Fox 2.5s Ride Terrible

I purchased my Fox 2.5 IFP shocks (no remote reservoir) off of OfferUp and noticed that they don’t ride good at all on the road. I thought it would be a significant difference from my previous suspension setup (stock struts on blocks), but it doesn’t seem to be that much better. I do see difference in the off-road capability and I for sure feel more confident going faster in the dirt. I also noticed a big difference while turning, but I’m assuming that has to do with the UCA’s I installed at the same time as the shocks (LSK).

The problem I am having is that something just seems off. Maybe I’m overthinking it and I should’ve gotten Kings if I wanted a soft ride, but I expected more I guess.

Here’s a photo of the suspension setup:

I also understand I have a ton a preload. It might have something to do with the ride quality but I’ve seen people say otherwise. I was thinking about getting longer springs to maybe help with the preload but I don’t want a rougher ride lmao.

Any help will be appreciated.

 

The first two questions I was going to ask: how much lift are you running with associated preload, and what spring rate is the coil. Pushing the preload will hurt your ride comfort.

 

For the first question I believe it’s 3 inches. I am not entirely sure because the person I bought it off of had it at this setting already, but from what I can see from looking it up, the max should be 3 inches. If I remember correctly they had told me it was maxed out. As for the second question, I would have to assume it’s just whatever comes stock with these shocks. From what I can see online, it should be a 700 lb spring rate.

 

My suspension experience comes from motorcycles mostly rather than trucks but on motorcycles cranking in lots of spring preload to get a desired ride height often degrades ride quality and it makes the suspension less capable over all. I would assume it is the same on trucks. Proper sag, proper spring weight, spring length & preload all play a role. On motorcycles getting the spring rate, length & sag right is the first order of business before even worrying about damping. I would assume the concepts remain the same regardless of how many wheels are involved.

 

I would relax the preload and take it down to 2” max. If memory serves, the fox kits are usually available in two options: either 0-2” or 2-3” of lift. Judging by how much preload is already dialed in to those, perhaps they are the 0-2” version cranked WAY to far. Either way, take a bunch out and see how it rides.

A 700 lb/in coil matches the factory spring rate. But combined with the extra damping of the larger shock body, it can ride stiff without additional weight on the front like aftermarket bumper, winch, etc. For a factory weight front end, a lighter spring like 650 lb or even 600 lb is often used (that’s what I’ve done with my last few setups).

Last, what is your tire pressure?

 

I appreciate the response. I just might go out and buy some Kings because it’s pissing me off how much I’ve had to deal with just to install this suspension correctly. Didn’t bring it up before and I won’t go into details, but my truck wasn’t able to drive for a few days just trying to install the shocks.

 

My only worry with dropping it down to 2 inches is fitting my 35s that I have on right now. I might just go buy some Kings and sell these if that’s the only option. That was the suspension I wanted in the first place anyway.

So what you’re saying is I should go down to a 600-650 lb spring? I don’t plan on adding any weight to the front. Not really into the aftermarket bumpers and don’t really care for a winch. Is there spring that is longer so it has less preload? I really hate the look of all the preload to be honest, I feel like it would look a lot better with a longer spring.

I am running around 30-35 psi. Don’t remember the exact amount but I recently lowered it to help even out the wear on the tires. I was running around 40-45 psi but I heard having lower psi helps the ride quality. Plus like I said, the center of my tread was wearing unevenly.

 

Tire pressure is good; occasionally somebody swaps tires at the same time and just inflates them to max PSI and asks why it drives like a dump truck..

As for fitting 35's, you should be fine dropping down to 2" depending on a few things like whether or not your 35's measure a true 35" tall (most don't, honestly). Technically, you can fit 35's at stock ride height with the right wheels. The tires rubbing (or not rubbing) has more to do with wheel offset, alignment, and upper control arms. The jist of it is that taller wheels are usually wider, which requires more clearance at the upper ball joint via a wheel with a more aggressive offset (stock is +60 which tucks the wheel inside the fender, whereas your Methods are probably between +27 and 0mm, which pushes the wheel out past the fender lip). Changing the wheel offset to a more aggressive one mean the arc of the wheel changes as you turn, which can cause the wheel to contact fender liners, mudflaps, body mounts, etc.

