W (or 250W if it's pure pedal assist without a throttle). Mine will pull almost 750W going uphill on a freshly charged battery. It has a very prominent "200W" label on the outside of the battery holder. If I rode it like an asshole, doing 45kmh on sidewalks, I doubt my "200W" label would do me any good. But I've had it eyeballed by police when they're doing their semi-regular "fine everybody without a helmet or a working bell" crackdowns on CBD commuters and have stopped me to check my bell works, and never had the power questioned.
- ggm 5y agoI would love to understand how the motor works out to adjust its component to torque so its assistive and not replacement. I guess a stage=1 is to make the throttle and the smarts are human (and its PBCK if it doesn't pick up right to conditions) and stage=2 is to move some of the smarts down the foodchain a bit. The high-end E-Bike I rode briefly did a marvellous job of detecting road conditions and maintaining semi-constant speed. The ones I use on the street are more crude, they use pedal effort as a primary guide to intent but back off aggressively, I guess to limit risk to pedestrians. I am pretty sure off-road wouldn't want that. (not a big e-Bike rider, just fascinated)
- ricardobeat 5y agoCowboy bikes (from Belgium) has the best assist system I’ve seen. After a minute or two it feels completely natural, to the point where you just feel like you lost your own leg strength if the power goes out. I think they recently expanded to the US, recommend trying one if you can!
- gkasev 5y agoThe torque is not adjusted I any way. I really designed it in a very simple way - you turn the throttle and adjust until you get the assistance you desire. The human brain is an excellent controller and after a while you stop thinking about it.
- ehnto 5y agoThere's a lot of regulations around e-bikes already, that enforce speed limits to the assist, after which it's all human power, zero assist. It is of course about safety, but it's also about dividing up the regulations between e-bikes and e-mopeds, the latter coming in so many shapes and sizes. That is also why the regulations usually specific that it must be pedal assist, not throttle controlled. If it walks and talks like a bike, and only goes as fast as the average cyclist, it is probably a bike. But if it has a throttle and goes faster than your average cyclist, it's probably closer to a moped at which point you need a license, different kind of helmet, turn signals, registration, so on and so forth.
- 5y ago
- ehnto 5y agoI love that you focused on commodity parts. That is excellent, I really like the placement of the system. Do you intend to take it trails riding? I would just be careful of those XT connectors and be mindful that you've reduced the clearance when traversing over ledges or rocks by moving the lowest point farther forward (you'll hit it quite a bit sooner essentially). I also love that it's internally geared, I've always felt this made way more sense for mountain bikes anyway given the weather protection. Good stuff!
- keville 5y agoI don't think the "gearbox" mentioned in the article is the kind of internal gearing you're referring to here. It appears this e-bike only has a single-speed chain drive, and only a throttle for adjusting motor speed.
- gkasev 5y agoThank you! I'm mostly going to ride it on flat off-road terrain. I'm not really happy how those XT connectors stick out :/.
- NicoJuicy 5y agoSite is getting hammered and they already scaled up. Very useful site with more similar examples, but just in case you want to save them some bandwidth in load ( it contains multiple images of the bike): https://archive.is/QMx56 https://archive.is/QMx56
- dangle1 5y agoI like the friendly message from the person running the website to the author: >Hey, congratulations. Traffic is flooding in from ycombinator to this thread and we're getting slashdotted :shock: I just now had to upgrade the server to a huge one temporarily. Are you important on there or something?
- langsoul-com 5y agoI think it's just a case of a smaller site so the community is more tight knit.
- mperham 5y agoWell done, a very unique design! What made you spec the motor so high? A 2400W motor is very powerful for a bike. For Americans, 750W is one horsepower so that's over 3 HP which should get the bike to ~40mph or 70km/h.
- pcdoodle 5y agoOne word: Hills.
- dmix 5y agoI've got a 750w and it handles hills pretty well. To the point where you don't need to actually pedal unless it's a long steep one but even then it's like pedalling on a straightaway (using pedal assist is of course is always optional). Before I got the bike I wanted the most powerful one available but I realized after getting one you don't really need that. And it's actually kinda dangerous, even for a experienced cyclist who's used to speed. Even the standard tier batteries are more than enough for any urban biking in terms of distance. I rarely use even 20% at 48V, 10.5A.
