Tire decision help

[Kaisen]

Please tell us more on how you feel about the import drivers stretching side walls

I think it's idiotic. The first to do it were the Germans, stuffing wide BBS RS from Porsches and BMWs under MK I Golfs. The skinny tires were the only ways they would tuck under without rubbing (even with rolled/stretched fenders). Horribly unsafe, and not TUV legal. They should know better.

and the Cali-lean Chevy Trucks.

I had to Google that one. You mean where the front suspension of the truck is slightly higher than the rear suspension? Trophy trucks have that stance for a number of reasons. And desert-running trucks are popular in So Cal (where the term must have originated). It helps weight transfer. Other that that, I don't see a negative on the dynamics of the truck. Certainly not one that impacts its safety. Can you?

And you drive a Chevy

Among lots of other things, yes.
I had a 1985 Euro M6 and a 1987 BMW 535is (and lots of other BMWs over the years), so maybe we've got more in common than you think

 

[Kaisen]

Out of curiosity, who are you to tell anybody what to do?

And who are you to care? If I listed my professional credentials or experience, would it change your mind? Nope.

Are you just sitting there looking at numbers on a screen or do you have real experience with skinnier tires?

Real experience

BTW, I drove a bunch of winding mountain roads this weekend with a Discovery on 215/85-16 tires and no rear sway bar. No problems whatsoever. Most cars couldn't even keep up with me!

Keep in mind, a vehicle's suspension is a system and your 1996 Disco wouldn't be as affected by a 215/85R16 tire as a 2001 Montero, now would it?

It's not the tire alone, it's what you're putting it on, and how you intend to use it.

See above. A 205/45R16 might be a great tire, but not appropriate (in fact, unsafe) on a 16x10" BBS RS with backspacing for a Porsche 930 but fitted to the rear of a Golf Mk I whose rear drums are re-drilled with a Porsche lug pattern.

So don't think I'm damning 205/45R16 tires....get it?

LT215/85R16E have their place.....yet not a single modern light duty truck or passenger vehicle you can buy today in North America offers that size.
And there is a reason.

My much bigger and heavier 100 Series Land Cruiser is sitting on 255/85-16. No problems there either.

If LT215/85R16Es are great on your Disco, why not put them on your Cruiser? (See my point yet?)

 

[tacollie]

My 235/85r16 Duratracs had a wider contact patch than my 255/85 Discover STs did. I loved my 235's. They work great on IFS trucks. If 265's are cheaper I would probably go that route though.

 

[Kaisen]

My 235/85r16 Duratracs had a wider contact patch than my 255/85 Discover STs did.

Interesting, isn't it? You have to look at each tire individually. Even if they are the same sizing, they aren't necessarily the same size.

He's right, a Duratrac LT235/85R16E is 7.7" wide at the tread, where a LT255/85R16E Cooper ST is only 7.2" wide at the tread
The tire that is supposed to be 20mm wider, is actually 13mm narrower

 

[stioc]

The actual tread width is never the same as the section width i.e. even a 265 which has a section width of ~10.5" is only 7.8" for the tread width for the AT3s. Interestingly enough I measured my 235 Duratracs' tread width and it's approx. 8" same as a 265 AT3!

<snip>

Interesting, isn't it? You have to look at each tire individually. Even if they are the same sizing, they aren't necessarily the same size.

He's right, a Duratrac LT235/85R16E is 7.7" wide at the tread, where a LT255/85R16E Cooper ST is only 7.2" wide at the tread
The tire that is supposed to be 20mm wider, is actually 13mm narrower

Agreed

 

[Kaisen]

Agreed

Agreed. Some Coopers are notoriously narrow at the tread, given their advertised size

 

[Buliwyf]

Bud just put 235/65 r18 on his F150. An inch or two taller than stock. An inch or two narrower. But it has a higher load rating. It handles better and feels safer to me. Some of these balloon type tires might help the ride more than anything else.

