Perch collar level / lift for Sasquatch from RPG

[Silent Panda]

A few things to be warry of with a spring seat spacer kit for those with Bilstein dampers:

1 - With the stock Bilstein dampers, there is ~1.9" of FA damper travel and and ~3" of rear damper travel from curb height before ESCV engagement in the rebound direction. On the front damper, you will be in ESCV 100% of the time with this lift. Rebound ESCV damping is ~5x the damping in the normal ride zone...this will create some interesting body control situations.

2 - The longevity of the shock will be at risk because of this constant ESCV engagement. The damper is not tested for 100% ESCV engagement, the design intent is 10% (if I remember correctly).

3 - The stock spring is traveling 2" more than designed. It may be going into bind at full travel...at a minimum, it would be harder to achieve full articulation due to the increased spring rate at full compression.

As one of the guys responsible for the birth of the ESCV tech, I would never recommend a spring seat lift for these dampers.

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[rsmtracker]

I have to ask how is this solution different from a 5100 IFS coilover/strut with the adjustable snap rings that let's you move the spring collar and adjust your height typically from 0.75" to 2.8" ?

 

[Silent Panda]

I have to ask how is this solution different from a 5100 IFS coilover/strut with the adjustable snap rings that let's you move the spring collar and adjust your height typically from 0.75" to 2.8" ?

The 5100's do not have ESCV and the coil that comes in the kit is made to those lift positions so that it doesn't go solid.

 

[77Highboy]

Lots of good info here, great discussion....here's my take and my current thinking:

1) Best lift solution really a function of a) suspension being modified and b) use case, ie mild off road / easy trails on one end vs extreme rock crawling on the other end of the range of uses, the latter really requiring suspension purpose - designed to the use case.

2) In my case (some day), my order is a 2 dr Sas BL 2.7L. Use case is mild off road (hardly ever), mostly looks, and may run 37s....BTW - I get the many views on whether 37s are overkill on the 2 door or not, but that's for another thread.

3) For this "lite duty off road" use case, it sounds to me like either a spacer or perch collar would be fine...noting that most spacer lifts say "non-Sas", although there are a few mild ones out there (1") that seem to say they are OK with Sas.

4) I am leaning toward the perch collar based on what I am learning (thanks to this thread) of the engineering behind perch vs spacer. To me, perch collar seems more like the way adjustable coil-overs are designed. Also as RPG notes, this is how most Raptors accomplish lift, or at least was the case up until 2019 or so as I seem to recall.

5) As for some of the negatives on perch collars, I think the real issue really comes down again to #1 above - assuming a) the suspension, Sas BL Billstiens in this case, has appropriate range to tolerate a preload yielding a 2" lift, and b) mild use case, seems like they would be fine.

6) Based on feedback direct from RPG, they say they would never recommend spacer lifts, (as I understand) due to the potential for resulting down-travel to exceed CV bind point. From this, I assume the trade off is slightly stiffer ride from more preload from the perch collar, vs potential for CV damage from extended down travel from spacer lift, in the event of encountering such condition as to cause it.

Conclusion: perch vs spacer maybe doesn't matter in the "lite" use case, and in fact (countering my going - in position) could be that spacer lifts would have basically zero impact to ride quality vs perch collar where more pre-load = lift at the expense of ride quality....although perhaps (or probably?) negligible.

In other words, one vs the other "all depends, YMMV".

All this then raises the question of "if you want to lift, and go to 37s, then why Sas vs aftermarket?" Which also raises questions about 2.3 vs 2.7, whether 4.7 gears are all that important, even with 37s, in the "lite / hardly ever off road" use case, etc, etc....(head exploding, already covered on other threads....)

 

[Rkgzx9leftcoast]

@evilletruck
For @Rkgzx9leftcoast

Thanks ... yeah...couldnt remember

 

[Rkgzx9leftcoast]

I wonder why they don’t do a split collar like the Raptors?

I Believe its the Fox design on Raptors VS the Bilstien design on Broncos. The Bilstien has a large C clip around the outside to the shock body in a cut groove that he stock bottom spring perch sits on, the RPG perch collar slips down over that C clip and then the lower spring seat sits on that raised by the amount them machined it at.

 

[71to21-2DR]

I Believe its the Fox design on Raptors VS the Bilstien design on Broncos. The Bilstien has a large C clip around the outside to the shock body in a cut groove that he stock bottom spring perch sits on, the RPG perch collar slips down over that C clip and then the lower spring seat sits on that raised by the amount them machined it at.

Oh… makes
Sense. I think Im going with Zones 3” UCA/puck lift. Seems easier. Then later swap out for coil overs, and your covered. Do the front first… then save up for the rear, so on. 1400 bucks for 2!

 

[rcman989]

6) Based on feedback direct from RPG, they say they would never recommend spacer lifts, (as I understand) due to the potential for resulting down-travel to exceed CV bind point. From this, I assume the trade off is slightly stiffer ride from more preload from the perch collar, vs potential for CV damage from extended down travel from spacer lift, in the event of encountering such condition as to cause it.

With this reasoning they must not sell extended travel coilovers from like Fox or King then since all of these increase droop travel like a strut top spacer does…

 

[rsmtracker]

The 5100's do not have ESCV and the coil that comes in the kit is made to those lift positions so that it doesn't go solid.

