Thoughts on tires, tall or wide, advantages?

[Pskhaat]

The suspension cycles the tire through its camber angle, unless it's a solid axle truck...The tire on a solid axle would remain loaded pretty much the same, but not on an independent suspension.

Aye, but so does the steering even on front live axled vehicles due to the kingpin angle.

does the distribution in the main load bearing surface remain about the same magnitude and the edges become less important?

ntsq spoke to this, but without rim/spacer adjustments on a larger diameter tire regardless of width the patch will not center about the turning axis where I would highly guess those bearings would take additional moment. What I'm getting at is even at a wider tire (not taller) during steering you are also placing more moment at those bearings during steer as well as moving more pressure towards the outer tire edge, which most of us can empirically see through our tire wear with wider tires.

 

[colotaco]

I think there have been a couple of threads on here, but check this link out. Some rational info on the subject:
http://www.expeditionswest.com/research/white_papers/tire_selection_rev1.html

I like 255/85/16's for what I do.

Can 255/85/16's fit on a 15" rim?

 

[durango_60]

Can 255/85/16's fit on a 15" rim?

Nope, check out a 33x10.50 15

 

[charlieaarons]

I wish I could find more tires for a 16" wheel that are 36"+ tall and 9-11" wide.

Michelin 255/100R16 XZL.

Charlie

 

[Redline]

When we talk about tire widths, how important (or not) is the section (overall) width, or is it the tread width that we should really care about? Some tires have a more tapered sidewall design and the section width is not necessarily a good indication of how much tire is on the ground. Do we use section width because that is data that is always available, tread width is often not?

To expand on Scott B's example:

The section width on my 4Runner's stock 265/70R16 Michelin Cross Terrain all-seasons was a fairly wide (for the size) 10.8-inches. (This is mounted on an 8" rim per the Tire Rack's website, my stock wheels are sevens). The tread width is not listed for this exact tire but 8-inches seems to be pretty common for the 265/70 size.

Most 255/85R16s have a section width of 10-10.3 inches. A 10-inch section width and tread width of about 8-inches is common. If the tread width is what's most important (instead of section width) then we have exactly the situation Scott B. outlines in his quoted post. Taller tire with essentially the same width as the stock tire.

Since we usually add a lift to clear taller tires, if we don’t increase our section or tread width have we failed to increase our overall track-width to add stability to the platform as is often recommended for a lifted vehicle? Does a moderately lifted expedition vehicle lose as much stability as a typical 4x4 rig that may be lifted higher, or has a shorter/narrower wheelbase?

And what about using a tire that is narrower (tread) than the stock tire, but still 33+ inches tall? This is currently the case on my 4Runner, where I'm running a very narrow 255/85, Cooper ST. This tire has a tread width of only 7.2-inches even though the section width is 10.0 and the height is 33.21-inches. This tread width is closer to a 235/85R16 than most 255s. Do the slightly bulging and outboard sidewalls sitting above the inboard edges of the tread possibly help add even more contact pressure to the super narrow tread?

For the record, the 4Runner does have a moderate OME lift of about 2.5-3-inches. It also has FJ TRD wheels which have less backspacing and are 7.5-inches wide, giving the vehicle a slightly wider track width. But the wheels are not much wider and the tires/wheels are well under the fenders with all 255/85 tires I have tired. The vehicle feels very stable in normal on/off-highway conditions, though these super narrow Coopers are new additions. Past treads were 8-inch wide tread 255s. My seat-of-the-pants opinion is that this platform is relatively wide, low, and long (wheelbase) and is quite stable. But would the platform be significantly more stable on side hills if a much wider tire like a 285/75R16 was used?

It is also important to note, that there is a "sweet" spot for a tire aspect ratio and vehicle weight. I go into that a little more in the white paper, but for the typical truck and SUV on this forum, it will be around 85% aspect ratio. Tires get wider as they get taller to ensure sufficient tire contact (scrub and deflection) with turning.

It is all a balance. Just enough flotation for sand and mud and snow, but as narrow as possible to benefit from the items listed above. I have found that sweet spot to be at about 85% aspect ratio. If you want something "meatier", use the 75%. What I try to do is keep the width about what stock is, and just go taller. That usually means jumping from a 75% aspect ratio tire to the 85% aspect ratio tire, which gives you a 5% increase in ground clearance.

Lets compare a 265/70 and a 255/85, something that relates to a Tacoma, 4Runner, most Tundras and Sequoias too.

265/70 R16 = 30.6x10.6/16
255/85 R16 = 33.3x10/16

So, you have nearly the same width as factory, yet gain 1.35" in ground clearance. Significant...

 

[michaelgroves]

Well, this topic is a month old, but as I have just seen it now for the first time, I thought it should be resurrected!

I liked Scott's approach of considering the "ideal" model first - friction being independent of the tyre's "footprint", since downward force is inversely proportional to footprint, and then seeing how the real world differs from that ideal model. I.e., basic principles first, then modify them to represent the more complex scenarios...

