To assemble, you just need two wrenches, both 13mm
Decide which inserts to use:
If the seat tube of your bike's frame has a diameter of 36 mm, use two blue plastic inserts.
If the seat tube of your bike's frame has a diameter of 32 mm (many mountain bikes), use only one of the largest, blue plastic insert.
If the seat tube has a diameter of 28 mm (most bikes), use the white insert inside the blue insert.
If the seat tube has a diameter of 25 mm (a few models, particularly ladies' and junior bicycles), use all three inserts (red inside, white in the middle, blue outside).
Assemble clamps over the insert(s):
Let the opening in the insert(s) point straight forward. Place both sides of clamp over the insert(s) and bolt together as shown in illustration. Please see to it that the clamps are fastened high enough.
Assemble spring to S-tube:
There are three 'bumps' on the outer end of the S-tube. They act as a thread guide for the coil spring. Screw the spring about 1 inch down on the S-tube. Leave the eye on top in position as shown in drawing (the end of the spring wire at the eye should point straight in towards the bike.
Attaching the S-tube to the clamp:
Mount the S-tube onto the bolt, and secure it by inserting the locking pin through the hole in the S-tube and the bolt.
Assemble the cord, clip and safety releases:
Thread the outer hole at the wide end of the safety release on the top of the spring. (a little force may be necessary) Thread the cord through the hole in the bottom of the plastic hook and tie a simple knot at the end of it. Pull this knot back into the 'transverse' hole in the base of the hook. Thread the loose end of the cord through hole 1, 2 or 3 of the safety release according to the following guidelines:
Hole 1: All children, or adults weighing less than 110 lbs. (50kg) or small dogs weighing less than 44 lbs. (20kg).
Hole 2: Adults weighing over 110 lbs. (50kg) and dogs weighing more than 44 lbs. (20kg).
Hole 3: Strong, skilled adult cyclists and with large, strong eager-to-pull dogs.
Note: Use hole 2 or 3 only if all requirements for that hole are met. Make a simple knot at the end of the cord so it does not slip out of the safety release. The total length of the cord, plastic hook and safety release should be about 12 - 16 inches or 30 - 40 cm (shortest for large dogs.)
Check from time to time that none of the nuts are loose.
Take a test ride.
If the heel of your shoe hits the horizontal part of the S-tube, loosen the three front nuts so the clamps can be "wiggled" up until the heel of your shoe is clear of the S-tube in all pedal positions.
If the heel of your shoe clears the S-tube by more than 1 inch in all pedal positions, the clamps should be wiggled down.