- KennyBlanken 5y agoAn average "likes to do a couple 40 mile sporty bike rides a week" cyclist probably can do around ~150-200W continuous and maybe peak for 10-15 seconds at around 750-1000w. A hill that takes 20-30 seconds to climb, less than 500W most likely. Depends on their weight and training. Cargo e-bikes tend to be at or less than around 1kW. 750W is still considered fairly powerful, and 500W is much more typical and still plenty enough for even a cargo bike to get up a hill, with appropriate gearing. 250W is about the standard for low-end e-bikes. 2.4KW is gross overkill, especially if you're not doing direct drive. More watts just means you can go up the hill faster. This assist motor is driving the wheel through the rear derailleur so it potentially has a pretty wide range of gearing.
- gocartStatue 5y ago250W pedal-assist only is all you can (legally) get as a bicycle in Europe. I have only one friend that can sustain 250W for hours (on a road bike), and he's a serious everyday "bicycle is the default vehicle" type. 250W is plenty for casual rides. Not judging the choice here, though, must be quite a beast ;)
- analog31 5y agoNice work. I'm still clinging to my conventional bikes, but anticipate when something will eventually push me over the edge, such as old age or a long distance commute. I've been reading whatever I can learn about e-bike technology so I'm ready. So far the simplest assist I can think of would be a front wheel hub motor and a switch that turns on a constant amount of torque. This would still let me control my speed by how hard I pedal. Of course I'm scratching my head over how I would control it, since it would probably not be an off the shelf controller. But I'm also fascinated by the electronics, and having to design my own controller would be a benefit, not a liability. I also have an obsession with knowing how things work, that I have to contend with. Of course all of this is until I think of something better.
- derekp7 5y agoFor a controller, look at the Cycle Analyst from Grin Technologies. It is somewhat hackable, can hook up to a crank based torque sensor, or use a cadence sensor. Personally I just use a throttle that "remembers" a given setting when you hold it in a given position for a couple seconds, and throttle enough to bring me up to say 8 mph, then peddle to get to 15 or so. Basically I peddle about how hard I want to, then adjust the throttle to give me the speed I feel like going. But you can also do fully peddle-based (cadence or torque) assist to make it feel more natural (then it would be like riding with a strong wind at your back).
- analog31 5y agoNice documentation at their site. Thanks for the tip!
- gkasev 5y agoYes, I have a long commute to work (18km one way) and this was my main motivation for building the bike. On the controls side of thing, I have the ECU and an Arduino Nano. The Arduino uses the BEC port of the ECU as a voltage supply to run a simple routine translating the analog output (potentiometer) from the throttle handle to a PWM signal that the ECU can understand. The way that the assistance work is that while you are pedaling, you can turn the throttle and adjust until you get the assistance you want - pretty simple. After a while it becomes natural.
- placson 5y ago
- placson 5y agoNice design but that external chain looks scary.
- throwoutway 5y agoWow, I had no idea this site existed and it appears to have a huge community that's active. The build itself is also quite nice and worth a read
- Avlin67 5y agoefficiency: not so much noise: quite a bit also bear in mind that just 100w added to someone which is already sportive is quite sufficient for commuting. going harder would put excessive wear on bike chains that for me are already excessively thin. now, tires and brakes. did you use bicyle grade tires that are way too soft or some ebike rated tire that are much harder ? also brake, olease check your brake, you don’t need to be electric for make the brake suffer, so that you need bigger discs, ceramic pads…
- gkasev 5y agoThank you! Yes, brakes are important and I have 203mm discs front and rear. After building this, I'm dreaming of building something very elegant - a 50W to 100W torque generator that is tiny in size and very lightweight, and it fits within the hub of the wheel. Maybe not using batteries at all, but supercapacitors the are charged when you brake and discharged when you accelerate.
- coding123 5y agoMore people need to be doing things like this.
- barbarbar 5y agoWhat is the max velocity? I sometimes see people on new fast e-bikes and it seems a bit scary. And sometimes the rider also looks a bit scared or not really in control.
- gkasev 5y agoI designed it for 40km/h max, but this is way too fast. Given the KV rating of the motor and your max voltage you can calculate the max rotational speed of the motor = KV*V. From there it is just a matter of multiplying by all gear ratios along the drive train to calculate the rotational speed of the rear wheel. Knowing the circumference of the 26" wheel gives you the max speed.
