Infiniti QX 80 suspension

[Golfer503]

I am using a QX 80 to tow a FC 27FB with a Blue OX sway pro w/d hitch. The only issue i have is the TV seems to porpoise from front to back quite a bit. Has anyone else had this problem and resolved it? Thanks Gary

[1973Argosy]

Not sure if they make them for the Infiniti, but a set of firestone riderite airbags under the rear fixed the porpoising on my expedition

[PKI]

We get a bit. I kind of expected the characteristic, because the BO is a design that uses a flexible spring to transfer weight and control sway. The TV to Coach connection is more like a hinge than a stiff bar, hence the bounce on some transitions. The TV does not slam the coach and the coach does not jar the TV, but your rear suspension should dampen it out quickly.

I have always considered this characteristic to be one of the advantages of the BO hitch design in that it was soft on the AS, as long as the movement is not excessive, which is of course a subjective analysis. Suggest you contact BO tech support and get their recommendations. Also suggest that you verify the TV receiver is rigid and does not flex. That would add to the motion.

And then the disclaimer - just because I think it is not a bad thing does not make it a good thing. Investigate and determine the reality for yourself. You may decide a force projection design is a better solution for your application.

Edit - there is some flexibility in tire side walls. It's another spring in the system. Low profile less. High profile more. Light Truck less. Run flat less. Standard passenger car tire more. May be a dead end, but a consideration.

Edit - if your hitch shank extends the ball behind the bumper, drilling a new hole to move the ball as close as possible reduces the lever on the TV and improves the suspension/sway control. If you have the H-beam shank, you will need to go to a solid shank to provide the material to drill an alt hole.


Travel safe. Pat

[ROBERT CROSS]

Roads....seams in the pavement will sometimes cause it.

More common....too much or too little WD, tongue high or low. (TV & AS not level).

Bob

[dkottum]

Are the shock absorbers on the QX 80 worn.

Porpoising may be from not enough load transfer to the truck's front axle by the w.d. hitch. And there are limits what it can do. It's a half-ton vehicle; too much load behind the QX 80 rear axle, and/or too heavy hitch weight of the Airstream will put too much load on the truck's rear axle, more than the w.d. system can help.

Airstream warns 1,000 lbs hitch weight maximum in your Airstream Owners Manual, and your QX 80 will have a maximum load on the axles (GAWR) printed on a door sticker. Start by weighing the rig hitched up ready to go to see what you have on the truck's axles, if you haven't done so.

And as Bob says, some roads (segmented concrete) are lousy.

[wulfraat]

I have the same suv. Sounds like you may not have enough weight distribution to re-load the front axel.

As a point of reference my front wheel well measures 36" unloaded, 37" with the hitch in ball but without weight distribution and I return it to 35 3/4 when weight distribution bars are applied.

I would notice a lot of "bouncing" and understeer otherwise (used to return the front axel to 36 1/2 but it wasn't enough weight transfer). Rides very well now. My tongue weight has been measured at 780lbs.

[Golfer503]

Payload of QX 80 is about 1650 lbs
Tow capacity 8500 lbs
Tongue weight about 825 lbs
AS 27FB rated at 7400 lbs fully loaded. I am running at about 6800 to 7000 lbs depending on water,gray and black tank levels
Both TV and TT are level. w/d hitch moved about 400lbs to the front.

Will try next travel day with less tension on the w/d bars
Thanks for the input, appreciate it. Gary

[wulfraat]

You need more (not less) tension on the WD bars to transfer more weight to the front axel.

Make sure to check your measurements before / after applying weight distribution.

Also - read your driver door sticker for actual payload. Mine is less than 1,500lbs once fuel weight is taken into consideration.

[dkottum]

As long as you're out there, it would be good to just get one weighing at a CAT Scale and see what the truck's individual axles are actually carrying, as well the the trailer axles together. You may be able to move some load around in truck and trailer for better w.d. adjustment, and a much improved ride.

Does the QX 80 have auto leveling air bags?

[wulfraat]

Yes the QX80 has rear air bags. When the tongue weight is loaded on the receiver they will recover about 1/2" - 3/4" of sag on the rear suspension. This recovery does not move any weight to the front. With the internal layout of the QX there isn't much you can do to distribute load other than to remove any non-driver related weight from behind the drivers seat.

