dealer installed big tires, what now?

[Kidwell1500]

I bought a 2019 5th gen 1500 laramie 6.4 box from the dealer new in 2019. They had put 18 inch off road bead lock wheels (mopar part) on it with Nitto Ridge Grappler 295/70R18's. The speedo has never been right when compared to GPS so i assume it was not reprogrammed for larger tires. This raises a couple questions:
1. I've put 45K on the ODO-- is my odometer off in my favor? Could it actually be more miles?
2. Is my transmission going to see long term effects?
3. Would changing the tire size back down to what it's supposed to be hurt anything at this point?

I'm considering moving to a Michelin defender for the smooth ride and road noise factors but unsure of what size to get because they have both 65 & 70. Appreciate any advise or knowledge. Thanks!

 

[SD Rebel]

It depends on the size of tire your truck came with originally, which should be on your door jam sticker to do a proper before & after comparison. The tires you have now are 34", not a big deal if your truck same with either 32 or 33" tires or have the 3.92 rear axle.

Also, how off is your speedo? Either way, bigger tires without a reprogram will mean that your odo is off in your favor, you have driven more miles than your truck is stating.

Your drivetrain will experience more strain with larger tires, however it's a pretty common mod to go with 34-35 in. tires, not really a big deal in the long term.

Going back to a smaller size will only improve your fuel economy at the expense of looks, which maybe a worthy trade off. It should also feel a bit peppier as well especially if moving from larger A/T to smaller all seasons.

 

[Kidwell1500]

It depends on the size of tire your truck came with originally, which should be on your door jam sticker to do a proper before & after comparison. The tires you have now are 34", not a big deal if your truck same with either 32 or 33" tires or have the 3.92 rear axle.

Also, how off is your speedo? Either way, bigger tires without a reprogram will mean that your odo is off in your favor, you have driven more miles than your truck is stating.

Your drivetrain will experience more strain with larger tires, however it's a pretty common mod to go with 34-35 in. tires, not really a big deal in the long term.

Going back to a smaller size will only improve your fuel economy at the expense of looks, which maybe a worthy trade off. It should also feel a bit peppier as well especially if moving from larger A/T to smaller all seasons.

Thanks so much for your response and input. The sticker in the door jam says 275/65/18-- on it now are 295/70/18. Speedo is off about 5 mph when going ~60, it reads slower but it's relative to how fast i'm driving. I do indeed have the 3.92 rear so maybe not too much strain to cause issues, thanks for confirming my unjustified paranoia.

Now i just gotta decide what to do about new tires---looks or fuel economy and an improved highway ride.

 

[SD Rebel]

Thanks so much for your response and input. The sticker in the door jam says 275/65/18-- on it now are 295/70/18. Speedo is off about 5 mph when going ~60, it reads slower but it's relative to how fast i'm driving. I do indeed have the 3.92 rear so maybe not too much strain to cause issues, thanks for confirming my unjustified paranoia.

Now i just gotta decide what to do about new tires---looks or fuel economy and an improved highway ride.

Absolutely, with the 3.92 rear axle, your current tire size is only about 1" taller than factory Rebels with 33" tires, next to nothing when it comes to the drivetrain. Your speedo and odo however are a little off, but 5 mph at 60 mph isn't huge, most people don't bother to adjust at that point especially since it does favor you in terms of mileage.

I will say, you will likely gain 2-4 mpg switching to regular sized street tires instead of the 34" A/Ts, along with better ride quality and noise. It's just less good looking on a truck.

 

[Bt10]

Thanks so much for your response and input. The sticker in the door jam says 275/65/18-- on it now are 295/70/18. Speedo is off about 5 mph when going ~60, it reads slower but it's relative to how fast i'm driving. I do indeed have the 3.92 rear so maybe not too much strain to cause issues, thanks for confirming my unjustified paranoia.

Now i just gotta decide what to do about new tires---looks or fuel economy and an improved highway ride.

I have the defender LTX in 275/70/18, and they only come E rated. They are not intended to ride soft. With the 3.92 axle, you are still way above the 3.21 crowd in the "less drivetrain strain" dept. And yeah, a lot of people upsize tires without a heavy duty trans rebuild.

 

[O'Town Ram]

I have the defender LTX in 275/70/18, and they only come E rated. They are not intended to ride soft. With the 3.92 axle, you are still way above the 3.21 crowd in the "less drivetrain strain" dept. And yeah, a lot of people upsize tires without a heavy duty trans rebuild.

The LTX M/S2 are E rated. The LTX M/S are SL rated. So there is an option.
To the OP:
Tough choice, looks over practicality. I love the LTX M/S tires. Great ride. Quiet. Super long lasting. But, I do not look as cool as some of the other guys

 

[MikeyHo808]

The LTX M/S2 are E rated. The LTX M/S are SL rated. So there is an option.
To the OP:
Tough choice, looks over practicality. I love the LTX M/S tires. Great ride. Quiet. Super long lasting. But, I do not look as cool as some of the other guys

You drive a brand new Limited. Nothing more cool than that, brother.