- squarefoot 5y agoExcellent build, also very beautiful to look at; I hope to see a video of it in action. It's strange that the author encountered difficulties in soldering XT90 connectors; I actually never soldered more than a few of them but never had any problems; it is possible that either they were of dubious quality (far east clones with possibly sub par copper contacts?) or they weren't clean enough. Nothing that a good solder iron, as the author suggest, and good use of flux can't cope with. For those in need of a good solder iron, avoid cheap no-name ones or Hakko 936 and similar clones and all those using the same stylus (there are at least a dozen different rebrands) because they all are bad: they indeed work with very small solder joints but will fail with bigger contacts or larger pcb tracks, although the power should allow them; the reason is always the same: too small thermal mass and bad thermal contact between the internal heater and the tip. Any used Weller WTCP will perform a lot better roughly for the same price, or check the Pinecil, which for the price performs really well and is also a 100% Open Source Risc-V platform. https://pine64.com/product-category/pinecil/?v=0446c16e2e66 https://pine64.com/product-category/pinecil/?v=0446c16e2e66 About bicycles, unfortunately I'm too big for them; even if I wasn't overweight, my mass would exceed 100Kg anyway, but hope to see 3 wheeled EVs imported or produced in Europe. Someone here mentioned Arcimoto a while ago and now I'm in love with their Roadster model after seeing a video. Unfortunately, high price aside, it's US only at the moment.
- jacquesm 5y ago> It's strange that the author encountered difficulties in soldering XT90 connectors; I actually never soldered more than a few of them but never had any problems; it is possible that either they were of dubious quality (far east clones with possibly sub par copper contacts?) or they weren't clean enough. Or simply use too small an iron for the job. XT90 isn't the problem here, more likely it is the fact that the wire drains heat so fast that you don't get to a nice temperature.
- jillesvangurp 5y agoNice build. I was watching a video of some Russians converting a very old bike using the motor of a washing machine. Very amusing: https://www.youtube.com/watch?v=dDizHIjZqBM https://www.youtube.com/watch?v=dDizHIjZqBM That contraption looks a bit scary of course but it goes to show that building a e-bike is not that hard. Which is I guess why there are so many companies doing that right now. This one is really nice though. I live in a big city (Berlin) and e-bikes are perfect for getting around town. You see a lot of the delivery services using them. Also in a weird bit of investor inception, you see drivers of one VC funded company basically using the e-bikes or scooters of other VC-funded companies.
- jacquesm 5y agoThat's a beautiful piece of work, if I may make a couple of suggestions: - chamfer all exposed 90 degree angles - shrinkwrap the whole thing so it is protected from the weather and dirt - add a connection at the top of the motor frame to the bike to better deal with the reaction forces
- gkasev 5y agoThank you! A better (more solid) connection between the kit and the frame would be on the top of my priority list, if I were to build it again.
- jacquesm 5y agoKeep an eye on those bolts, they're right next to the shaft where shear forces are huge and from the looks of it they are only M6. You may want to use a harder grade to reduce the chances of them being sheared off.
- GrumpyNl 5y agoI love the design and build, great job. As a dutch guy i miss splashbacks. You can get some very cheap click ons like these https://www.bikester.nl/red-cycling-products-universal-spatbord-set-M301955.html?vgid=G338722&cgid=37008 https://www.bikester.nl/red-cycling-products-universal-spatb.... It will save you from the black stripes on your back and face.
- gkasev 5y agoThanks!
- jakecodes 5y agoHey there! Nice work, looks great! I've built a few of these and the biggest concern with those motors (I've tried them before) is that they aren't made to handle the torque of even small hills. They'll burn out on mile 25. It's not the wattage that's the problem, they just start to slip and burn out unless you gear them down a lot, but then you lose a lot of their speed. Maybe I've just always bought cheap stuff. Also worried about the tension on the chain, is it adjustable? I also had trouble with XT90 in the past. I would melt them. Proper soldiering iron fixed that. Nice build! It's super unique!
- tromp 5y ago> aren't made to handle the torque of even small hills. To get up steep hills, you need not only a powerful motor, but also chains and gears to handle that power: https://electrek.co/2022/02/23/biktrix-xd-unveiled-as-mind-bogglingly-powerful-electric-bike-motor-with-300-nm-of-torque/ https://electrek.co/2022/02/23/biktrix-xd-unveiled-as-mind-b...
- loeg 5y agoSure, for these absurdly powerful e-moped conversions. But even ordinary bicycle chains need to be able to handle 1000W, which is more than the vast majority of ebikes.
- oofnik 5y ago