265/75 vs 235/85

DD196

DD196

Observer
Greetings! First post in the Nissan forum. Yesterday I picked up a 2002 SE Xterra/125K in great shape with all maintenance up to date, but it needs new tires. Plans are for a day trip/adventure/exploring truck so maybe expedition lite? Backroads, forest service roads, up to moderate trails. No rock crawling. 98% dry conditions, rocks, gravel, hardpack, sand. Looking at 265/75 or 235/85 on the stock alloy wheels. The 265/75s have an 8.5" tread width, the 235/85s 7.1" tread width. Is the added floatation worth the greater cost and 5 lbs per tire? Anyone with experience with the 235/85s in the southwest?

Looking forward to a mild Xterra build!
 
R

RonapRhys

Adventurer
As a short answer (which means I'm lying because I don't do short answers): It depends on you.

  • Wider treads and flotation is only part of it. The bigger part, since most of us aren't in situations where flotation would even be a thing, is that wider tires give you a larger contact patch thusly increasing traction.
  • Spreading the weight of your vehicle over a larger area reduces environmental impact.
  • Taller tires take bumps a bit easier as they're smaller in relation to the tires.
  • When you air down, and you should, you still keep the lift. What I mean by keep the lift is that if you've added larger tires, you'll lose some of the lift they give you but if they were large enough you'll be down to factory height, which is higher than you would've been when you aired down smaller tires.
  • Airing down also improves ride quality as it's just not as jarring. Plus, your tires do a better job of conforming to the obstacle.
 
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richard310

richard310

pew pew
The narrower 235/85 will help with less rolling resistance, but like was said earlier, they are the same diameter and you lose that 1" of contact surface area. I am running 265/75 on my Xterra and have thoroughly enjoyed the slightly wider/taller than stock tires. I also debated the different widths but ended up sticking to the 265/75's I had before. With a lift, extra junk on/in the rig, it all equals out anyways and I've given up trying to increase MPG's. I'll just get another vehicle for day-to-day use if I really have to worry about it.

As far as sandy washes, I've been in my fair share. I believe it mostly depends on the tread and type of tire but between the two, I'd prefer the wider tire due to the larger contact patch rather than the skinny type where one would get stuck easier. Spreading out the contact patch (especially when aired down) decreases your chances of digging in and getting stuck. You would have more control of the vehicle on sandy washes with a wider tire. Different with snow, where you'd want the skinnier tire to cut through the snow along the actual ground floor depending on the snow levels.
 
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DD196

DD196

Observer
Thanks. If I'm driving in snow I took a wrong turn. Had a lifetime of driving in snow in Pa. Moved here to get away from it!:safari-rig:
 
D

dnellans

Adventurer
I've had 265/70 BFG AT, 265/75 BFG AT, 255/85 Cooper ST, and am now on 235/85 BFG AT on my 2004 Tacoma ext cab. I loved the 255/85's for wheeling purposes but they were just too big (a for real 33") without regearing the taco for around town and the more MT style tread was bad in the snow of santa fe, NM. So when it was time to replace those I debated about going to 265/75's in the BFG AT's again or down to the 235/85s. The 235/85's are actually slightly taller than the 265/75's in practice and even with a 2-2.5 inch lift and upper control arms the 265/75's would barely just barely rub the frame at full lock + stuff. I know this because there was always a very slight shiny spot on the frame, it wasn't enough to feel when driving or wheeling but it clearly was happening. Long story short - I like the 235/75's more than the 265/75s for intangible reasons. I never had any problems with the 265/75's in the snow in salt lake city, but I feel slightly more comfortable driving with the 235/85's for whatever reason.

The milage difference or on-road behavior is a moot point, I bet you'd never be able to tell a difference in a blind test, both are great. I do think the 235's -look- slightly better on my taco, they sit within the fender wells just a little bit better. A couple times a year the truck ends up in true sandy washes as part of some desert dirtbiking trips - the mojave trail is one of those destinations. 95% of the time I don't even have to air down with the 235's and I never did with the 265's either. 4wd + 4low and a locker is all that is needed to keep the truck going, so I don't think the additional floatation is all that different either, though clearly there would be more if push came to shove with the 265/75. i pull my 1,500lb jumping jack with dirtbikes on top up the sandy washes without even thinking twice - put it in 4-low, 3rd gear manual and just chug on up. I've even pulled RV's and a portapotti flatbed truck up/down a wash without bothering to air down or apply the locker... figuring i'd air down only if necessary and it simply hasn't happened.

