FX4 Suspension Bounce

P. A. Schilke

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Soooo. When I aired my tires "down" today I noticed that they were aired up way over the 30 psi recommended on my door sticker. I actually aired down to the recommended 30 PSI and after being on the beach I had to drive on pavement to find a safe spot to air back up. OMG the difference in the ride was tremendous. At 30 PSI the truck felt soft, and bouncy, and dangerous. I'm only posting here because we were talking about the soft ride but I hadn't experienced it until today because my tires were aired up so high. Needless to say I aired them back up to 45 psi. I'm curious as to why they would only recommend 30 psi in these tires when Max on the tire itself says 51 psi.
Hi Steve,

All Ford Vehicle dynamics evaluations and tire wear testing was done at 30 psi. The Max tire inflation is just that, the Max. This is not the OEM pressure. You do not indicate your vehicle, its tires or 4x2 or 4x4 etc so cannot comment more than it is not recommended you run your tires above OEM recommendations. Your dealer did not adjust tire pressures as he is paid to do in pre delivery. If you have an FX4, then you bought an offroad package where on road is a bit softer than the STX. FX4 shines off road...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
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FX4Offroad

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Hi Steve,

All Ford Vehicle dynamics evaluations and tire wear testing was done at 30 psi. The Max tire inflation is just that, the Max. This is not the OEM pressure. You do not indicate your vehicle, its tires or 4x2 or 4x4 etc so cannot comment more than it is not recommended you run your tires above OEM recommendations. Your dealer did not adjust tire pressures as he is paid to do in pre delivery. If you have an FX4, then you bought an offroad package where on road is a bit softer than the STX. FX4 shines off road...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
I'm running my FX4 Lariat at 40 psi (according to the display) and it rides fine to me. This is how I got the truck and haven't changed it yet.

I'll be adding an A.R.E. topper soon. Should I air them down to ~30 psi now and add a few more when I get the topper?
 

IdriveG5

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Normally I am fine with the ranger bounce with tire pressure set around 30 cold not to bad, thou with the crazy winter temperature fluctuation I get in NC, my tire pressure fluctuate too much from one week to the next. It really showcases how critical the tire pressure must be on this truck with FX4. With the warm temperature today, my pressures rose quite a bit, and for the first time I got that sea sick feeling in the truck!

Question I have with this sensitivity, I am looking to get different tires on my truck and see some people have posted that went with E rated tires on the truck. Some have stated seemed to help the bounce/wallowing. Thou in my head, with a E rated tire being stiffer I would think it would exacerbate the bounce even more with the softer FX4 suspension off the top. Anyone explain how the opposite is happening? Thanks in advance!
 

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Hi Steve,

All Ford Vehicle dynamics evaluations and tire wear testing was done at 30 psi. The Max tire inflation is just that, the Max. This is not the OEM pressure. You do not indicate your vehicle, its tires or 4x2 or 4x4 etc so cannot comment more than it is not recommended you run your tires above OEM recommendations. Your dealer did not adjust tire pressures as he is paid to do in pre delivery. If you have an FX4, then you bought an offroad package where on road is a bit softer than the STX. FX4 shines off road...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
HI Phil...when I set my tire to 30psi and temps gets low, it drops below that then the low pressure warning comes on...anything be done cancel out the warning? I've wondered about dropping even lower when off roading and the annoying warning pops up...
 

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You guys are crazy! Bounce LOL This Ranger drives like a Caddy compared to my last truck! Diesel F250 lifted 8" on 37's. That thing rode like a dump truck, This Ranger just floats down the road! Add 200+ lbs to the bed of the truck and it becomes a Bentley!
 


Msfitoy

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You guys are crazy! Bounce LOL This Ranger drives like a Caddy compared to my last truck! Diesel F250 lifted 8" on 37's. That thing rode like a dump truck, This Ranger just floats down the road! Add 200+ lbs to the bed of the truck and it becomes a Bentley!
That's what I think...I don't get all the complaints...albeit I didn't have my stock suspension for long but enough mile to not have noticed that it needed to be exorcised LOL...I'm now on Eibach with 285s and it really does ride like a Caddy...my wife's very impressed and we've spent a lot of miles in this Ranger...
 

IdriveG5

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You guys are crazy! Bounce LOL This Ranger drives like a Caddy compared to my last truck! Diesel F250 lifted 8" on 37's. That thing rode like a dump truck, This Ranger just floats down the road! Add 200+ lbs to the bed of the truck and it becomes a Bentley!
What I thought as well until today. With the warmer then normal temp made my tire pressure increase higher then I had been running and started experiencing it.

Also I would not call it a bounce, think should be called wallowing more.

Why my post above i was wonderin about E rated tires helping, which did not make sense to me? Maybe someone can enlighted about that, maybe placebo affect :) Or maybe people all going with bigger tires off that bat helps it hide as well. How tire dampening can work?
 

