TV tire size question

[okhcolot]

We are shopping for a new TV and have a 5.0 on order. We've decided on a Ford F150 with max tow package and 3.5 ecoboost with a 6.5' bed. We found a 2020 we like, and the pricing right now is really good with the 2021's coming out. My question is this; the vehicle comes with an off road package too, so instead of 18" tires it has 20" tires. Are there any advantages or disadvantages to a larger tire? Will this affect the bed height of the truck as it applies to the hitch and towing? Also wondering if this package would add much weight to the truck which would then affect the payload. I am a complete newbie when it comes to trucks but would appreciate any info!

[Centex]

When talking about the different wheel / tire options available on the F150 all have essentially identical outside ('rolling' ) diameter - they do not in themselves meaningfully affect bed height (other associated options / components like springs may affect that).

SO, the difference is in the wheel diameter, not the tire diameter, and resultant tire sidewall height - the larger the wheel, the lower/less sidewall for the tire (the tire is said to have a lower "profile", referring to the sidewall compared to the overall diameter of the tire).

Less sidewall (lower profile) generally is associated with a greater relative propensity for tire/wheel damage if you hit deep / sharp potholes or road hazards (there is less sidewall available to absorb the height of the obstacle and protect the wheel rim). That may or may not be significant, just depends on the circumstances when such an event occurs.

Less sidewall (lower profile) is generally associated with a relatively firmer ride, in the extreme 'harsh' (less sidewall means less rubber / 'cushion of air' to provide tire compliance over bumps).

In general lower-profile tires are relatively more expensive to replace, all other things being equal.

Note all of this is relative, all may or may not be of consequence to you, different folks have different sensitivities. Personally I prefer higher-profile tires (with corresponding smaller diameter wheels) for my trucks when available, YMMV.

Hope this helps rather than adds to confusion.

From https://tiresize.com/calculator/, here's an illustration using two of the commonly available 18" and 20" F150 wheel/tire options:

[okhcolot]

Ahh, that makes perfect sense, thanks for the explanation. So it would seem to me that adding a 20" wheel to an off road option would not make a lot of sense if the 20" is more prone to damage from off roading lol. Plus more expensive replacement tires isn't ideal. I'm guessing the 20" wheels are more for looks than functionality.

[Centex]

Originally Posted by okhcolot

I'm guessing the 20" wheels are more for looks than functionality.

Can't (won't) comment on the reasoning behind wheel/tire bundling options offered by Ford, that 'design' could be complex.

'Prudent' off-roading may be assumed to involve much lower speeds with much more latitude in picking your path to avoid tire-threatening situations(?). My preferences are driven by on-road / highway driving considerations because that's the vast majority of my use, YMMV.

I'll just note that review of the F150 Build Guides indicates several of the higher payload / higher tow-rating 'option bundles' offered by Ford for late model F150's tend to include to larger diameter wheels / lower profile tires. It is what it is.

[JeffreyG]

Originally Posted by okhcolot

Ahh, that makes perfect sense, thanks for the explanation. So it would seem to me that adding a 20" wheel to an off road option would not make a lot of sense if the 20" is more prone to damage from off roading lol. Plus more expensive replacement tires isn't ideal. I'm guessing the 20" wheels are more for looks than functionality.

Exactly. Large wheels / thin tires are generally only for aesthetics. Maybe on a sports car, they improve laterial grip too, but who really cares about skidpad numbers in a truck?


Downsides to large diameter wheels / low profile tires:
1) Usually an up-cost on the original vehicle.
2) Stiffer ride
3) Prone to damage in potholes
4) Increased unsprung mass, increased fuel consumption
5) More expensive tires at replacement time


I don't suggest people run tiny 15" wheels on big pickups. But 17" or 18" wheels are ideal for a fullsize PU and anything bigger is getting into a range that is not as good.

[Centex]

FWIW my 2005 F150 SuperCab with 6-1/2' box predates the 'low-profile tire craze', could only be had with 17" or 18" wheels.

Mine is OE with 235/70R17" tires, yielding a 'sticker payload' of 1729#, GVWR of 7050#, GCWR of 15000#, max GTW of 9500#.

The combo has served me well for 15 years of RV and heavy AG utility towing, there's a wide range of reasonably priced replacement tires, and I've every confidence it'll be a great TV with my 5.0TA.

Granted, it may not be the fastest through a slalom speed run, some low-profile 20" tires would probably help a tad bit there

[Vermilye]

I do find it a bit strange that the Off Road version of the F 150 is only available with 20" tires, at least when I purchased my 2018. Still, I have not had problems with them on or off road.

