Ride quality opinions requested -- 20" SL vs 18" E rated tires on 2023 3.5 Max Tow FX4

[Bryan Simon]

My truck is a "21 XLT 301A SuperCab 8' long bed HDPP with Max Tow, 3.75 diff. This config comes stock with General Grabber 265/70-18 load ranto the load range C is that there are very very few choices in that spec.

good to know there is another “Super8” out there
Mine is a 4x4 without the max tow and hdpp

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[dspa]

Hi All,

Sorry I didn't get back here, sooner. My test drive on Wednesday got canceled, rescheduled to Friday, then canceled again due to inclement weather.

I've fully returned my truck's rear suspension to stock (removed swaybar and aftermarket shocks) and this seems to provide the best ride with the Max Trailer Package suspension. I'm experimenting with weight in the bed. Biasing the sandbags rear of the rear axle seems to make the front a bit jittery, but smooths the rear out. I've since moved the sandbags to the front of the bed, behind the cab, and have yet to take a test another drive. I've got 400lbs in there right now. We'll see.

I've been able to determine that the vibration increases upon mild acceleration at higher speed and in higher gears (~80mph, 9th, 10th gears). I've played around with locking out higher gears but am not 100% sure it makes a difference. The issue seems intermittent, frankly. I went and spoke with the service manager at a different dealership in Albuquerque on Friday, and described this behavior to him. His response is that it sounds like it could possibly driveshaft imbalance or driveshaft pinion angle. I'm dropping off the truck for a week at his service department the week after next.

Also, the Tremor wheels came in, and I'm having the General Grabber SL-load tires installed Monday or Tuesday (depending on when they arrive at my friend's shop on Monday). I'm sure they will make the ride a bit softer, which is good. How much softer? Well, I'll find out, won't I?

Finally, I'm going to be listing some almost-brand-new Fox 2.0 shocks, Bilsteins, and a Steeda swaybar in the classifieds soon (hopefully tomorrow). Just a heads up in case any of you want any of that stuff. It didn't really do anything for me. Well, the swaybar DID reduce body roll, but that's not the fix I was after.

Dustin

 

[richardrocks]

Keep us posted!

I’ve spent hours reading up on vibration issues, and it seems that very few have had a dealer fully address this without a whole lot of denial. One guy finally took his under warranty truck to a private shop and ended up measuring the pinion angles himself and basically solved it on his own. Not sure why this is so challenging for Ford to acknowledge and address.

I also agree that the severity does seem intermittent. Some drives I feel like I can live with it and three hours later I’m livid.

 

[Calson]

My truck also came with the 20" Hankook Dynapro AT2 tires and the ride is as smooth as any car I have been in. The last thing I would do is replace these passenger class tires with e-rated tires which are going to have stiffer sidewalls and require a greater tire PSI than the factory tires.

If you have issues with the ride at 75 mph then it is not the tires per se. I would start by putting the two front tires on the rear axle and seeing how the ride is affected. If no change then I would have the shocks checked out to see is one of them is defective.

Tires can be out of round or have a manufacturing defect that is going to be most evident at high rpms. On rare occasions a wheel can not be uniform and tires shop installers would see the problem on a balance bubble and adjust the tire so as to minimize the problem. I would pay a visit to a tire shop and not the dealer to diagnose the problem.

 

[Samson16]

My truck also came with the 20" Hankook Dynapro AT2 tires and the ride is as smooth as any car I have been in. The last thing I would do is replace these passenger class tires with e-rated tires which are going to have stiffer sidewalls and require a greater tire PSI than the factory tires.

If you have issues with the ride at 75 mph then it is not the tires per se. I would start by putting the two front tires on the rear axle and seeing how the ride is affected. If no change then I would have the shocks checked out to see is one of them is defective.

Tires can be out of round or have a manufacturing defect that is going to be most evident at high rpms. On rare occasions a wheel can not be uniform and tires shop installers would see the problem on a balance bubble and adjust the tire so as to minimize the problem. I would pay a visit to a tire shop and not the dealer to diagnose the problem.

Same tires came with my truck as well and we love the smooth quiet ride. I'm running 38psi cold with 100lbs. or so in the bed.

 

[dspa]

Yes, I have been feeling pretty dumb for taking the brand-new Hankooks off. Expensive lesson learned.

