New disk brakes

[YonderGod]

I bought a new frame, not realizing it didn't have rear V-brake mounts. It's a Trek 3500, yes, it's a low end Trek, but better than my Walmart Mongoose, and I got it for only $30.
My yescom ebike kit came with disk brakes, but they are low quality. I adjusted them to get the pads as close as possible to the disk without touching, and they still have no power. I can easily roll the bike from a stop while holding the brake.
This is the kit I ordered, but the disk rotor and caliper pictured are not the same ones I got.

Is it possible I just need a new brake lever to make these brakes work? If so, I can get one for cheap from the bike kitchen. I doubt they have any decent disk calipers though, so new is my only option there. Any recommendations, for as cheap as possible? I'm only using my bike on the street/paved trails, no downhilling or anything.

 

[Leebolectric]

You are trying to add cable operated disk brakes?
Just add a set of BB5 or BB7 calipers by Avid...others work, but not as well as those.
Those levers will be fine...cables run normally as with v-brakes...no hydro fluid to worry about.
http://www.jensonusa.com/Mountain-Disc-Brakes?s=&c=C0000CMN

160 rotor should be plenty, but bigger gives more modulation...be sure to get one front, one rear...comes with adaptors, calipers, and rotors.

 

[Leebolectric]

Or..you already have calipers...but need better levers?
The Avid SpeedDial7 Levers are the very best I've found for this...awesome leverage and adjustable too.
http://www.jensonusa.com/Mountain-Brake-Levers/Avid-Speed-Dial-7-Levers?cs=Gray

Generally Road brakes use "short pull" cable movement....and MTBs use "long pull"...just look for something "long pull".

 

[Drunkskunk]

Likely the kit's levers are for V brakes. Those use a different pull length, so yeah, a basic Disc lever should work. However, it might just be that the caliper is total cr@p. A decent disk brake setup would be 1/4 the cost of that kit. But you can solve the problem for much less.

As Leebolectric said, the Avid BB5 and BB7 are perfect for this. The BB5 is a great all around brake and often available used, or as a take-off from various bike shops. The BB7 is one of the finest brake calipers of any type made, and usually only a few bucks more than the 5. You can grab a BB7 off Ebay for >$35, like this one: ebay.com/itm/New-Avid-Mechanical-BB7, or bid $1 on this set: ebay.com/itm/CHEAP-ASS-AVID-BB7

 

[YonderGod]

I didn't think of looking on ebay, thanks for the tip.
One of those links is for a front caliper, will those work on the rear? They don't look very different, but if that is the case I don't see why they would make 2 different ones.

Right now Im looking at
Used BB5 - $10
New BB5 with rotor- $25

Front BB7(If it will work) - $35


I'm leaning towards the new BB5, my rotor is a tiny bit bent, so I might as well get one with it, plus no wear on the pads.

 

[Paladin]

Some thing else to check is the amount of brake pad that is actually making contact with the disc.
I see a lot of bikes where the calipers/pad only grab maybe half of the top surface area of the rotor/disc.
In other words the caliper would need to be moved closer in towards the axle.
That make any kind of sense? More pad grabs more rotor.

 

[Chalo]

Likely the kit's levers are for V brakes. Those use a different pull length, so yeah, a basic Disc lever should work. /quote]

Mechanical disc calipers and linear pull brakes (V-brakes) use the same pull ratio, except for those mechanical discs designed for drop bar road bikes.

Every e-brake lever I have ever seen is configured for cantilever or caliper rim brakes. The ones in the eBay listing picture are like that.

BB7 brakes with Avid Speed Dial levers are a superb solution for the OP's problem. But he'd probably get substantial improvement just by installing V-brake type long pull levers on the brakes he's got.

 

[Chalo]

Right now Im looking at
Used BB5 - $10
New BB5 with rotor- $25

BB5 brakes are super lame. They're just a marketing attempt to ride a crappy product along on the coattails of a good one.