Originally Posted by VanFan
Please educate me. What's a "knuckle lift" and are there any viable alternatives?
You will be able to find some pix and videos of knuckle lifts via Google, but this is the condensed version.
A knuckle lift is a lift the raises the vehicle by adding height right at the wheel attachment. It is really just a fancy spacer for the wheel mounting. This means essentially all of the vehicle goes up with the exception of the wheel mounting and wheel. The other parts of the suspension in that area would go up on the body end and not go up the wheel end.
Knuckle lifts change the position of the wheel rotation points and road contact point of the tire in relation to the other suspension and steering points and can cause handling issues, some of which may be quite unpleasant. There are several threads on the forum discussing lifts, so if you are glutten for tech detail you could check them out.
IMO, the best way to evaluate how well a knuckle lift works on a particular vehicle is to drive one yourself that has been lifted with that product. Not all knuckle lifts are designed the same so results can vary a whole lot between manufacturers, who often are serious off road folks and tailor the products to that crowd. This can make them not a good fit for a camper vans sometimes. Reviews on lifts can help, but tend to be biased heavily toward liking them compared to what many of us would accept in negatives, so beware careful with reviews.
There are really very few options if you want to get 4" of lift in most vehicles, and no others if you want all the vehicle to go up except the wheels that I know of.
I think the best way for a normal lift is to perform major surgery and space all the suspension and steering parts down from the rest of the vehicle. This means moving all the suspension attachments as well as the steering linkage and steering box, and is a huge job to do. I think I have only seen one vehicle ever done this way.
You can usually get lower amounts of lift by using taller springs but you quickly run out of travel of the stock suspension. 2" max would probably be typical for many vehicles. You can get an idea of how high you could go by measuring the suspension downtravel from the stock location.