How to: 2020 Explorer ST - Performance Tires/Wheels Sizing Guide

[UNBROKEN]

A wider tire effects what ratio?

 

[peterk9]

The 3% diameter variance. That's what we're discussing. A 255/50R20 has a diameter of 263mm. Change that to a wider 265/50R20 and the diameter changes to 773mm. A 275/50R20 would be 783mm or right on the 3% difference. Many people aren't aware that a wider tire also affects the diameter and therefore may also affect the other features I had mentioned.
Some of the later 5th gens had a program whereby you could select a different programmed tire size so that the other components would adjust to the new size. I don't know if the 6th gen has the same ability.

Peter

 

[UNBROKEN]

You’re making the assumption that a wider tire is automatically a different OD...and OD is all that matters. If you choose a tire wisely you can go wider and maintain the same OD as stock. The width means nothing to the computer systems.
For example...a 315/35/22 is the same OD as the stock 275/45/21’s that came on my ST.

For your 255/50/20 example...the right choice for a wider tire in a 275 would be a 275/45, not a 275/50. The 45 is close enough in OD nothing would be affected.
Proof? I went from a 275/45/21 to a 305/35/22...zero negative effects on anything and the Speedo is dead on and verified with 2 separate GPS devices. That’s wider AND shorter...see how that works?

 

[peterk9]

You’re making the assumption that a wider tire is automatically a different OD...and OD is all that matters. If you choose a tire wisely you can go wider and maintain the same OD as stock. The width means nothing to the computer systems.
For example...a 315/35/22 is the same OD as the stock 275/45/21’s that came on my ST.

For your 255/50/20 example...the right choice for a wider tire in a 275 would be a 275/45, not a 275/50. The 45 is close enough in OD nothing would be affected.
Proof? I went from a 275/45/21 to a 305/35/22...zero negative effects on anything and the Speedo is dead on and verified with 2 separate GPS devices. That’s wider AND shorter...see how that works?

I'm fully aware of that as I have posted similar posts like that about changing sizes. My point was simply to state the a wider tire can affect the ratios. I have also changed sizes with little to no change to the diameter variance.

Peter

 

[Surfside]

Appreciate the tips and advice.

If I go with the 22 x 10.5 wheels, what is the best tire size? The original poster of this thread WISHD he gone with the 315/35R/22 tires, but that was for 11” wide wheels. I see that 315/35R/22 tires also fits a 10.5” wide wheel. Is that the correct size tire I should go with for the 10.5” wheels? Thanks...

 

[Surfside]

After some searching, it appears there are far more tire options at 325/35R/22 wheels. Very limited at 305 and 315. But maybe the 325’s are too big, idk.

 

[Surfside]

Sorry for all the questions, last one...

What would be the main difference between the 315’s and 325’s? More side bulge on the 325’s? I’m looking for the widest wheel/tire package without rubbing. Since I’m going with 10.5 wheels, would the 325’s make them look a pinch wider than the 315’s?

 

[UNBROKEN]

The best size IMHO for a 22x10.5 at +30 is a 305/35...especially if you plan to drop it. A 305/40 would work if you don’t want to drop it but go with a +35 offset for a little more clearance at full lock...and even then it’s gonna be pretty close.
Not to disparage the OP but the thread title is misleading. He didn’t do his homework properly and wound up with ill fitting wheels as a result.
Here’s mine on 22x10.5 +30 with 305/35’s and H&R drop springs. This is proper fitment.

 

[EnergyFX]

Alright, so let's clear a few things up here because there is a bit of misinformation going on.

1) Unbroken, nice set up man. The drop looks good
2) 315/35R22 on 11 inch wide rims with +35mm offset WILL fit under the ST with ZERO rubbing
3) If you choose to go with 10.5 inch wide rims you need to bring the offset down to +30mm
4) TO BE CLEAR, your target should be to push the sidewalls .9" further out. NOTE: the 315/35R22 on 11x22 with +35mm offset AND the 305/35R22 on 10.5x22 with +30mm offset BOTH push the outer sidewall out .88"... so point made and fact proven
5) 315/35R22 is nearly identical overall diameter to the factory 275/45R21
6) 305/35R22 is 1% smaller diameter - yes this is negligible and you, the cops, NOBODY will ever notice
7) The ST has its highest risk of rubbing at somewhere between 15-25 degrees of steering angle, NOT at full lock. Even with the 325s on it I have no rubbing at full lock
8) AGAIN, the target is to get the outer sidewall about .9" further out
9) Wheel Offset Calculator is a GREAT tool and make all this really easy to visualize

The comment about me not doing my homework does hit a bit of a nerve, but I don't think you meant to Unbroken. The detail of my original post alone should be enough to show the amount of homework that was done on this endeavor. The goal was to fit the absolute maximum amount of rubber under the ST without major modifications. I went into the 325s knowing it was going to be tight, but I also knew I could always step down to 315s if it didn't work out. I also knew that +35mm offset was where I really wanted to be for a nice flush appearance, but the math indicated that going +35mm with the 325s was going to get tight with the inner sidewall and the shock absorber.