I think it's worth noting that in the same vein, a tyre is somewhat like a balloon sitting on a flat surface. Put a given load on the top of it, and it deforms against the flat surface in proportion to its internal air pressure. The footprint of an "ideal" tyre deforms (for any given load) in direct proportion to its pressure, regardless of its width or its height.

Which means that a narrow tyre and wide tyre at the same pressure will have identical contact areas, albeit different shapes - the wide tyre will have a short fat footprint, and the narrow one, a long narrow footprint.

At a pressure of 2 Bar (~2kgf/cm2), and a load of 500kgf on the tyre, there will be 250cm2 of footprint. At 1 Bar, there will be 500cm2 of footprint. (I would guess that a 235/85-16 tyre at 1 Bar and a 500kg load would probably have a footprint about 25cm wide and 20cm long. A 185/65-14 at 1 Bar might have a footprint, say, 20cm wide and 25cm long).

This basic principle of pressure illustrates firstly why a narrow tyre doesn't necessarily offer less flotation than a wide one, and secondly, why airing down has such a huge effect. (Airing down to half pressure does in fact roughly double the contact area. Most of this is invisible, as it tends to increase the length of the footprint far more than the width.)

Now, granted, a tyre is not a balloon; it has a degree of rigidity, which decreases the actual footprint (but of course that is true of both wide and narrow tyres). Also, off-road terrain is not a nice flat hard surface - it gives way, and both wide and narrow tyres sink some distance into it, and then start behaving differently to each other.

But by far the biggest determinant of contact area (for any given load), is tyre pressure, NOT tyre dimensions. And actual tyre construction is (a very distant) second.

That's not to say that tyre dimensions are unimportant - it's just that contact area and flotation are not that dependent on anything other than pressure. Tyre dimensions do play an indirect part, in that the low-pressure deformation of a small tyre will be much more concentrated than that of a similarly aired-down big tyre. Not only will the small tyre heat up much more (because of the concentrated warping), but it can't shed the heat as quickly either. This makes a big tyre (diameter or width) more suitable for running at low pressures than a small one. The 185/65-14 example I used above, would have to deform hugely to carry 500kg at 1 Bar, and hence put down 500cm2 of footprint.

And of course, tyre dimensions play a big part in other aspects of handling and performance. Width and aspect ratio affect cornering ability. Smaller, lighter tyres with lower unsprung mass make for better suspension, acceleration, and braking. From an off-road point of view, even without a bigger footprint, tall tyres have huge advantages in terms of vehicle ground clearance, and in terms of how they themselves roll over obstacles more easily than small diameter tyres. But they require more torque to turn them, and hence sometimes put more strain on a vehicle's running gear.

Contrary to some of what's been said in this thread, for thick sand I would choose a tall narrow tyre over a short wide tyre any day, assuming both were able to run at the same pressures. In sand, the main issue is the wall of sand that builds up in front of each tyre. Each tyre is continuously trying to climb this wall, and at the same time, it's having to dig its way through the wall. For any given sand trap, this wall has three characteristics that affect how the tyre (and vehicle) copes with it:

1. The height of the wall. This largely depends on the pressure of the tyre, as discussed above. Both tyres should have similar levels of flotation, at the same pressure, so they will sink down to a similar depth into the sand.
2. The width of the wall. The narrow tyre has a distinct advantage here, as there is physically less sand to shift out of its way. That's why you need much more horsepower to get through sand with wide tyres.
3. The angle of the wall. The tall tyre can "climb" the wall at a significantly smaller angle than the small diameter tyre. This translates into less resistance, and less digging.

This explanation gels with my experience, by the way - I have done a LOT of sand driving in deserts, beaches, and general sand tracks, with vehicles of all kinds, and tyres of all shapes and sizes. In general, I would put the ability to air-down head and shoulders above any other factor when driving in sand. But as a distant second factor, I would rank having tall, narrow tyres as the best shape. (I could be convinced, that under some circumstances, tall wide tyres might be as good or better than tall narrow ones - but I would always choose extra diameter in preference to extra width).

So why don't tall tyres sell? Simple - other things being equal, a bigger diameter tyre presents a whole raft of disadvantages for the truck designer. Lots of rotational and unsprung mass (worse braking, steering, suspension, acceleration), higher centre of gravity, bigger wheel arches eating into load and engine space, bigger spare wheel to accommodate, more expensive etc. etc. etc. So they design the trucks to take a small diameter tyre, and to hell with optimum off-road performance. Then if the after-market guys want to sell you bigger diameter tyres, they first have to persuade you to raise your suspension, cut away bits of your bodywork, curtail your ability to turn sharply, alter your gearing, and uprate your running gear to cope with the extra torque requirement. Frankly, it's easier to sell you a set of offset wheels and wide tyres. So that's where the volume is.


Enough of a ramble - three cheers for whoever mentioned Michelin XZL 255/100-16's! That's a tyre! (But I really miss the old Michelin XCL in 9.00x16...)

Rgds,

Michael...

 

[Redline]

That is an excellent addition to this thread and this forum Mr. Groves.

Well, this topic is a month old, but as I have just seen it now for the first time, I thought it should be resurrected!

