Converting a beach cruiser with front wheel motor.

[Jmauld]

I am working on a similar build using a 3g Newport deluxe cruiser with the 3speed rear hub and coaster brakes. I initially went with a 1000w front hub motor and it was way too heavy. I’m not sure why, but these bikes handle very poorly with that much weight in the front wheel. I’m giving that motor to my mother to use on her three wheeled bike.


There is a TSDZ2 motor that is designed to work with coaster brakes. I installed that motor and love the way it feels now. It fits the laid back cruiser feel of the bike. Offering enough assist to cruise around easily or you can go full assist and move along faster than you should be going on a cruiser. I initially went with a 20AH battery, but also don’t like the bulk and added weight. Plus it could only be mounted on a rear rack. so I’m about to swap that for a 6.0AH battery. I’ll get a spare to take with me on longer trips, but the smaller battery can be integrated much easier. I’m hoping that I can make a small gas tank looking mount for it. The only drawback is that the TSDZ2 option is rather expensive. But it does answer the coaster brake issue very nicely.

Edit: you do want to limit speed. A 1000w motor will destroy that rear coaster brake. I installed a front disc brake on my bike.

 

[ions82]

I'd buy a cheap dual-crown chopper fork with a disc mount and use that with a front hub motor. I have a Nirve Cannibal with a Nexus 3-speed hub with coaster, and I welded a disc tab to the front. Stopping power for this type of bike is VERY important. One mishap would be far more costly than any brake upgrades. Do what it takes to make sure you've got good brakes. I can't imagine riding my chopper with only the rear brake.

https://www.ebay.com/itm/BICYCLE-1-THREADLESS-TRIPLE-TREE-FORK-XXL-long-DISC-TAB-CHOPPER-CRUISER/253121004157?hash=item3aef30027d:m:mugeSre3lbyGZbhR5o1geRg

I found that a front hub motor balances out a bike that already has a lot of weight over the rear wheel. In turns, the extra weight in the front wheel keeps it planted. Just don't hammer the throttle while still in a turn. Do you plan to use the battery from your other bike?

 

[Balmorhea]

I'd buy a cheap dual-crown chopper fork with a disc mount and use that with a front hub motor. I have a Nirve Cannibal with a Nexus 3-speed hub with coaster, and I welded a disc tab to the front. Stopping power for this type of bike is VERY important. One mishap would be far more costly than any brake upgrades. Do what it takes to make sure you've got good brakes. I can't imagine riding my chopper with only the rear brake.

On a chopper, a strong front brake can be just about as dangerous as insufficient brakes.

A triple clamp fork set up low over the tire can use strong front braking. The stretched chopper forks I’ve had can’t use strong front brakes to their potential, though. The front wheel skids from anything more than moderate braking. There isn’t enough forward weight to stick the wheel to the ground during forceful braking. I usually use a drum brake, or a caliper, or no front brake. Most of the braking should be on the wheel where most of the weight is during deceleration. On most choppers, that’s the rear. Thus, many don’t have front brakes at all.

A bike frame that hasn’t been built for a chopper fork can get even squirrelier from front braking, because the long fork tips it back and places the rider’s weight even farther over the rear wheel than normal.

I don’t think any of my own choppers have had forks more than about 25” from axle to lower headset race, but they’ve all been willing to skid the front wheel at inopportune moments when I grabbed too much brake.

 

[ions82]

On a chopper, a strong front brake can be just about as dangerous as insufficient brakes.

A triple clamp fork set up low over the tire can use strong front braking. The stretched chopper forks I’ve had can’t use strong front brakes to their potential, though. The front wheel skids from anything more than moderate braking. There isn’t enough forward weight to stick the wheel to the ground during forceful braking. I usually use a drum brake, or a caliper, or no front brake. Most of the braking should be on the wheel where most of the weight is during deceleration. On most choppers, that’s the rear. Thus, many don’t have front brakes at all.

A bike frame that hasn’t been built for a chopper fork can get even squirrelier from front braking, because the long fork tips it back and places the rider’s weight even farther over the rear wheel than normal.

I don’t think any of my own choppers have had forks more than about 25” from axle to lower headset race, but they’ve all been willing to skid the front wheel at inopportune moments when I grabbed too much brake.

That's why you cut the top of the fork tubes and adjust the triple clamps so it has the same axle-to-crown length as the original fork. I assumed this would've been understood, but it's very good that Balmorhea pointed it out. The frame on my chopper was designed for a long fork, so it works pretty well. It's not obscenely long, and there is still plenty of weight on the front contact patch because of the motor in the front wheel.

My Electra Townie had a light front end (with a motor in the rear), so I mounted the battery to the long head tube. Even with both bikes putting most rider weight over the rear wheel, I can rail turns because of that little bit of extra weight on the front end. It makes a HUGE difference for any bike with this type of design.