Adios 35's and hello Hello 275/70R18 Nitto Terra Grappler G2’s with Rebel 6 18x9 +1

[780]

20's will never ride as good as 18's

You stated it was due to 18's having more sidewall height. What if the 20's have the same size sidewall?

For example, the OEM FX4 18's come with a 275/65/18 (32") and OEM FX4 20's come with a 275/70/20 (33"). I can't imagine .5" of sidewall would make a noticeable difference in ride quality.

your switch to 18" wheels is the biggest reason for your better ride. 20's may "look" cool... but a big part of ride quality has to do with side wall height. a taller side wall simply gives more compliance to road imperfections.
i'll never have anything bigger than 18'" wheels.

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[CaptainAmericaRob]

it does. you have to take into account the stiffness of the sidewall, along with the height.
because OEM's want to limit the max O.D. of the tire and wheel assembly, due to packaging constraints within the wheel well opening, 18's and 20's will have a a nearly identical O.D.
So... to avoid wheel rim damage from a curb strike on the 20's , the 20" tires have a stiffer sidewall.
the sidewall's greater resistance to flex (for rim protection) means they generally will transmit more road vibration thru to the driver, giving them a harsher ride. some people may notice it less than others...trust me, it's there.
I worked in wheel and tire testing for years.

 

[Snakebitten]

Not to beat a dead horse, but the tire is only one component in the ensemble that makes up the overall ride experience.
It is possible to have your cake and eat it too if you tune all the components to your preferences.

 

[780]

due to packaging constraints within the wheel well opening, 18's and 20's will have a a nearly identical O.D.

The factory 18's are on a 32" tire and the 20's are on a 33" tire.
Anyhoo... I drove an similar truck (FX4 sport) on the 18's and actually ordered the 18's on my factory order before changing my mind and going with the 20's. I did not notice a difference in ride.

In regards to the OP, they went from a pretty aggressive AT to a pretty mild one. I'm guessing the tread would play a bigger difference in ride quality vs sidewall size. Guessing the larger tire was also a load range E. Not sure if the new tires are but if not, that could be a factor too.

 

[CaptainAmericaRob]

Like I said, some people notice it more than others. Different people will have different experiences with differently equipped trucks...
and yes the side wall is a major factor. The higher the load rating, the tougher the compound and stiffer the side wall.
If you don't believe me about the wheel/tire envelope being a design/engineering point, that's ok lol.
glad you like your 20's... I'll never want 20's on a truck. Its all a mute point. I don't care what anyone wants to run on their truck, I was just trying to offer reasons for the harsher ride.

 

[Snakebitten]

I don't think anyone is denying the compromises associated with a 20" VS 18" wheel in regards to influencing the ride quality.

What I do believe though is that it's not 100% cut & dry. Tire brand/model/spec comes into play too. Not every 20" tire is stiffer than every 18" tire. But I do understand the point.

 

[dkevox]

Like I said, some people notice it more than others. Different people will have different experiences with differently equipped trucks...
and yes the side wall is a major factor. The higher the load rating, the tougher the compound and stiffer the side wall.
If you don't believe me about the wheel/tire envelope being a design/engineering point, that's ok lol.
glad you like your 20's... I'll never want 20's on a truck. Its all a mute point. I don't care what anyone wants to run on their truck, I was just trying to offer reasons for the harsher ride.

I think the problem is you way oversimplified the situation. Considering OP switched from one wheel/tire setup to another wheel/tire setup where the sidewall height was almost identical between the 2 (35" tires on 20" wheels, vs 33" tires on 18" wheels).

I would agree with a statement that in general, 20's will ride worse. But this is not a universal truth by any means. Everything from weight of the wheel/tire combo, suspension design, rubber compound, and so many more factors affect ride quality, which itself is a subjective matter. If you want more grip and performance as opposed to a plushy ride, than maybe a larger wheel is for you. If you want better acceleration and stopping, then a lightweight larger wheel can reduce the unspring mass and can get you that performance.

Maybe just avoid the generalities.

 

[CaptainAmericaRob]

I think the problem is you way oversimplified the situation. Considering OP switched from one wheel/tire setup to another wheel/tire setup where the sidewall height was almost identical between the 2 (35" tires on 20" wheels, vs 33" tires on 18" wheels).

I would agree with a statement that in general, 20's will ride worse. But this is not a universal truth by any means. Everything from weight of the wheel/tire combo, suspension design, rubber compound, and so many more factors affect ride quality, which itself is a subjective matter. If you want more grip and performance as opposed to a plushy ride, than maybe a larger wheel is for you. If you want better acceleration and stopping, then a lightweight larger wheel can reduce the unspring mass and can get you that performance.

Maybe just avoid the generalities.

well i thought i went into fairly good detail, stemming from my years of working in the wheel and tire testing lab... but ok, forget i said anything. lol to each their own

 

[dkevox]

well i thought i went into fairly good detail, stemming from my years of working in the wheel and tire testing lab... but ok, forget i said anything. lol to each their own

I enjoyed reading your replies. I only meant to share my opinion as to I why maybe the reaction to your initial "20s are always worse" comment may have not been what you expected. It did very much seem you missed that these were completely different od tire/wheel combinations that were being compared.

 

[Travis.harris1]

You make a really good point.
Adding a substantial increase to the wheel/tire weight changes what is called "wheel rate" in the suspension tuning world.

Which really is just another term for "spring rate", but measured at the center of the wheel, rather than directly above the spring itself.

For trucks with Ford's CCD (active dampers), the wheel rate for the front suspension is listed in the VDM module, as well as the value for unsprung weight. Hypothetically speaking, if you had CCD and you upgraded to 35's, you would need to inform the truck of the change so that it could "adjust" its algorithm for increased damping, or else the ride would be affected.

In the analog suspension, you described exactly that, subjectively, of course.

I have installed Load E ~35" KO2's on my previous truck and then installed aftermarket dampers/springs to account for the substantial increase in unsprung weight. Truck road better than this CCD equipped truck.

Again, all this is subjective. Not everyone would like what I like, nor would many even care? Lol
But in my opinion we are blessed to live in an Era where you can have a truck that looks good, runs like a sports car, and handles great too! My dad and grandpa's trucks?

@Snakebitten how would you inform the truck of the change?

 

[Snakebitten]

@Snakebitten how would you inform the truck of the change?

If you have CCD, you can use FORscan to access the VDM module and edit the fields related to unsprung weight and wheel rate. (The VDM mysteriously only has wheel rate {spring rate} for front end)
In theory you are increasing/decreasing the value in Kilograms and thus influencing the algorithm for voltage sent to each damper valve.

 

[Ranger621]

I ditched the 20's for Rebel 18's with 275/70-18 Goodyear Ultraterrain. I love them. No level yet, but no rubbing or clearance issues either

 

[LegaZ88Z]

I ditched the 20's for Rebel 18's with 275/70-18 Goodyear Ultraterrain. I love them. No level yet, but no rubbing or clearance issues either

Do you have a picture of the truck on 20's? I'm contemplating the downsize in rim size at the moment. Everyone's input and especially the photos before/after are helpful to me. Truck looks great btw!

 

[Ranger621]

I switch the tires and wheels so fast after buying the truck I do not have any original wheel and tire pictures. However, I kept my 20's and put Blizzak 275 /60 R20 on them which I just switched over to for the winter. I'll take some pictures of that combo and post them.

 

[Ranger621]

Here's a picture of my 2010 F150 Lariat with 275/70-18 Goodyear Trail Runner tires on 18"'s with the front leveled.

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