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2021 AT4 - Stock Wheels, Biggest Tire W/Out Rubbing


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Wanted to post my research and share my decision on selecting larger tires on a Factory '21 AT4, 20" Wheels. 

 

There are a lot of threads on this topic, all with great content, but there are some conflicting posts on size choice/rubbing/mpg impact that can make the decision difficult. As others have noted not all tires measure the same height/width/weight, so a one-size fits all approach likely cannot be taken. 

 

**In case you don't want to read through all the details below, I went with BFG KO2 in a 275/65R20. No rubbing, plenty of UCA clearance, ~1MPG loss, speedometer is off between .5 to 1MPG depending on speed. ~1MPG loss does not reflect accounting for speedo variances. I will need to update this post with a manual calculation. I do think you could fit a slightly larger tire, depending on manufacturer choice (see below variations of sizing). 

 

Tire Size:

Based on reading through other posts I narrowed my tire size to three options: 

1. 275/65R20

2. 285/65R20

3. 295/60R20

 

I personally didn't want rubbing issues after tire install. Minor trimming (IE: mud flap trimming) wouldn't be a big deal, but having owned a truck that had rubbing issues, it gets old quick and I wanted to avoid modifications if possible. 

 

Pros/Cons of each tire size I contemplated:

  • 275/65 - great tire size as you get 34" in height, but can appear to have a narrow stance depending on tire choice. Stock tire (Bridgestone Dueler A/T 275/60/20), width would remain the same as stock. Originally ranked 2nd of the 3 options. 
  • 285/65 - best of both worlds, gains in height and width. Ranked 1st of 3 options. Big concern around rubbing issues, especially at full lock on an incline. Likely could avoid by adding a levelling kit. Conflicting results on CV angles and longer-term impact of adding a level kit. 
  • 295/60 - prefer the stance of a 295, but didn't have a high level of confidence there would be clearance from the UCA. Rubbing concerns similar to 285/65. 

 

Tire Brand:

1. Falken Wildpeak AT3W

  • 275/65 - 34.1" X 10.6", 66.1lbs
  • 285/65 - 34.6" X 11.2", 67.7lbs
  • 295/60 - 33.9" X 11.6", 69.4lbs

2. Toyo AT3

  • 275/65 - 34.1" X 11", 54lbs
  • 285/65 - Not Offered
  • 295/60 - 33.9" X 11.8", 60lbs

3. BFG KO2 

  • 275/65 - 34" X 11", 57.3lbs
  • 285/65 - 34.5" X 11.5", 60.3lbs
  • 295/60 - 33.9" X 11.8", 68lbs

**4. After decision came across Mickey Thompson Baja Boss A/T (some great reviews coming out on this tire). 

 

Pros/Cons of each tire size I contemplated:

  • Falken - awesome tire with some fantastic reviews. Major consideration was the weight.
    • Example: 275/65/20 weighs 66.1lbs 
      • Toyo AT3 = 54lbs
      • BFG KO2 =  57.3lbs
  • Toyo AT3 - I've had several sets of Toyo AT2's. Really like the upgrades made to the AT3, but wanted a slightly more aggressive sideway. I also found it very difficult to find inventory at the moment. 
  • BFG KO2 - tried and true, some question around if newer technology is surpassing. Obviously not enough of a concern as this was the tire of choice. 

 

 

 

 

MC AT4 1.jpg

MC AT4 2.jpg

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13 minutes ago, MC AT4 said:

Nice! Any pictures? Did you have to add a wheel spacer? 

If your talking to me everything is stock. I plan on adding a leveling kit. It’s close to running one of the bars in full lock, but not that close if it makes since. I’ll get some pictures later. Just had them put on Saturday.

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On 7/26/2021 at 1:30 PM, MC AT4 said:

Wanted to post my research and share my decision on selecting larger tires on a Factory '21 AT4, 20" Wheels. 

 

There are a lot of threads on this topic, all with great content, but there are some conflicting posts on size choice/rubbing/mpg impact that can make the decision difficult. As others have noted not all tires measure the same height/width/weight, so a one-size fits all approach likely cannot be taken. 

 

**In case you don't want to read through all the details below, I went with BFG KO2 in a 275/65R20. No rubbing, plenty of UCA clearance, ~1MPG loss, speedometer is off between .5 to 1MPG depending on speed. ~1MPG loss does not reflect accounting for speedo variances. I will need to update this post with a manual calculation. I do think you could fit a slightly larger tire, depending on manufacturer choice (see below variations of sizing). 

 

Tire Size:

Based on reading through other posts I narrowed my tire size to three options: 

1. 275/65R20

2. 285/65R20

3. 295/60R20

 

I personally didn't want rubbing issues after tire install. Minor trimming (IE: mud flap trimming) wouldn't be a big deal, but having owned a truck that had rubbing issues, it gets old quick and I wanted to avoid modifications if possible. 

 

Pros/Cons of each tire size I contemplated:

  • 275/65 - great tire size as you get 34" in height, but can appear to have a narrow stance depending on tire choice. Stock tire (Bridgestone Dueler A/T 275/60/20), width would remain the same as stock. Originally ranked 2nd of the 3 options. 
  • 285/65 - best of both worlds, gains in height and width. Ranked 1st of 3 options. Big concern around rubbing issues, especially at full lock on an incline. Likely could avoid by adding a levelling kit. Conflicting results on CV angles and longer-term impact of adding a level kit. 
  • 295/60 - prefer the stance of a 295, but didn't have a high level of confidence there would be clearance from the UCA. Rubbing concerns similar to 285/65. 

