Hi All, I see mention of Caster angle on lifted/levels vehicles often but not so much on stock height. I have a 2017 F250 CC SB with plow and camper packages that does have some death wobble in it. I have gone over and front end with great detail and anything worn was replaced. I would like to know what the best Caster angle for this set up is?

 

According to Ford spec 1.5 to 4

According to Ford TSB regarding death wobble caster should be in lower range of spec or say 1.5-2

According to MOST self proclaimed experts on youtube, etc caster should be at or above upper range of spec or about 4-5.5

According to me and IMHO, if you have a DW issue it is likely not a caster issue if you are 1.5-5. Its much more likely a worn steering component. You may not have found it yet but its there.

Been there, just fixed DW issue on my 2017 with 133,000 miles after the most recommended alignment expert in my area could not find anything worn on my front end. Me and my son found the worn components. I ordered the parts and replaced

i now have no DW, no steering damper/stabilizer (have not put it back on yet) ...... caster is 2 left and 2.5 right.

NOTE: My stock caster 2 weeks ago was 3/3.5. I added 1.5" progressive leveling springs. After this work caster is now 2/2.5.

 

That was wording from TSB 18-2268 which was later superseded by 19-2274. 19-2274 no longer included any wording or the step to reduce caster. It's possible that they removed the caster change part because they realized that, like you have said, if it is in range it is likely something else that is causing the DW.

 

OK thanks much!

 

On my non-lifted (stock height) 2021 F-250 with Snow Plow prep package I was able to get caster to 4.4 degrees with Carli 2 degree caster shims. Made a huge difference in tracking straight and getting rid of wander. I did not have death wobble just wanted more caster for straighter tracking.

Install of the caster shims takes max 20 minutes per side. Then go get it aligned.

One of the best mods/improvements I have done on my truck.

It does increase steering effort when turning while not moving, especially when loaded such as towing. Not that big of a deal though, it's not that bad you can just hear/feel the PS pump struggling a bit. My truck does not have the adaptive steering option maybe that would overcome some of it.
Seems like Ford chooses low caster angle to save money on fitting a more powerful power steering box/pump.

 

Think of a shopping cart with the front wheels that wobble like mad. Thats from not enough caster. Sure when all parts are new and tight, the front end wont wobble, at least to the driver it doesn't, once a part starts to wear, then one wheel will start to wobble. With new tie rods, new track bar and new track bar ball joint, both front wheels are locked to each other. When one wheel hits something it will start to wobble, but the other wheel prevents it. Introduce any part from those three with wear, now when one wheel hits something, and starts to wobble, the other wheel can no longer absorb it, the wobble increased dramatically and now you have death wobble.

This is on a stock setting. Going back to the cart with wobbling wheels, the caster is nearly 0, the closer the caster is to zero, the more likely it is to wobble. The ball joints are your caster angle, the pivot point for the wheel. The further back the top ball joint is in relation to the bottom ball joint, the more positive the caster, the less likely for the wheel to wobble. Ford specs are up to 3.4* positive caster. With good sturdy components, there is nothing wrong with 3.4*. Makes it easier to turn the wheel when rolling, less stress on the gear box. It also makes it much easier for the wheel to lose tracking, AKA Wobble. Increasing caster decreases the chance of wobble and allows the wheel to track straighter on its own.

Anywhere between 4 and 5* equally done on both sides goes a long way to prevent death wobble, especially as the parts wear. You can replace all the parts long before they are really needed to be replaced to prevent it, or, add some caster to put it between 4 and 5 and prevent it altogether. When you hit a bump with stock caster settings, regardless of new parts or not, you can feel the wheel want to shake, but when the caster is up around 5, you hit a bump and there is nothing in the steering wheel. I completely eliminated all of that by adding 2 1/5* cams. I could have just replaced the cams and that would have solved it all as there was very little play in any of the parts, but I could feel it want to break loose on some hard hits, now its like the truck saying, is that all you got?

When you do a lift, especially any time the front axle is dropped with new control arms, unless the control arm has a way of rotating the axle, always plan on increasing caster, when the body is raised from the axle, the axle tends to twist top forward decreasing caster. The more caster, the straighter it will track, the better it will corner, and the faster it will return to center. While mine doesn't ride on rails, too damned big and heavy for that, it does drive nice and straight and corners amazingly compared to before, I gave an audible WOAH the first time I made a right above 20 MPH with how well it turned.

Is increasing caster the do all end all for Death Wobble? No, worn components can still cause it to happen even with increased caster, however, the parts will be truly worn when that happens, not slightly worn good for another 30K miles worn. Worn like, You really should think about replacing it worn.

On mine, since I had to replace the seals, it was easier to remove the spindle to replace them all, so while I had it out, I replaced the ball joints, 142K on them, might as well. There was no play in any of them. The lower tie roads were new when I bought the truck at 132K. The drag link and upper tie rod had no play in it, but since I have it apart. the only play I did find was a little side play in the track bar bushing. Side as in can move the bar back towards the bumper a bit, and the ball joint itself if I really pried on it would move. None of this would cause death wobble with how the caster is set now, but sure induced just enough for it to think about it at 3*.