Replaced bilstein with fox after 25,000 miles, f150

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Granted I’m a bitoger, and I initially sprung for bilsteins, so I’m probably a little pickier than most, but I pulled them off today and installed fox IFP 2.0s in the rear today.

the oem shocks saw tow duty and were useless with a load by 18,000 miles. The bilsteins went on and frankly, I felt they were a little soft to begin with, but they definitely helped so I stayed with them. They were certainly buttery under 40mph but basically had no rebound control over that. So at commute speeds, any dip or bump caused the rear of the truck to continually “pogo” up and around, to the point of feeling nauseous the last time I did a long interstate drive. I also noticed the truck seemed to be sitting close to level lately and wondered if it was the springs.

so at a little over 43k I swapped the foxes in. It’s a clear difference. The 5100s came off with some pressure in them, but probably about half of what they started with. First test drive on city streets, they felt a lot like an accord would. You could feel the moderate bumps but it was a single event, no bobbing, and something else, maybe secondary axle shake? Notable disappearance of brake dive and acceleration squat. i also noticed the factory rake is back again, with the rear slightly higher.

i think my 150 may be stiffer sprung - if I recall they said one of the packages on it was a stiffer suspension. Maybe it’s the fx4? But clearly as they wore in, the bilsteins were under-damped for the springs. Either that, or its possible they’ve backstepped in quality, as I saw rumored on another thread. I’ll also note that digressive valving, which is what the 5100s advertise, may be the opposite of what is needed for highway use and towing. The digressive valving softens when the shock has to respond faster, e.g., they loosen up on the highway… which you’d want on a fast dirt trail but maybe not for highway and certainly not with highway travel with a trailer and expansion joints.

anyway, for on-road handling and load carrying, I’m going to state that my initial impressions are fox > bilstein, and the longevity of these 5100s has not been like a set I had 10 years ago. If the foxes loosen up 10-15%, they should be near perfect for my preferences. If that happens, I could see doing the fronts sometime in the future. They are certainly more communicative of bumps and whatnot. Bilsteins were moving toward buick while the fox feels more like accord.

2018 f150 XL, stx, fx4. 200lb camper shell, hellwig rear sway on the softest setting, oem 20” wheels, usually 100lbs of gear in the bed.

-m
 
Talk to me. The f150 forum I found had someone saying they thought the 5160 was valves the same, with extra capacity from the reservoir. what is your impression of the 5160?
 
Granted I’m a bitoger, and I initially sprung for bilsteins, so I’m probably a little pickier than most, but I pulled them off today and installed fox IFP 2.0s in the rear today.

the oem shocks saw tow duty and were useless with a load by 18,000 miles. The bilsteins went on and frankly, I felt they were a little soft to begin with, but they definitely helped so I stayed with them. They were certainly buttery under 40mph but basically had no rebound control over that. So at commute speeds, any dip or bump caused the rear of the truck to continually “pogo” up and around, to the point of feeling nauseous the last time I did a long interstate drive. I also noticed the truck seemed to be sitting close to level lately and wondered if it was the springs.

so at a little over 43k I swapped the foxes in. It’s a clear difference. The 5100s came off with some pressure in them, but probably about half of what they started with. First test drive on city streets, they felt a lot like an accord would. You could feel the moderate bumps but it was a single event, no bobbing, and something else, maybe secondary axle shake? Notable disappearance of brake dive and acceleration squat. i also noticed the factory rake is back again, with the rear slightly higher.

i think my 150 may be stiffer sprung - if I recall they said one of the packages on it was a stiffer suspension. Maybe it’s the fx4? But clearly as they wore in, the bilsteins were under-damped for the springs. Either that, or its possible they’ve backstepped in quality, as I saw rumored on another thread. I’ll also note that digressive valving, which is what the 5100s advertise, may be the opposite of what is needed for highway use and towing. The digressive valving softens when the shock has to respond faster, e.g., they loosen up on the highway… which you’d want on a fast dirt trail but maybe not for highway and certainly not with highway travel with a trailer and expansion joints.

anyway, for on-road handling and load carrying, I’m going to state that my initial impressions are fox > bilstein, and the longevity of these 5100s has not been like a set I had 10 years ago. If the foxes loosen up 10-15%, they should be near perfect for my preferences. If that happens, I could see doing the fronts sometime in the future. They are certainly more communicative of bumps and whatnot. Bilsteins were moving toward buick while the fox feels more like accord.

2018 f150 XL, stx, fx4. 200lb camper shell, hellwig rear sway on the softest setting, oem 20” wheels, usually 100lbs of gear in the bed.

