37s installed but have a few questions

[Badassbronco]

I just installed 37s Mickey Thompson Baja Legends EXP after 31k on the stock Goodyears. At the moment, they are a a tad quieter and smoother ride. Steering feels easier as well. I do notice the acceleration and braking have decreased a little.
A few questions
1) With the tires being 70lbs, do I need to reinforce the tailgate? If so, would something like the Rough Country or Hooke Road suffice?
2) They set the PSI to the 39psi. I thought I read that larger 37s you should use a lower psi? If so, what?
3) Tire barely squeezes under tire taillight. Should I get some sort of extender?
4). No rubbing atm, what’s the best way to test? Should I still get the tire clearance kit?
5) I own OB2 adapter ELM327 for Forscan. I can go in and just set size to 37” (36.4)?

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[CitrusBronco]

To many threads with all the info you need posted here.
Quick answers. yes, fine, no, yes.
Longer.
1- based on previous posts you may suffer from tailgate sage or warped sheet metal. Ford upgrades the carrier for 37 on the Braptor. Several models to choose from, I went with what I felt is the best product for my needs from Turn off-road.
2- you will likely get a slight mpg increase at 39psi vs 32 psi for on road use but it will feel stiffer. I run mine there for longer road trips, around town I’m at 34 psi at the moment.
3- why extend it since it fits. Mine works fine with the 37 no extension.
4- yes it will rub, no one is using 37 without rubbing in stock form.

 

[rodriguezmf1250]

Ditto Citrus, in other words, your next purchase is a lift....

 

[1BadArea51]

4). No rubbing atm, what’s the best way to test? Should I still get the tire clearance kit?

Try reversing into an inclined drive way with an approach that has your steering wheel at full lock. You will most likely rub on crash bars, plastic mesh thingy in the rear, and fender liner.

5) I own OB2 adapter ELM327 for Forscan. I can go in and just set size to 37” (36.4)?


Probably not. You set it in millimeters.. I measured my 37" Nitto ridge grapplers, and entered the exact circumference in mm. Wouldnt take.

I used Fords ProCal tuner to flash the unit, which opens up a slightly larger maximum, but still short of the circumference i measured. My speedo is off a few mph (shows fast)

 

[Badassbronco]

Ditto Citrus, in other words, your next purchase is a lift....

I have a 2.25” lift as is. Probably one day I’ll swap it out for something nicer.

4). No rubbing atm, what’s the best way to test? Should I still get the tire clearance kit?

Try reversing into an inclined drive way with an approach that has your steering wheel at full lock. You will most likely rub on crash bars, plastic mesh thingy in the rear, and fender liner.

5) I own OB2 adapter ELM327 for Forscan. I can go in and just set size to 37” (36.4)?


Probably not. You set it in millimeters.. I measured my 37" Nitto ridge grapplers, and entered the exact circumference in mm. Wouldnt take.

I used Fords ProCal tuner to flash the unit, which opens up a slightly larger maximum, but still short of the circumference i measured. My speedo is off a few mph (shows fast)

Did you install the tuner yourself?
I thought the tuner goes up to 37s?

Mickey Thompson states my tires are 36.38” which is on the smaller side similar to BFGs

 

[Brian_B]

Yes you can use Forscan to adjust the tire size, but there is a "secret" maximum number the computer will accept before it throws an ABS code and breaks cruise control - it will work and the speedo calibrates, but cruise control won't set. I think it was 2,879? (*edit*) Went and looked it up: 2,779 (579 in ProCal)

https://www.bronco6g.com/forum/threads/nitto-ridge-grappler-38x11-5r17.112350/page-4#post-2557186

Usually most every 37 will fit in there - and it isn't a precise measurement, so don't go thinking that if you pull a number off a spec sheet or measure your tire that that number should exactly work - Forscan math is fuzzy, and the number may need some massaging.

For tire pressure - go look up "Chalk Test". It's super easy, will put your tires exactly where they need to be based on your specific vehicle weight and ride for best tire longevity (not for best mileage). 2Drs tend to run a bit higher pressure than 4Drs - I know in my 4D my bigger tires chalk tested to around 28 psi, but I run them on the highway around 32psi to get a bit better gas mileage. The higher you run them, the better MPG you get, but the ride will be much stiffer and you will wear the center of the tread out faster and get fewer miles out of them.

For rubbing - if you aren't taking it off road, and you aren't getting any rubbing right now, then I don't know that I would worry to much about it. Rubbing tends to mostly occur when you have the steering wheel full clocked, and/or when you have the suspension fully articulated. It is possible that under full stuff that a wheel could hit the fender itself and cause some lasting damage. Hard to do that at Starbucks, but if you go over a curb or hit a good ole' East Coast pothole or something it's possible without going off road. Most of the time, rubbing is just against the fender liner or mud flap and it'll make some noise, but if you don't do it often it won't necessarily break anything. Repeated occurrences though and it will eventually self-clear.

For the tailgate - I recommend some sort of reinforcement, but Ford rates the tailgate at 133lbs for holding weight. Part of that is aesthetics, and some are objectively "better" than others, but any of them will do the job, truth be told. For the taillight - there are extensions available, but that's a cosmetic decision.

 

[Brian_B]

I used Fords ProCal tuner to flash the unit, which opens up a slightly larger maximum, but still short of the circumference i measured. My speedo is off a few mph (shows fast)

The max tire size is the same regardless of if you use ProCal or Forscan -- they just enter the number in different units. Forscan uses "mm" (not really, but close), whereas ProCal uses Revs/Mile. That maximum number that you can enter before you get a silent ABS code doesn't change

 

[CitrusBronco]

I have a 2.25” lift as is. Probably one day I’ll swap it out for something nicer.

If you add a signature with your build description that will help people when discussing something with you.

with the 2.25” lift you might still rub depending on wheel offset and if you go into something at full steering lock.

 

[1BadArea51]

I have a 2.25” lift as is. Probably one day I’ll swap it out for something nicer.

Did you install the tuner yourself?
I thought the tuner goes up to 37s?

Mickey Thompson states my tires are 36.38” which is on the smaller side similar to BFGs

yes did it myself, the protuner is similar to that of running forscan. you need a windows laptop to register the tuner device and download the firmware.


then you follow the controls on the device itself.. its like a bulky tablet.

i tried inputting my 37s in mm using forscan first, didnt take.

then i used procal.. and it still didnt let me put in my exact size.. so i set it to the maximum value I found online. i dont know if procal unlocks larger values... someone else in this thread said it doesnt..

the tuner is worth it! my 2.7 badlands has more pep and shifts much better with my 37s

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