so here are some initial observations on my forx 2.5 shocks as I always wanted to know if the fox or king shocks would get me to the final best possible ride.


truck is a 2010 f-450 drw diesel, empty weight of 9600lbs. plus 40 gallons of fuel, 300lb toolbox, 200lb diamond plate bed cover and we are easy over 10K lbs....this is unloaded.

truck has 91k miles now. bought it with 84k. shocks at the time were new replacement rancho OEM versions. tires are new michelin 225/70/19.5. the truck always rode like a bouncing boat.


switched to rancho 9000 and not much of an improvement other than to say the dial selector let you switch from very weak shocks to weak shocks.

switched to blistien 5500 and the ride was about the same as the rancho's .

I figured the problem was the vehicle weight, since in the past, ranchos or bllistiens on f-250's or f-350's provided acceptable results.


I spent some time deciding between fox for king shocks. build wise they are about the same to the point like it looks like some copy cat stuff may have been going on....the parts breakdown are almost identical.

king shocks wants you to fill out a form with detailed measurements and to get those measurements you have to remove your shocks and lift the chaisis until the wheels are off the ground (lift from beams and not from axles).....then you have to figure out how to compress the springs and leafs some how to get the truck to bottom out on bump stops...a fork lift would be great for that but dont have one. in the end, using my best approximation....I was 3" too short at stock hight for any of the upper level king shock options. a good 4" lift kit would set me back almost 2K with out the shocks (dana 110 rear axles). so the king option was put on hold.

back to the fox shocks. fox does a better jpb on their fox ride web site of having a different part number for each truck, and each lift possibility. so basically if you know what your lift is (mine was zero), you could in theroy buy the shocks using stock part numbers. so I looked up my truck, wrote down the part numbers and then went to the resale sites to make the purchase. the part numbers I got was for 0" to 2.5" inch lift in the front and 0" to 3" inch lift in the back. which I thought was good in case I ever need to add 2 or 3 inches later down the road. so I thought.

before I go one...I learned that no one has these shocks in house...they all drop ship and the order is filled from the manufacture. so those that believe that certain resellers do custom valving for customers...thats not true...the process is the reseller identifies the part number for your lift and uses the OEM's part number list to provide you with the OEM's build solution for you.

so the shocks arrive. I ordered the DSC adjuster versions which cost more but let you add dampening above stock (vs just controlling the existing dampening range).

the install was a challenge since the shocks do not come with straps that you cut that helps with the install. these shocks come pressureized at 200 PSI and there is no way your going to compress them. to get them installed...you have to lift the chasis untill the wheels are off the ground....for the front this puts the eyelet in almost perfect align ment and a cold chisel doing the wiggle dance will get the lower bolt aligned. for the back, the eyelet was still a few inches off so I had to use a bottle jack to lift the lower eyelet until i was able to put the bolt in.

WORD OF WARNING. you definetly need 2 better than floor jack solutions and 2 tall jack stands. using a floor jack didnt work since you have to jack up the chasis from the beam and not from the axle, standard floor jack diid not work. putting a bottle jack on the floor jack got it to the right height....until the truck fell over .....two floor jacks with bottle jacks and the truck still fell over. the fianl solution was 2 harbor freight 2000lb transmission jacks one under each beam and it went right up. the transmission jacks reach almost 40 inches so not bottle jacks needed. I tried to push the truck off and it was solid so the tall jack stands went in and job done.


now..the ride. rides great. much better than any thing tried on any prior attempt on any truck. excellent dampening. driving on all bumpy roads results in a totally new driving experience. takes pot holes, rail road tracks, and speed bumps excellent. there is a guy on youtube that setup some metrics and used some technology to measure the before and after and my riding experiences is consistent with those results.

