[eugenesan]

You don't have to lift the front to fit the 245/75 tires.
I have no experience with snow chains but if they require 1" or larger gap, they probably won't fit with 245/75.

The width difference between the tire and the rim is a gray area.
People do that all the time but many tire shop will refuse to do that for several reasons.
I've researched the subject and consulted experienced tire shop manager and according to him .5" difference is not terrible but there might be consequences that might include:

• Visual inconsistency. The sidewall won't be at the designed angle.
• Possible excessive wear of the side wall. IMHO that is not likely.
• Possible excessive wear of the middle of the thread. IMHO if you keep the pressure somewhat below the maximum, let's say 65psi, the wear won't be significant and actually might be offset by the side wear caused by the steering action when the tires are at the front. Note, I'd rotate the tires every 5k.
• Possible fatal failure under heavy loads. That one is the most critical factor, obviously. Even .5" difference will reduce maximum load when taking sharp turns and performing emergency breaking. It's hard to come up with actual number, but limiting maximum weight by 20% feels about right.

You have to install the leveling kit to get the tires to fit... What will work for stock 6" rims. Largest size available without modification of wheel wells or other bits and ability to fit snow chains.

 

[Mokii]

You don't have to lift the front to fit the 245/75 tires.
I have no experience with snow chains but if they require 1" or larger gap, they probably won't fit with 245/75.

The width difference between the tire and the rim is a gray area.
People do that all the time but many tire shop will refuse to do that for several reasons.
I've researched the subject and consulted experienced tire shop manager and according to him .5" difference is not terrible but there might be consequences that might include:

• Visual inconsistency. The sidewall won't be at the designed angle.
• Possible excessive wear of the side wall. IMHO that is not likely.
• Possible excessive wear of the middle of the thread. IMHO if you keep the pressure somewhat below the maximum, let's say 65psi, the wear won't be significant and actually might be offset by the side wear caused by the steering action when the tires are at the front. Note, I'd rotate the tires every 5k.
• Possible fatal failure under heavy loads. That one is the most critical factor, obviously. Even .5" difference will reduce maximum load when taking sharp turns and performing emergency breaking. It's hard to come up with actual number, but limiting maximum weight by 20% feels about right.

This is super helpful. Thank you for a straight forward and well organized response!

It does seem like if you are going to 245 in general (70 or 75 ratio), you should probably upgrade to aftermarket rims in the 7" width range to accommodate. This unfortunately precludes you from doing any wheel/rim upgrade in sequence instead of all at once. I think the route I may take is to keep the stock wheel size and tire size for the moment. The risk of bullet #4 is also a liability question as an upfitter advising on wheel/tire combos (as are the other bullets but somewhat less so) so airing on the side of caution here, and also being able to run snow chains, keeping consistent speedo readings, no modifications to wheel well, etc. make some sense to me. Just my .02$ to your very useful response. Thanks!

 

[the_alpine]

But how did you find a KO2 245 70 16 that was rated to at least 2,600 lbs/wheel for nonPmetric sizes and 2,900 for Pmetric sizes? Every KO2 I pull up in that size is load rated below the stock wheel's E rating and load capacity. When adding the weight of a build of really any sort is not going to do so well when pushed at highway speed. I could be off here but after perusing this forum today and the past few... it seems like you want an E load wheel and 245/75/16 works for some and doesn't work for others, mainly due to aftermarket rim offset and/or lifts or suspension modifications.

Why does this need to be so hard? : ) 2021 3500 159 EXT Promaster with Heavy Duty and RV package. 6" aluminum stock rims. Will 245 75 16 E rated BFG KO2's even work on a 6" rim? I think they need the 6.5" min according to Discount Tire... If they can fit the stock 6" rim, will they fit without modification to the rear wheel wells and when at full turn, will there be no rubbing....

Or would a D rated tire with the following specs work on the 6" stock rim? What about the Load Range, Max Load and Load Index. We are building a pretty light camper set up but there will easily be 1200lbs added payload when fueled, watered, and loaded up.

• Size: LT245/70R16
• Load Range: D
• Max. Load= 2,535 lbs
  Max psi= 65 psi
• Serv. Desc: 113/110S
• Load Index 113= 2,561 lbs (1,164 kg) per tire
  Load Index 110= 2,337 lbs (1,060 kg) per tire
  Speed Rating “S”= 112 mph (180 kph)
• Severe Snow Service Rated

I made the decision to be ok without E rated.

 

[Mokii]

I made the decision to be ok without E rated.

Any issues? How long have you ran the set up? How many miles? What kind of terrain? Are you on stock 6" wide rims? Are there any full lock rubbing issues (when the steering wheel is turned all the way one direction?) Thanks!

 

[the_alpine]

Any issues? How long have you ran the set up? How many miles? What kind of terrain? Are you on stock 6" wide rims? Are there any full lock rubbing issues (when the steering wheel is turned all the way one direction?) Thanks!

No issues, no rubbing, stock steel rims, 20k miles over a year period. Lots of highway miles, lots of dirt and off-road as well. Love em.

 

[msh441]

I’ve heard so much about the BFG AT/KO’s fitting for some w/o modification... and not for others, not so much.

I’m heavily leaning torards the 255/70-16’s on the Ultra brand ‘Toil’ wheels. The 45mm offset on the Ultras versus the OEM Ram 68mm wheels means the inside of the tire will be no closer to suspension or brake hardwar than 225/75-16’s w/stock+68mm offset Ram rims.

