3G Bikes Cruiser build plan

I’ve got a 3G bikes Newport Deluxe, aluminum frame with 26x3.45” tires, that I’m in the planning stages of converting to an e-bike. My goal is to ride this around the beach as much as possible. 20mph speed limit, but I’d like to get there reasonably quick, with a range of 25-35 miles.

The first challenge that I have is that this bike just has a a rear coaster brake. I’ve ordered parts that will hopefully allow me to put a disc brake on the front. Once that is sorted out, I’ll order the motor and batteries. I’m hoping to get a motor/controller combo that will do regen braking and allows the option of setting up a rear disc brake.

So far I’m looking at the following parts list and would like your feedback on this list if you don’t mind. I’ve got a bunch of questions below. These are really questions that I need to research answers for. I’m mainly looking to see if you guys spot any obvious mistakes or headaches that I’m about to get into.

Q128H-135, 48v 800w motor
The bike is aluminum and has a 128mm bolt-in rear. I understand that I could stretch the frame or this motor can be reconfigured for a 120mm freewheel setup, where I could use spacers to place it properly in the frame. A freewheel allows for a single speed or a multiple speeds? I would try to build a disc brake setup with this motor, if I can fit a brake caliper to the frame. The bike isn’t setup for a derailleur and shifter so I would leave it as a single speed at first. I suspect that I will want to upgrade later though.

S12SN 1000w, 40A controller
This controller used with the above motor should allow me to reach my speed/power goals, and also allow me room to grow if I want to add power later. Also, I believe it supports regen braking in case I need to rely on that as a rear brake (I’d prefer a disc brake for safety reasons). Does the regen act as just an on/off function, or can it be linear with brake lever setup? Will the controller allow me to set a speed limit, instead of a power limit? (I don’t believe the seating position on this bike is conducive for high speeds)

48V10AH/14AH CASE-08 BOTTLE BATTERY PACK
This has an optional “inner controller”. From what I’ve seen, I don’t think this controller will allow me to reach my goals, so I will not select that option. I need to take measurements to see if this will fit in the frame.

S-LCD8 screen

Thumb throttle
I’m used to riding ATVs and think I would prefer this over a twist throttle. Although it could get in the way if I switch to rear gears in the future.

PAS
I will plan on adding this as a future revision.



I also need to figure out how to install the motor in the wide 26” wheel. I guess step one is measuring to figure out how long the spokes need to be. It’s probably easier to just take it to a bike shop, but I’d like to learn this process anyway. It seems like a useful skill and my son is really getting into biking.

Well, that’s all for now. I’ll post pics of the bike once I put it back together. It’s in parts right now while I was taking measurements and trying to figure out a reasonable path forward with this project.

Step 1) The Q-128 is geared and, AFAIK, can't be adapted for regen. Look at ebikesca for a geared rear hub with it. Also, you might consider a new front fork with brake mounts and a front hub motor or a different frame which already has the features you need.

Thanks, I’ll spend more time looking at motors. I may just drop the regen requirement. There are several mounting points on the rear triangle where I could make a bracket for a rear caliper

And you might be right about finding another frame. This bike has a lot of odd features, that make it a great cruiser, but really difficult to modify. The front head tube is 9” long and 1-1/8”. The front wheel is offset about 2” forward. I gave up looking for a fork that would meet those specs fit the 3.5” tire and still look appropriate on the bike.

Check bike island; $80 for a fat steel fork with uncut steerer and disc brake mount.

That steerer is only 235mm. I need at least 265mm, to give the stem enough tube to clamp.

I did place a mtb suspension fork in the bike and it doesn’t look too out of place. But the longest uncut stem that I can find is 255mm. Which I might be able to work with that.

This one might work. It will add some rake to the bike though.
https://www.ebay.com/itm/Kona-P2-29er-Disc-Brake-Steel-MTN-Fork-1-1-8-Steerer-465mm-Axle-to-Crown-NEW/264461816593?hash=item3d93271311:g:0CgAAOSwGhxboriu

Just more notes. I used my mtb wheel to check if a 135mm hub would fit in my 127mm dropouts. It went in with no problem. Even though my bike frame is aluminum, my stock fork is steel. I might try having a welder attach a brake caliper mount on this fork.

Now that I know the 135mm hub will fit, I’m considering this kit, since it looks like it will do regen braking. https://www.leafbike.com/products/diy-bike-conversion-kit/26-inch-48v-52v-1000w-rear-wheel-electric-hub-motor-kit-1067.html

if you have to, you can add steerer length by welding steerer tube from another fork to the one you have. just make sure the weld is between the headset bearing points. you can insert another tube inside the steerer before welding to provide extra strength.

or if you find a fork with a pressed-in steerer, you can press out the short one and press in a new longer one.

Jmauld said:

Just more notes. I used my mtb wheel to check if a 135mm hub would fit in my 127mm dropouts. It went in with no problem. Even though my bike frame is aluminum, my stock fork is steel. I might try having a welder attach a brake caliper mount on this fork.

Now that I know the 135mm hub will fit, I’m considering this kit, since it looks like it will do regen braking. https://www.leafbike.com/products/diy-bike-conversion-kit/26-inch-48v-52v-1000w-rear-wheel-electric-hub-motor-kit-1067.html

Click to expand...

About $450 with shipping. Put 48v, 1000w into the ebay browser and get a similar system for about half, or try ebikeling for about the same price as ebay. I've had good success with ebikeling and accesseries (or something like this) on ebay.

The ebikeling kits all say no regen braking.

I just ordered this AW kit from Amazon:
https://smile.amazon.com/gp/product/B00YBWA5VC/ref=ppx_yo_dt_b_asin_title_o00_s01

I’ll limit the power to around 60%, because I’m not comfortable with 1000w through the front fork.

Now off to find a battery that will fit in my frame.

Decided on a 48v, 20Ah li-ion soft case pack. A bit pricey, but I figure I won’t normally run out of capacity with that, and if I limit discharge rate, the pack should last a while. I’ll mount it on a rear rack at first, but I would like to make a holder that looks a little more cruiser-like, and that will protect it from an impact.

The kit arrived and I have it installed, temporarily at least.

View attachment 1



I can’t test this until my battery arrives, hopefully on Saturday.

Once I do a few rides and decide if I want to keep FWD, I will put the motor into my original wheel which is wide enough for a 3.45” tire. The bike looks odd with that little 1.5” tire on the front. I did test fit a brake disc, which mounts against the hub motor just fine, but there is very little room between the disc and the motor. I question whether or not there is room for a brake caliper. I haven’t looked yet, but someone probably makes a spacer that will move the rotor away enough to provide clearance for the brake caliper.

The controller is a KT controller and after web searching a bit, it looks like it might have regen/EABS functionality. I don’t have the two grey wires that people have always mentioned as being associated with EABS, so we will see after I power it up and try to access the setup parameters.
View attachment 2

I really didn't like the front hub motor and the "scooter" feel that the setup above provided, at least for this bike. 1000w was simply too much for a cruiser and there was too much weight on the front wheel. It would do 28-30mph without me pedaling. It really didn't feel stable and the braking system on the cruiser simply can't keep up with that much speed/power.

With that out of the way, I pulled the front hub and got a TSDZ2 mid-motor setup instead. I don't know why I didn't go this route initially. This is much more natural and fitting for a cruiser style bike. also swapped the front fork for a suspension fork that my son had left over from a mtb that he upgraded. It's all black so it doesn't look too out of place. It makes adding a front brake easy, and I'll take that over the slightly out of place look of a mtb fork on a cruiser.

I'll get some pictures once I'm happy with wire routing, and battery mounting.