Downsizing Tires

Blueboy

Well-known member
Apr 20, 2004
3,211
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Back in the USA; Rockwood, PA
I found some photos on another forum of a guys D2 running them on the same rims that I have (8 inch) and it really doesn't look weird or anything. Sidewalls are maybe a little flush with the rim but otherwise it seems good.
Yep, agree doesn’t look weird at all.
Maybe buy them and mount one. If you don’t like it, there are many LR rim options out there. Thinking though you’ll be ok. Now the question becomes what TIRE? 😂
 

donniefitz2

Well-known member
Sep 15, 2020
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Scottsdale, AZ
fitzventure.com
Yeah, I'm pretty sure I'll end up getting Cooper's new Rugged Terrain MT. I have the STT Pro's now and they're great, but a little loud.

I came across these steel wheels on Amazon. All of the dimensions will fit a D2 except the center bore. I could have a machine shop bore the center to 70.1mm and have a nice set of black steelies to go with that tire size, which would be an awesome combo. I just have find the weight rating for them. It's just and idea though.
 
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Lake_Bueller

Well-known member
Aug 11, 2004
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Beloit, WI
Yeah, I'm pretty sure I'll end up getting Cooper's new Rugged Terrain MT. I have the STT Pro's now and they're great, but a little loud.

I came across these steel wheels on Amazon. All of the dimensions will fit a D2 except the center bore. I could have a machine shop bore the center to 70.1mm and have a nice set of black steelies to go with that tire size, which would be an awesome combo. I just have find the weight rating for them. It's just and idea though.

I don't remember the exact size, but I had a set of 16" steel rims that came from Summit Racing. They were a Chevy rim. And they were cheaper than those from Amazon.
 

donniefitz2

Well-known member
Sep 15, 2020
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Scottsdale, AZ
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Well, after reading countless vintage forum posts, rabbit holes regarding steel wheels, and an embarrassing wealth of tire size knowledge, I decided to say to hell with it, I'm keeping my 285/75 STT Pros. They probably have another 20,000 miles in them. Just rotated them on the driveway today and they look pretty good.

I'm going to save my pennies and eventually re-gear my diffs. But, I'm going to set my own gears. Always wanted to do it. I have a parts truck, so I'll just pull the diff centers out of that, set up some nice new gears (4.12 Ashcroft and probably TruTracs too) and replace mine with those 3rd members once they're done. If I blow it and the new diffs fail, I still have my old ones to fall back on.

The lesson is this, boys and girls, once you go with big meaty tires, it's really, really hard to go back.
 
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p m

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Apr 19, 2004
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No, seriously. The efficiency of TrueTracs is pretty much proportional to the ratio of the effective radius of the brake pads to that of the tire.
265/75s are probably close to the useful end of that; you have to be on the brake pedal HARD for these tires to lock up. By this time, you're on borrowed time with CV joints and engine/transmission mounts.
 

p m

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It is a stronger carrier. But I've broken three axleshafts and one CV joints with TTs, and I am not a throttle jockey. I carry spare axleshafts on challenging trips.
 

donniefitz2

Well-known member
Sep 15, 2020
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Scottsdale, AZ
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Probably a good idea on a long off-road trip. Have you ever blown a stock diff? I know the single pin diff is weak, but in my research, I don't see many people actually reporting having blown one to pieces. Back in the day, I did blow the spider gears out of a Dana 35 (Jeep YJ), but I was young and dumb and dumped the clutch at a high rev to do so.
 

Blue

Well-known member
Mar 26, 2004
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AZ
Don, I carried that spare package of axle shafts on every off road trip more than 100 miles away. Just chuck it on the floor behind the front seats.

Why not put an ARB in the rear?
 
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donniefitz2

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Sep 15, 2020
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Scottsdale, AZ
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I recently unboxed those axles. They're in great shape. Heavy though. I'll probably bring them on a dedicated 4x4 trip. I'd love an ARB in theory, but I'm not a fan of all of the air plumbing it requires and the cost is high. I wish there was an electric locker or a lunch box locker options for these trucks.
 

Howski

Well-known member
Oct 19, 2009
1,487
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Alabama
I ran a TT front/Detroit rear in my D2 on 285/75/16. Had just the Detroit first and the TT up front was a nice addition. Certainly not as effective as the ARB front locker my friend had in his similarly built D2 but felt it was an improvement over open
 

K-rover

Well-known member
Jan 15, 2010
2,165
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Raleigh, NC
Probably a good idea on a long off-road trip. Have you ever blown a stock diff? I know the single pin diff is weak, but in my research, I don't see many people actually reporting having blown one to pieces. Back in the day, I did blow the spider gears out of a Dana 35 (Jeep YJ), but I was young and dumb and dumped the clutch at a high rev to do so.
Ive personally seen more diffs blow than axles. Primarily on D2s with open diffs and big tires. I ran 34x9 swampers on open diffs with no issues before doing Ashcroft 4:12s and air lockers. Currently on 35x12.50s
 

donniefitz2

Well-known member
Sep 15, 2020
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Scottsdale, AZ
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Okay, instead of wondering if 235/85 r16 would be the tire for me, I went ahead and just bought some and had them mounted. I chose the Toyo Open Country AT III. Mostly I chose this tire because it's light for an E rated tire (44 pounds) and it's an all terrain. This will net me a 15lb reduction per corner over the Coopers. That's a lot. And man, it's a difference I can definitely feel.

So, I'll cover the bad part first: They look wimpy. Now, this might just be because I'm so used to the look of the 285/75 STT Pro's, but man, I don't know if I'll be able to get used to this.

On the upside, there's the following
1) This thing drives and rides like a dream. Seriously, it's like a completely different vehicle.
2) It actually goes forward and stops. With the bigger tires, it always felt like I was accelerating out of a hole and stopping didn't inspire confidence.
3) Road noise is non-existent. This is largely do to the AT tire not necessarily the size.
4) Bumps and bad roads feel much more tolerable.
5) I was able to take an inch of lift out of it (blocks). Now that I'm back to the standard 2" OME, there's less body roll and better steering of course.
6) From inside the vehicle, this tire and size combination are a no brainer.

Now, I haven't tested them off road yet, but I'm sure they'll be good, not worried about that. I just don't know if I can get used to the look. I feel like I neutered my truck.

It's really just vanity, I know. So, I did keep the Coopers and I have a spare set of rims. I'm going to force myself to leave these tires on for a few weeks before I make any final decisions.

Here's a few pictures of what it looks like now (it sits perfectly level, it's just in a slanted driveway) (compare to my avatar).

What do you all think? Am I just being a bitch about it, or does it look bad?

IMG_1273.jpegIMG_1270.jpegIMG_1272.jpeg
 

Blue

Well-known member
Mar 26, 2004
10,053
865
AZ
That's a lot less tire but if it makes radical positive changes for you then it's worth it.

Funny.....today I talking tires to a buddy and I said (again) that I pussed out when I bought these Nitto Terra Grapplers and I've resolved to just go buy Cooper STT Pros in 285/60/18 for the LR4, drive-ability be damned.