Need help getting the security pin in western WA

[70chall440]

Thanks for the information. This info is for my 14 Ram 2500 with 5.7 which has a listed front curb wt of 3880 and a rear of 2895. From what i am seeing it seems like I could run 35# on all corners unloaded and perhaps 60# rear loaded?

 

[lpennock]

Thanks for the information. This info is for my 14 Ram 2500 with 5.7 which has a listed front curb wt of 3880 and a rear of 2895. From what i am seeing it seems like I could run 35# on all corners unloaded and perhaps 60# rear loaded?

Here are the TRA ratings for a 35xR12.50r17LT (Note Toyo MT are rated a bit higher than this)
1875@25
2155@30
2405@35
2625@40
2840@45
3000@50
3065@55
3130@60
3195@65

See if your Nitto are 3195@65 or 3640@65 and if they are the higher number I can post the load table for them.

 

[70chall440]

Here are the TRA ratings for a 35xR12.50r17LT (Note Toyo MT are rated a bit higher than this)
1875@25
2155@30
2405@35
2625@40
2840@45
3000@50
3065@55
3130@60
3195@65

See if your Nitto are 3195@65 or 3640@65 and if they are the higher number I can post the load table for them.

Thank you sir, I just looked at they are 3195 @ 65

 

[70chall440]

I am thinking to set the pressures in the truck at 50 for the front and 30 for the rear. Truth be told, I have been running 63 in them pretty much since I got them in 2015 and they still look pretty good with about 40K on the odometer.

 

[70chall440]

Also related, I want to correct the speedo and from what I can find the circumference of my 35" tires should be 2791mm however I watched a video where the poster was using 2714mm. Anyone have any suggestions here?

Reference pulling the PIN, does AlphaOBD do this automatically or is this a function that I have to activate/run? I have not messed with it yet and if it is intuitive I apologize in advance.

 

[AH64ID]

Info I found shows that tire at 598 rev/mile, which puts the rolling diameter at 33.73”. That makes a rolling circumference of 105.97” or 2691mm. That’s where I would start.

I would run 40/30 empty for tire pressure. Maybe even 35/25 for winter driving.

 

[brucejohnson]

Here is what I found for the Trail Grappler:

Diameter: 34.84

 

[AH64ID]

Here is what I found for the Trail Grappler:

Diameter: 34.84
View attachment 132100


View attachment 132099

That’s true circumference, not rolling circumference which is always smaller.

 

[70chall440]

Thanks all, so perhaps the 2714 might be in the ball park? For the TPMS I will go a little low, say 35 front and 30 rear to keep the light off but close enough to warn me.

 

[Cummins12V98]

So the next thing I have to decide is what pressure to put into the truck, I am running 35x12.5R17s on the truck which are Nitto Trail Grabbers and list a max of 65 psi. I know that I really need to do a chalk test to determine the best psi for full contact but I am not doing that now, so I am thinking 60 psi might be what I use.

Weigh your truck. Now look at the load/pressure chart for your tires. Add 5psi to the rears numbers and 10 to the fronts. Now you will get best stopping, ride and wear. Carry on!

 

[brucejohnson]

That’s true circumference, not rolling circumference which is always smaller.

Yep, Thanks for the reminder. Do you have a simple chart or formula, or is it based on the 3% "typical" correction factor of a squishy passenger car tire? I couldn't find anything on the internet for rolling radius specifics. Just have my flickering brain cell full of lost and scrambled data from decades and decades ago.
Variables, as pressure, temperature, speed, construction, bias vs. radial, tire tread wear and other strange stuff tweak the number somewhat, too. Might even fall into the "close enough" category, where close only counts in horseshoes, hand grenades and atom bombs. As long as officer friendly doesn't mind and you're not ticking up miles faster toward reaching the warranty finish line, all should be good.

 

[AH64ID]

Many companies publish rev/mile data, which is usually around 45 mph to provide a decent average.

Even if a specific company does not publish that data another companies specs for the same size tire will be a better starting point than static circumference.

 

[brucejohnson]

Many companies publish rev/mile data, which is usually around 45 mph to provide a decent average.

Even if a specific company does not publish that data another companies specs for the same size tire will be a better starting point than static circumference.

Would that be like the last column, 597 Revs/Mile on the Nitto chart I posted?

On Edit: Probably answered my own question. The figures provided for the static circumference produce a 578.88 Revs/Mile and the Nitto's 597 Rev's/Mile compute to a 3.13% correction factor after crunching all the data. So, it is pretty standard when set with the criteria to derive the Revs/Mile. Now if I were going 150 mph that number would require additional math to allow for tire expansion, and tickets.
Thanks for sparking the learning lesson of the day.

 

[70chall440]

Again, thanks all for weighing in on this. I am not looking for perfect and at this point I want the speedo to be accurate and I want the light off.

Has anyone pulled the PIN using AlphaOBD? I have looked at it and did not see anything related to this so I am wondering how to get the pin.

 

[lpennock]

Again, thanks all for weighing in on this. I am not looking for perfect and at this point I want the speedo to be accurate and I want the light off.

Has anyone pulled the PIN using AlphaOBD? I have looked at it and did not see anything related to this so I am wondering how to get the pin.

Post 6

Radio Frequency Hub -> Radio Frequency HUB MY2013-2021 -> Read PIN

 

[brucejohnson]

Again, thanks all for weighing in on this. I am not looking for perfect and at this point I want the speedo to be accurate and I want the light off.

Has anyone pulled the PIN using AlphaOBD? I have looked at it and did not see anything related to this so I am wondering how to get the pin.

Did you find/try Ipennock's map in post #6?

 

[brucejohnson]

Post 6

Radio Frequency Hub -> Radio Frequency HUB MY2013-2021 -> Read PIN

Ah. Ya beat me to it by a milisecond!

 

[70chall440]

Awesome thanks, somehow I completely read over that (post #6)

I am going to work on the truck today and hopefully get these items sorted out. This endeavor has made me revisit the truck overall and do some other "upgrades" such as the tailgate lowering strut some rear seat USB ports, etc. I do love this truck overall, am not real happy with the Uconnect crap which died (the nav) but I can live with it.

 

[brucejohnson]

SWEEEET!!!
Is that how the kids get to school?
Love it. Looks good, no, GREAT!!

What's that on the pavement in the background? Practicing for twin "69"s.

 

[70chall440]

Yeah yeah everyone talks smack about the yellow... but I do love it...