What does all this mean??? It means that 315/35R22 on 11 inch wide rims with +35mm offset is the fattest meat you can fit with all proper clearances and no rubbing or other negative side effects.

It also means that 305/35R22 on 10.5x22 with +30mm offset will fit as well with all proper clearances and no rubbing or other negative side effects, but it is an almost half inch narrower tire. Unbroken, you have about .75" between your inner sidewall and your shock absorber, don't you?

As for my "ill fitting" 325s... the rubbing really is very minor. After over 12k miles on the new wheels (yes I drive a lot... my commute alone is 45 miles one way) there is no indication that the rubbing is even occurring. And I have yet to take the time to see if I can do a bit of work to the wheel well liner to get rid of the problem altogether.

Surfside, you are absolutely welcome to call me. I will shoot you a PM with my number. Same goes for anyone else, just hit me up via PM and I'll shoot you my number.

I appreciate how much this thread has grown. My whole goal with starting this was because, in all my 'ahem' homework, I could not find any good usable info on tire/wheel sizes and offsets for the 2020 Explorer ST. I wrote this so others could learn from my trials and experience.

 

[UNBROKEN]

The full lock statement is semantics. On the way to full lock yours rub the inner fender. You didn’t even have to post it...I already know. Your math is still off on fitting your combo flush with the fender. You’re right the number to hit is .9” further out compared to the oem 21” combo. To hit that number you would need a +40 offset. I haven’t physically measured but you would be dangerously close to the strut at that number. I’ve helped quite a few people with fitment on these things...I would never recommend an 11” wheel for the front. Your way earlier post about shaving the mounting pad To get to +35 is borderline dangerous and I would never recommend that either....not to mention +35 will still be outside the fender with a 325.
I’ve fit countless custom built wheels for friends, people on multiple forums and myself over the years. I’m all for fitting a wide tire...but I’m more for doing it correctly. Just because it physically fits doesn’t make it right.
There’s no misinformation going on. My math is correct.

 

[EnergyFX]

I've stated multiple times that my 325 setup is not ideal and I plan to change over 315s. I've been very transparent about the fact that I tried to push the envelope and I have clearly stated that the 325s are just a hair out of the max range for the front. Custom wheels can be milled to any offset as long as it is within their engineered range. The ones I bought were ordered at +30mm but I could have ordered more offset in them. More offset can absolutely be machined off, but it's important to use a quality machine shop. If you have "fit countless custom built wheels" as you claim, then surely you know that. So, yes, I can sent these back in to get re-milled and it is perfectly safe.

I didn't come here to have an internet flame war with you, man. If you "know the math" then you know I'm correct about 315/35R22 on 11x22" with +35mm offset being a perfect fit. If someone wants 12.4" of tire width under their ST then that's the ticket. And if they want 12" of tire width then your 305/35R22 on 10.5x22" with +30mm offset is also a perfect fit. I'm not sure why you are coming here trying to say your setup is the only proper fitting setup.

You keep focusing on my 325s when I've clearly said don't do 325s, do 315s instead... and now you've supplied a 305s setup that is also a good fit. It's all good info.

 

[Surfside]

Ok. I know I want to stick with the 10.5” wheels. The tire size is my dilemma. At 305 and 315, there appears to be only 2 tire brand options for both. Not ideal imo. A few thoughts....

1. I do not plan to drop it.
2. A 305 is a smaller diameter wheel. Don’t want to go smaller.
3. I like that the 315/35/R22 is the same diameter as original. Although I wouldn’t mind going slightly larger if possible without rubbing.
4. If I went slightly larger, that would appear to throw off the speedo reading and I don’t know how to correct that or who I would take it to.
5. I didn’t want a super low profile. It’s an SUV and I’m of the opinion there should be some rubber between the wheel and road.

It seems the easiest choice would be the 315/35’s to get the same diameter and speedo readings, but would just have to live with the 2 questionable tire options.