 

Tire Brand:

1. Falken Wildpeak AT3W

  • 275/65 - 34.1" X 10.6", 66.1lbs
  • 285/65 - 34.6" X 11.2", 67.7lbs
  • 295/60 - 33.9" X 11.6", 69.4lbs

2. Toyo AT3

  • 275/65 - 34.1" X 11", 54lbs
  • 285/65 - Not Offered
  • 295/60 - 33.9" X 11.8", 60lbs

3. BFG KO2 

  • 275/65 - 34" X 11", 57.3lbs
  • 285/65 - 34.5" X 11.5", 60.3lbs
  • 295/60 - 33.9" X 11.8", 68lbs

**4. After decision came across Mickey Thompson Baja Boss A/T (some great reviews coming out on this tire). 

 

Pros/Cons of each tire size I contemplated:

  • Falken - awesome tire with some fantastic reviews. Major consideration was the weight.
    • Example: 275/65/20 weighs 66.1lbs 
      • Toyo AT3 = 54lbs
      • BFG KO2 =  57.3lbs
  • Toyo AT3 - I've had several sets of Toyo AT2's. Really like the upgrades made to the AT3, but wanted a slightly more aggressive sideway. I also found it very difficult to find inventory at the moment. 
  • BFG KO2 - tried and true, some question around if newer technology is surpassing. Obviously not enough of a concern as this was the tire of choice. 

 

 

 

 

MC AT4 1.jpg

MC AT4 2.jpg

Great post!  Thanks for taking the time to share your decision making process.  
 

I’m thinking of doing something similar as I research tires for my 18” wheels.

 

I’m curious why you opted for the 275/65 over 285/65 KO2s.  Was it weight, or size?

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5 hours ago, AML said:

I really like this setup. Any chance you can measure the rake on your truck? I'm seriously worried about rubbing, the rake can vary on these things.

I did already, because I want to level my truck and some of the kits are different. My front and back are right around 2” off.

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Nice write-up. I went through a similar amount of research before deciding on tires.

 

Not to hijack your thread but since "stock AT4 tire size" threads always get a lot of attention (and come up in google results) I figured I'd throw in that I kept stock wheels on my AT4 and fit 295/60R20 Cooper STT Pro's

 

Their actual dimensions are: 34.3" x 11.50"

 

They fit with no rub except a hard turn into an incline - they can barely clip the wheel well liner. It could be pulled out of the way but it happens so rarely I don't fool with it.

 

The only disclaimer is that I do have a 1" level on the front but the tires fit before that as well.

 

11.50" actual measured width is close to the max you can go on stock wheels on these trucks for sure. I can pass a finger tip between the UCA and tire but barely!

Edited by kenac
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On 7/30/2021 at 10:00 AM, Kanon Morris said:

Great post!  Thanks for taking the time to share your decision making process.  
 

I’m thinking of doing something similar as I research tires for my 18” wheels.

 

I’m curious why you opted for the 275/65 over 285/65 KO2s.  Was it weight, or size?

Thanks! It primarily came down to not wanting to have rub issues. The peace of mind outweighed gaining an additional .5” width and height.  I have an incline turning in and out of my driveway that at full lock I feel had a good chance to rub. There appears to be a lot of folks running 285’s, it likely comes down to the specific tire. Based on the tread design of KO’s I’d expect 285’s would have cleared with zero or very minimal rubbing. 

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7 hours ago, kenac said:

Nice write-up. I went through a similar amount of research before deciding on tires.

 

Not to hijack your thread but since "stock AT4 tire size" threads always get a lot of attention (and come up in google results) I figured I'd throw in that I kept stock wheels on my AT4 and fit 295/60R20 Cooper STT Pro's

 

Their actual dimensions are: 34.3" x 11.50"

 

They fit with no rub except a hard turn into an incline - they can barely clip the wheel well liner. It could be pulled out of the way but it happens so rarely I don't fool with it.

 

The only disclaimer is that I do have a 1" level on the front but the tires fit before that as well.

 

11.50" actual measured width is close to the max you can go on stock wheels on these trucks for sure. I can pass a finger tip between the UCA and tire but barely!

Glad to get some good conversation going on this topic. Lot of good examples out there worth sharing. Any photos of front or rear stance? I do wish I had a slightly wider tire for a slightly wider stance. Curious if the additional .5” makes much of a visual difference. 

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59 minutes ago, MC AT4 said:

Thanks! It primarily came down to not wanting to have rub issues. The peace of mind outweighed gaining an additional .5” width and height.  I have an incline turning in and out of my driveway that at full lock I feel had a good chance to rub. There appears to be a lot of folks running 285’s, it likely comes down to the specific tire. Based on the tread design of KO’s I’d expect 285’s would have cleared with zero or very minimal rubbing. 

Yeah, that’s actually why I chose 275/70R18.  I didn’t want to risk any rub down the road.  Probably could’ve gotten away with 295/70R18, but I’m happy with what I got.

 

Next purchase will probably be some 20” takeoffs with slightly larger KO2s or Toto MTs when the time comes.

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