Step 1: Modifying The Carrier (or Bag)

Our doggie is 15 lbs, 20 long (when lying down, stretched out), 9" wide, and 14" high. She seems to love her Sherpa (Original, Large, 20"x 11.75" x 11.5") Soft-sided carrier, which we use for general travel. But I noticed she often curls up inside, and uses only about 3/4ths of it, so I decided that we could get away with a slightly smaller carrier for the bike.

The idea here, is to balance two, conflicting desires:

• Get a big enough carrier so that the pup is comfy for long rides. Tip: Many (but not all) small dogs and cats enjoy moderate confinement, as demonstrated by their preferrence to hide under furniture when feeling threatened. They do however, need to have enough room to adjust themselves periodically. The longer they are confined, the more important it is for them to be able to move around.
  
• Keep the carrier as low as possible, and as far back as possible, so as to maintain as much rider visibility as possible. Note: I am 5'6" tall, so my angle of vision is lower than many riders. If your torso is taller than mine (long legs don't count) then your visibility will be better.

The store-bought carrier I bought has worked out very well. See the Materials Needed section on an earlier page of this article, for details.

First, I took off the shoulder strap. Then I pulled out the faux sheep-skin bottom board, and unscrewed and removed the feet from the bottom. The sheep-skin bottom board was re-inserted, at the project's completion. The other parts were discarded.

Next, a segment of a leash was sewn to the inside of the carrier. When finished, this leash restrains the pet during loading and allows you to open the carrier top while you tend to other destination tasks, like removing your helmet. It is not intended to allow the pet to sit up above the carrier while riding.

The leash length was determined by measuring the distance in her neck's height between sitting and lying. I cut the leash off to that length, plus 1" for attachment. Then I sewed the leash segment in place. See photo below.

The only remaining modification necessary for the carrier was to sew nylon strapping to its bottom, so that it could be secured to the home-made mount. See the Step 4: Constructing the Straps section later in this article for details.

Tip: Unless you intend to also use your store-bought carrier separately from the bike, you can cut off the carrier's handle grips. Note however, if you prefer to put your pet into the carrier -- off-bike -- these handles can simplify the installation and removal from the bike. It's a matter of personal preference. I left my handle grips on for a while, but eventually cut them off because it got to be a hassle to snap the handles back together for each ride so they wouldn't flop around in the wind.