2019 f-450 with 37’s on 22.5’s

lifted 3.5 in the front and 5” at the rear

the front lift is a spacer over the coils , extension arms on anti sway bar, pitman arm drop, fox 2.5 shocks for the lift, 1000lb summo springs, centramatics . Tires are toyo mixed use 16 ply tires.


Had a few cases of what I would call as a slight death wobble…it’s probally my own fault related to my front 3.5” lift, 37 tires on 22.5 rims, 16 ply tires, etc. I have all the correct parts for the lift and everything is relatively new with just 21k on my 2019 f-450.

the slight wobble is at about 65 to 70 mph and mainly occurs while driving in the right most lane which is the lane most heavy trucks use…the lane sometimes has deep weight tire track gullies which leaves the road depressed where the tractor trailer ride. Some times my front tires get cuaght riding up these depressions and some steering resistance and counter steer occurs. Does not happen in center or left lane which for the most part are smooth. And does not happen below 60mph

now…what I have noticed is if I drive with my “auto magic engine brake “ on I can ride these gullies with no problems. Which I find strange.

had some of this flight death wobble today…so in the morning I’m going to check the torques on the main bolts of my lift install just to double check for loose bolts.


i have a tool to check chamber but not with me…so I will have to check that when I get home. Wondering if I increase my camber if that would help.

If I don’t find anything that will reduce this by checking the install…will think about adding chamber or even switching to front drive tires instead of mixed use tires that I have now. The Toyo mixed use my be too grabby for front drive use.



any comments appreciated.

 

Camber isn't your issue, it's caster, and most likely you have to little caster. I know in all the threads that I read, you probably need to be around positive 4°-5°.

 

Here’s my current tires which is a mixed use tire

 

Investigating if switching to a pure on road tire or a steer tire would help.

 

Or just don’t drive in right lane over 60 mph

 

This Michelin steer tire would run 640 each ,

 

that would be an easy change and wouldn’t hurt anything to try it.


thanks

 

It could just be a tire out of balance. Rotate tires if you can or have them rebalanced. The track bar seems to be the most common culprit of death wobble. It could be a combination of things. Large tires on modified trucks tend to cause more problems.

I just had the death wobble on a single rear wheel F350 with the tremor package. The lower joint on the track bar was worn out on my truck at only 40,000 miles. I replaced the drag link first , but that seemed fine. My truck now drives better than it did when it was new. It wondered a bit more then my 2016 f250 ever did from day one. I blamed it on the tremor having larger more aggressive tires than the tires that came with the FX4 .

 

just checked and so all bolts for the arm drops are torqued correctly

my arm drop kit is for 4 to 6 inch lift kits and I have a 3.5 front lift. Measured the bolt distance changes and it’s 4” , which is supposed to give me + 5 degrees caster

since the problem only occurs in lanes that have deep heavy truck gullies I’m inclined to think this is a tire problem so leaning towards changing the front tires from drive to steer.


All other lanes of travel are fine…on a smooth surface the truck easily does 80 with no oscillation or steering feed back.

 

I run the roadmaster steer tires in 19.5 oem flavor.

I would advise a rebalance and move them side to side before I bought tires

 

+1 on Roadmasters, they were a HUGE help in road wander on the 450. Since you lifted the truck you need to add some caster, the higher it is lifted, the closer to 0 the caster will go, and 0* is a terrible thing on these trucks. You need at a bare minimum 3* preferably 4-5* caster.

The 2012 350 I had was terrible with DW until I put a Bilstein on it, but that just masked the issues, what it came down to were worn ball joints, all 5 of them. After doing a full rebuild of the front end and adding 2.5* caster, the steering was rock solid.

 

I have an arm drop kit that lowers the arm bolts 4” , it was made for 4” to 6” lift so I’m pretty sure I have the correct caster for my 3.5 lift.

since it only happens on lanes that have deep tractor trailer depressions and it does not happpen on regular smooth roads I am inclined to think having drive tires on the front at high speeds is not the way to go.

 

Killing some time today

im at a commercial truck center

going to have the do a complete alignment and wheel balance…just to eliminate those factors.

 

If the front tires are rounded, that will certainly cause rut wallowage. I doubt you had DW, if you did you would know as you nearly have to come to a complete stop before it subsides. Being an F450 I bet its just the crappy drive tires that don't belong up front.

 

night and day difference with proper steer tires. in over 30K miles I have rotated once, need to do it again but the wear is fine.