Sure the factory Bilstein ESCV's are are step up from the more regular 5100's, but that wasn't the point. The point is 5100 do use whatever factory coils the vehicle comes equipped with and the only changes to attain more lift are the seat positions you choose adding more coil preload every time you choose the position above stock height which is how you can go from 0 to 2.8" depending on application. Look at the size of the RPG collar, your stock coil won't go solid. I have no idea where you guys are getting that idea from. The RPG collar will lift you 2 1/4" is not adding 4" preload or anything crazy. Only thing i'll be concerned with is how much droop you have left in your factory strut/coilover after the collar is installed.

You'll need to know the max extended lenght in your factory coilover assembly. Based on the measurement you can measure the lenght of the assembly at ride height.

You don't want to have the same length at ride height as you have when the CO is out of the vehicle because that will mean you have zero droop left in your CO's. Typically you want a min of 1/2"difference, at least with the Toyota application. Look at the above graph you want to have some droop left in your CO shock shaft, if it's maxed like below you have too much preload and your shock won't be able to extend past its max at full droop and you'll feel that as a harsh event cause the shock can't dampen on rebound anymore.

Doubt RPG didn't design that collar with this in mind considering they do stuff for the Raptor which has a more advanced suspension system.

Top spacers do function completely different, they relocate your entire assembly down acting like a much longer CO/strut which leads to overextension of your CV axels and tierods, poor angles for your UCA's which sometimes can result in your coil springs hitting the arms, UCA BJ's binding, CV boots getting ripped, CV axel failures, tierods failures etc etc etc. That's why most aftermarket offer UCA's with BJ's with a broader range of motion and also offer an offset in the BJ to account for the caster lost after lift asides from also been stronger arms with better bushings etc. A small top spacer (1/2") is fine for the most part, maybe 1". Remember you also have a leverage ratio built in your control arms that multiplies the travel in your wheels, that's why spacers for IFS are not 1:1, meaning a 1" spacer won't lift you 1", it would lift you typically 1.5-1.6" So a 2" spacer at the top is acting as a 3" longer CO for example. How much can you droop an IFS before things start binding is dependant on the application.

Most Extended travel CO's are 1" longer than stock, some can be 1.5 or maybe even 2", it depends on the application lower control arms, tierods, cv axels etc etc. You cannot play with IFS travel like you can with a live axel. Top spacers at the back of the Bronco will be more forgiven since you don't have IFS in the rear. The collars for the front that add preload to the coil will be better fit than a top spacer, assuming the lift provided is still within the limits of your front CO travel.

My .002 cents.

 

[internationlriders]

Does anyone know the exact measurement (height) of these spring perches? I'm mostly wondering exactly how much less measured travel there is with them installed. It would be cool if you could order a 1" spring perch for the front and 1" spacer for the rear, that should fit 37s fine since it's only 1" extra tire diameter anyways.

 

[77Highboy]

Does anyone know the exact measurement (height) of these spring perches? I'm mostly wondering exactly how much less measured travel there is with them installed. It would be cool if you could order a 1" spring perch for the front and 1" spacer for the rear, that should fit 37s fine since it's only 1" extra tire diameter anyways.

Great info here. From everything I have read, I'm leaning toward the RPG Collars, or the Zone 3 Sasquatch lift. Pretty sure I read somewhere that the Zone 3" kit includes both perch collars and top spacers, plus the UCA. Seems like the best way to go, if true, splits the work between collar and spacer. But so far I'll be danged if I can find or confirm whether the Zone lift works this way, or if its also just spacer alone. Anyway, these seem like reasonable approaches to run 37s without a full CO lift upgrade.

 

[BigMeatsBronco]

This is a terrible idea. Your shock will run toward the top of it's stroke all the time, have minimal down travel and hammer the topout bumper on every minor road dip.

You are absolutely correct...it will have less that 1” of droop with this setup, totally dumb.

 

[BigMeatsBronco]

Yes, on a budget you pick your poison. Give up travel or risk binding. I can't say I've been a part of race teams, but I have some hands on practical 4x4 suspension knowledge. I've done a radius arm SAS, a 4 link SAS, a torsion bar to coil over IFS conversion. All custom designed and fabricated because of no aftermarket support.




Like I was saying, I used arbitrary fictious numbers for simplification. It's closer to a 2:1 ratio on the Bronco.

2:1 is accurate

 

[BigMeatsBronco]

Great info here. From everything I have read, I'm leaning toward the RPG Collars, or the Zone 3 Sasquatch lift. Pretty sure I read somewhere that the Zone 3" kit includes both perch collars and top spacers, plus the UCA. Seems like the best way to go, if true, splits the work between collar and spacer. But so far I'll be danged if I can find or confirm whether the Zone lift works this way, or if its also just spacer alone. Anyway, these seem like reasonable approaches to run 37s without a full CO lift upgrade.

Simple fix for all of this is to drop the diff (and narrow it too) this will alleviate the issue of CV bind at a new lower droop...therefore enables the use of the full suspension travel with just a spacer...simply and easy folks.

 

[Big Diamond]

Bumping this tho ask how the people that have this installed like the perch collar so far.

How is the ride quality? How has it been off-road?

I purchased a Sasquatch suspension for my Non sad Black Diamond and it has the perch collars installed already. Trying to decide On weather to keep the collars on or not.

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