Re: my second build!
In my mind a decent set of V-brakes with high end pads (quality pads make a huge difference with any kind of rim brake) is the minimum level of brake quality I will accept for a motorized bicycle that is heavier and capable of going faster then a pedal only bike. On low powered electric builds where the motor doesn't put out much more then the human pedal power puts out I'll accept less then that but those are the exception not the norm. I prefer disk brakes with high quality free floating mechanical calipers most of all, either 180mm for standard duty or 203mm for heavy duty applications.
On my primary commuter 1.6hp Robin Subaru 35cc 4-stroke powered motorized bike I'm running a front 180mm disk brake with the original caliper with a quality free floating caliper on standby on the shelf in my shop for the moment the cheapo caliper the bike came with starts showing the slightest signs of trouble or when the pads it came with wear out and on the rear a set of generic Shimano V-brakes with the best quality pads that my LBS sells. The only reason I’m even using V-brakes on the rear for it is because the Staton-Inc axle mount kit I’m using with it doesn’t allow for a disk brake to be used with the motor drive sprocket on the left side of the rear wheel and some kind of rim brake is the only kind of rear brake that can be used with that set-up.
On my commuter electric powered motorized bike I'm running 203mm disk brakes front and rear with high quality free floating mechanical calipers. That bike is my highest performance motorized bicycle I have and has enough power to pull the front tire off the ground and burn out the rear tire in a rolling wheely half way out into the intersection if I ram it full throttle from a dead stop when the light turns green. 1,400watts (barely below the 2hp legal limit for my state) on a "Brute" rear hub motor that is wound for high torque instead of high speed on a 48V system with the battery weight mounted low on the rear axle packs a heck of a wallop for low end torque.
For my medium weight long tail electric assist cargo bike I’m running 180mm disk brakes front and rear with the high quality free floating mechanical calipers. Since that bike is using only a 360watt 24V system that drives through the chain right along with me pedaling and doesn’t go much faster or weight much more then it would with pedal power only and just lets me more easily haul groceries and stuff home on a bike the smaller disks work just fine for it.
For my heavy hauler low-boy front flatbed cargo bike that I just built using a hybrid dual power set-up with a mated 1.1hp Robin Subaru 25cc 4-stroke and a 500watt 12V permanent magnet motor/generator unit I have both 203mm disk brakes with the quality calipers and quality V-brakes with high end pads mounted front and rear with double cable pull brake levers on both sides of the handle bars with the brakes adjusted so that the disk brakes grab first and then the V-brakes as well if you squeeze harder. Right side lever runs to the rear disk brake and the front V-brake and the left side lever runs to the front disk brake and the rear V-brake. The reason I rigged them that way is for redundancy so if one brake lever were to break in half or something I could still safely stop. The reason I’m being so careful with that one is because I built it to be able to haul hundreds of pounds of weight on the front flatbed, we are talking a 1/4-ton bicycle pickup truck that can really haul its rated load in cargo if necessary.
I also have another electric assist bike that has a small electric gear motor and battery pack rigged up to it that has a whole lot of torque but at slow speed just to help out with climbing hills and the rest of the time on the flat you can go faster just by pedaling only and the motor is geared down so much that it can’t keep up with your pedaling unless your going up a hill. The whole system weighs less then ten pounds including the batteries and everything and on that bike I only have those brakes that came before V-brakes that work like V-brakes but use a triangle shaped loop of cable hooked to the two side levers being pulled straight up from the middle and not even with the best pads but it falls into the category of a bike with just a hill helper motor and not a real motorized bike. That little motor sure comes in handy on the hills though.
I'm also looking into putting a "commuter booster" friction drive set-up or similar on a drop bar road bike with the narrow tires and if I do so I'm going to want to buy a bike with at the bare minimum quality rim brakes. Also, looking at getting a "bumble bee bolt-on" and putting it on a laid back cruiser or chopper type bike to have as a loner m-bike for when someone else wants to go riding with me and they don't have a motorized bike of their own so I don't have to loan them one of my good bikes and worry about them hurting it. I'll probably end up buying a cruiser bike frame that has mounts for rear V-brakes and then swapping out the stock front fork for an after-market universal triple tree chopper fork with disk brake caliper mount.
Long story short, I’m overkill on brakes for my bikes (and I didn’t even get into the pedal only bikes just the ones with motors). But it is also true that so far I haven’t been in any wrecks because my brakes weren’t good enough either.
P.S. = For those wondering how I ended up with so many m-bikes and e-bikes I did my first build (the one with just the hill climber helper motor) and then I started using it to get me back and forth all the time and hardly driving a full size vehicle at all and took all the money I saved and put it into the next one, and then the next one, and then . . . . You get the idea. WARNING You Can End Up Spending All the Money You Save On More Bikes, And More Motors, And More Improvement Parts, And Riding Gear, etc . . . . And In the End Don't Save Any Money And Possibly Spend Slightly More And End Up With A Shop Full of Bikes !!!
Last edited by turbo1889; 12-09-2012 at 01:23 AM.