37’s on stock wheels

Dahlsfarrier

Tremor Buff
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Southern California
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2020 F350 Tremor 6.7
So I’m at 32k miles and starting to shop tires. I pull a trailer everyday for work, the Duratracs have been good and I almost had decided to buy another set but I want to go bigger. I’d like to go with the Toyo AT3 37/12.5/18. I’ve run the Falken and Les Schwab version on my Ram trucks and they hold up early well for my application, they also come with a 50k tread wear guarantee. I don’t really want to lift or level my truck, I’ve seen different posts that 37’s will fit and don’t mind minor trimming if necessary. I’ve also seen that some use wheel spacers to get 37’s on with the stock wheels. I’ve ran spacers on my Jeeps for years with zero problems so I’m not opposed to that but wondering if it’s necessary?
 
Here's a consolidated answer so people don't need to search through a million posts. Feel free to correct if I accidentally got something wrong.

Will 12.50 wide tires fit on the stock wheels?
Maybe. Most 12.50 tires are designed for 8.5" width rims at minimum. 9-10" is recommended. Stock wheels are 8 inches wide. There aren't too many 12.50s that will fit 8" rims based on factory documentation. The Toyo R/T and M/Ts, for example, require an 8.5 minimum. The A/T III will do fine with a spec of 8" minimum.

Can 37s fit on stock wheels?
Yes. 37x11.50r18 tires exist, and are designed to be fit on our 18x8 wheels.

Will 37s rub on stock height?
Assuming the same section width and wheels (11.50 wide tires on 8 wide wheels), they will rub quite a bit on the bottom rear of the fender by the driver/passenger doors while the wheels are slightly turned. The exact location is where the bottom trim meets the running board. It is plastic, so it shouldn't be much of a problem. Rubbing will be more evident with lower offset (wheels sticking further from hub), along with more rubbing at the front of the fender and basically all over the place. BUT, lower offset makes it less likely for the tires to rub on the inside, so there's that. Bottom line is that 37s on stock height is a pretty adventurous endeavor.

Will 37s rub on a 2.5" level?
Actually, yes. It will rub at partial turn at the bottom rear of the fender where the trim meets the running board, but it won't rub as severely as no lift. It will take care of itself and stop rubbing over time. Most people probably won't notice the rubbing since it's so light. It will only occur at low speed on uneven roadway turning at just the right angle. I recommend proactively taking care of it on your own with a dremel or something. That's what I did. Otherwise, with the right offset (zero max on 12.50 tires, for example), it won't rub anywhere else, front or back. Positive offset will only increase the likelihood of rubbing on the inside of the tires.
 
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Here's a consolidated answer so people don't need to search through a million posts. Feel free to correct if I accidentally got something wrong.

Will 12.50 wide tires fit on the stock wheels?
Not responsibly. 12.50 tires are designed for 8.5" width rims at minimum. 9-10" is recommended. Stock wheels are 8 inches wide. Some small shops will install 12.50 wide tires on our stock wheels, but they shouldn't.

Can 37s fit on stock wheels?
Yes. 37x11.50r18 tires exist, and are designed to be fit on our 18x8 wheels.

Will 37s rub on stock height?
Assuming the same section width and wheels (11.50 wide tires on 8 wide wheels), they will rub quite a bit on the bottom rear of the fender by the driver/passenger doors while the wheels are slightly turned. The exact location is where the bottom trim meets the running board. It is plastic, so it shouldn't be much of a problem. Rubbing will be more evident with lower offset (wheels sticking further from hub), along with more rubbing at the front of the fender and basically all over the place. BUT, lower offset makes it less likely for the tires to rub on the inside, so there's that. Bottom line is that 37s on stock height is a pretty adventurous endeavor.

Will 37s rub on a 2.5" level?
Actually, yes. It will rub at partial turn at the bottom rear of the fender where the trim meets the running board, but it won't rub as severely as no lift. It will take care of itself and stop rubbing over time. Most people probably won't notice the rubbing since it's so light. It will only occur at low speed on uneven roadway turning at just the right angle. I recommend proactively taking care of it on your own with a dremel or something. That's what I did. Otherwise, with the right offset (zero max on 12.50 tires, for example), it won't rub anywhere else, front or back. Positive offset will only increase the likelihood of rubbing on the inside of the tires.
thanks for all the info I agree.
 
Thank you and yes that’s about everything I found as I continued researching. The only thing I will add is that the tire I’m looking at in a 37/12.50 is ok on an 8” wheel according to Toyo

Which tire is that? The ones I've looked at of theirs were all 8.5" minimum according to their documentation.
 
Which tire is that? The ones I've looked at of theirs were all 8.5" minimum according to their documentation.
5C82BD82-2AC6-40C7-975C-2FD2D379552B.png
 
Just for reference, fitted the front and did a clearance check. It’s about an inch away from the fender and bumper. It will barely touch the radius arm at full lock. I might put a small spacer to get it even with the fender and give me a bit of clearance on the arm. Only concern is then it might touch the fender??‍♂️
 

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All done and drove it home, slight rub on the arm at full lock to the left and no rub to the right. Looks way better in my opinion. No spacers and no lift or level kit
 

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Looks good, That's probably the route I'm gonna go with now. Been looking at the AT/3 and the Ridge Grappler. I like the look of the AT/3. How's the ride?
I only had about 9 miles to get home, tires are at 65psi and felt way better than the duratracs at 70. I’ll pull the trailer to work tomorrow and let you know.
 
Looks good, That's probably the route I'm gonna go with now. Been looking at the AT/3 and the Ridge Grappler. I like the look of the AT/3. How's the ride?
It looked like a big ass tire before they went on! I got home and my wife said WTF they’re huge...i thought you weren’t going to change anything! ;)
 

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So I’m at 32k miles and starting to shop tires. I pull a trailer everyday for work, the Duratracs have been good and I almost had decided to buy another set but I want to go bigger. I’d like to go with the Toyo AT3 37/12.5/18. I’ve run the Falken and Les Schwab version on my Ram trucks and they hold up early well for my application, they also come with a 50k tread wear guarantee. I don’t really want to lift or level my truck, I’ve seen different posts that 37’s will fit and don’t mind minor trimming if necessary. I’ve also seen that some use wheel spacers to get 37’s on with the stock wheels. I’ve ran spacers on my Jeeps for years with zero problems so I’m not opposed to that but wondering if it’s necessary?
Thanks for starting this thread. I really like the stock wheels and was curious about 37s.
 

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