-m
I have installed a few sets of bilsteins: f250, Ram 2500 and Tundra. Never had any experience like your report. In fact, my ride quality was always an improvement. Used the truck On road and off road daily. Hauled horses in gooseneck, hay wagons etc. Sorry to hear quality may be lagging now.
 
That’s an interesting question. I’ll try to figure out where I ordered them through. It was either tirerack or amazon.

update: Amazon
 
I have installed a few sets of bilsteins: f250, Ram 2500 and Tundra. Never had any experience like your report. In fact, my ride quality was always an improvement. Used the truck On road and off road daily. Hauled horses in gooseneck, hay wagons etc. Sorry to hear quality may be lagging now.
I was thinking the same thing.. I have them on my Dakota and RV. Both are the best riding vehicles we have. Think I got them from a suspension website can't recall, can't trust Amazon or eBay.
 
I dunno, I run 5100s on my '11 F350 CCLB at all four corners. No complaints but maybe I'm just oblivious to problems I don't know I have, or maybe I expect less ride quality from a wonton ;)
 
I’ve had King 2.5” shocks on my F150 for about 20 years. They will control any bounce you can throw at it. Fully rebuildable and valved to your preference by the factory. At the time they were custom built to order and brackets had to be made too. Now you can get them off the shelf, still unmatched quality.
 
I have always had good luck with the standard gas Bilstein (HD, B6, 4600). I hope this was a fluke for your application, and not Bilstein quality slipping.
 
I've been running the same Bilstein HD's on my 98 Chevy K1500 for around 20 years and they still seem to operate like they did when they were new. Mine came with a lifetime warranty and I think I bought them from Autozone. This truck came with factory Bilsteins since it has the Z71 package but they were way softer than the HD's and didn't seem to last that well.

I have never tried the 5100's on anything though.
 
It may really have been my error for getting the 5100s and not the 4600. Or it could be that the spring rate on my truck isn’t correct for how the 5100s are tuned. (Despite what customer service says, I obtained compression and rebound rates between the 5100 and 4600 years ago and they weren’t the same). so, it totally may be that they are nicely broken in now, and it just wasn’t the right application. My f150 does ride harder sprung than several others I’ve been in. Or they could have been factory rejects or knock-offs too, since they came from Amazon. ever since we started seeing counterfeit spark plugs, Im starting to buy from other vendors now for items like this.
 
I've been running the same Bilstein HD's on my 98 Chevy K1500 for around 20 years and they still seem to operate like they did when they were new. Mine came with a lifetime warranty and I think I bought them from Autozone. This truck came with factory Bilsteins since it has the Z71 package but they were way softer than the HD's and didn't seem to last that well.

I have never tried the 5100's on anything though.
Just realized I still have Bilstein OEM struts on my 1998 BMW. 203k miles. I pulled them off to replace the bearings and bump stops and they felt better than the cheap replacements I had. I put them back on and got my money back on the others. Not ideal performance anymore I’m sure but it’s days are numbered….
 
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I have 6112's on the front and 5160's on the rear and at 25K miles on them they're still great. Much better than stock. I do not do any meaningful towing or hauling though so it's basically a glam truck.
 
There has been no decline in Bilstein quality I have noticed and I use them a lot and have used them on trucks and my Expedition but only the B6 4600 in the trucks and SUV. The twin tubes seem to work better than a monotube in these applications, the B8 work great in lighter vehicles.
 
Copy that.

update - with a couple hundred miles on the foxes on the rear, they are settling in very nicely. The harshness is settling out and they seem well-matched for the rear axle. I am pleased enough to consider staying with the brand for the fronts. The fronts don’t need it yet, but I did reach out to sales to discuss recommendations for models and spring rates. I might consider buying a pair. Sadly, sales has not responded.
 
I’ve been runnning bilstein 5100s on my 2011 since I bought it at 37k. 130k now and they still ride great. Better then our 2018 did new without a doubt. Possible QI issue or counterfeit product on your purchase?
 
Man IDK. i wonder if the FX4 has a stiffer spring rate that isn’t right for these, and they loosened up just enough to “cross the line” for me? They were never “firm,” more of a floaty comfy feel. Idk if that’s right for 5100s or not?

the fox 2.0s have settled in nicely in the rear, like, perfectly for my taste. It is controlled, probably a touch on the firm side, but they open up before it becomes harsh. They remind me very much of KYB GR-2s. Sold. I’ve ordered the fronts. I’ve written fox to ask for the adjustments to keep the oem ride height. I hope the changeover isnt too difficult.
 
The local fab guy who actually has a lot of experience in the industry absolutely hates Fox due to poor customer service.

Curious if they respond to you and if they're helpful
 
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