We continue to preach how strut spacers just aren’t going to cut it for any kind of performance gains. When you put a strut spacer on top of the shock tower in order to gain some additional height in order to clear larger tires, you’re directly impacting the factory strut in more than 1 way. The spacer will cause the factory shock tower to be pre-drooped, which eliminates downtravel of the suspension equal to the spacer’s physical height. And the factory struts and shocks aren’t valved to handle a 25-50% increase in unsprung weight due to larger wheels and tires, a significant change.
In the case of this 2020 Ram 1500 4WD with a 3” lift spacer, the physical spacer was about 1.5” thick. The factory struts have a 21” extended length by about 15” collapsed, leaving 6” total travel; 3” up and 3” down from ride height - not a lot. With the spacer addition, it eliminates 1.5” out of that 3” down travel. While not too big of a deal on the street, with little need for droop travel, it will cause problems off-road under any kind of moderately difficult terrain that maximizes shock travel to keep the vehicle stable.
With a change over to a leveling strut that preloads a coil spring to achieve vehicle lift, this doesn’t compromise droop travel. This customer opted for a Bilstein 6112, set to the max lift height of 2.6” of lift, the top circlip. While this resulted in a net loss of about half an inch, the ride quality vastly improved since the shocks can now handle the bigger wheels and tires a lot better, along with restoring the vehicle’s full suspension travel, plus some.