Downsizing Tires

[donniefitz2]

I'm currently running 33" Cooper Discoverer STT Pro tires (285/75/16) on my '03 D2. While I love how they look and I like having a lot of sidewall when aired down off-road, I'm doing more highway driving than I expected to do in this truck (AZ to CO). In particular, I'm doing a lot of mountain passes at high elevations and the lack of power and semi-squirrely drivability is painful.

Of course I could step up to 4.11 gears, but then I would want to replace the diff centers and then we're talking big $$$$. Not sure that's worth it.

As far as lift, I have the OME HD 2 inch (no rubbing issues or anything).

So, my question: has anyone stepped down from a 285/75/16 to something like a 265/75/16? Would it make much of a positive difference in drivability?

The smaller tire is narrower, lighter and obviously shorter so I'm thinking it would be a performance improvement but not sure if it's worth the sacrifice (love the look of the 33's).

 

[Blue]

Hi Don! Photos below are from my (now your) truck when I changed from 265/75/16 BFG ATs to those 285/75/16 Coopers. This was actually my first set of the Coopers...you are riding on the second set. And also note that the 265 BFGs were well worn in the photos. I'll find a general photo of the truck on the 265s when they were newer.

To be perfectly honest, I didn't notice any difference going from 265 to 285. I expected to notice since the tires are larger and heavier, but I didn't. The only thing I noticed was the brand new rubber lugs squirming a bit more on the pavement but that settled down after a while.

I was running my D2 on the original bushings throughout and I removed one of the sway bars (can't remember which). I had the OME HD springs and OME Nitrocharger shocks. I ran that thing up to and a bit over 100 mph on the highway frequently on runs back & forth to Utah and California. When I had it in the Colorado mountains I was still on the 265s and that is probably where it would make the most difference.

 

[donniefitz2]

No better source than you, sir! Good to know that you didn't notice a difference. I mean, I'd hate to go with a smaller tire and regret it because there's little or no difference. I've gone back and forth to my property in CO three times now and the only real problem is Mt. Ord (highway 87) and a few other passes.

Thanks for posting the pictures, that really helps.

The lack of power is manageable (hit the Econ button on the AC a lot) but not ideal. I might just suck it up and re-gear then.

 

[pdxrovermech]

235/85. Pizza cutters handle so much better.

 

[4Runner]

I have found that when you run larger tires/ taller or wider, they amplify and suspension wear you have. As you go larger, the schedule for suspension preventive maintenance gets more frequent to keep it well mannered. I tend to not go any taller than 32” on my Rovers though I completely understand and like the looks of some larger fitments. Unfortunately gearing , cam and higher compression are the only fixes for a little more power to spin your 33’s. But that also has its limits as the air thins out. On a side note, those are my favorite rims for a D2.

 

[Blue]

I had always wanted to re-gear but I would have gone with new full diffs and HD axles and you're right, that's serious money. Even after the engine replacement all my serious money was tied up replacing every other damn component on that thing and re-gearing went by the wayside.

 

[donniefitz2]

Yeah, that's the problem with re-gearing. It's about $300 per axle, then you need bearing kits for each (maybe $150). If I'm tearing the diffs out, I would have to replace the weak spider gears, so that's a minimum $500 per axle for TruTracs, not even thinking about air lockers. If I do the work myself, I'm in it for a minimum of $2000. If I have a pro do it, that would probably add $500-$600 to the bill.

That's a lot for a truck that I'm calling a budget build. I'm only in this thing for about $10k as it is.

On the other hand, if I downsize the tires and get a little power back, I could sell my current tires and get some money for them and then buy a new set. The net cost of that would probably be something like $800 or even $600 depending on the tire I buy and what I get for the current tires.

Of course, this assumes a smaller tire would make an appreciable difference, and so far, it doesn't sound like it would.

I wish there was a way to try out a set of tires for like a week before committing.

 

[p m]

235/85R16 is a great size.
7.50-16s are a bit smaller and narrower.
8.25-16s are taller and about the same width.

 

[Blue]

I always wanted to try 235/85’s

 

[Blue]

And correct me if I’m wrong, but 235/85 is a little less than 32” tall…

 

[Gordo]

Or u can source a 1.4 transfer case from an old defender. Hard to find but they are out there. Might be able to just change the gears but I’m not sure on that. I bought an old defender 130 rolling rusty chassis a few years back just for one. 200$

 

[rover rob]

And correct me if I’m wrong, but 235/85 is a little less than 32” tall…

depends on the brand I have them on 2 of my trucks different brands, one is slightly less than 32 the other set is spot on 32

 

[Lake_Bueller]

My 99 TReK is running 255/85 BFG Mud Terrain (33.1") tires (they were on the truck when I bought it). My G4 is running 265/75 (Toyo Open Country A/T)(31.6") tires.

My experience is that the 265/75 are infinitely better in their handling. I've never experienced any wandering with the 265/75 tires.

The 255/85 are brutal! I'm attributing part of that to lugs. If they weren't basically new, I would replace them sooner than later.

 

[donniefitz2]

Good to know. 255/85 is pretty close to what I have now, although a tiny bit taller and a bit skinnier.

 

[DiscoHasBeen]

Buy a cheap set of rims and the right size tire for the ride/handling you are looking for. What's it take to change out four wheels, 30 minutes? Best of both worlds.

 

[Blueboy]

235/85R16 is a great size.
7.50-16s are a bit smaller and narrower.
8.25-16s are taller and about the same width.

Yep, had 265/85 on the Rangie for awhile and switched back to the 235s. Just a great all round size imho.

 

[donniefitz2]

Looking at the 235/85, but, my wheels are 8 inches wide and that size seems to fit a max of 7.5 inch rim width. At least as far as Discount Tire's recommendations go. Are you guys running that tire size on stock 8 inch wide wheels?

 

[Howski]

I’ve not run them myself but have known a few folks running 235’s on a 8” wheel with no issues

 

[Blueboy]

Looking at the 235/85, but, my wheels are 8 inches wide and that size seems to fit a max of 7.5 inch rim width. At least as far as Discount Tire's recommendations go. Are you guys running that tire size on stock 8 inch wide wheels?

Good point. Some Audi folks run 235s on 8” rims. Possibly another option would be 245/75-16. These were std on 8” rims for Jeep Rubicons.
Feel sure others will chime in as well.

 

[donniefitz2]

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.