The bike was cut behind the bottom bracket, and a grinder was used to clean up the cuts before welding the extension piece.
Step #3: Extend the rear triangle
A scrap piece of rectangular steel 10.5" long was used to extend the rear triangle.
Step #6: What force gas shocks to use?
The gas shocks used on this bike each have a force of 90lbs. The rider weighs 120lbs, which is 66% of the total force of the shocks. This works well for riding slowly, but riding faster over small bumps and cracks in the road makes the bike slowly compress. Locking shocks or higher force shocks may help in this regard.
Step #8: Putting the bike back together: chain
The shifters were not reinstalled, making the bike single speed. The rear derailleur was used as a chain tensioner and a small piece of wire was used to lock it in position. Two new chains were combined to make a single large chain.
Step #9: Putting the bike back together: brakes
New 78" brake cables were used; the back cable used the existing cable standoffs and zip ties to hold it in place. The front brake cable used a single zip tie to hold it in place.
Step #10: Finishing touches
The bike was stripped and repainted; a BMX bike peg was added to the left side as a step for getting on the bike.