As you can see, the total suspension travel range has not changed. Only the static ride height position within that range has changed. Now, the suspension has 7” of up travel and only 1” of down travel! Not an ideal use of your available wheel travel range to say the least. Yes, that 3” increase in static ride height will give you that extra ground clearance, but your suspension is no longer sitting in its travel correctly.
One common side effects of an IFS suspension that sits too high and is sprung too stiffly is “topping out”. A simple speed bump can cause this. You drive into the speed bump and after the initial compression, the suspension rebounds and extends, sharply hitting the top of its travel range and causing a harsh knocking sound. This is because it only has 1” of available down travel before it maxes out – not much travel to work with. This can damage your suspension components over time and makes for an uncomfortable ride. This also translates into reduced traction and performance when trying to carry momentum up hill climbs. As the suspension compresses and extends, it will be bouncing off of the top of its travel range and the tires will begin to hop rather than staying in contact with the trail surface.
Now, I will say that this is a simplification of a more complicated issue and there are other factors that come into play. And I am not saying “Don’t lift your IFS” or “all IFS lifts are bad”. They still give great clearance benefits. I just don’t recommend going any higher than 2.5”. As far as real world down travel numbers go, I am sitting 2.5″ higher than stock ride height with Tundra Bilstein 5100’s and SPC Upper control arms. This setup gives me 2 1/8″ of down travel which is enough. However, I wouldn’t want any less than that.
So, how does all of this relate back to how IFS suspension lifts do not truly increase tire clearance? The location and height of your bump stops is what determines the max compression of your suspension, and this, of course, is where you will experience the greatest amount of tire rub. When you lift your IFS by 3”, you are not moving the location of your bump stops by 3”. They stay where they are. Therefore, at full compression, your tires will be in the exact same place as a stock suspension setup at full compression. No tire clearance is gained. The goal of the firewall tub is to create enough space in the wheel wells that the tires will not rub at full compression. Now, you may see how suspension lift height is completely irrelevant when truly clearing bigger tires for functional offroad use!
A Side Note: If you bought your 35’s to flex on curbs at the mall, you probably never will fully compress your suspension. In this case, a tall, stiff suspension lift will keep the tires higher in the travel range and reduce the frequency of tire rubbing. However, if this sounds like you, this article probably isn’t for you anyways…