That said, would a 325/35 on 10.5” wheels work? They would only be .3 (1%) larger in diameter, the speedo difference is minuscule, and there are far more tire brand options. If the 325/35’s on 10.5” will fit, what do you recommend the offset should be?

Again, really appreciate the help and advice.

 

[Surfside]

BTW, I know UNBROKEN and EnergyFX are slightly disagreeing on some measurement issues - in a friendly manner - but I enjoy hearing from both. The more discussion, the more ideas and food for thought. Thanks to both of you.

 

[EnergyFX]

Both 315s and 305s will work with 10.5" wheels, so you're good there. But you'll want to decide on one or the other because the tire width will dictate what offset you want to go with. If you choose 315s then you want a +35mm offset. If you choose 305s then you want a +30mm offset. Or you can split the difference and go with +32.5mm offset and have options. At +32.5mm the 305s will be tucked under the car about 1/8" further and the 315s will be pushed about 1/8" past the fender.

325/35 really needs an 11" wide wheel. Trying to put them on a 10.5 isn't recommended and will reduce the life of the tires and may cause sidewall fatigue. Clearance wise both 10.5" and 11" fit just fine, its the tire width and diameter that dictate the "fitment" dialog.

As far as tire diameter, you are correct that 315/35R22 are almost identical diameter to stock. 305s are about 1% shorter and 325s are about 1% taller. All are fine from a speedometer standpoint and will all be within 1mph reading at 70mph.

If you really want to go with the 325s then just know you will have the slight rubbing i mentioned. You can maybe try going with a +32 or +33mm offset, but that is going to get your inner side wall close to the shock absorber. 325s at a +33mm offset will probably have you at only about 3/16" clearance, maybe even less.

Also, just for some additional thought... all three tire widths (305, 315, and 325) are compatible with 11" wide wheels. And going with a +32.5mm offset puts you an a perfect median between all three and will give you the flexibility to change up the tire width as you choose. You will still be tight with the 325s and that size is still not recommended, but you might just be able to squeeze them in there... possibly with no rubbing. 305s and 315s are still your safer bet.

 

[Surfside]

Ok, thanks man.

So, it appears the 325's will fit both the 10.5's and 11's. That's the part that was throwing me. I didn't realize the same width tires fit different width wheels... or different width tires fit the same width wheels.

How about the 305/40-R22 tires? I think UNBROKEN suggested a +35mm offset for that size. Would that size and offset get me flush with the fender with zero rubbing? Far more palatable tire options for that size. They would be .9" (2.9%) larger in diameter and +2.1 mph of speedo difference at 70 mph. If I went this route, how can I correct that?

If that doesn't work, I guess I'm gonna have to go with the 315/35/R22 tires on the 10.5 wheels with the +35mm offset and hope that other brand tires become available in the near future.

 

[expl0r3r613]

The best size IMHO for a 22x10.5 at +30 is a 305/35...especially if you plan to drop it. A 305/40 would work if you don’t want to drop it but go with a +35 offset for a little more clearance at full lock...and even then it’s gonna be pretty close.
Not to disparage the OP but the thread title is misleading. He didn’t do his homework properly and wound up with ill fitting wheels as a result.
Here’s mine on 22x10.5 +30 with 305/35’s and H&R drop springs. This is proper fitment. View attachment 320469View attachment 320470View attachment 320471

What Wheels are these?

 

[peterk9]

What Wheels are these?

Welcome to the Forum.
FYI, the member was last seen here on September 8, 2020 so he may no longer be following this thread. However, I did some searching and found the following. I hope it helps. BC Forged EH181 wheels installed.

Peter

 

[Jtur40]

Hello fellow Explorers. First post here, but have lurked for a few months until now.

In this thread I will detail fitting 325/35 R22 tires under an otherwise stock 2020 Explorer ST.

New vs. Stock Side-by-Side Comparison. The new skins are a full 2" wider than stock but only .3" taller diameter:
View attachment 317182

View attachment 317183



So, the wife and I recently purchased a 2020 ST and we have been loving it. However, I wasn't pleased with the factory tire sizing and overall look/stance of the truck. The factory tires just looked too narrow for a performance SUV and they were way too tucked into the wheel well. I spent weeks looking for any information on non-stock sizing and offset that would properly clear. There isn't much out there yet on this new truck, so.... I gathered what info I could, studied and measured the factory clearances, and ultimately took a bit of a risk and ordered some custom milled wheels and tires. In this thread I will attempt to share as much info as I can in case anyone else wants to take the same plunge I did, including what I would do differently knowing what I do now.

