First EBike build

[Xenarius]

Hi All,
My name is Phil.
I'm building my first Electric Bicycle and was hoping to have some input from such intelligent people as i seem to notice lurking these forums.

The Aim.
Build my firs e bike. Why? for fun!

Knowledge.
Worked for 4 years as a motorcycle mechanic so i have a decent idea about building and maintaining electrical circuits and advanced mechanical skills.
Some welding experience but no access to a welder.
Almost no experience with bicycle building or maintenance.

Tools.
Access to a full motorcycle workshop of tools, in the process of ordering some bicycle specific tools.

Parts.
Ok, so before i found this lovely forum and even after finding it Iv'e had a little trouble finding the info i need as to which parts to order since i don't know the names of most of the parts or the suppliers which i should look up.
The following is a list of what i have purchased already and any input would be greatly appreciated.

The Frame:
I found this frame on eBay, looks decent, haven't seen any reviews but the same frame appears to be on a few builds i've seen floating around.
http://www.ebay.com/itm/262779833552?_trksid=p2057872.m2749.l2649&var=561761879474&ssPageName=STRK%3AMEBIDX%3AIT

The Motor:
Seeming to be the simplest build i thought a hub motor would best suit a first build and after reading some reviews i decided on the MXUS 3K Turbo.
https://www.aliexpress.com/item/MXUS-V3-3000W-brushless-no-gear-hub-motor-for-rear-electric-bike-electric-bicycle/32649215681.html?spm=2114.13010608.0.0.5z9rgB

Suspension:
Spent some time trilling eBay for parts that matched the fittings of this frame and came across these front and rear shocks. I considered an air shock for the rear but dont really have much knowledge about them.
http://www.ebay.com/itm/192095147442?_trksid=p2057872.m2749.l2649&var=491990608290&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/162045818512?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Chain drive:
Bought these chain and sprockets however not sure if they are all compatible but seemed to be as far as i can tell.
http://www.ebay.com/itm/361336689258?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/332131644534?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/122367260873?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


That's all i have at the moment and there were some questions i was hoping you guys could shed some light on for me.

Seat:
Suspension or non suspension seat post on a full suspension frame?
Would a small racing seat be better if i plan to pedal regularly?

Wheels:
I want to lace the MXUS into a moto rim but not sure which size would be best. I was thinking 1.6-1.85 wide and 17, 18 or 19 inch diameter but not sure which would be better.
Should i also lace the front wheel with a moto rim or would that be overkill? I am a heavy guy (115 kg)

Brakes:
I want to go with hydraulic disc brakes and have seen some sets labeled as "E-Brakes". Would they be more suitable or should i go for a higher spec disc brake and get cutout sensors for the levers?

Controller/battery/LCD display:
Any suggestions for my setup?

BMS:
When is this necessary? i don't know anything about these =/

I would appreciate any help either by way of reply or pointing me to a resource i don't mind doing some research but right now there's just so many different things I'm trying to learn.

 

[automan25]

SEAT/SADDLE:
I use a Selle SMP Hybrid. This is easily the most comfortable saddle I've ever ridden with, and I've used the Brooks saddles everyone gushes over. I can't imagine you'd need a suspension seat post with a fully suspended bike. I have neither and with that seat I'm perfectly comfortable.
https://www.amazon.com/Selle-SMP-Hybrid-Cycling-Saddle/dp/B003R4JFL6/ref=sr_1_4?s=sporting-goods&ie=UTF8&qid=1489772002&sr=1-4&keywords=selle+smp

BRAKES:
Since you're building a bike from scratch, definitely do hydraulic disc brakes. The additional speeds you'll appreciate it when slowing down from the elevated speeds you'll surly be riding at. Luna carries a set of Shimano hydraulic levers with the sensor already integrated. https://lunacycle.com/sondors-upgrades/shimano-hydraulic-disc-brake-set-for-sondors/ I haven't used them before. My bike already had hydraulic brakes so I went with the sensor retrofit kit, which so far has worked well.

 

[Drunkskunk]

Welcome to the forum.

