Ebike friction drive motor ?

I like that and the price is cool.
24v will only boost you to 12-15 mph. However, it will make a very light kit.
I would wire a push button switch to your handlebar, similar to the Hill Topper kit.
it should not be too difficult to build a mount for the motor.
Check out the gas friction mounts in the "Non-kit DIY" subforum for ideas.
i cannot tell if a controller will be needed. A controller shouldn't cost but $50 or so.

Pretty sure Deacon has done exactly this concept. Either search for his thread, or PM him. Have fun with the build!

I built whole lot of these. The set up is simple you wire 24volts of battery to the motor with a 20amp house type wall switch in the middle. I put min in the positive side so I always know which leg is which, then mount it on the handle bars.

You need to pedal it first to get it started then bring on the motor to help you roll. I always used mine in pulse mode. On and off to take it up to full spend then back down. You also need a kill wire since the switch will eventually give out.

If you get this sudden desire for more speed, get a bigger motor don't over volt that one it will melt the brushes. You have no way to control the max amps going into the motor.

All that said go for it... there is one suggestion I might make. If you are going to mount it on the rear, try to figure a way to lift it off the tire when you are starting out, or on a long coaster stretch of road to cut the drag. Also a spring if you want it to lift, or a turnbuckle for testion.Otherwise it is pretty straight forward. Good luck. Email me anytime.

I agree with the Deacon about the lift clutch. Many gas friction builders use a spring loaded lift clutch. The Thatsdax friction kit allows you to lift the drive roller off the wheel for easy pedaling. The Dax requires you to dismount to lift the roller, but it is done by easily loosening a skewer (like on skewer axles) and it requires no tools to lift.
The bumblebeebolton kit allows the rider to lift the motor without dismounting. Many ways to skin a cat.

Sorry, but I had just one more point about using a controller. A controller with the appropriate LVC (low voltage cutoff) will prevent you from over discharging your batteries. Over discharging your batteries will dramatically reduce your battery life span (especially for low cost SLAs). That is why I would spend the money to add a 24 volt dc controller. I would be hesitant to use a controller that works with multiple voltages (24v, 36v and 48v) unless i knew for sure that I could adjust the LVC to an appropriate level for a 24v battery pack. Its like insurance.
The Deacon has enough experience with DIY e-bikes that he can prevent over discharge without a controller.

The LVC for a 24v controller is in the neighborhood of 22v, if memory serves. The specs on the controller usually say if there is a low voltage cutoff installed, but I rarely see that cutoff voltage listed.
Some controllers are programmable - Just hook them to the USB on your computer.
I have seen LVC switches installed on battery packs. I don't know how much they cost or how to install them.

A 24v controller wont break the bank at around $20, add a throttle control for another $10 and you would have a rather civilized bike. Don't worry about the switched brake handles, I cant see a need for them. The controller will have an LVC, most are on the conservative side taking good care of the batteries. I can appreciate the simplicity of a switch on/switch off system. I believe I would use a good old school knife switch that wouldn't fail as Deacon says the light switch will, you could even make one. I am assuming you are looking at a brushed motor. Heres a example controller, pick one for your motors specs. http://www.ebay.com/sch/i.html?_odk....H0&_nkw=e+bike+24v+speed+controller&_sacat=0

You need a speed controller, don't even think about switching full battery power to the motor directly.

Unless you are the kind of guy that likes to get the car moving by revving the motor to 3 grand and dumping the clutch.

I never had a controller that didn't shut down on low voltage. Yet even without a controller you feel the sag when the batteries get down to 12volts. Battery sag is pretty hard to miss.

a 24v controller is pretty inexpensive, then of course you also need a throttle which isn't expensive either. there are some more things to consider with a controller. for instance watts and what that means.

If you want to take the calculations out of the the calculator and to the real world. Every battery has a limited number of amps. Consider it like a gas tank on your car. The wattage of you controller is like the governor on a old style motor.

It tells your motor how many amps it can have on the top end. Ie a 500 watt controller will deliver more amps at one time than a 250watt controller. However if you run the motor wide open a lot the 500 watt will also have less than half the range. It's all interrelated It kind of a zen thing.

If you want to pedal most of the time go with a relatively small motor and controller. I have run an 800 watt friction drive motor and it runs like a scalded dog and climb like a mountain goat and it tried to kill me so I suggest you use it just as a helper motor and forget trying to replace a harley with a schwinn

I disagree. I did it for years.