2.5 triple bypass vs remote resi rear shocks

Hey guys,

I am debating whether or not I should go bypass or remote resi with compression adjust for my rear suspension upgrade. Input appreciated from the group!

I have a 2018 CM. Currently, I have fat bob's coilovers on the front and 1.5" blocks and airbags in the rear. I am running 295/70/18 tires on stock SR5 wheels with spidertrax spacers. Front sway bar is removed and I trimmed a little plastic to eliminate rub. I plan on a BMC in the future to reliably clear the 35's with fresh tread, but I also dream of some 37's some day...I tow a 5500 pound travel trailer (equipped with WDH) fairly regularly with 6 people in the truck (I have 4 kids plus the wife with me). I also like to hit the trails and fire roads and go fast when I'm doing it. If I felt comfortable with the suspension, I wouldn't hesitate to jump this truck (a little).

I will eventually upgrade the front suspension, but the rear is first. My plan is to install Deaver U748's (or possibly some other custom, progressive pack from Deaver or Alcan), remove the airbags or install daystar cradles, and install Deaver spec'd ADS 2.5 shocks. The real question at hand is would I be better served by the 2.5 RR with clickers or the trip bypass?

I like the idea of the bypass rears and everyone who installs them loves em, but it also seems like adjusting the shocks for towing/non off-roading use might be easier with the clickers. I am willing to sacrifice towing/on road performance for higher off road performance. I also spoke with Matt at MCM who was great, I plan to buy from him once I decide what I want.

Sorry for the long winded intro, but I wanted to provide some background on use case. I probably sound like every other person looking for the "perfect" blend of on road/off road capability. I know that doesnt really exist, just trying to buy once cry once on this and have a truck that can do what I need.

 

Bumping to see if anyone has input. Thought this would have gotten more traction….

 

Remote reservoir shocks don’t do anything other than let you run the longer before the fluid gets super hot which eventually will lock a shock. If you get the clickers you get your base valving plus you can stiffen them up.

Bypass shocks are the ish. It turns a standard shock that dampens based on shock shaft speed into one that dampens based in shock shaft speed AND shaft position. Which means it can ride like a caddy at your standard ride height and then stiffen up as soon as you’re out of that zone.

Neither of these will help you when towing. Shocks just control dampening they don’t support any load. At 5500 pounds you will still want the air bags with u748. They will sag like a mofo while towing if you don’t.

hope that helps.

 

contrary to popular belief, R/R shocks are designed to free up real-estate within the primary shock body by relocating the oil/nitrogen floating piston and nitrogen charge. This allows for more space for the main piston increasing a shocks stroke length in the same length shock body as say an internal floating piston (IFP) shock. This does not apply to emulsion shocks. The oil volume in the R/R is so small that in a non-adjustable setup, there little heat dissipation benefit. However, a r/r with adjustable damping will have a just a slight heat dissipation advantage as there is valving present in the R/R, where there is a restriction in flow, heat is generated…the work of the shock is shared between both the main piston in the primary body and the adjustable valving in the R/R.

keep in mind most non-bypass reservoir mounted adjustment knobs are usually dialing in compression only. Some like Fox have dual compression adjustments, high speed for fast piston motion (bumps at speed) and slow speed for slow piston motion (turning, acceleration, deceleration etc) whereas King has single adjustment been called ”mid-speed” based on out of box the behavior.

Compression adjustments is great when conditions of operation or the vehicle itself change, but the set compression damping curve is applied throughout the entire shock stroke length.
Too slow of compression and the suspension won’t effectively move without raising the vehicle’s height in relation to the terrain.
Too fast of compression and you’ll blow through the travel and send the unsprung weight (everything not supported by the suspension driveline,wheels, control arms etc) crashing into the sprung weight (everything supported by the suspension, frames, body, bumpstops (super important btw))

What about rebound? Rebound is equally important to insure a composed ride. Without proper rebound damping a few things can happen.

Rebound too fast: super lively, springy, “bucky” feeling because well nothing is there to control the oscillations produced by the spring assembly.
Rebound too slow: wheels aren’t able to drop into terrain at “speed”, “pulling” down the vehicle’s body towards the terrain. Or being packed into the travel, where repeated hits occur and the shock will not allow the suspension return to ride height fast enough, thus each subsequent hit will settle lower and lower into the vehicle’s suspension travel.