1st off, The Factory Setup:

• Factory Wheel Size = 21x9 (WxD)
• Factory Wheel Hub Bore = 70.5mm
• Factory Wheel Offset = +37.5mm
• Factory Wheel Bolt Pattern = 5-114.3mm
• Factory Tire Size = 275/45 R21

2nd, My Aftermarket Setup (not recommended, read on for why):

• EnergyFX's New Wheel Size = 22x11 (WxD)
• EnergyFX's New Hub Bore = 70.5 (no change from factory)
• EnergyFX's New Wheel Offset = +30mm
• EnergyFX's New Wheel Bolt Pattern = 5-114.3mm (no change from factory)
• EnergyFX's New Tire Size = 325/35 R22

3rd, What I Should Have Done (WISHD). If I were to do this over, I would go with the following (note: this setup is technically unproven as of this post, but is provided based on an actualized installation of the above "EnergyFX's" setup and my observations.):

• WISHD Wheel Size = 22x11 (WxD)
• WISHD Hub Bore = 70.5 (no change from factory)
• WISHD Wheel Offset = +35mm
• WISHD Wheel Bolt Pattern = 5-114.3mm (no change from factory)
• WISHD Tire Size = 315/35 R22

The goal was to get a setup where the outer edge of the tire is flush with the outermost edge of the wheel opening on the fenders, with maybe just a hint of tire protrusion at the sidewall bulge. In my personal opinion, a slight protrusion gives a vehicle a good sporty, almost muscular look. I did not want any of the tread pattern to protrude. Unfortunately I missed that mark by just under 1/2 an inch or so (meaning I wish my tires were tucked about .4" under the truck vs. what I ended up with). I may look into sending my custom rims back in to have another 5mm milled off to bring the offset up to +35mm, but it will have to be after I wear these tires down since the extra milling will cause clearance issues with the 325/35 tire size.

With the "EnergyFX's" setup, there is about 1/3" clearance between the front tire and the front suspension (the front shock). This is .72" closer to the suspension than factory and is about as close as I would recommend getting to the shock. It is possible I may have a bit of rub under extreme cornering, but I won't know for sure until summer comes around and I can get a chance to try some aggressive driving and see the results. With the shorter sidewall I get from the 22s I do not anticipate this being a big issue. For now, it looks to be a good setup (reducing inside clearance by .72"). There is still quite a bit of inside clearance on the rear tires.

Factory Tire/Wheel Size vs. EnergyFX Tire/Wheel Size:
View attachment 317184

Factory Offset vs. EnergyFX Offset:
View attachment 317185

In hindsight, I believe a +35mm offset with 22x11 wheels would have probably been perfect, but would require a 315/35 R22 size tire. This would have also been an exact diameter match to factory. I plan to get to this size once I wear through the existing tires. I'll hve to send the wheels off to get the extra 5mm milled off the offset, but that's small price to get to perfect.

Factory Tire/Wheel Size vs. WISHD Tire/Wheel Size:
View attachment 317186

Factory Offset vs. WISHD Offset:
View attachment 317187

Rubbing/Interference: With the "EnergyFX's" setup, there appears to be a small amount of rubbing at hard-over steering. It is not severe and is probably not an issue, but is an annoyance nonetheless. This is another reason why I do not recommend the setup I went with and instead suggest the "WISHD" setup. From my observation there should be zero interference or rubbing with the "WISHD" setup, but that is yet to be officially confirmed.

View attachment 317188

View attachment 317189

View attachment 317190

View attachment 317191

View attachment 317192

View attachment 317193

View attachment 317194


Here is an IMGUR album that has all photos from this post plus a few more:
2020 Explorer ST Wheel Info and Aftermarket 22x11s

This was a great post. Just got my 21 ST about a month ago and I am in the process of starting my upgrade. See way to many stock ST’s around and need mine to look different. Will probably hold off till spring to put some miles on the current tires. Looking forward to adding more meat under the vehicle.

 

[peterk9]

This was a great post. Just got my 21 ST about a month ago and I am in the process of starting my upgrade. See way to many stock ST’s around and need mine to look different. Will probably hold off till spring to put some miles on the current tires. Looking forward to adding more meat under the vehicle.

Welcome to the Forum.

Peter

 

[Overmakta]

How about 305/40 front and 325/35 at the rear with +30? Or will this upset some electronics?