Custom hardtail commuter

Hello everybody,
it is about year ago, when i completed my first ebike. As a donor bike i used old secondhand steel hardtail mtb with crappy fork.



Then i added magicpie hub motor, 48v 20ah Panasonic 18650PF battery pack, magicpie external controller, thumb throttle and over time changed lot of bicycle parts. And after year it looks this



It is reliable fun commuter, even my commute to work is around 2km, i usually take ride around 20 to 40km just for fun. Max speed around 40km/h, range without pedalling with full throttle and smile on face between 40-50km to the cut off (of course i do not discharge battery this deep often).

But there are some issues that cant be elegantly fixed on that platform and i also want better performance (better acceleration, top speed around 60km/h, no-pedal range at 40km/h with rare blasts to full throttle at least 100km to the cut off). I wanted better fork, with single crown to keep build look still like bicycle and thru axle and sadly, these days there arent much options without taper steerer tube and this frame has too narrow headtube to fit them. Furthermore, the triangle is too small to fit adequate battery to meet my requierements. Because i dont trust aluminium frame running with heavy hub motor, because there arent any steel standart bicycle frames that can accept taper steerer tube (except special expensive custom frames) and because i didnt want to pay 500 dollars for plain chinese stealth bomber frame clone, which is price here, shipped and taxed or around 900 dollars for qulbix, i decided to build my own steel heavyduty hardtail frame with thick clamping dropouts, generous battery room and 44mm ID headtube, that can accept taper forks. I started with some sketches, this is first versions, final version with multiple modifications was ruined within the frame building. Geometry was stolen from previous bike and modificated.




I also bought new, stronger and better motor, MXUS V3 4T laced in 18x1,6" moped rim and 90/90 tire.



Then i bought some square steel tubes 40x40x2mm for main triangle, 40x20x2mm for the tail, L-shaped 20x20x3mm steel for battery and saddle mounts, piece of 16x40mm steel for dropouts, straight cromoly 44mm ID headtube and 73mm cromoly BSA bottom bracket housing. First i cut tubes, battery and saddle mounts and milled dropouts.




Next i had to call my colleague with mag welder to get all together. It was real guerilla welding, so the geometry may not be excellent, but it looks nukeproof and that was goal.





Some painting....




Almost done...




That is all for now, thanks for reading and sorry for my bad english.

I applaud your initiative to make your own bike. Best of luck getting it just the way you like it.

Well done, and thanks for posting this!

I have a Suntour NCX suspension seat post that I like very much. It's not as sophisticated or as capable as a true rear suspension, but...its light and cheap, and it works well enough to make it worth the price...

Thank you very much for your support guys.
Suspension seatpost would be great, but because of long (200mm) headtube and geometry top of the saddle must be max 5-10cm above upper frame tube, so i can touch the ground when stopped at least with my toes. There just isnt space for suspension seatpost. Frame was designed for some diy moped-style comfortable saddle. Today i made seat pan for first experimental saddle.




Unfortunately, my memory is bad and made it with 5mm wider span between mounting holes. Tommorow i will try to make it again, maybe little wider. Then i will glue some foam on it, cut it to the single shapes and coat it with rubber.

This is fantastic.

I'm looking at making my own frame next. Why did you chose square box over tube?

And why did you go 2mm over 1mm say? 2mm is quite thick no?



Sent from my CLT-L09 using Tapatalk

Thanks.

Square tubes are much easier to make alignements, no notching, just cut it to propper angle. Only notching i had to do was around the headtube. Also, i didnt realised it before i saw it done, i definitely love their look. If i had notcher before, maybe i would have made it from round tubes, but now, if i make another frame, it will be from square tubes for sure.

2mm is just for better feel, easier welding and also i cant find cheap tubes with thinner walls. I dont mind weight as i dont plan to pedal on it and just laced mxus in moped rim with tire has near 15kg, so kg here, kg there, doesnt matter. I hope. We will see. :lol:

Yeah look is awesome.

I think you have right dimension box. Doesn't look too small or too big. Really nice.

I was looking at a tube notching pedestal jig for about £70. Although I have loads of steel box so will probably give the first one a go in box. Thanks to your frame looking so bad ass.

Sent from my CLT-L09 using Tapatalk

I am happy that you like it, thank you.

Today i made new saddle pan, with right positioned mounting holes. Its from 10mm aluminium and painted with rattle can. I made it 35mm wider then previous version to make it more comfortable.



I glued one layer of 3cm XPS and 3*1cm of play mat on it. Hope it will be good choice.



Then I cut angles on sides for better ergonomy and coat with rubber using stainless steel rivets.
During process i make some scratches on the paint, it holds really bad. Of course i roughened and degreased the surface well before painting. But it doesnt matter, it will not be seen, i just dont want to have some shiny blank aluminium on all-black bike.




It is just testing version, so i dont mind the folds and other "details". But on the bike, it doesnt look so bad at all.