Judging by your parts selection, it looks like your goal is to build the biggest, fastest ebike you can for as cheap as possible. That's a plan that can work just fine if you accept the trade offs.

That said, I do see 1 big problem, and two minor ones.

Zoom forks = AVOID AT ALL COSTS. They really are that bad. you can buy a zoom fork on alibaba for $5, and there is a reason they are that cheap. They are worse than total crap.

The DNM rear shock is actually fairly good for a cheap shock. And if you're on a budget, you should look at DNM front forks as well. DNM will never compare to a Rockshox or a Marzocchi, but it's surprisingly good for the money.

Forget hydraulic brakes on a budget. While the very high end hydraulic brakes are good, anything less that the absolute best isn't very good. Mechanical Avid BB7 are better than almost every other brake made, better than all other mechanical disk brakes, better than almost all other hydraulic disk brakes. And around $60 for both wheels on ebay.

The "Ebike compatible" part is a switch in the brake that activates a motor cut-off circuit. You don't need it. it's like having the motor kill switch wired to your brake lights on a normal motorcycle. There are some useful things you can do with this switch, however, and you may want to add one later, like Regen braking. but add the switch later, after you get the bike working with the best brakes you can mount.

You picked out a 27 speed drive line. You're buying on the cheap. Those things don't work out well. the 9X gear clusters need high precision and straight running gears to work well. cheap parts will have some wobble. the square taper front sprocket you picked out will wobble some just because it's a square taper. the 9 speed rear gear set will have some wobble and float just because it's a freewheel and not a CST. All that leads to chain wander, and makes getting the derailleurs adjusted nearly impossible.

Plus, you don't need 27 speeds on a super powered ebike. You probably don't need more than 1 speed. You'll understand better after a month of riding.

Since you're on a budget, start with a simple 7 speed. 7 gear cluster in the rear. 1 gear in the front. a nice cheap 7 speed derailleur, and a nice cheap 7 speed chain. a 7 speed can have wander and play. it can be imprecise. it can be made to work on a budget and it will very likely be 6 speeds more than you will ever use.
KMC is a good brand chain.

You need a BMS with any lithium battery for the same reason you need a condom when picking up girls at a bar.
Without it, you may get lucky for a long time, especially if you are careful. but eventually you will end up with something that flares up and burns intensely.

You didn't mention what battery you've been looking at. with that motor, you're going to need a good one.

 

[Xenarius]

Thanks for the replies.
I'm not really on a budget as such ill just buy things in accordance with my cash flow.

RE: automan25
The selle SMP seat looks interesting but i feel like it would rub in places.... An expensive test if i don't like it. And the brooks saddle looks awfully uncomfortable, no padding?

The shimano brakes look reasonable. Is upgrading disc diameter as simple as getting an adapter bracket on most calipers?

RE: Drunkskunk

I bought the zoom fork more as a placeholder, i understand they are cheap forks however i'm keeping an eye out for a set of the DNM USD forks and would like a twin disc front end (maybe its my motorcycle bias?)

I'm not familiar with mechanical brakes, do you have to replace/adjust cables often? Can i fit larger rotors with an adapter or do i buy a caliper to suit the larger rotor? I see there are options for hydraulic and cable cutoff switches so i don't mind either way i'm just more familiar with hydraulic brakes.

The bottom bracket in the frame is a square taper, is this hard to replace? i assume square is at the cheaper end of the spectrum.
I never intended to use all 3 sprockets on the front and they may not fit with the frame anyway, the plan was a 9 speed setup. I can pedal quite hard and was hoping to be able to pedal with the bike up to about 40 km/h (is that possible?)
What is CST?

When selecting a derailleur would i look for a short or long cage? i was thinking short since i was not planning on changing gears up front?

I didn't mention a battery because there are so many and i'm not sure what to go for. I could build one out of 18650 cells but what setup should i use? there's plenty of space inside. Do i buy a controller to suit the battery and motor or do i buy a controller to suit the motor and a battery that fills the gap? i'm totally lost at this point which is why i asked for suggestions. =)

Id like to be able to do 80-100 km on a charge (unreasonable?)