[Brian B-P]

I don't think the inclusion of 20" wheels in the off-road package on an F-150 is surprising at all. While it doesn't make obvious technical sense, it does make marketing sense: both off-road packages and larger wheel packages are purchased mostly for appearance rather than for any functional reason.

[oldwave]

Originally Posted by Centex

FWIW my 2005 F150 SuperCab with 6-1/2' box predates the 'low-profile tire craze', could only be had with 17" or 18" wheels.

Mine is OE with 235/70R17" tires, yielding a 'sticker payload' of 1729#, GVWR of 7050#, GCWR of 15000#, max GTW of 9500#.

The combo has served me well for 15 years of RV and heavy AG utility towing, there's a wide range of reasonably priced replacement tires, and I've every confidence it'll be a great TV with my 5.0TA.

Granted, it may not be the fastest through a slalom speed run, some low-profile 20" tires would probably help a tad bit there

What tires have you been using, I’m about to replace them on my 2004.

[C&G in FL]

I don’t think it has been mentioned but my first F-150, bought in a hurry off the lot, had the 20-inch wheels, and as Brian stated, they had a “nice” appearance. But the larger rims added just enough weight to put me 25-lbs over the limit so it was considered a commercial vehicle in Florida, which meant it had to be registered in December, rather than my birth month, necessitating two trips to the DMV (and long waiting times) rather than one. That was irritating but not necessarily a reason to criticize 20-inch wheels. The OEM tires were Pirelli. To say they were the worst riding/handling tires on any vehicle I have ever owned would be an understatement. But the real reason I would never put 20-inch wheels on another F-150 is that when the tires needed to be replaced, a trip to several tire outlets revealed that I only had three choices, Pirelli again or two others. That was in 2014. Perhaps more tire manufacturers are now marketing tires that would be appropriate replacements.

[okhcolot]

It seems that most trucks left on the lots right now have 20" wheels. We've only found one that meets all of our parameters AND has 18" wheels. Makes it more difficult to negotiate, but I'm convinced from everything said here that we are sticking with smaller wheels.

[Centex]

Originally Posted by oldwave

What tires have you been using, I’m about to replace them on my 2004.

Currently Michelin LTX M/S2, I'm not certain that particular tire is still available in the OE 235/70R17 size for our '04-'05 F150s.

Still happy with them @ ~35k miles, still lots of tread, but I think they may be getting 'noisier' of late (I do religiously rotate at ~4k miles - free including rebalance at my local Discount Tire Store).

Edit - here's a recent pic where the tread happens to be visible if you zoom in

[Brian B-P]

Originally Posted by C&G in FL

But the real reason I would never put 20-inch wheels on another F-150 is that when the tires needed to be replaced, a trip to several tire outlets revealed that I only had three choices, Pirelli again or two others. That was in 2014. Perhaps more tire manufacturers are now marketing tires that would be appropriate replacements.

Yes, the 20" wheel size has become so common on full-size light trucks that there probably isn't a major manufacturer without at least one model of tire in the 20" size that something like an F-150 would use. That doesn't mean that they are the right choice for everyone, only that availability and choice should no longer be issues.

I plugged a typical recent F-150 into the search tool at TireRack.com, picked the 20" size offered (275/55R20), and was shown 75 brand/model choices: 21 brands with up to 9 models per brand.

Changing technology - as just as importantly changing fashion - can be a problem for tire availability. Many common cars of the 1980's used sizes which are no longer available, or available only in some undesirable off-brand... because everything has larger wheel diameters and lower tire profiles now. I suppose the good thing about the stunning lack of progress in anything related to trailers has a good side - the same tire sizes used on Escape-sized trailers a quarter-century ago are still the most common sizes.

[oldwave]

Originally Posted by Centex

Currently Michelin LTX M/S2, I'm not certain that particular tire is still available in the OE 235/70R17 size for our '04-'05 F150s.

Still happy with them @ ~35k miles, still lots of tread, but I think they may be getting 'noisier' of late (I do religiously rotate at ~4k miles - free including rebalance at my local Discount Tire Store).

Edit - here's a recent pic where the tread happens to be visible if you zoom in

Thanks, those are what I was leaning toward.

[Ian and Sue]

Originally Posted by oldwave

Thanks, those are what I was leaning toward.

I have run these tires on a couple of trucks and they are great...enough traction, good wearing, not noisy, they seem to handle well wet and dry too. I do run another set of rims and Bridgestone Blizzaks in the winter here in the mountains though! Gotta have good snow tires to live around here.