285/75R18 AT tires: A good choice for expedition-travel, domestic full-size trucks?

Given the purpose this truck will be used for, I would go for:

  • Toyo Open Country MT 315/75R16 tires

    Votes: 0 0.0%

  • Total voters
    33

LJinLA

Observer
The specific truck at hand is a 2nd generation 2500 Dodge Ram diesel. 4x4, manual transmission, 3.54 gears, that is completely stock.
It will be used for long distance expedition-like travel on highways, country roads and light trails, with a very light camper on its bed.
The tires I have in mind, in this size, are either the Toyo Open Country AT's or the Cooper Discoverer St Maxx, but I am also open to consider others, if you have any to suggest.
It looks like that a 2" leveler kit should clear these tires, that are about 35" tall and 11.5" wide, on a 2nd generation Dodge Ram diesel 4x4. Initially, I thought of keeping the 16"x8" wheels that are currently on the truck and going for 315/75R16 tires. However, the 285/75R18 tires seem to be a much better choice in that, while being as tall as the 315's and therefore providing the same ground clearance (and decent RPM's with the 3.54 gears on this truck, with highway fuel economy in mind), they are more than one inch narrower and about 7-8 lbs. lighter than the 315's, which is a plus when it comes to expo travel. They are some sort of "pizza cutters" when compared to the 315's.

I would love to get some feedback and comments on this from those of you who have gone this route. Also, what would be the proper wheel backspace/offset needed for 18"x8" rims in order to optimally use this tire size on a 2nd generation Dodge Ram? I'd much appreciate suggestions as to what specific wheels I should look into from those of you who own or have owned these specific trucks and done that. Many thanks in advance...
 

Regcabguy

Oil eater.
I'd get in touch with Aaron or Don Thuren at Thuren Fab. They'll be able to answer questions and not oversell you.
They're wizards on the Dodges. The 18's are going to yield a heavier load rating but with a light camper might be overkill.
The 285 width should work great.
Thuren's a really nice guy and a small business operator.
 

chet6.7

Explorer
FWIW,I went from 285's to 315's on my 2nd gen with a 2" level and never looked back.They were mounted on Mikey Thompson wheels,I had a manual V10 with 4.10's,the 315's helped on the interstate.
There was an issue with the 5th gear on the 4500 trans.
Thuren's website has several articles that may have the info you need,if not call Aaron at Thuren.
 

LJinLA

Observer
@Regcabguy
Thanks for the advice...I know about the guys at Thuren Fab and their wisdom/expertise :) However, I was hoping to first hear about the personal experiences of folks here who "have been there, done that" before contacting the wizards with the intent of moving in this or that direction. I'm still in the researching phase of this project, hence the value of hearing from guys here willing to contribute their practical experiences.

@chet6.7
Do you remember the backspace or offset of those Mikey Thompson wheels and did you experience any rubbing with the 315's? I assume your truck was a 4x4? What was the impact on general driving and on mileage x gallon when you went from 285's to 315's, city/interstate, if you can recall these details? I know you had 4.10s and a gas engine, so it's a bit different, but I'm interested nevertheless. Thanks for your input..

@malibubts
Thanks for the link, good information, indeed.
 

plainjaneFJC

Deplorable
The specific truck at hand is a 2nd generation 2500 Dodge Ram diesel. 4x4, manual transmission, 3.54 gears, that is completely stock.
It will be used for long distance expedition-like travel on highways, country roads and light trails, with a very light camper on its bed.
The tires I have in mind, in this size, are either the Toyo Open Country AT's or the Cooper Discoverer St Maxx, but I am also open to consider others, if you have any to suggest.
It looks like that a 2" leveler kit should clear these tires, that are about 35" tall and 11.5" wide, on a 2nd generation Dodge Ram diesel 4x4. Initially, I thought of keeping the 16"x8" wheels that are currently on the truck and going for 315/75R16 tires. However, the 285/75R18 tires seem to be a much better choice in that, while being as tall as the 315's and therefore providing the same ground clearance (and decent RPM's with the 3.54 gears on this truck, with highway fuel economy in mind), they are more than one inch narrower and about 7-8 lbs. lighter than the 315's, which is a plus when it comes to expo travel. They are some sort of "pizza cutters" when compared to the 315's.