 

[dspa]

Well, truck dropped off at dealership this morning for at least the next week to diagnose the vibration issue, along with now a slipping/surging issue on medium-high acceleration (especially uphill).

 

[minirx7]

I have Max Tow on factory Hankooks on my SCREW short bed. With about 44,000kms (more than 50% was towing my 7000lb trailer), i am happy to say, i am pretty happy with the ride quality.

I dont feel like the truck rides uncomfortably at all ( i was wondering if max tow was going to be bad for daily, but i needed it for my RV). When towing though, the Hankooks have held up ( usually pump them up to about 44psi cold) . Still got decent tread on them, and was wondering if i should replace these with E-Rated but so far travelling while towing, had no issues.

Last long trip was 5600kms from toronto, washinton, virginia beach, SC/NC, Disney World Fort Wilderness, back through Tennessee and new york to Toronto. NO problem cruising at 70mph with lane keep on for the most part. VERY Happy with this truck.

Just got a new job and i daily drive this to work, and i am very comfortable driving on highway/in traffic (more comfortable than my Model S!).

 

[dspa]

Hi All,

Sorry for the long delay in replying. We went out of town for early summer vacation and the truck was at the dealership for nearly two weeks during and after that time. Throw in kid's softball, birthdays, anniversaries, Mother's Day, Father's Day, end of school year, other obligations, etc... time just got away from me.

The dealership did a thorough go-over of the truck, checking driveshaft balance, pinion angle, and the entire suspension, wheels, tires, etc for issues. In the end, they did yet ANOTHER rebalance of the tires and the truck now rides more smoothly than it has in the past. It's still not perfect, but I have come to believe that the newer asphalt we've been getting laid down here on our freeways and state highways is not particularly smooth, and may actually have some sort of rippling in it that increases/decreases based on temperature, moisture, and sunlight exposure. The chassis of this truck is extremely sensitive. I never thought I'd say this, but I think maybe manufacturers are making modern vehicle chassis TOO stiff. Anyway, where I'm going with this is that I think this is not so much an issue with the truck (except perhaps for its exceptional stiffness), and more an issue with pavement quality and my OCD and sensitivity to vibrations.

Long story short: I spent a lot of money on shocks, wheels, tires, a swaybar, and a lot of time in tire shops chasing a problem I can't fix. Expensive lesson learned, or at least I hope I've finally learned it.

I'm going to be posting the shocks, OEM tires, and sway bar for sale in the classifieds TODAY (only about a month later than I originally planned). So if any of you who have been watching this thread are interested in any of them, now's your chance.

Thanks again for everyone's time, interest, and input in this topic. It's truly been a learning experience for me (and financially painful), so hopefully I can spare someone else the same grief in the future.

-Dustin

 

[Area5150]

Greetings from New Mexico!

Short time lurker, first time poster!

At the end of March, I purchased a new 2023 3.5EB Max Tow FX4 short-bed and generally love the truck.
What I have been less-than-enamored with, however, is the ride. On perfect pavement, at lower speeds, it is extremely smooth. However, at highway/freeway speeds, the thing is jittery as [insert colorful metaphor here]. The 2001 Dodge Ram 2500 Cummins I replaced (and am sorely missing at the moment) rode way smoother at highway/freeway speeds.

This new truck came with the 20" Hankook Dynapro AT2 tires. I first had those tires rebalanced at the dealership. Then I tried having those tires replaced with Michelin Defender LTX M/S. Then I had those road-forced and re-road forced several times. Not sure I'm welcome at that Discount Tire location anymore. I've tried replacing the rear shocks with the Fox 2.0 and the Bilstein 5100. Both were easier to compress than the stock shocks (which goes against the stories I've read about the pre-14th gen trucks). I've also dropped the PSI in all the tires to levels most of you would probably consider irresponsible. Anyway, I've basically come to the conclusion that, barring some problem with the driveline, this truck just rides like, well, a truck. I have come to realize I basically bought the stiffest F-150 you can get.

That all said, I'm looking at sizing down the tires to 18". I ordered the Tremor wheel kit from Ford which I think will look awesome on my gray blacked-out Platinum truck. However, I'm a little concerned with what I'm finding on load ranges on tires for smaller wheels. It appears, to keep my factory circumference (going from 275/60R20 to 275/70R18) would basically require I change from SL to E rated tires.