And look from the bellow on rivets and mounting screws.



Now i have to make battery box (there will be enough room for 3kwh in 18650, controller, cycle satiator and even the power cord) and wait for front wheel, then its just work for about hour to swap old battery, controller and front brake from commuter V1.0 and i can make some test riding.

Awesome.

This has certainly inspired me to kick off my next project.

What colour scheme are you going for?

Sent from my CLT-L09 using Tapatalk

Its nice, that my build inspire others, thank you man. I will follow your build, it looks like interesting chopper. My bike will be probably all black, nothing special, i want to keep it stealth as posibble and colourful bike attracts too much unwanted attention in my opinion.

And little machining today...

Battery box update.





Here are outer dimensions of battery box.



And assumed battery pack dimensions. I will probably use LG MJ1 in 20S12P, which should give 3024wh. Kelly KLS7218S controller and Cyclesatiator will be placed in the box above battery.



All dimensions are divided by 1.5, because area of configurator application was too small.

Front wheel finally arrived, so i move on.



Box sides are made from 6mm white unknown plastic, sprayed black. After full day of painting, soldering and screwing bike is ready to ride.



First impressions werent best, but after several kilometers, i can say, it really match my requirements. Position is more relaxed, like chopper, but i can still stand from the seat very easy, bike is much more stable thanks to bigger wheelbase, but still pretty manoeuvrable, fork doesnt have tendetion to bend to the side when braking with 203mm disc, thanks to lower headtube angle i can ride up crubs almost without knowing it. Just its relative heavy, even just with 1kwh battery and without fenders, light etc. it is maybe 10kgs heavier then previous version. When riding, it isnt problem, but isnt very manipulation-friendly. And i have two "issues". First, the seat is hard and not very good shaped, so in next weeks i will work on better version. And second, placing the moped tire on rim was hell and i did it wrong, so tire bead doesnt sit well and equally in rim and rear tire wobble around 1-2cm axially and radially too and bike bump. Hope i will fix it easily.

Very nice build. That battery pack is huge! Do you have any more photos on the battery build?

Battery box itself is huge, but for now i will ride it with 13s7p, so most of it is empty :lol: I have no photo of inside, i will shoot it.




On top side i have two threaded bushigs (one in front for lights, switch, throttle and regen in future, one in back for motor) and hole for third bushing on back for taillights, when i invent some nice ones. Connectors are XT60 for charging and antispark XT90 using jumper as main switch, because i wasnt be able to found switch, that can hold 72v/50A (assumed power with new battery) and have antispark function for electronic protection. Jumper also serves as a key, but i will probably make some spare ones and take them like EDC in wallet, bag, etc., because im sure, i will lost it over time :lol:

The rear tire finally sits well on the rim. For now i have just near 100km on the new frame and i am very happy with it. But i would need your advice. Top speed with the new MXUS 3k 4t in 18" moto rim, with around 24 inch tire outer diameter, hotoff charger, is around the same as with magicpie in 26" mtb rim with the same battery and controller (13s7p 18650PF/magic external controller 25A continuous and 50A peak), 42-43km/h on flat with no wind, which i expected. But after some discharge (around half of total capacity), even if the battery is cooled down over 8 hours, the top speed rapidly drops under 35km/h on the same routes, where i am sure i have never dropped deeper under 40km/h, with battery almost discharged, with magicpie. Where could be problem? Maybe bulkier MXUS in heavy rim and tire needs higher voltage to run efficient? Or more amps? On ebikes.ca hub simulator i couldnt find magic pie to compare them in graphs... Thanks

Thumbs up on including a pet in the pictures, and nice ambition building your own frame!

I am sending promised pictures of inside of the battery box. Battery pack is tight padded with leftovers of XPS and EPE foam. Controller is on 10mm aluminium plate, because i drilled the box right for the KLS7218 controller and thus need an adapter to fit magic controller in same holes. Wiring and padding is just temporary, i will do it better for the new battery and controller.



XT connectors are mounted to the panel with PCB mounts from hobbyking.



I also figured out the problem with top speed. I had low pressured rear tire to get softest ride that is on hardtail possible, but this rapidly increase consumption, so max range was just 30km on 974wh and the mentioned low speed was because i was just above cutoff. Now, with harder rear tire, the range is 40km, which is around 25wh/km - no peddaling, full throttle nearly all the time. Not great, not terrible. For a bike this heavy :lol:

I like it. Can't wait to see the battery box filled up. :thumb:

Too bad you don't have room to add suspension to that seat. If there was a way to angle that top tube down a little and weld on a seat post or something. That would cut down on the unsprung weight out back for some of the smaller bumps, not to mention add some comfort.

Little update. New fork, 16S4P 50E battery, 60V/45A sinewave KT controller, 3T mxus in 24" bicycle rim with schwalbe pickup tire and rear fender. Top speed tested on flat - 71.5km/h.