With some encouragement from Peter_C, I decided to bite the bullet, and upgrade the brakes on my Rover from the stock Zoom brakes to the Avid BB7, which are the most recommended mechanical disc brakes on all the cycling forums and discussion groups. I pull a 75 pound dog trailer and dog combination periodically, and the Zoom brakes, while stopping the trike OK with that weight on a steep hill, seemed to be at the end of their limit as far as smoothness. I found the BB7 mountain
disc brakes on sale at Jenson.com for about $47 a wheel which is a really good price. Naturally, if you haven't ordered your trike yet, having the dealer or Terratrike install the brakes would be the easiest way to do it.
You need the following tools, in addition to the two brake sets ( which include new rotors) , to install the brakes properly:
1. A torque wrench, and I strongly recommend the Park Torque wrench TW-2 3/8 " wrench. It's easy to use, and will last forever, and runs about $48 at Bikeman.com
2. Park SBS-1 Socket and Bit set. ( $26 at Jenson USA) These tools fit the 3/8 drive and will fit every nut and bolt on any trike or bike and should last forever. You have a T-25 torx to install the new rotor on your wheel, and torque it to the proper spec, after you remove the existing rotor with the 3mm allen tool that is included in the set. There is also a 8mm allen for removing the front wheels on your trike, which is really easy, using the Torque wrench.
Now all you have to do, is remove the existing brakes from the trike, by loosening the brake cable clamp, the bolts that mount the disc brake assembly to the bracket, and then loosen the 8 mm allen holding the wheel on and pull the wheel off. The wheel bearings are sealed, so you don't have to worry about ball bearings rolling away when you pull the wheel.
Once the wheel is removed, you use the 3mm tool in your tool kit attached to either a 3/8 drive or to your torque wrench, and remove the old rotor from the wheel. Starting with the right wheel, as you are sitting on the trike, you install the new rotor using the supplied Torx 25 and torque to 6.2 NM or 55 in pounds. These brakes a very well made, and they have even put a thread locker on the bolts, so that once tightened they won't come loose. I would recommend that you tighten the bolts holding the rotor to the hub, slowly and alternate from one side of the rotor to the other, rather than tightening them in a row. On the right wheel, the Avid logo must face out, or away from the spokes
. On the left wheel, you flip the rotor over so that Avid logo is on the spoke side.
Now hear is the tricky part. When you remove the old mount, make sure you save the two washers that are between the mount and the bracket for each brake assembly ( there are 2 for each bolt, or a total of four) . These serve as spacers and should be used in the same place as they where on the original brake,when you put the new brake mount on. The other tricky part is to make sure you use the new correct bracket that is furnished in your brake kit, and it is turned the correct way. You want to use the bracket that says only 160mm on it. Do not use the bracket that says, 160F-140R, which is the wrong bracket.
If you use the wrong bracket, the wheel won't turn after you mount the brake. Now the second thing in mounting the correct bracket to the brake assembly, is to have the bracket pointed in the right direction on each wheel. There is an arrow on the bracket, and that arrow should point towards the rear of the trike, and should be visible when looking at the bracket though the spokes. If you turn the bracket around, and mount the brake with it pointed the wrong way, you won't be able to get the wheel to turn.
These are the only tricks to getting everything installed correctly, and then all you have to do is look at the instructions that come with the brake, torque everything to specs, adjust the brakes and go for a test ride. If you pull the little metal ends off the brake cable, you could either slip them back over the cable and crazy glue them back on, or go to a bike shop and buy a few, so that you can put them on the cable end after you have everything installed.
Peter has some pictures that he did, when he did his, so I imagine he will probably post them on this thread. Again, it was with Peter's help, that I got these brakes and managed to get them installed.
There are also many videos on the internet on setting up BB7 brakes, that you might want to look at. http://www.youtube.com/watch?v=x1kezXQVnLY
If you are not mechanically inclined, you could always bring your trike to a bike shop, and installing disc brakes is an easy project for them.