Also, based on the sized calculators, the wider tore is 1/10ths of an inch shorter than the 245/75’s, while still being taller/wider than stock tires.Not a lot, but a little breathing room when compared to the 245/75’s.

not to mention Load and spped rating are still within the acceptable range (E1 load, 10-ply, S speed).

Curious if anyone else has tried it, already?

 

[eugenesan]

Can someone riding 245/75r16 report how those affect MPG, Breaking, Rolling on declines, Accelerations, handling etc.

Last week, I installed Toyo AT3 in 245/75r16 and they are really bad in all of the above.
Now I wonder if it is the size in general or make/model/size combo that causes all the issues.

 

[Juve]

Can someone riding 245/75r16 report how those affect MPG, Breaking, Rolling on declines, Accelerations, handling etc.

Last week, I installed Toyo AT3 in 245/75r16 and they are really bad in all of the above.
Now I wonder if it is the size in general or make/model/size combo that causes all the issues.

I really haven't noticed any difference to be honest. The initial rotation from a stop seems a little harder, but other than that I can't say that I notice much. I drive the van every day, and drove it on regular tires for over 1.5 years, and now on AT.

 

[Nurse Ben]

I'm running the Ultrafoil 16" with 245/70-16, fit was tight out back so I trimmed the wheel well (plastic and metal), no issues with fit.

The nice thing about the reduced offset on the Ultrafoils is the wheels are set out from the van on either side, which gives it a wider stance.

No need to make changes to the front wheel wells.

Handling is great, no realignment needed.

My suspension is a single leaf; removed the overload leaf, a 1.5" lift block, and overload bumpers, stock shocks.

 

[surfhikevan]

Perfect, just followed you guys! Great content from the quick browse

Christian Shaffer on Youtube upgrades and switching to the larger tires. shows them cutting the opening larger, removing a little metal and a lot of plastic. So they do fit fine and I plan on the same.

 

[Baxsie]

. . . cutting the opening larger, removing a little metal and a lot of plastic . . .

. . . they do fit fine . . .

Cinderella's step sister?

 

[Swamplizard]

Had a scare today - Boys at Costco mounted KO2 245/70R16 on my 2015 promaster 3500 diesel. I left the facility and heard the dreaded click clack of rubbing rubber on something hard - rear only ... no issues in the front. Almost panicked but trust you folks on here know your stuff. Went back and they Techs crawled around the Van in the parking lot - all baffled.
When I mentioned it seemed to be in the rear left - one guy slid under on his back (skinny Dude) and sure enough the tire was rubbing on a ratchet set socket someone had left on the shock absorber nut. Pulled it off with pliers - ALL Set! Phew that was a close one!

 

[Swamplizard]

Thought I'd made a $1,000 booboo for a second there.

 

[2019 Ram PM]

Had a scare today - Boys at Costco mounted KO2 245/70R16 on my 2015 promaster 3500 diesel. I left the facility and heard the dreaded click clack of rubbing rubber on something hard - rear only ... no issues in the front. Almost panicked but trust you folks on here know your stuff. Went back and they Techs crawled around the Van in the parking lot - all baffled. When I mentioned it seemed to be in the rear left - one guy slid under on his back (skinny Dude) and sure enough the tire was rubbing on a ratchet set socket someone had left on the shock absorber nut. Pulled it off with pliers - ALL Set! Phew that was a close one!

Glad it was just the forgotten sockets! BTW, on your K02 70s, did you have to trim any?

 

[2019 Ram PM]

I have the 136 short roof and hat the stock tires. Want 245 70 16 but don't want to trim, as it may void my warranty. I'll get the 45 mm offset if I have to. But was hoping for now, I could use my stock Ram rims. Any help is greatly appreciated! Steve

 

[Uvan]

@2019 Ram PM
All newly registered members MUST make an introductory post in the Introductory Post Forum as per forum rules. "Promasterforum.com Introduction Section " Please be aware until you do make the required introductory post any posts you make may be deleted

 

[2019 Ram PM]

Thanks for all your info folks. I've come to the conclusion that, I'm gonna go w/the 245/70/16 which is nearly the same outer diameter (29.5 vs 29.3 stock) and just a little wider which should fit w/o having to cut anything. Though I'd love to go bigger but, they'd probably void the warranty.

 

[HippieGypsy]

Though I'd love to go bigger but, they'd probably void the warranty.

If you put a non spec tire on your PM I would think you run the risk of the warranty not being honored for ANY malfunction that could even be remotely attributed to tires. Brake, suspension and transmission issues could all be attributed to "the wrong size" tires even if in reality the tires played no part in any malfunction. Of course I can't say definitively that this would happen but in numerous examples available in this forum RAM has shown itself to be resistant to honoring the warranty given any excuse not to. The latest example:

SOLVED: Water in transmission - Warranty being denied -...

This post has been updated to explain what happened. Greetings to all, 2019 Promaster - 2.5 years old - 10K miles - Original Owner - Also have 100,000 Ext Warr This has been the toughest challenge I have ever faced by an automotive company. Was towed to the dealership because tranny would...

www.promasterforum.com

If this forum member had not persevered RAM would have got away with this expensive failure that was caused by a design defect they've known about for a decade.