My post from Dumb Question thread:
Lemme try this. It may take a few renditions...
View attachment 13414
The shock sets the travel window for the suspension. Your suspension can not move more than the shock's travel. A spacer lift moves the travel window down.
You have the same travel as when it was stock but you've moved that window down to gain the lift. You "up travel/down travel %" is unchanged from stock (assuming you don't have coil bucket contact but that's for later). If you had 4" down travel, you still have 4" of down travel.
When you lift by using heavier rate springs, longer springs or the preload adjustment on the 5100s or Rads or whatever, you are keeping the travel window the same as without the spacer and changing your "up travel/down travel %" within that window.
Let's say (because I don't have a stock X or access to the actual measurements) you have a shock that has a total stroke of 8". At OE ride height you have a 50/50% of up/ down travel. 4" up and 4" down.
You add a x" lift top spacer to that shock to lift the vehicle. You have not changed the weight of the vehicle or the spring rate. So you get x" of lift by lowering the entire travel of the shock but you maintain your 50/50 split in up/ down travel.
Now. Let's say you pull that spacer and instead you use the 5100's adjustable spring seat to get x" lift. Now what you've done is gained x" of lift by subtracting x" from your down travel amount and adding it to the up travel amount. You are still operating in the same hypothetical 8" of travel, but you are in a different location in that travel window. (4" + x") up and (4" - x") down. Adding a heavier rate spring to lift or a longer spring will have the same effect as moving the spring seat.
First things first, we're playing with IFS. IFS with short OE control arms will not post impressive travel numbers. You can get usable travel out of them but even in highly modified form they will not do what a SFA does in mostly stock trim. It's the nature of the beast.
Bilstein 5100:
- Affordable good quality front shock
- Valved to provide OE ride with OE spring rate (~430in/lb IIRC)
- Same mounting length as an Extended Radflow (+0.25")
- Not rebuildable so you just order two new ones and dumpster the old ones
In my experience, having had the Fat Bob's Garage coil-over converted 5100s with 600lb/in springs on them, they will not control those spring rates. I even spoke with Greg at PRG and he said that the 5100 isn't designed for that and that it would suffer. Having run them for even the little amount of time I did, I will agree whole heartedly. It hopped and bounced and just wasn't good. I bought a set of Extended Rads with 650lb/in coils ASAP and the ride was 1000x better, even going with a heavier spring rate and still running an OE bumper and no winch or skids.
Stock Width Suspension: You are very limited in what you can do to it and maintain any down travel that won't adversely affect the life of your ball joints, TREs and CVs. According to PRG's suspension post, you have about 2" of down travel over stock that you can gain before you bind the CVs and start causing issues. That requires some form of aftermarket control arm to get that added droop and either longer shocks or a spacer.
My setup is as follows in the front:
- Extended Rads w/ 650lb/in coils
- SPC UCAs and coil buckets ground for full swing clearance
- 0.5" thick (1" lift) spacer on top of the Rads
With this setup, I have roughly 2.75" of lift the way my coil overs are set, carrying a full Shockworks bumper and Warn Zeon winch with synthetic line. I only have about 2 inches of down travel though. It can ride a little rough in the rocks because of this. Am I happy with this setup? Mostly... On the highway it rides GREAT. It carries that heavy load on the front end very well and handles good. We take it on family trips all the time. It's 80% my DD. With this setup, I have enough up travel that my upper ball joints are hitting my inner wheel wells on full compression.
Now, some things I've been thinking about:
THE most common lift for a 2nd Gen Xterra is spacers in the front. It's cheap, quick and gains you clearance. It also operates within the limits of the ball joints, TREs and CVs. I've been wanting to put a 1.5" lift spacer on top of my Rads and then adjust the preload to where I wind up with about the same 2.5-2.75" of total lift.
That would increase my down travel in the front by roughly 1". That's a lot of work (but not much money really) for an increase in down travel of 1" but I'd like to try it. That will put me right up against the maximum amount of down travel that the OE width front suspension is capable of.
And with all that said:
To buy just my front setup as it sits from Nisstec would be $1631.05 before tax or shipping. Add another $180 to that because I put new LCAs on when I did the lift anyways.
A Titan swap using 2.0" body Rads, SPC UCAs, and the extended brake hoses from Nisstec is $1675.60 + shipping and tax. Add in $180 worth of LCAs and a set of the QX56 CVs (can't find part # right now) and that's only about $200-300 more total than my setup and almost double the total travel.
And it's not written anywhere that you HAVE to try to run 35's or really high lift on a Titan Swap. You could easily run ~3" of lift total and 285s on stock wheels and have great wheel travel, the same ground clearance as my setup and for not much more monies. I've actually considered this as my next step. I'm happy on my 285s, I'm happy on my 2-3" lift but that little bit of added front travel would be helpful.