That being said I often tow with driver + 6 passengers and dog without issue. The key for the QX to behave properly is proper weight distribution - especially with a tongue weight of 825lbs....

BTW golfer - how did you measure the fact that WD moved 400lbs to the front axel? That would likely be too much weight transfer on a dead tongue weight of 825.

[ROBERT CROSS]

Originally Posted by wulfraat

......
.....BTW golfer - how did you measure the fact that WD moved 400lbs to the front axel? That would likely be too much weight transfer on a dead tongue weight of 825.

^
X2
??

Being that some of that 825 is also moved the the trailer axle= not enough TW.

Bob

[JMZJSNOW]

Originally Posted by Golfer503

I am using a QX 80 to tow a FC 27FB with a Blue OX sway pro w/d hitch. The only issue i have is the TV seems to porpoise from front to back quite a bit. Has anyone else had this problem and resolved it? Thanks Gary

I also have a QX with a Blue Ox sway pro w/d hitch and am having terrible issues hauling. I could not get above 45mph getting the new trailer home. Have tried every adjustment I can think of. My problem is when I hit around 40+ I feel like I am riding on top of a balloon. Not porpoising, not swaying, but feels like BOTH at the same time. Have tried adjusting weight on hitch (probably at 750-800 lbs now). I keep thinking it is the QX air bags. They work to level the QX, but are they helping, or making it worse? My neighbor has the same exact engine, trans, frame, etc in his Nissan NV van. Only difference is rear end. I have the standard airbags, his comes with beefed up springs. He can tow same trailer all day long no issues. HELP! Anyone else run into this? Solution? TIA

[rowiebowie]

Originally Posted by JMZJSNOW

I also have a QX with a Blue Ox sway pro w/d hitch and am having terrible issues hauling. I could not get above 45mph getting the new trailer home. Have tried every adjustment I can think of. My problem is when I hit around 40+ I feel like I am riding on top of a balloon. Not porpoising, not swaying, but feels like BOTH at the same time. Have tried adjusting weight on hitch (probably at 750-800 lbs now). I keep thinking it is the QX air bags. They work to level the QX, but are they helping, or making it worse? My neighbor has the same exact engine, trans, frame, etc in his Nissan NV van. Only difference is rear end. I have the standard airbags, his comes with beefed up springs. He can tow same trailer all day long no issues. HELP! Anyone else run into this? Solution? TIA

Welcome to the forum JMZJSNOW!

Have you thought whether your new QX has some electronic aids for towing that are not calibrated well making your airbags or stability control act up in detrimental ways?

[wulfraat]

Originally Posted by JMZJSNOW

I also have a QX with a Blue Ox sway pro w/d hitch and am having terrible issues hauling. I could not get above 45mph getting the new trailer home. Have tried every adjustment I can think of. My problem is when I hit around 40+ I feel like I am riding on top of a balloon. Not porpoising, not swaying, but feels like BOTH at the same time. Have tried adjusting weight on hitch (probably at 750-800 lbs now). I keep thinking it is the QX air bags. They work to level the QX, but are they helping, or making it worse? My neighbor has the same exact engine, trans, frame, etc in his Nissan NV van. Only difference is rear end. I have the standard airbags, his comes with beefed up springs. He can tow same trailer all day long no issues. HELP! Anyone else run into this? Solution? TIA

Having towed with the QX for many thousands of miles with a 25’ and 30’ I can tell you this is not right.

It does have soft suspension but it should not feel like you are on a balloon from a stability perspective.

My first question is what tires do you have and what pressure do you run them at? If you don’t have 20” rims running at 40-44psi it may be your tires that are causing much of the “floating” sensation.

Also - do you have CAT scale weights to share? Are to confident that you’ve got good weight and balance / weight distribution?

Finally, I’m not familiar with the blue OX, but I can tell
you that the QX will benefit from a good amount of anti-sway friction control to reduce “tail wagging the dog” given the relatively short 121” wheelbase. I used an equalizer and due to the design it definitely made a difference in helping the trailer track a straight line behind the QX. Obviously a propride is the ideal hitch but I did fine with a very well calibrated equalizer.

[JMZJSNOW]

Originally Posted by wulfraat

Having towed with the QX for many thousands of miles with a 25’ and 30’ I can tell you this is not right.

It does have soft suspension but it should not feel like you are on a balloon from a stability perspective.