I would love to get some feedback and comments on this from those of you who have gone this route. Also, what would be the proper wheel backspace/offset needed for 18"x8" rims in order to optimally use this tire size on a 2nd generation Dodge Ram? I'd much appreciate suggestions as to what specific wheels I should look into from those of you who own or have owned these specific trucks and done that. Many thanks in advance...

There are not a lot of different tires in this size. I have the Toyo open country A/T in this size, the XT version, which is a little more meatier than a regular A/T I think the tires are a little loud, I doubt all go with them when this set wears out. They look cool if that's whats important though. I just checked and the only Cooper in this size is the A/T 3 discoverer.
 

chet6.7

Explorer
@chet6.7
Do you remember the backspace or offset of those Mikey Thompson wheels and did you experience any rubbing with the 315's? I assume your truck was a 4x4? What was the impact on general driving and on mileage x gallon when you went from 285's to 315's, city/interstate, if you can recall these details? I know you had 4.10s and a gas engine, so it's a bit different, but I'm interested nevertheless. Thanks for your input..
I don't remember the MT wheel specs,I do remember the combo weighed about the same as the stock steel wheels and the puny 245's that came on the truck.The truck drove much better on the bigger tires,on and off-road,there was not any rubbing with a 2" spacer,it was a 4x4.
I do not remember much about mileage stats,the best I ever got was 12,that was an anomaly as 11.1 was most common MPG #.
Everything I did to that truck decreased the MPG,Warn front winch bumper with 4 Hella lights lowered MPG,Callen camper lowered MPG,315's lowered MPG.The MPG was usually 8.6,but I never changed the gear that drove the speedo,so an exact figure was a guess.
I don't get the MPG many claim out of my MY14 6.7 either,I keep setting trucks up the same as I have since the 70's,bigger tires,camper shell ect.,it all decreases the MPG,it is the price I pay to drive what I like.
 

LJinLA

Observer
@plainjaneFJC
Yep, you're right, I double ckecked and no ST MAXX tires in this size. The reviews about the A/T 3 discoverers aren't as good when compared with those about the ST MAXX's. I'm finding out that the same goes for the Toyo Open Country A/T's, a bunch of complains about them - the high-rated reviews tending to go to the Toyo OC MT's and Cooper ST MAXX's.

@chet6.7
I know it for a fact that a lot of guys with 2nd gen Dodge Cummins used/use big mud tires such as the Toyo M/T 315/75R16's with absolutely no complaints both on road and off road and only say great things about them. Sure, fuel economy takes somewhat of a hit but, as you say, fuel economy is not the only factor to base one's choice on. Toyo lists the M/T 315/75R16's as 34.9" tall and 12.9" wide, and at a weight of 76 lbs. Other sources have them at 81 lbs. They are definitely wider and heavier than the 285/75R18's. I have no first hand experience with them.

While the 315/75R16's are readily available everywhere, the 285/75R18's are harder to find, have a smaller tread depth and are way more expensive, less tire for the money.

Should I just forget about the 285/75R18's and just go for the 315/75R16's? Or forget about both and go for some other size, with in view what I'll be using the truck for? Still brainstorming about the whole thing, and would much appreciate more input coming from you, guys.
 

Buliwyf

Viking with a Hammer
What size OEM take off wheels are available for that Dodge? I'm getting a set of extra Ford 18" wheels OEM off Ebay for under $1000.

Are any 17" OEM wheels available? 285/75r17 Cooper ST Maxx (34") is what I'm putting on my 17x7.5" wheels.
 

LJinLA

Observer
What size OEM take off wheels are available for that Dodge? I'm getting a set of extra Ford 18" wheels OEM off Ebay for under $1000.

Are any 17" OEM wheels available? 285/75r17 Cooper ST Maxx (34") is what I'm putting on my 17x7.5" wheels.