 

[Erik N]

FWIW, I own 2 Suburbans. One with skinny tires for the fishing in the West Coast mountain rocky trails, and the other with fat tires for fishing the beaches in TX.

I greatly prefer the narrower setup. It allows me to crawl around obstacles, as opposed to needing to plow over them. If I didn't need the flotation in the soft stuff, I would run narrow on both of them.

Sizes are 255/85 and 285/75. Both around 33" diameter.

Also, all things being equal, I feel a narrower tire is less prone to flip the rig. Less contact patch=less traction=easier to slide/skid instead of grabbing/flipping.

Oh, and get load range "E" fer crying out loud, and never worry about them again!

My 2 cents.

 

[mortonm]

Your 7,000 pound truck was also engineered for it. It didn't come standard with 265/70-16s and you're wanting to fit taller, 2" skinnier tires instead. Spring rates, swaybar rates, bushing durometer, suspension geometry, etc are all set up for 265/70s. Going to a skinnier tire with significantly higher sidewall aspect may spell trouble in a high-speed emergency maneuver.....especially in a tall skinny high-center-of-gravity Montero. You must consider each application individually. There may be a place for a 235/85, or 255/85 but it's not every truck on the market like ExPo'ers appear to embrace.

And, your NEWEST truck is twenty years old......no manufacturer has specified 235/85-16s on a single-rear-wheel pickup truck for over 15 years. Times (and tire technologies) have changed.

Out of curiousity to your point about certain vehicles being engineered to certain sizes what say you to Nissa

To my knowledge all first gen Xterras came with the same suspension components front and back regardless of trim or year. The heights for all the models are nearly the same.

The 2wd trucks came with 235 75 R16 tires (29")
The 4wd trucks for '00/'01 came with 255 65R16 tires (29")
The 4wd trucks from '02 to "04 came with 265 70R16 tires (30.6")
The supercharged models came with 265 65R17 (30.6") tires.

Doesn't appear that the nissan engineers were worried about spec'ing different width tires. If he is really that worried about track width changes he can get a new set of wheels with a different ofset to keep the track the same (I'm sure that is what Nissan did)

I felt no ill effects moving from 255 65 to 235 85.

 

[Kaisen]

Out of curiousity to your point about certain vehicles being engineered to certain sizes what say you to Nissa

To my knowledge all first gen Xterras came with the same suspension components front and back regardless of trim or year. The heights for all the models are nearly the same.

The 2wd trucks came with 235 75 R16 tires (29")
The 4wd trucks for '00/'01 came with 255 65R16 tires (29")
The 4wd trucks from '02 to "04 came with 265 70R16 tires (30.6")
The supercharged models came with 265 65R17 (30.6") tires.

Doesn't appear that the nissan engineers were worried about spec'ing different width tires. If he is really that worried about track width changes he can get a new set of wheels with a different ofset to keep the track the same (I'm sure that is what Nissan did)

I felt no ill effects moving from 255 65 to 235 85.

There WERE changes to different models, and certainly differences between 2wd and 4wd models. So if you're asking if a 255mm wide tire vs a 265mm wide tire, or 65 series vs 70 series tire....they're a lot closer than going from a 265mm to a 235mm AND at the same time going from 70 series to 85 series.

And an Xterra isn't as tall, heavy, top-heavy, or sloppily-suspended as a 2001 Montero.

 

[redthies]

Kaisen, you post in a ton of threads related to tires or OEM mechanicals, and with a lot of confidence. This seems to lead to a lot of people challenging your facts/opinions. I am curious to know what your background is, and whether you are in the "industry" for a living, or just well read and willing to offer your theories. I for one would love to know how much weight to lend your posts. I'm happy to acknowledge a true expert in his field. Better to know why we should listen to someone's input than either believe whatever is put in front of us, or write someone off as a crackpot. (Not that I'm doing either at this point).

