Spacer lift vs. preload collar lift kit explanation

[Old Spice]

I see that Westcott used a preload collar lift (pre-collar lift) on their 4Runner build and thought this was the same as a spacer lift kit. Turns out they're not the same.

A pre-load collar lift adds preload to your existing suspension springs by using a collar, effectively lifting the vehicle with minimal changes to the suspension geometry.

More specifically - like a coilover, it puts more preload on the spring, retains factory travel, still uses factory bump stop (doesn't take all the force on factory shock), and doesn't bottom out prematurely. It also helps redice dive and body roll.

Here's how Westcott explains the difference:

 

[Keroppi]

Helpful. Sounds like precollar lift kit is an intermediate lift option between a cheap spacer lift and a full coilover suspension system then.

 

[coolshade]

Can someone explain to me why they think adding spring preload will add more tire clearance?

Think about taking your car in stock form and sticking 35s on it, and the 35s rub somewhere in the travel.

Adding preload spacers just adds spring preload which raises the car in it's travel at static ride height (more bump travel, less droop). If you then compress the suspension in it's travel by the 2" (or whatever lift you achieved through preload), it would then be exactly the same as stock, and rub in all of the same places. You're not really adding any additional clearance throughout the range of travel. Sure, it adds more clearance at ride height, but as you cycle through the suspension, you'll rub in all the same places.

Top spacers (or longer struts) would actually add tire clearance. Seems like most companies are doing a combination of both on the 6G which makes sense.

 

[spyder40]

Went the route of Fox coilovers tuned by Accutune for my 2021 along with Icon UCA's. Much better router than changing preload or spacers. Got rid of the brake dive and rides like a dream along with more travel. Set the castor to 3 degrees and it drives straight as an arrow and no twitchy. Adding preload will make it harsh riding.