Buliwyf, as far as OEM take off wheels go, my understanding is that 4th generation Ram 18" wheels, unfortunately, are not compatible with 2nd generation Dodge Rams. (If anyone knows otherwise, please let me know...)

As to 17" OEM take off wheels, 3rd generation Dodge Ram aluminum wheels are compatible with 2nd gen Rams, however, they are 8"-wide wheels with a 6.13" backspacing (which on an 8" wheel is the equivalent of a +38 mm offset) - it tucks tires too much in on a 2nd gen Ram, resulting in a lot of rubbing at various points and many guys using these on their 2nd gen trucks end up having to use 1.5" to 2" wheel spacers, which change the effective wheel backspacing of said rims from 6.13" to 4.63" and 4.13" accordingly.

H2 wheels are compatible with 2nd gen Rams and have a 5.5" backspacing. 16"x7" steel Ford van wheels have a 4.5" backspacing (a 4.5" backspacing on a 7" wheel corresponds to a 5" backspacing on an 8" wheel - both equal to a +12 mm offset), and it seems a lot of guys have mounted even 315/75R16 tires (12.5" wide) on the 7" Ford steelies without complaint, while others who have done that complain that the wheels are too narrow for large tires and the tires end up prematurely worn out in the center. Whom to believe?

The OEM Ford 18" wheels you are getting off Ebay are going to your 2017 Ford F250, correct? I don't think they would fit on a 2nd gen Dodge Ram..

Come on, guys, keep your input coming, don't let this thread die with so little contributed information. Thanks..
 

Buliwyf

Viking with a Hammer
Yeah, I'm not familiar with Dodge wheels. I like to stick to OEM take off wheels because they're strong and cheaply available. I like to stay as small and skinny as possible for off road. The minimum wheel width rules are for street use.

If you're open to MT's, the Cooper STT Pro and Maxxis's new tire are great options.
 

LJinLA

Observer
Yeah, I'm not familiar with Dodge wheels. I like to stick to OEM take off wheels because they're strong and cheaply available. I like to stay as small and skinny as possible for off road. The minimum wheel width rules are for street use.

If you're open to MT's, the Cooper STT Pro and Maxxis's new tire are great options.

Agreed with you about going for OEM wheels whenever feasible. However, if one is forced to use wheel spacers in order to go for OEM wheels, such as in the case of using Dodge Ram 3rd gen aluminum wheels on 2nd gen Dodge Ram trucks as pointed out in my previous post, the wheels spacers then become a weak link and that's not so good.

I'm open to MT's. Unfortunately the 285/75R18's (the tall and skinny tires - which IMHO would be a good compromise for both highway and off road use) are not available in neither the Cooper STT Pro's nor the ST Maxx's. Of my two proposed tire sizes, only the 315/75R16's are available as STT Pro and ST Maxx. However, both the 285/75R18's and 315/75R16's are available as Toyo Open Country MT's...and they both get excellent reviews.
 

LJinLA

Observer
I'd get in touch with Aaron or Don Thuren at Thuren Fab. They'll be able to answer questions and not oversell you.
They're wizards on the Dodges. ... Thuren's a really nice guy and a small business operator.

Thuren's website has several articles that may have the info you need, if not call Aaron at Thuren.

Thanks for suggesting it, guys.
Thuren Fab's Tech webpages no longer have info/articles specific to 2nd generation Dodge Ram trucks. I contacted Don in email about it and he responded that their main focus is moving forward with [3rd and 4th generation trucks] as that is best for business. However, he did ask me a few questions about my plans for the truck, let's see what comes out of it...
 

locrwln

Expedition Leader
I know the Coopers ST-Maxx's don't come in the 285/75R18, but have you looked one size up?
LT305/70R18 126\123Q E BLK 8.5 - 10 9 12.5 35.08 70 3750 18.5

I have a friend that is running that size of 'Maxx and he has nothing but good things to say. As you can see, they are a true 35" tall tire with a healthy 3750lb load rating. That is probably going to be the size I go with.
.
Jack
 

chet6.7

Explorer
I would have gone with 305's but they required a wider rim than the 315's,I was able to stay with the stock wheels.
 

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