 

[mortonm]

There WERE changes to different models, and certainly differences between 2wd and 4wd models. So if you're asking if a 255mm wide tire vs a 265mm wide tire, or 65 series vs 70 series tire....they're a lot closer than going from a 265mm to a 235mm AND at the same time going from 70 series to 85 series.

And an Xterra isn't as tall, heavy, top-heavy, or sloppily-suspended as a 2001 Montero.

From what I can see the Xterra in all models is listed as taller than the Montero, and only weight about 10% less, the other factors I cant comment on.

All that I was trying to allude to, as well as others who differ from your opinion, is that just because you switch your tires from 265 70R16 to 235 85R16 it doesn't meant that all of sudden his Montero will turn into complete disaster on the road and be dangerous and rolling over on every corner.

Will he notice a difference, of course, they are different sized tires, but you just adjust to the new tires, notice the limitations and move on. It isn`t quite nearly as dramatic as you suggest.

In the end run what you feel is safe, and what you think looks good, everyone else`s opinion is just that

 

[huntsonora]

Kaisen, you post in a ton of threads related to tires or OEM mechanicals, and with a lot of confidence. This seems to lead to a lot of people challenging your facts/opinions. I am curious to know what your background is, and whether you are in the "industry" for a living, or just well read and willing to offer your theories. I for one would love to know how much weight to lend your posts. I'm happy to acknowledge a true expert in his field. Better to know why we should listen to someone's input than either believe whatever is put in front of us, or write someone off as a crackpot. (Not that I'm doing either at this point).

 

[Kaisen]

I am curious to know what your background is, and whether you are in the "industry" for a living, or just well read and willing to offer your theories. I for one would love to know how much weight to lend your posts.

It's my industry, education, and profession, for the last couple decades. And my passion, for a lifetime.

From what I can see the Xterra in all models is listed as taller than the Montero, and only weight about 10% less, the other factors I cant comment on.

All that I was trying to allude to, as well as others who differ from your opinion, is that just because you switch your tires from 265 70R16 to 235 85R16 it doesn't meant that all of sudden his Montero will turn into complete disaster on the road and be dangerous and rolling over on every corner.

Will he notice a difference, of course, they are different sized tires, but you just adjust to the new tires, notice the limitations and move on. It isn`t quite nearly as dramatic as you suggest.

In the end run what you feel is safe, and what you think looks good, everyone else`s opinion is just that

The 2001 Montero's hard points.....the roof above the windshield....is nearly 6" taller than the old Xterra. And the Montero 4x4 weighs up to 1000 pounds more than a base Xterra (4718 base Montero vs 3589 Xterra, GVWR is 1085 lbs greater in the Montero). Now add the capacity of two more passengers in the Montero's third row, and/or cargo packed into the 30 cubic foot larger interior.

And you're comparing a Body-on-frame Solid-rear-axle leaf-sprung Xterra to a unibody, IRS, coil-sprung Montero. Do you think they will behave similarly? Do you think they will have a similar center of gravity? (Hint: heavy frame, heavy solid axle, lower roofline)

Couple all of this with the sad reality that the Montero is ALREADY known as "a complete disaster on the road and dangerous and rolling over on every corner"
Perhaps not that radical, but relative to your Xterra, it's safe to say it's not as safe in the handling department

Guys, do what you want. You will anyways. But don't be blind to how different tires will change how your vehicle behaves. If you're willing to make those compromises in safety to (maybe) benefit in certain off-road conditions, do so fully aware of the potential consequences.

 

[Erik N]

And you're comparing a Body-on-frame Solid-rear-axle leaf-sprung Xterra to a unibody, IRS, coil-sprung Montero. Do you think they will behave similarly? Do you think they will have a similar center of gravity? (Hint: heavy frame, heavy solid axle, lower roofline)

The Montero has IRS? Cool.

I sure wouldn't mind a 4-corner independently sprung rig. I thought that was only in an Expedition or a H1 or that big Nissan SUV.