5100s have only 3 settings

so im lifting the truck and these 5100s only have 3 settings.. i dont care how many settings they have bit the difference between the bottom and highest setting is barely over an inch... How does this give 2.5 inches of lift?

am i supposed to flip the perch over for the full 2.5? i know that preoading due to a steeper A-arm angle should give it a bit more than an inch but that doesnt seem like it would double the lift given by the new perch hight...

 

Spring preload gives more lift than just the amount you move the coil seat. And there is a leverage ratio to the suspension.... the strut mounts to approx the center of the lower control arm therefor approx double the lift is given to the actual coil seat position

 

coil preload and lift are not in a 1:1 ratio. the settings on the 5100 body are actually "estimates" for the truck's lift height as well, you may get more/less than 2.5" depending on the coil

if you flip the perch over you risk too much preload on the coil, which will ride like crap and wear your suspension

 

On IFS trucks you get double the lift you put in. So since the top setting is a little over an inch from the bottom(stock) setting, the amount of lift will be roughly double that. like Konaborne said... it also depends how worn out your coil spring is. It could be slightly over or slightly under 2.5"