VALUE. so was it worth the 2K for these shocks. you could spend 400 bucks for ranchos or bilsteins, less than 1k for shock 2.0 and equiv shocks, etc. so why spend 2k for shock 2.5 with resivoir and dsc. if you have a 10,000lb truck like a 450 or 550 drw, using fox 2.5 will give you a ride that is acceptable enough for you to stop with the find the right shock game. BUT, if you have an f-350 or f-350, I would say that 2.5 with resivoir would be over kill. for SRW ranchos/blistiens would be fine and for DRW 350 fox 2.0's would be fine. so if you have an srw and rancho/bliestiens...I would not make the move to 2.5 level shocks.

DETAILS. so a couple of tweak issues. the shocks come with 200PSI of nitrogen and can handle 500PSI. FOX says not to use PSI to change ride control (revalve for that) BUT to use PSI to change ride height. after the install, there was no change of ride height...which was a surprise since combined...we added 1000lbs of upward spring force (1.2 X PSI X number of shocks). I checked the shocks and they sit with 3/4's of the shaft in the shock body....leaving only 1/4 of the shaft for compression travel...AND...that is something I do not like....I would rather see at least 1/3 of the shaft avail for compression travel at the least. keep in mind...when fox says the shocks are good for 0" to 3" lift veicles, the 3" of lenth you are not using on a stock lift winds up in the shock body.

MITIGATION/TWEAKING. you can recover 3/4th of an inch if you use a thinner grommet between the bolt in hole for the top stud and the top of the shock shaft. the shocks came with 4 heavy duty 1/4 thick large polyurethane washers for the eyelets which I did not need....so using one of those in place of the 1" grommets would give me 3/4" more compression travel. ADDING Nitrogen. Perhaps I can gain a few inches if I add more nitrogen...looking for a way of brining the shocks to 300PSI. I'll need a 200 dollar valving kit and some tanked nitrogen which I can get at my local welding shop. probally spend 300 just to be able to and nitrogen at will to tweak this. AND/OR, Yep, we are back to adding lift...a 3" lift would result in having at least 1/3 of the shaft avail for travel on compression in stead of the 1/4 of the shaft legnth I have now. FOX thinsk the 1/4 shaft travel is OK so I would not put this as a crisis...but something I have to resolve.

NEXT STEPS. PSI or lift. will try adding PSI first. the 3" lift is on my short list. I'll need special blocks for my dana 110 rear (square axle) axles which come in 3", 5" and higher options for the rear. price is about 300 just for 3" inches. for the front, I think I am going with the DAYSTAR polyurethane 2.5 lower spring isolators which will provide 2.5 lift in the front. some folks have complained that 2.5 of lift using spacers throws the front end out of alignment...soso add a few hundred bucks for an adjustable track bar.....now we are at 1000 to 1200 for the 3" lift...AND...some f-450/550 owners with 110 axles report lots of axle wrap on lifted 110 trucks...so quite possibly...a traction bar kit for the 110 will be needed...another 1200 bucks...ouch..ouch..ouch. hopefully the increase in PSI will be enough.


spray the shocks down with oil so grime and road salt does not stick to them...and get the boots for the shafts.

 

Excellent post. Reps sent.

Few questions:

1. By Bilstein "5500" (see your post above), did you really mean "5100"? I've never heard of the 5500, and couldn't find them on the first page of google search results... which did have a lot of 4600 and 5100 hits.

2. Looks like you skipped the 2.0 because you have an F-450, but yet still suggest the 2.0 series would be fine for an F-350 DRW. Yet, by my reckoning, the SPRUNG weight of the F-450 and F-350 CC DRW pickups should be nearly identical, as the F-450 pickup body and FRAME is the same as the F-350 CC DRW pickup body and FRAME. (F-450 chassis cab frame is different, but not the pickup). Since the differences between the F-450 pickup and the F-350 counterpart are all in the axles, wheels, tires, and brakes... all of which are UNSPRUNG... is it your suggestion that the greater mass of the UNSPRUNG weight (as opposed to your previously mentioned tare weight of 9,000+ lbs) is what really drives the need for higher shock dampening capacity?

