Help me build a bike!

[Rishabh_verma]

Hi! I'm new to the e-bike world and I'm attempting to build an ebike, I feel like I've done way too much research with everything and confused myself so maybe I could grab some help?


Desired max speed on level ground: max 60kph
Desired max range: 80km at 40kph
I don't have a preferred wheel size, whatever works best.
Planning to put it on a disc brake, will probably start/upgrade to hydraulic.
Rider weight: 170lb
Terrain: mostly flat but I'll have some hills, occasionally I'd like to be able to cruise up something with a 7% grade for 12ish km
Budget: somewhere around $1500 to $2000 CAD, The less the better I don't need unnecessary accessories/features.

I live in B.C. Canada, which is known for its hilly terrain, I could also drive to Grin Technologies, so kits from there would be a decent suggestion.

 

[Deacon Blues]

Grin sells quality stuff, but it's pricey.
With your "max 60kph" comment I wonder if you've ridden at anywhere close to that speed on a bicycle.

 

[Rishabh_verma]

Grin sells quality stuff, but it's pricey.
With your "max 60kph" comment I wonder if you've ridden at anywhere close to that speed on a bicycle.

I haven't. I realized that its a very high speed but to be a bit more specific, I'd ride at 30-40kph most often, and felt that having the ability to go that fast would be good. A max of 50 would do just as well.

 

[legsofbeer]

Desired max speed on level ground: max 60kph

I wouldn't do that speed without wearing motorcycle leathers and a snell rated helmet. Too fucking fast, you can't react quickly enough to situational changes out of your control.

Desired max range: 80km at 40kph

Unrealistic given today's battery tech, unless you want to put two *good* batteries on your bike. I get about 25 miles at 25 mph on a 674 Watthour 48V battery (did this once to measure range). A second one would cost me $550 (US) plus the mounting rack and Y-plug and cable. But... I do get 50 miles on a single charge if I restrict my battery pull to 167 watts (at full charge, less apparent wattage over the 50 miles of discharge to empty).

Planning to put it on a disc brake, will probably start/upgrade to hydraulic.

If you're planning on doing 50kph+ you'd better figure out stopping better than that. Hydraulic brakes and maintain the f*ck out of them.

Budget: somewhere around $1500 to $2000 CAD

Good luck with that.

 

[Rishabh_verma]

Okay yeah I just realized how idealistic this build was. To keep it simple, ill ask a couple questions that would fix up my mind.

For the donor bike, should I bother with a full suspension? I'm not doing anything crazy like jumps. If I don't do full suspension the other option would be a hardtail (obviously).

What would be a good rear wheel direct drive motor? I've been looking at the 9c RH212, are there any other suggestions?

 

[indianajo]

For the donor bike, should I bother with a full suspension? I'm not doing anything crazy like jumps. If I don't do full suspension the other option would be a hardtail (obviously).
What would be a good rear wheel direct drive motor? I've been looking at the 9c RH212, are there any other suggestions?

On rolling hills over 26 to 30 miles, I found a DD 1000 W motor used about 40% more electricity at 8 mph uphill and up to 30 downhill, than a geared 1300 w hub motor. My trip would run the 17.5 ah battery into the cutoff zone on the last couple of hills on the first one. A Mac12 uses about 20% less watthours than the 1300 w ebikeling geared hubmotor. Mac12 gets me there decreasing from 53 to 47 volts. The hills here are mostly modest but there are three at 15% for a hundred feet.
No suspension is okay at 8 mph, but I only go 30 mph downhill on extremely smooth pavement. Many hills I brake to 15. I use 2.1" tires inflated to about 40 psi. Faster on rougher pavement would require a good suspension. Many comments here about how useless cheap suspensions are.
If you want to go 40-60 km/hr I suggest buying a licensed insured motorcycle. Even a 21 ah battery would go maybe 10 mlles at that speed.

 

[tomjasz]

Nice... 44MPH with rim brakes. FFS!

 

[theemartymac]

Hi! I'm new to the e-bike world and I'm attempting to build an ebike, I feel like I've done way too much research with everything and confused myself so maybe I could grab some help?


Desired max speed on level ground: max 60kph
Desired max range: 80km at 40kph
I don't have a preferred wheel size, whatever works best.
Planning to put it on a disc brake, will probably start/upgrade to hydraulic.
Rider weight: 170lb
Terrain: mostly flat but I'll have some hills, occasionally I'd like to be able to cruise up something with a 7% grade for 12ish km
Budget: somewhere around $1500 to $2000 CAD, The less the better I don't need unnecessary accessories/features.

I live in B.C. Canada, which is known for its hilly terrain, I could also drive to Grin Technologies, so kits from there would be a decent suggestion.

As others have suggested, you can have some of those things, or the others, but not all of them.

You could get 80km out of a 40kph bike, but that will take a large dual-battery setup. And that's $1,000-1,200 for batteries alone. To get it out of a big single, you will need to run ultra light, super efficient components, and skinny tires. Ultra light usually means $$$$, and maintenance - especially once you start upping the total weight of the bike with the kit and cargo.

You will want hydraulic discs at those speeds, or very high end mechanical discs. Don't underestimate the power required to stop from higher speeds, and remember that you lose a lot more ground to reaction time at high speeds, so you really do need to be able to make that up once the brakes are applied.

7% is starting to get steep on a bike (In Vancouver or Victoria, 7%-12% is quite common), and to get peak climbing efficiency AND top speed you will most likely need a mid-drive. A light hub can go very fast, but won't climb efficiently. A good climbing hub won't speed efficiently. It is also hard to get a standard cassette and sprocket combo that will allow you to pedal efficiently at 50+kph (Just give up on the 60 number), and still climb like the wind. It's potentially doable with custom a cassette build, but you generally choose a bike that performs very well at one end of the spectrum or the other, or is just a decent generalist in the middle. Not all three.

$2,000 CAD is NOT a lot of money in the Ebike market unless you already have a good quality bike to build on already. The Bafang 750/1000w kits are well over $1,000 CAD with good batteries. The Grin kits are even more.