toyo 37x13.5 on a stock rim

[stxraptor]

It's time for me to change tires and always had my eye on the toyo open country mt 37"x13.5/17. I like the factory rims and don't plan on changing them. I want to upgrade the tires from the stock 35" BF Goodrich to the Toyo
37" x 13.5, which is both taller and wider. Has anyone done this combination? Do you have nay pic's? What problems did you have? Did you need an perch mod?

 

[bstoner59]

You might not be able to fit the wider tire with the stock rim. I had 12.5 General Grabbers in the stock rim and they were pretty close to the upper arm.

The 37's will require a perch mod. Middle if you're not going to off-road the truck and top if you are going to play hard in the dirt. You will also need to massage the wheel wells, front and rear, a bit to make room for the 37's.

 

[stxraptor]

You might not be able to fit the wider tire with the stock rim. I had 12.5 General Grabbers in the stock rim and they were pretty close to the upper arm.

The 37's will require a perch mod. Middle if you're not going to off-road the truck and top if you are going to play hard in the dirt. You will also need to massage the wheel wells, front and rear, a bit to make room for the 37's.

The logic I am going with on upgrading from a 35" to 37" and 12.5" to 13.5" tire is: on the 13.5" tire width would result with only a 1/2" wider on either side. So the tire will stick out a 1/2" more on the outside and 1/2" on the inside wheel well. On the height, that same principal applies, the 37" tire will add only 1" closer to the fender and 1" to the height to the road surface. In my opinion, it seem that those measurements would not make much of a difference. I will try and post the results with pictures as soon as I get them installed. I was hoping to find someone who installed the same combination.

 

[Maxx2893]

Trust us it will make a huge difference. Under compression and when turning especially. Also stock is a little less than 35 and narrower than 12.5

 

[TEXAS MOTORWORX]

Totally agree with Maxx, the stockers are 34.4in tall, and 12.4in wide... Although you logic is mostly correct, there are a lot of unknowns you aren't factoring....

The biggest being the front and rear tangents of the tire. When under normal driving conditions the entire tire is not in the wheel well, but with a slight bump the tire goes up filling the wheel well more and it hits the bumper as well as the front of the fire wall. Due to the articulation and compression of the suspension we have seen as much as driving over a curb make this happen during our testing.

Under full compression the .5in wider out board that you are referring to, will in fact impact the gray fender flare under full articulation, with enough force to severely damage it and your fender.

The .5 inch on the inside and out actually makes a huge difference in turning. When turned all the to lock the tire will grab the inner fender liner... when driving forward the tires rotate in such a way, that it will grab the liner and rip it out. Once you do this, you expose the fire wall and a seam weld for the cab. IF not taken care of you will shred the tires under turning and suspension compression.

With all that said, we have Toyo MT 37's on our trucks and are currently working on a lessons learned as well as a "Here you go if you want to try it" guide.

This is a learning experience for us, and I am sure we will find more must do's on our adventure.

Not trying to scare you, just trying to give you a heads up.

 

[bstoner59]

Oh as a side note I do have 37x13.5 tires on my truck as well. I did have it on the mid perch first then decided that wasn't enough clearance. Give it a shot and post up your results. That's what we are all on here for...to learn from others

 

[DynoDynge]

Oh as a side note I do have 37x13.5 tires on my truck as well. I did have it on the mid perch first then decided that wasn't enough clearance. Give it a shot and post up your results. That's what we are all on here for...to learn from others

How are they affecting your speedo & mileage? Any noticeable differences?

 

[TEXAS MOTORWORX]

How are they affecting your speedo & mileage? Any noticeable differences?

Here are the computer read outs from the truck with the adjusted numbers for the larger tires.

But, we were seeing 13.7 and 14.1 before we made the change and now the truck is saying 11.7. So there was hit to our fuel economy, just not as bad as the truck thinks it is.

The speedo is 3 mph off when checked to GPS.

 

[bstoner59]

How are they affecting your speedo & mileage? Any noticeable differences?

AHHAHAHA!!! I've never seen anything better than 13.8 mpg!!! I'm still getting the same mileage according to the computer...but the speedo is off. 3-4mph under at 70 according tp the GPS Speedo app on my Droid. I don't know how accurate the speedo was with the 35's...never thought to check.

 

[Conejoracer]

AHHAHAHA!!! I've never seen anything better than 13.8 mpg!!! I'm still getting the same mileage according to the computer...but the speedo is off. 3-4mph at 70 according tp the GPS Speedo app on my Droid. I don't know how accurate the speedo was with the 35's...never thought to check.

With my stock BFGs at 60% tread
my speedo reads 4 mph faster than I'm really going per gps and the occasional roadside radar trailer.