P. A. Schilke

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What I thought as well until today. With the warmer then normal temp made my tire pressure increase higher then I had been running and started experiencing it.

Also I would not call it a bounce, think should be called wallowing more.

Why my post above i was wonderin about E rated tires helping, which did not make sense to me? Maybe someone can enlighted about that, maybe placebo affect :) Or maybe people all going with bigger tires off that bat helps it hide as well. How tire dampening can work?
Hi IdriveG5

Tire sidewall compliance does affect ride. Make it too compliant and then you feel like the suspension wallows. Way too stiff and the shocks are not adequate to handle and the customer thinks the suspension is too harsh....Hitting this sweet spot if the genius of the vehicle dynamics engineers. This is where experience counts as the novice engineer would be clueless. I always took novice engineers and paired them with my sage "old" engineers...Those novice engineers that took to the leaning went on to great things. Those that were "know it alls" floundered... Wheat from the chaff, eh? Aftermarket Tire suppliers are in the business of selling tires...most do not test for ride quality etc. I know that BFG/Michline and Conti/General pay attention to this but cannot speak of the other suppliers of aftermarket tires.

As for airing down for serious off roading, I have no idea other that i know of folks that remove the TPMS sensors, put them in a canister with a schrader valve inflated to pressures above the TPMS trigger point and carry this canister in the Ranger. Maybe a Forscan parameter, but I have no experience with Forscan... Others chime on on this???

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retried
 

IdriveG5

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Hi IdriveG5

Tire sidewall compliance does affect ride. Make it too compliant and then you feel like the suspension wallows. Way too stiff and the shocks are not adequate to handle and the customer thinks the suspension is too harsh....Hitting this sweet spot if the genius of the vehicle dynamics engineers. This is where experience counts as the novice engineer would be clueless. I always took novice engineers and paired them with my sage "old" engineers...Those novice engineers that took to the leaning went on to great things. Those that were "know it alls" floundered... Wheat from the chaff, eh? Aftermarket Tire suppliers are in the business of selling tires...most do not test for ride quality etc. I know that BFG/Michline and Conti/General pay attention to this but cannot speak of the other suppliers of aftermarket tires.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retried
Thanks Phil! What I was thinking, just had it backwards! I compare this to my mountain bike, however i adjust my tire pressure for a given terrain, i then may have to adjust my suspension seetings. Because of how the tires affect the initial rebounding of the bike. Of course on the ranger we cannot adjust it. Now i get why others are waiting for some adjustable suspension. Seems like the ranger has a small sweet spot with tire pressure and the suspension. As always thanks for your input!
 
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treimche

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I was definitely used to the FX4 bounce and didn't notice it anymore until after returning from a nice long holiday trip. Was gone for 12 days, and had a POS Nissan Versa rental car for a few of those days. The instant I got back in my Ranger, the floaty bouncy feeling was very noticeable again. I have Fox suspension waiting for me to have time to install and I can't wait.
 

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Can't say I notice any significant bounce, but I am coming from an '03 Ranger FX4 Level II, which was a much rougher ride (loved that truck though, amazing offroad!). The new truck drives and rides like a luxury car in comparison.

My truck came w/ tires inflated to 40 psi. I will be airing them down for offroad use.
 

IL8APEX

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Shortly after driving away from the dealership I had to run an errand to the local home improvement store. While I was there I picked up 200lbs of play sand, because I've never met a truck that didn't handle better in the winter with 200lbs of sand behind the rear wheels.

Sure enough, it calmed down the rear end of the truck significantly. Far less bouncy. As a side benefit about 1/2" of rake is also gone!

This isn't so much a solution as an observation and discussion point. It makes me wonder, however, if a different (less stiff) leaf spring might smooth the ride? The math on Coil springs is so much easier!

-Tom
 
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treimche

treimche

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Shortly after driving away from the dealership I had to run an errand to the local home improvement store. While I was there I picked up 200lbs of play sand, because I've never met a truck that didn't handle better in the winter with 200lbs of sand behind the rear wheels.

Sure enough, it calmed down the rear end of the truck significantly. Far less bouncy. As a side benefit about 1/2" of rake is also gone!

This isn't so much a solution as an observation and discussion point. It makes me wonder, however, if a different (less stiff) leaf spring might smooth the ride? The math on Coil springs is so much easier!

-Tom
Maybe 200lb in the box plus the Fox rear shocks and it would be night and day difference.
 

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As for airing down for serious off roading, I have no idea other that i know of folks that remove the TPMS sensors, put them in a canister with a schrader valve inflated to pressures above the TPMS trigger point and carry this canister in the Ranger. Maybe a Forscan parameter, but I have no experience with Forscan... Others chime on on this???

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retried
No kidding?! People actually do that? Kinda like putting one's liver in a can so they can drink moreo_O:LOL:
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