3. On the Fox 2.5, as far as your plan to get boots for the shafts, do the shocks mount rod up or rod down?


Thanks again. And did I mention REPS sent? I hope others get the hint... it takes a lot of time to break down a buying / install / thought process like that, in resolution to an oft reported problem of balancing empty ride quality with potential weight carrying capacity.

 

[QUOTE=Y2KW57;17645838]Excellent post. Reps sent.

Few questions:

1. yes


2. no. the f-450 and f-550 have thicker frames than 250/350. the 450/550 drw have dana 110 axles. the lift blocks on the 110 axles are massive and totally different than 250/350. forgot to mention my truck is the 10 bolt version. associate suspention parts are also different as well as the front axles.

the spring load discussion was in reguards to the fox 2.5 shocks. they come at 200 PSI. they provide a formula to predict sprint weight using PSI X 1.2. between the 4 shocks, almost 1000lbs of spring wieght is introduced...this is opposing spring tension which should have raised the truck,,,but no change in truck height occured.

3. i ordered and installed the boots. you can install the rear in any position since external res shocks are pressurized at the end of the resivior. front shocks can only go one way since the top is a stud.

ride problem was more of a boating feeling as bouncing off all pot holes, pot hole repiars, road joints, etc. doesnt do that now. just need some tweaking to set my ride height and shock rest points.

 

Agreed whole-heartedly on the quality of the write-up. Thanks to the OP for this excellent breakdown of the selection process and install. Reps sent.

 

My dad has always had a nitrogen tank for rebuilding motorcycle shocks. You might be able to get the pressure increased at a local motorcycle shop if they rebuild shocks.

 

True, but only chassis cabs have the thicker frame, not the factory built F-450 pickups. The frame to the F-450 pickup is no different in terms of thickness and shape, than the frame to the F-350 pickup with the same wheelbase.





All of the foregoing is true, no argument from me. But all of the foregoing are also UNSPRUNG items. From the 10 lug wheels, to the lift blocks, to the massive axle, and to the associated suspension parts... and don't forget the bigger brake rotors and calipers... all this heavier equipment is located on the underside of the springs. Since we obviously ride in the sprung part of the chassis, not on the unsprung part, comparing weights of the sprung part we ride in would yield very little difference between the F-450 pickup and the F-350 DRW pickup with the same wheelbase.


I'm not pointing this out to be argumentative. I'm simply trying to understand potential reasons for the difference you are feeling with the shocks you now have. If you had said your truck is dark blue, and therefore the upgrade to the $2K in shocks was money well spent... that would be money wasted on a white truck, then obviously, there would be little factual foundation upon which to draw such a conclusion.


I would bet a hefty sum that the comparative weights between SPRUNG bodies and frames of an F-450 pickup and an F-350 DRW CC pickup are very similar. There might be a nominal difference in rear stabilizer bar weights, the weights of the spring leaves themselves, as well as the weight of a unique vibration dampener mounted aft of axle on the curb side that the F-450 pickups have that isn't found on the F-350 pickup. But the aggregate of those minor differences in sprung weight wouldn't add up to a child in the passenger seat.


Therefore, I'm really curious as to what the actual mechanical cause might be for the improvement in ride that you report. One thing that came to mind is the reaction energy that a heavier unsprung mass may transmit through the suspension, or mask by virtue of it's own mass... that otherwise becomes dampened quicker by a more robust shock. That is the type of thing I am wondering, with a selfish interest in mind, since I own an F-550 with an even heavier Dana 135 axle with a 14.2" ring gear, vs the 12.2" ring gear of the Dana 110. The Dana 135 also has a 3 gallon fluid fill, adding yet more unsprung weight.




I've re-read the above sentence several times, but still can't get my slow witted mind wrapped around it.





Can you post a photo of your rear shock, curbside (passenger side rear)?