My first question is what tires do you have and what pressure do you run them at? If you don’t have 20” rims running at 40-44psi it may be your tires that are causing much of the “floating” sensation.

Also - do you have CAT scale weights to share? Are to confident that you’ve got good weight and balance / weight distribution?

Finally, I’m not familiar with the blue OX, but I can tell
you that the QX will benefit from a good amount of anti-sway friction control to reduce “tail wagging the dog” given the relatively short 121” wheelbase. I used an equalizer and due to the design it definitely made a difference in helping the trailer track a straight line behind the QX. Obviously a propride is the ideal hitch but I did fine with a very well calibrated equalizer.

***

Tires are factory 22's (18 was the standard). I put new pirelli tires less than 8k miles ago, still brand new. Pressure was set at 35, maybe too low for this application? Don't have CAT scale weights, as I went directly home with it, then to storage (all under 45mph) due to situation. So not confident of good weight and balance, however, trailer is new, tanks empty except fresh was 1/3 full. Was level to eye. Plenty of weight on hitch making rear end sag until I turned on QX to auto-level, which it did. Blue OX is 5 star rated from reviews, not cheap, and we tried basic friction and tight high friction settings. Same either way. Still lost here. Wonder if the short wheelbase and trailer being 36' is doing it?

[wulfraat]

I had the 22” pirellis as well (sorry I mis quoted 20’ above). Yes recommend you move to 40-44 psi - 44 should be the max on the sidewall - which you’ll want given the loaded axle weights.

Fender / wheel arch height should be with 1” front - to rear if you have the right amount of WD applied. Air suspension will only recover about 1/2” of sag - actual leveling needs to be accomplished with weight distribution.

Sounds like you need to get more aggressive with your chain links.

At 36’ what trailer do you have?

[JMZJSNOW]

Originally Posted by wulfraat

I had the 22” pirellis as well (sorry I mis quoted 20’ above). Yes recommend you move to 40-44 psi - 44 should be the max on the sidewall - which you’ll want given the loaded axle weights.

Fender / wheel arch height should be with 1” front - to rear if you have the right amount of WD applied. Air suspension will only recover about 1/2” of sag - actual leveling needs to be accomplished with weight distribution.

Sounds like you need to get more aggressive with your chain links.

At 36’ what trailer do you have?

Awesome info and assistance. Totally need to go up on air pressure to 44. I noticed a couple inches of sag when they put the trailer on (Grand Design 32bhs - sorry, wish I could afford the Air Stream as I love them!). Nice set up you have! Colorado? When we turned the QX on, it raised much more than 1/2". I'm guessing 1 1/2" to 2". They originally set Blue Ox with about 6 links showing (slight bend in bars). In my trial and error testing to fix this, I did tighten it as much as possible with only 3 links showing and much more bar bend.

[wulfraat]

That’s a mighty long box behind 121” wheelbase. Be safe out there in the cross winds.

For what it is worth after about 3k miles of towing my 30’ (after upgrading from a 25’) with the QX I upgraded to a much longer wheelbase 3/4 ton truck. I may have kept towing with the QX if we didn’t live in Colorado, but 10,000’ mountain passes put it near the limits going both up and down. Modern Diesel + long wheel base and an additional 4K lbs in front of the trailer made a big difference in overall stability and handling of the 54’ train.

[JMZJSNOW]

Originally Posted by wulfraat

That’s a mighty long box behind 121” wheelbase. Be safe out there in the cross winds.

For what it is worth after about 3k miles of towing my 30’ (after upgrading from a 25’) with the QX I upgraded to a much longer wheelbase 3/4 ton truck. I may have kept towing with the QX if we didn’t live in Colorado, but 10,000’ mountain passes put it near the limits going both up and down. Modern Diesel + long wheel base and an additional 4K lbs in front of the trailer made a big difference in overall stability and handling of the 54’ train.

I'm thinking so. Good advice, much appreciated! May need to switch TV or TT. Spoke with my dealer about going to shorter version (they have a 31' that is about 1200 less lbs). Also went and looked at a Nissan Titan XD 5.0 Diesel that tows 12000. Looks like we got too much trailer.

[ROBERT CROSS]

Does your air suspension activate with key off & not running?
Most OEM air suspensions require the WD to be set when suspension de-activated.

What is your spring bar rating?

Bob
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