Cammo is right on the money.
I had TF big bores on the rear for about 3 years. Great shocks and for $$$$ unbeatable. Never had a problem, never leaked oil etc.....
I have since up graded to KONI Raids (not to confused with Heavy Track) as I have just bought camper trailer and was chasing an increase in damping and longevity. The Raid's certainly have provided that but at nearly $1000 per pair they are a big spend.
Without the camper trailer, the TF would still be on. In fact they sitting on shelf and just might see another stint on the rear ..... One day