The ride height has less to do with clearing big tires, though, so 2" vs 3" usually makes very little difference. The front shocks have a specific amount of up travel and down travel; when you crank up the preload, you lose down travel and trade it for up travel. Say your shock has 6" of travel (gives you about 11" of wheel travel but we will make it 12" to make the math easy); if you adjust the coil 2" on the shock body, you know have 1" of shock down travel and 5" of up travel before bottoming out the shock itself. However, if you have the coil cranked up too far, you will bind the coil as it compresses before the shock bottoms out, which means you are losing total travel. Instead of 6" total travel, you know have 5 or 4" travel, which makes the truck ride like garbage.

The solution, as you have intuited, is to either find a longer coil or coil designed for the additional lift without adding preload, or turn down the preload. Turning down the preload costs nothing but a little time, so I would try it first and see if the ride at least improves. Else, a coil better suited for your desired lift and and plushness would be a good choice. I should also add that Fox recommends a 50k mile (or less) rebuild schedule for their shocks deepening on use, so they may be due for a rebuild. Furthermore, outfits like @AccuTune Offroad can rebuild the shock AND re-vavle it to be more streetable and plush. They can also provide a softer coil, or at least point you in the right direction. I don't recall offhand if Eibach coils fit the Fox 2.5, but I think they are a standard 3" ID x 16" long coil which Eibach makes in a variety of spring rates and are available from multiple sources. I put Eibach 650 lb springs on my Dobinsons when I set them up.

Bummer that the shocks aren't working out like you hoped. I've been snookered by second hand gear and it's absolutely aggravating.

 

Just for comparison, here is my dobinson setup; the small amount of preload provides about 1.75” of lift. Note that I have the wheel dropped out so that the coilover preload is exposed, else the UCA sits pretty level instead of pointing down like in this picture.

 

I really appreciate your help. Thank you so much

 

Just a heads up, but if you need to turn the ring to reduce preload, you need to compress the spring first and get the load off. I called Fox and they indicated that the threads are not designed to have the ring turned when it’s under load.

Most of those cheap compressors you can rent won’t fit due to the spring diameter and shock size. You’ll need to use a wall mount compressor like a Branick.

 

Thread jack incoming...
What a great explanation and easy to understand. I have been educating myself on suspension by reading here in the forums. I am leaning towards Eibach adjustable for the front and do not want any pre-load. Do you have a part number or link for the springs you choose (I'm looking to level in the front ~2")?

 

Lots of great suggestions. @xkjay Fox recently discontinued their 2.5 IFP coilovers, so I don't even have part numbers to look up to help you. I was going to question which shocks exactly you have, bc then we could help determine if they are lifted too much or not. We could also confirm spring rates to make sure thats not an issue either. 2.5 IFP shocks wont offer the ride quality and performance a remote reservoir shock will. I see you mentioned a few times you want to go with King, let us know if thats something we can help you with. We have those in stock

 

How many miles are on the shocks? They might need a rebuild.

 

Changing the spring won't change the preload for a given lift. Aftermarket shocks achieve lift using a combination of a) longer shock, and b) spring preload. If the shock length gives you an inch and you want 2", then the additional inch of lift will be from adding spring preload (vs stock). Usually the longer length will get you an inch or so, but it varies.

If you want "no preload" (ie stock preload) you need to find out how long the Eibach shock is compared to stock, figure out the lift vs shock length ratio (my best guess is ~1.7) and use a top spacer to add the additional shock length for 2" lift. Don't forget to extend your bumpstops.

Advice... just set your Eibach to 2" and be happy.

 

This needs to get branded into everyone's brain. Bumping it up an extra inch causes all sorts of issues.

Plus I should mention that most places seem to screw up the alignment on these trucks, so that could be an additional issue... but don't worry about that until you get the lift dialed.

 

Thread showing on a coilover shock does not equal preload, just want to clear that up real quick. Although it may look odd, without knowing the spring rate there is no way to tell how much preload is on that spring. You can have too much or not enough preload on a spring. Zero preload for OEM vehicles like this is not really a thing, unless its setup very very wrong. [preload tech]

@rruff Different springs will definitely change the amount of preload you need to get desired lift height.

 

I tend to over think things and make them more complicated than they need to be.. thanks for your advice. I do believe I’ll do just as you suggest.

 

Interesting thread as I have yet to install my Fox 2.5s. So at what height over stock does Fox set the coil springs when shipped?