So, after all my jabbering, here's the question for you experts out there - will 18" E rated tires give me a softer ride than the 20" SL rated tires I have now? If not, what would you recommend I do? (I realize that's actually 2 questions)

Thanks for sticking with me all this way (I know I tend to get wordy), apologies for my overuse of parenthesis, and thanks in advance for any advice and opinions!

-Dustin

Alot to unpack here. Ultimately ride quality is really subjective and will be different across owners. I am not sure what you can do to soften the ride if the stock shocks and SL rated tires were too rough. I certainly would not recommend going to a E rated tire.

For point of reference, I have the exact same truck and while the additional leaf does make it a bit more twitchy I dont find it as harsh as you but again... subjective. I would say you will be a more compliant ride with a smaller diameter wheel but I dont believe you have to step up to an E rated tire to get that on an 18" wheel.

 

[dspa]

Alot to unpack here. Ultimately ride quality is really subjective and will be different across owners. I am not sure what you can do to soften the ride if the stock shocks and SL rated tires were too rough. I certainly would not recommend going to a E rated tire.

For point of reference, I have the exact same truck and while the additional leaf does make it a bit more twitchy I dont find it as harsh as you but again... subjective. I would say you will be a more compliant ride with a smaller diameter wheel but I dont believe you have to step up to an E rated tire to get that on an 18" wheel.

Hello!

Thanks for your thoughts. I do appreciate them. It’s funny you should reply to this thread today… I’m actually having a vibration analysis done this week. My friend who owns an Indy shop here in Albuquerque took a drive with me and agreed something doesn’t seem right at the 75-80mph range, so we’re engaging a local expert on the issue.

I came to this platform from a 2001 Ram 2500 Cummins - not the smoothest vehicle in the world. I don’t expect a ride like a luxury sedan. It is a truck, after all. What I do expect is a vehicle that doesn’t vibrate and I’d happily accept a firmer ride to that end. Wheels and tires are (most likely) not the culprit, so hoping the analysis can point me in the right direction. I love this truck in every other way, but I can’t deal with the incessant vibrations.

I never mentioned this here, but I also found the transmission underfilled from the factory. I discovered this while attempting to diagnose a separate issue — a rumble-strip-like vibration (through the whole vehicle) on acceleration at certain speeds. I did a drain and fill up to the proper level and that seems to have improved this particular issue quite a bit, though it’s still there.

All vehicles have their quirks. After all, they are imperfect machines made by imperfect people. Vibrations of this nature are just something I can’t deal with. It makes the whole vehicle feel like junk to me. That may not be rational, but it’s how my brain works. OCD at its finest, I suppose.

 

[nitrobass24]

I also have a vibration at 75-80. It goes away at 85+

just wish I could make BC work above 80mph

 

[GIjoe]

As a result of my own experiences i don’t have this miracle opinion of road force balancing like many do on here. I’ve gone through balancing and re balancing over and over all the while the fact that I had 2 out of round tires going unfounded until I did my own check and found it myself, problem solved. Several sets of tires all road forced balanced with the same shaking and vibrating while I’m told they balanced out just fine. My last 3-4 sets of tires from DT all came with vibrations and/or shaking at freeway speeds. I wish they would give print outs like they do for alignments. Anyways..rant over.. have you tried balance beads? A friend swears by them and that would have been my next experiment.

 

[dspa]

Which tires did you buy from DT, if I may ask? I'm running the Michelin Defenders.
I've definitely considered the possibility I've had a couple sets of out-of-round tires. At this point I want to see what the vibration analysis reveals before I throw any more money at this. It sickens me how much time/money/energy I've put toward this already.
I also wonder if the stock suspension just isn't up to the task of masking harmonics that set up at certain speeds. Seems like Ford tunes these trucks to ride nice and soft at lower speeds (test drive speeds?). I'm not a suspension expert so anyone's guess is as good as mine on that front.

 

[tidefan1967]

I swapped the factory 20” with Goodyear Fortitude HTs for 18s with General Grabber HTS P275/65R18s from my dads 21 Lariat FX4 and the ride and vibration freeway speeds were considerably better. I swapped them and then made a short trip down the interstate and then swapped them back. Replaced the factory Goodyears with a set of General HTS60s with the same size but there was barely any noticeable difference between the two. Going to put his 18s back on and do some further testing. Maybe I just need to go to 18s permanently. Will report back later on.

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