Keep in mind that that since you’re planning on towing, there will be a big potential of energy being transferred to and from the trailer to the tongue to the frame of your vehicle that is supported by said suspension and the oscillations are controlled by your shocks. Because of the outside force, even if you valve rebound for 748s which can store a lot of energy when compressed, you may have the potential to overcome the shocks ability to dissipate the energy of both, the vehicles forces as well as the forces introduced by the TT…

Add combinations of the situations described above and you have the potential for a very unpredictable ride…

Now that the gibberish is out of the way.

Be realistic in your expectations. Design for 90% of your use case and be prepared to make some compromises…

big trucks that tow heavy tend have limited suspension travel, high spring rates and aggressive shock damping usually tailored around what might be close to anticipated “max” payload or more.

Other items

Wheeling the rig where droop is important to you, it is imperative that you look into either an icon RXT, TC or Camburg Shock Relocation kit (with a proper length shock), bedcage and longer rear brake lines as the increased droop capability of the 748,k37,rxt, etc or hell even stock leaf pack with block or shackles is severely hampered by the maximum extension of a 10” length shock…unchecked over a “jump” that you stated…you run the risk of topping out the shock and severely damaging the vehicle…

other items not covered…but relative
Proper bump positioning
Damping curves
Shock body size 2-3.5”+ and shock fade resistance
Leaf spring longevity
NVH complaints of tappets

TL/DR: having compression and rebound adjustments are great and highly desirable when forces vary, but get the balance correct or you’re gonna have a bad time…having zones is nice if you can maintain your position within the primary “ride” zones, with the added weight compression of the suspension is unavoidable placing your shock piston further into the “ride” zone potentially right next or into the bump zone which will actively use all of the compression valving in the piston itself, which could be a very unsettling ride…based on the massively variable load maybe having a non-bypass shock with DSC for consistent damping regardless of ride height.

recommendations: call a dedicated shock specialist and be prepared with items like rear axle weight with and without your “payload” and tongue weight when trailer is “wet”. @AccuTune Offroad or DirtySouthMotorsports.

End word vomit/rant…Not drunk, just tired and on my phone…


-JS

 

I have to disagree on a few points. First being, as a shock gets too hot it will be unable to provide damping and potentially have seal failures, but I've never heard of a shock just seizing up from getting too hot.

Additionally, having adjustable damping can be very helpful when towing or carrying a load to help maintain control of the vehicle. The same way different weight vehicles have different valving, different load or towing situations can be benefitted from different valving. It may not be mandatory, but it's certainly nice to prevent the suspension blowing through travel and bouncing as long when you hit bumps on the highway.

To the OP, bypasses are undoubtedly the better off-road option. You might be able to get bypasses with the reservoir having a compression adjuster to get easy overall valving changes without touching the tubes. You can also get bypass tubes with hand adjustable check valves so you can easily adjust them, which is a common upgrade. I'd probably suggest looking at that as an option, though just a reservoir will be easier to adjust and access.

 

FWIW, I have the ADS 2.5 RR's and I wish I'd gotten the bypasses.

 

Out of curiosity, does your use case align with OP?

 

Seems pretty similar. I don't tow a 5500lb RV, but I do usually have at least a few hundred pounds extra weight on the back, if not 8-900lbs.

I like the shocks, but after 2 years and a fair amount of offroad miles, I think having the ability to fine tune the ride would be worth the extra $.

 

Fair enough, I’d be cognizant on where the main piston ends up in relation to shock stroke. Wouldn’t be super useful to only have 5-15 percent of ride zone available before hitting the bump zone. Once in the bump zone, compression adjusters won’t do anything. Same for the top out zone, once there rebound adjustments won’t do anything…

 

Bypass shocks are a different league than standard shocks. However OP is doing a lot with this truck.

im a little suspect on the trailer towing, removing airbags and going to deavers. Even though the 748’s are made for heavier use, will they haul all the weight you’re taking?

and if you get them strong enough for the weight, they wont be fast enough to keep up with what a bypass shock can do when empty

 

I stated that poorly, sorry I was pretty worn out yesterday. What I meant that the fluid no longer has room for expansion. You want the nitrogen on the other side of the remote reservoir piston to allow for fluid expansion. I didn't mean it would lock the shock shaft would no longer move. And to your point it will blow the seals out before that happens.

No one is going to get out and adjust their shocks every time they tow. Maybe if you are taking long trips or something it would be worth it. You still won't be adjusting the rebound so... i mean why. But if you are going to see enough of a difference by adjusting your shocks, youre at the point where you need a weight distribution hitch, etc anyway. But absolutely it would be better to adjust them.