Good to hear. Brandon and I might have a different (bone jarring breaker hammer, vs floating bouncing boating) problem, because our chassis cabs springs are much shorter, eyelet to eyelet, than the longer, more comfort oriented pickup frame springs that you have. We also have three times the number of springs in the rear spring pack (11 or 12, vs 3 or 4). So now I'm wondering if the Fox 2.5 solution that worked well in your F-450 pickup would translate at all to the chassis cab, despite the similarities in UNSPRUNG running gear.





Empty? Or when loaded to the max GVWR you typically use the truck to haul?

 

Thank you for the in-depth write up. I agreee with most of it with the following exceptions/comments -

1) I have the Carli tuned 2.0 on my CCLB. With the huge change between stock and new shocks, I will be going to either the 2.5s or Kings the next time around and I expect to see a similar increase in ride comfort due to the things I have read. I think that the right shock is not limited by F250-F450, DRW or SRW. More just a matter of budget and making sure that it is tuned to match.

2) 2.0s, 2.5s and Kings are available in custom lengths and tuning when purchased through the right vendor.

3) Shock boots can be a bad thing and would really come down to your driving conditions. They can hold in the dirt and crap and do more damage to the seals and shafts than just the open setup. Probably why Fox sells a sheild, instead of boots.

4) A good set of OUO traction bars will only help your suspension setup and I would recommend them.

 

Spring load discussion 101.

the fox 2.5 shock come filled with 200psi of nitrogen . With 200 psi, the spring loaf rating is 240lbs (1.2*psi)

the psi range of the shock is 10 to 500 psi.

adding psi is mainly recommended to tweak the ride hieght. As you add psi, shock shaft extends, truck lift increases.

with 4 shocks at 200psi my truck lift change was 0. So 1000 lbs of spring pressure was not enough to change the lift height.



lift height is of mention because if I raise my lift height, more shaft travel will be possible...I’m currently sitting at 1/4 shaft exposed and would like to get to at least 1/3 exposed. This would give me more compression range shock travel.

To do that

a. Add psi
b add a lift or level kit
c. Use a product like summosprings

I don’t think this tweak is critical for normal driving but I would like to avoid hitting the shock bump stop in the event of an extreme encounter.

 

UPDATE

installed the summosprings all around. These are progressive bup stops about twice the size of stock bump stops and an easy double in width. they basically look like rubber ribbed coffee cans.

end result front got lifted 1" with the summo springs preload. with the progressive bump stop im no longer concerned about bottoming out the shocks. I put 1000lb springs in the front (1500 and 2500 are avail) and I put 2500lb springs in the back (only option).

ride is great, no rock or roll in any direction.


so this wraps up the suspension upgrade

2K for the fox 2.5 shocks with resivior
400 for the rear sulastic springs
400 for the rear summo springs and 200 for the front summo springs.

 

I’m going to try the summo springs on my F450. Thanks Fritz.

 

I didn't realize that you already had the Sulastics. Wouldn't those have been a contributing factor to the wallowing boat ride?

Is it possible that in the stacked sequence of aftermarket suspension products, each successive solution is needed to resolve the side effect sins of a previously applied solution?

 

You can call


David Vargas

Customer Support



SuperSprings International, Inc.

505 Maple Avenue, Carpinteria, CA 93013

Office: (805) 219-6647

Toll-Free: (800) 898-0705

Fax: (805) 745-5501

Email: david@supersprings.com

http://www.SuperSprings.com

 

No, the ride issues driven by our local bad roads have been a problem for 7000 miles since owning the truck.

the sulastics improved the rear hard lunches on bumps

the fox shocks improved everything across the board

the summosprings are an attempt to prevent my shocks from bottoming out . The summosprings preload some dampening and are progressive in nature .

Between all all three I am at where I want to be.

later down the road I might tweak the nitrogen psi.

 

regulator kit came in today. I already had the nitrogen.

brought each shock to 350 while on the ground.

ride is perfect.

 

That's insane. Can you please also post a photo of the passenger side rear shock installation on your Dana S110?