 

[USAEBIKECO]

A front hub motor is a better option in my opinion. It balances out the weight of the bike.

 

[Xenarius]

A valid point, but i don't think its going to be a major issue since myself and the batteries are going to be exerting our weight forward of the bikes center of mass.

Also the rear swing arm is designed to take a heavy hub motor and i believe i lack the expertise to build a robust enough front end for the size of motor i already have.

 

[MadRhino]

Your thread has a lot of details about what you plan to buy and build, but says nothing about the essential info that we need in order to give you the best counseling.

Those infos are: how fast you want it, where you will be riding it, how far you want to go on a charge, how tall and heavy are you.

 

[Xenarius]

Nelson37,
I appreciate the honest response, ill try and do some more reading but just like when i was an apprentice mechanic it takes time to learn things.

Firstly, i get it, zoom forks total cheese. Any recommendations? I'm 180cm and 115kg.

I don't plan on doing a lot of downhill/uphill, i would like to ride some trails but the ones i know are fairly flat and crazy speeds are not a necessity but they are fun
If i do happen to run out of battery i would like to be able to pedal for a distance and i have plenty of room in the dropouts to fit the cassette i bought although not horribly difficult to replace if i find i dont need it.
size? brand?

Ill likely be standing up a lot so maybe something that wont get in the way. I've seen a few cheap saddles on ebay i might just buy a few different styles and see which one suits my ass.

Already got the motor. Any comments on Sabvoton controllers?
For example if the controller is rated at 120 amps and the battery is capable of 100 amps constant am i likely to damage the battery or the controller?
Would it be better to pick the controller based on the battery or the motor?

I know what a BMS is, my question was more along the lines of do i buy a battery with a BMS or if i build a pack from 18650 cells should i also buy a BMS and build it into the pack.
Some controllers can also act as a BMS? Some chargers have integrated BMS?
ill be doing some more reading tonight, any suggestions on material? the search function on this site is a little rough.

I understand the safety issues with Lipo batteries and personally was leaning towards making my own pack, seems simple enough but ill try and cram some more info inside my skull before I bite the bullet.

I appreciate the honest response, ill try and do some more reading but just like when i was an apprentice mechanic it takes time to learn things.

I work for a zero/torrot dealer maybe i could see if they can hook me up with some batteries, they look tasty, maybe i could pinch a few things from this beast.
https://torrot.com/en/muvi

MadRhino,

Somewhere around 30-40km/h is the most i think id need. I plan to ride mostly flat trails with the occasional commute to my local train station (don't have a car to get out to the tracks i want to ride)
Ideally 100km would be great but i could work with 60-80km on a charge. Im 180cm (5"9) and 115kg (250lb) in the winter and about 105kg (230lb) in summer

Anyone have some suggested terms i should brush up on?

 

[MadRhino]

Since you don't need a fast bike and will be riding mostly on the flat, a long range is not much of a problem.

There is not much concern about brake and suspension either. You should not go as low as a Zoom fork, but no need spend a lot on high end suspension that is not required on your terrain.

Since you have the motor already, you will have to match wheel size/voltage for 50 kmh. You don't need heavy rims and tires, but MTB tires wide enough for dirt are a must. Even on the flat, riding a wet trail on skinny tires is PITA.

If you plan to pedal, you need to keep it within pedalable weight and geometry. You will not need many gears. Except for PAS systems, most ebike riders are not using shifters. Almost all of us end up building single speed on fast bikes, at your target speed, 5 spd are more than enough and too many is only a hassle.

Buy a programable controller. You will be able to set power to optimize your ride. A long range can require a big and heavy battery when power is too high, while riding on dirt is not fun at all when power is too low. So you will be happy to be able to program your controller and find the sweet spot. You don't need an expansive controller, for your target speed and flat terrain. A 12X4110 will be more than enough. Power wiring ( battery and phase ), should not be smaller than 10ga silicon wires with robust connectors. This is important for efficiency and reliability. This will also let you upgrade power in the future if you feel the need.

Good luck with your build.