God you guys type a lot. I was doing this on my phone and switched to a computer.

 

Great info here, thanks for the input!

With regard to planning my use for the truck, I’d say it’s 75% daily driver and 25% towing with the family and camper. Both of those scenarios come with some off roading sprinkled in, just depends on where we are and opportunity that pops up.

Sounds like anything a RR shock can do a bypass does better. Check. Figures for the price upgrade we should see a performance upgrade. I didn’t realize you could get toolless bypass adjusters on those tubes but as one poster pointed out rebound is unaffected so why bother. I think I tend to agree with that logic since I’m kind of a set it and forget kind of guy. I’d prob want to valve/adjust them to suit most of my driving uses and deal with the decreased performance in the other scenarios and just live with it. Life’s a compromise!

Sounds like the bypass shocks are a good way to go and I’ll not be disappointed with their performance. Next problem to figure out is springs. I think here if just have to make the same compromise as with shock tuning. I need a spring that can perform well unloaded while wheeling but not fall completely on its face while towing. I’ve hit the scales several times while loaded and have my axle weights but I’ll have to dig them out of the glove box to double check numbers. I’m sure Deaver or Alcon could set me up with a spring pack that’ll do the job, I should prob contact them directly to go over loads and see what they say. I think with the help of the WDH and some air bags I could get away with a slightly softer spring so I don’t have to sacrifice too much ride quality.

Question for the guys who have run airbags on similar setups: assuming I use the bags with cradles, is uptravel limited by the bags/cradles? Do the bags/cradles truly limit suspension function? Seems like some guys will say the ride goes to complete shit and others say “best of both worlds”. I’ve had my bags on for a couple years now and they’ve been good towing aids but I’m not currently running cradles. My current opinion is ride gets rougher with the bags but again, my only experience is with no cradles and I’m on stock leafs.

 

I have Airlift bags with the internal bumpers, and they definitely hinder up travel even with the hose completely removed. To the point I completely remove the bags when I'm not towing/hauling something heavy (ie if it's under about 5000lbs towed I leave the bags off). The cradle is a must also in my opinion, otherwise the bag can limit droop. Honestly for your use case I think you're best with just some reservoir shocks, they will ride great onroad and offroad, are way cheaper, and with compression adjusters you can easily and quickly change the compression if you're inclined. Bypasses are very nice, but I don't think you're going to get your monies worth out of them. If you're driving fast enough offroad where the bypass really gets into its own, then the front end will be the limiting factor for performance. A reservoir and add a hydraulic bump stop and you have a relatively simple and very capable setup.

 

We're working on a towing solution rear update for the old mans rig. He's moving to a spring under setup with bypasses and towing. Here's the direction we are going. It's had great results on the raptor guys. Basically adding a secondary shock with quick removal pins.


https://www.fordraptorforum.com/thr...movable-towing-solution-see-pics.58963/page-5

 

Excellent feedback, thank you. Sounds like some resi’s with adjustment combined with a good spring pack and the airbags/cradles are my best compromise. I think I still like the ADS/Deaver combo for the shocks and springs. I need to get all the stuff ordered so me and my boys have something to do one of these weekends.

 

thats a pretty slick idea. If someone can come up with a turnkey solution like this for the Tundra I bet they’d sell a couple. Lots of guys wanting the most from their trucks in terms of towing performance as well as off road fun time. I am looking forward to keeping up with my buddy in his Raptor on some CO trails once I get my suspension figured out.

 

Someone was doing a secondary air shock that you could just pull the air out of real fast to help support the back end on a raptor. I seent it. And someone else was doing quick swap bump stops. The towing one was longer and super high pressure as I recall. Also on a raptor. There’s cool stuff out there for towing. It’s all for raptors.

 

I have Helwig air bags with cradles on factory leaf springs with OME shocks. These airbags allow you to keep the factory bump stop in place. The air bags limit up travel even when completely deflated and bump stop never touches the frame anymore.

The result is a ride that is as smooth as factory in most situations however.... the truck rides very rough over speed humps because the leaf spring allows about 3 inches of easy compression and then the empty airbag comes into play and basically stops any further travel in less than .5 inches of compression. An empty air bag will really increase that spring rate right at the end.

Running 5-15 PSI in the bags with no load will minimize that issue over speed humps but the down side is that it rides like an empty 1 ton all the time.

I will admit though, the truck rides really nicely with either 1500 pounds in the bed or a 31 foot airstream in tow and the airbags inflated to 55 PSI.