 

Did not know this. Good info to know. I’ve had adjustable Bilstein coilovers on other vehicles before, and they were easy to adjust using spanner wrenches with the front end jacked up and the tires off. Having to routinely R&R coilovers and pay a shop $50 each time to use a wall mount or caged spring compressor until you get the desired ride height sounds counter-intuitive and like a real PITA. I’m surprised to hear Fox 2.5’s aren’t designed as user-friendly adjustables. Had I known this, I would’ve gone a different route with my suspension.

 

I was defining it as spring force at static height. At a given shock length and given height, I don't think that can vary. If we are talking about the spring force before installation, this will be less for a stiff spring, and more for a weaker one.

 

If you can get that done for $50, then

 

I bought mine years ago and honestly regret them. Difficult to adjust and need to be rebuilt too often and it is not a DIY job. I know some folks back them off without compressing, but Fox told me it’s not designed that way and I don’t want to risk it.

I won’t buy Fox again, I’ve been replacing my Fox suspension and installing Bilsteins on my new vehicles.

 

True of all the fancy shocks. The gas pressure and low friction seals are the cause I think.

 

I've alway felt this is a bit of a conundrum. I ran 6112/5160's for over 100k miles with decreasing performance only near the end of service (one of the rears was bad but not blown). I looked at super-hoopty Fox and King 2.5's with big reservoirs and pistons, cooling fins, special valving - the whole nine yards. All of the big spenders poo-poo "cheap" bilsteins for leaking excessively, sometimes claiming they are designed to leak so you buy them more. Yet, the rebuild schedule for fancy shocks is more of a MAXIMUM time between rebuilds (which equates to about two years of my driving, or less), and it's suggested that they are rebuilt more often than that depending on use. Then I see big player shocks from the likes of Icon, Fox, etc, failing within a few thousand miles and the manufactures simply saying "yup, you wore them out and got your monies worth; now you can pay us $$$ to rebuild it".

Sorry for the rant. Says the guy who spent more on his current set of reservoir shocks than he did on his first four cars... combined...

 

https://www.tundras.com/threads/fox-2-5-coilovers-2-lift-issue.25980/

Helped a few who unfortunately purchased the same shocks, I made the same mistake. Can’t lower them less than 3” lift causing the shock to top out on everything as sold by Fox, and not worth investing any money to improve imo.. Know someone Fox sent the reservoir version to replace due to the terrible ride/topping out few years ago.

 

Correct: That's what preload is - the amount the spring is compressed (preloaded) when installed onto the shock with the shock at full extension.

A bit of a ramble...

Spring rate versus damping is an age old quandary. A bit over simplistic but spring force is positional in nature - The further the spring is compressed the more opposing force it exerts regardless of how slow or fast that change in position takes place. Damping on the other hand is speed related (shock shaft speed, not vehicle speed). The faster the shock shaft is moving the greater the opposing force generated against that movement. Move the shock shaft slowly and there is very little damping going on.

On motorcycles a proper spring rate is pretty easy to figure out and the first thing to get sorted. All one needs is to know how much suspension travel is availible and then shoot for a suspension sag (with rider) that is about 30-33% of the availible suspension travel, preferably with relatively small amount of spring preload. A few easy measurements and one knows if their spring is in the right ball park.

Is this same general rule of thumb (or a similar one) used for trucks?

 

A stock Tundra is closer to 50% sag I think, around 5" up and down travel. With a combination of higher spring force and slightly longer shock to obtain lift, the sag will drop... a lot if you have >3" of lift.

I disagree that preload is a bad thing. The only way to reduce preload as you defined it, is to have a high rate spring. I don't have much experience, but the Ironman extra long low rate springs (19" and I think 590 lbs... or 490?) combined with high digressive damping, work well for me.

And... you may be thinking that the shock could just be made longer to get more lift, but this puts the CVs and other suspension components way outside their operating range at max extension. Also it must be hard to increase the shock travel, since they only are a little more than stock. In other words, a long shock will cause excessive extension and limit compression (up travel).

I definitely recommend sticking in the 1.5-2" range for lift. This is enough for 37s, and you don't need any lift for 35s.

 

Well, it used to be $20 at Hall’s Tire Shop in Lancaster, TX if I did it myself, but that was about 7 years ago or so.

 

This is disappointing to hear. I’m running 6112s that are on their last legs and figured I’d splurge on the Fox 2.5’s as an adjustable upgrade.