19bonestock88’s commuter bike BUILD: replacing the “Green Line”

[19bonestock88]

Eventually I wanna get a hub motor and see how much help I get with 1500W of electric assist... which might be enough to “level the hill” and cut my commute time... how much battery would I need (at 48 or 52V) to get 5mi found trip?

[jimhs]

Hi,
Buy a used bike.
I bought a slightly used road bike for 190£.
Previous owner paid 500£...

[Stubby79]

You don't necessarily need that kind of power. My hybrid has a 300w geared motor (better for low end torque) and I can tackle big hills. Oh, it wipes me out, but I get up them without stopping, and the motor can take up the slack once I get to the top.

I'd expect a 500w geared motor would likely be able to climb said hills with little work on my part. If you went mid-drive, the steepness/length of the hill wouldn't matter...you could just gear down until the motor could keep up, whatever it's output.

OTOH, if you're going gear-less, yes, you might want a big motor. At ~800w, with small "moped" wheels/tires, my other electric "bike" with its gearless hub can only just get me up the steep hills, losing momentum. I can climb said hills quicker with my geared hub and me pedaling, unless i hit them at full speed and they're not too long.

[19bonestock88]

I want the power available, to be able to run a really big chainring and be able to pedal assist at 30+mph... ideally by adding the motor, I’d like to get my commute time down close to where it is in my car... I’d love a powerful mid drive but the kits are a little pricey, and I’d rather save that for when I eventually build a tadpole trike...

[vskid3]

Originally Posted by 19bonestock88

I agree, but I’m not about to shell out $500+ for a name brand bike... the $100 I paid for mine was enough...

However I do want to upgrade the shifters, and maybe the wheelset...

I would look at how much the upgrades you want/need to do will cost vs buying an entry level bike. If you electrify, there are some parts you may want to upgrade on your current bike that would already be good enough on a better bike. Your brakes will need to stop you from higher speeds with increased weight. I used an entry level mountain bike for my ebike and I still put a few hundred into upgrades (some more necessary than others); I probably would have come out ahead if I'd spent a little more on the bike in the first place.

Originally Posted by 19bonestock88

Eventually I wanna get a hub motor and see how much help I get with 1500W of electric assist... which might be enough to “level the hill” and cut my commute time... how much battery would I need (at 48 or 52V) to get 5mi found trip?

5 miles won't require much capacity, but 1500w will require either decent capacity or cells that can provide a lot of current. You'll likely use 25-30 wh/mile, so 150wh would be just enough, about 3Ah for a 48v battery. However, you'd be drawing 10C at 1500w, which is pretty high for most batteries if you want it to last many cycles (The C rate is how much current you're drawing vs the battery's capacity. Drawing 1A from a 1Ah would be 1C, 5A from the same battery would be 5C.).
A battery like this would be a pretty good fit https://lunacycle.com/52v-samsung-in...ah-high-power/ If you want smaller/cheaper, building a pack out of RC lithium cells would probably be your best option, but also the most likely to catch fire if you don't treat it right.

[19bonestock88]

I plan to upgrade my brake pads soon, as mine are garbage, but the only reason I wanna upgrade the shifters is that I dislike the grip shifters and would rather something else... with my current budget it’ll be a while before I can electrify, so I’m just researching kits and components...

I’m planning to build disc wheel covers at least for the rear wheel, if not both... I don’t know if I should change tire size when it’s time to replace mine (currently running 700x35C)

I also plan on building a recumbent trike at some point(my back is already bad) which I plan to electrify and add a body (similar to the corovelo thread), so im torn on what components to buy, either to pass onto my wife or re-use on the trike...

[Stubby79]

Originally Posted by 19bonestock88

I want the power available, to be able to run a really big chainring and be able to pedal assist at 30+mph... ideally by adding the motor, I’d like to get my commute time down close to where it is in my car... I’d love a powerful mid drive but the kits are a little pricey, and I’d rather save that for when I eventually build a tadpole trike...

Ok, then yes, you'd want ~1500w. Upgraded brakes would be a good idea! Regen might be a good idea too, as it can safely slow you down pretty quick without locking the wheel.

[Grant-53]

Zinn Cycles Standard bicycle fitting This site will help you fit the bike to your body. Seat position and stem length go a long way to ending back pain. I found the right position for me and I use cycling as part of my physical therapy for lower back pain due to muscle imbalance. My current machine is a Roadmaster with a step through frame I bought used for $80. It is much like what you have from what you describe. Upgrade to mountain bike pads and get out the WD-40 and some diet cola to get rid of the rust. Get everything working smoothly and adjusted. Find a seat with coil springs if not already equipped. Plot your gear combinations so you know the best shift sequences. Hill climbing comes hard at first but after ten days you should start getting your wind. Aero mods will help. Disk on the rear wheel only. See the tail cone used on Oscar Egg's Rocket. Check the state laws on motorized bicycles, top speed allowed will be 30 mph or less.

[19bonestock88]

Oddly enough, my bike is also a Roadmaster, just not a step through...

This is my first bike on which I think I’ve got the seat adjusted right, though I don’t know if I have the right crank arms...

I hear that the seat needs to be adjusted so that at the bottom of the pedal stroke your knee is almost straight... with it set like this, I can *just* touch the ground with one foot...

Also not sure about stem(part that connects handle bar to fork?) length, but mine is whatever came stock on the bike, though I’m considering changing the handle bar(either by cutting/welding/bending or buying new) to something more aerodynamic and ergonomic

[MetroMPG]

"at the bottom of the pedal stroke your knee is almost straight... "


I've always gone with... "so your knee has a slight bend in it". Sounds like that's pretty close to what you did.