Long story short - I doubt you'll really notice a performance difference with either one on the road or in 95? % of all offroad situations unless you're truly rock crawling or in sand that will bury you up to the frame rails. In the snow I like the 235's but its mostly mental, the 265's never failed me either... Go for something different and try the 235's, if you don't like them in 50k miles you can go back to 265's, its not like you're going to absolutely hate either one vs the other!
 
stioc

stioc

Expedition Leader
I've tried 255/65/16, 245/75/16, 235/85/16 and 265/75/16 on my truck with different types of tire brands, all documented in the build thread. Here's my personal experience- from a strictly aesthetics point of view it depends on the amount of lift you have and the tire pattern. Skinny tires look better on a stockish rig, wider tires fill the wheel wells out a bit more and look better when you have more lift than stock. Large tread blocks on a tire (MT types) often make the tires look skinnier e.g. 265/75/16 in AT and MT - the ATs will look wider.

Performance wise I didn't notice much difference across any of those tires, the 235s did seem to dart around the freeway a bit more and needed more attention at the wheel. The 235s are only available in E load rating which you may or may not need/want.

Tires wise here's how I rate the ones I tried:

1. BFG MTs (not a daily driver so these work great, I don't expect them to last more than 40k or so, they're lounder too but not too bad at higher speeds, they just look right on my truck and perform great offroad)
2. BFG ATs (quiet, great performance, never had any issues with them, my fav AT tire so far and they would've lasted me over 60k easily)
3. Toyo Open Country (not the newer IIs. They were good tires, smooth ride but better suited for the milder terrain)
4. Goodyear Duratracs (Look good initially, then I got bored of the looks, noisy, too soft, vague handling and didn't balance right- others have had better luck than me though)
 
DD196

DD196

Observer
Thanks for the 1st person reports, just what I was looking for. This is a good read as well: http://expeditionportal.com/where-the-rubber-meets-the-road/

Funny thing, I had Cooper A/T3s on a past truck and really liked them. Nobody here stocks them and I was going to go with the ATPs from Discount but after reading the test I ordered A/T3s in 265/75-16. I live "over the hill" from Prescott so the Expo test is as relevant as it gets for me.
 
mortonm

mortonm

Expedition Leader
I've had 235/85 on my '01 Xterra for three years and have never regretted then for a second in nearly 50,000 miles.

I love the look although subjective. Unless your constantly dealing with deep sand/mud/snow the 235/85 will provide better traction otherwise. Same weight, smaller contact patch = more contact pressure.
 
DD196

DD196

Observer
Pretty sure that if both sizes have the same psi the area of the contact patch is the same and the force to the ground is the same, the shape of the contact patch is different. 40 psi in a 265/75 is the same as 40 psi in a 235/85. For the BFG A/T KO the tread width is 8.5" vs 7.1" vs 8.7" for the stock 265/70 size.
 
mortonm

mortonm

Expedition Leader
DD196 said:
Pretty sure that if both sizes have the same psi the area of the contact patch is the same and the force to the ground is the same, the shape of the contact patch is different. 40 psi in a 265/75 is the same as 40 psi in a 235/85. For the BFG A/T KO the tread width is 8.5" vs 7.1" vs 8.7" for the stock 265/70 size.
Click to expand...

I meant pressure from the vehicle. The contact patch is not the same, the 265 tire is over an inch wider, despite having the same length as the 235.

This means the same truck at the same tire pressure will have a higher contact pressure with the 235s. (Same mass less surface area = higher psi on the ground
 
DD196

DD196

Observer
40 psi is 40 psi right? A 4000 lb truck with 40 psi in the tires will have 100 square inches of contact no matter the width of the tread. The 235 will be narrower and longer, the 265 will be wider and shorter but both will be 100 square inches at 40 pounds per square inch. Or, 25 square inches per tire.

Better get to bed or Santa won't bring you that new ARB compressor..:safari-rig:
 
stioc

stioc

Expedition Leader
Mortonm is correct. The amount of "pressure" (from the weight of the vehicle- not air pressure) "per-sq inch" is higher for skinnier tires because of the very fact that the contact patch is smaller. On a wider tire the weight is spread over a larger contact patch area so while the the weight of the vehicle is constant but on a per-square inch basis it's lesser. Imagine a 10lbs weight on a 4" diameter pipe vs. the same 10lbs weight on a nail. Or another example if your vehicle's jack sinks into the sand what do you do? you put a 12x12 wooden base under it so the weight is spread over a larger area and won't allow it to sink.

In theory this is true in reality I'm not sure it really matters since we're talking about a small difference.
 
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