I liked Scott's approach of considering the "ideal" model first - friction being independent of the tyre's "footprint", since downward force is inversely proportional to footprint, and then seeing how the real world differs from that ideal model. I.e., basic principles first, then modify them to represent the more complex scenarios...

I think it's worth noting that in the same vein, a tyre is somewhat like a balloon sitting on a flat surface. Put a given load on the top of it, and it deforms against the flat surface in proportion to its internal air pressure. The footprint of an "ideal" tyre deforms (for any given load) in direct proportion to its pressure, regardless of its width or its height.

Which means that a narrow tyre and wide tyre at the same pressure will have identical contact areas, albeit different shapes - the wide tyre will have a short fat footprint, and the narrow one, a long narrow footprint.

At a pressure of 2 Bar (~2kgf/cm2), and a load of 500kgf on the tyre, there will be 250cm2 of footprint. At 1 Bar, there will be 500cm2 of footprint. (I would guess that a 235/85-16 tyre at 1 Bar and a 500kg load would probably have a footprint about 25cm wide and 20cm long. A 185/65-14 at 1 Bar might have a footprint, say, 20cm wide and 25cm long).

This basic principle of pressure illustrates firstly why a narrow tyre doesn't necessarily offer less flotation than a wide one, and secondly, why airing down has such a huge effect. (Airing down to half pressure does in fact roughly double the contact area. Most of this is invisible, as it tends to increase the length of the footprint far more than the width.)

Now, granted, a tyre is not a balloon; it has a degree of rigidity, which decreases the actual footprint (but of course that is true of both wide and narrow tyres). Also, off-road terrain is not a nice flat hard surface - it gives way, and both wide and narrow tyres sink some distance into it, and then start behaving differently to each other.

But by far the biggest determinant of contact area (for any given load), is tyre pressure, NOT tyre dimensions. And actual tyre construction is (a very distant) second.

That's not to say that tyre dimensions are unimportant - it's just that contact area and flotation are not that dependent on anything other than pressure. Tyre dimensions do play an indirect part, in that the low-pressure deformation of a small tyre will be much more concentrated than that of a similarly aired-down big tyre. Not only will the small tyre heat up much more (because of the concentrated warping), but it can't shed the heat as quickly either. This makes a big tyre (diameter or width) more suitable for running at low pressures than a small one. The 185/65-14 example I used above, would have to deform hugely to carry 500kg at 1 Bar, and hence put down 500cm2 of footprint.

And of course, tyre dimensions play a big part in other aspects of handling and performance. Width and aspect ratio affect cornering ability. Smaller, lighter tyres with lower unsprung mass make for better suspension, acceleration, and braking. From an off-road point of view, even without a bigger footprint, tall tyres have huge advantages in terms of vehicle ground clearance, and in terms of how they themselves roll over obstacles more easily than small diameter tyres. But they require more torque to turn them, and hence sometimes put more strain on a vehicle's running gear.

Contrary to some of what's been said in this thread, for thick sand I would choose a tall narrow tyre over a short wide tyre any day, assuming both were able to run at the same pressures. In sand, the main issue is the wall of sand that builds up in front of each tyre. Each tyre is continuously trying to climb this wall, and at the same time, it's having to dig its way through the wall. For any given sand trap, this wall has three characteristics that affect how the tyre (and vehicle) copes with it:

1. The height of the wall. This largely depends on the pressure of the tyre, as discussed above. Both tyres should have similar levels of flotation, at the same pressure, so they will sink down to a similar depth into the sand.
2. The width of the wall. The narrow tyre has a distinct advantage here, as there is physically less sand to shift out of its way. That's why you need much more horsepower to get through sand with wide tyres.
3. The angle of the wall. The tall tyre can "climb" the wall at a significantly smaller angle than the small diameter tyre. This translates into less resistance, and less digging.

This explanation gels with my experience, by the way - I have done a LOT of sand driving in deserts, beaches, and general sand tracks, with vehicles of all kinds, and tyres of all shapes and sizes. In general, I would put the ability to air-down head and shoulders above any other factor when driving in sand. But as a distant second factor, I would rank having tall, narrow tyres as the best shape. (I could be convinced, that under some circumstances, tall wide tyres might be as good or better than tall narrow ones - but I would always choose extra diameter in preference to extra width).

So why don't tall tyres sell? Simple - other things being equal, a bigger diameter tyre presents a whole raft of disadvantages for the truck designer. Lots of rotational and unsprung mass (worse braking, steering, suspension, acceleration), higher centre of gravity, bigger wheel arches eating into load and engine space, bigger spare wheel to accommodate, more expensive etc. etc. etc. So they design the trucks to take a small diameter tyre, and to hell with optimum off-road performance. Then if the after-market guys want to sell you bigger diameter tyres, they first have to persuade you to raise your suspension, cut away bits of your bodywork, curtail your ability to turn sharply, alter your gearing, and uprate your running gear to cope with the extra torque requirement. Frankly, it's easier to sell you a set of offset wheels and wide tyres. So that's where the volume is.


Enough of a ramble - three cheers for whoever mentioned Michelin XZL 255/100-16's! That's a tyre! (But I really miss the old Michelin XCL in 9.00x16...)

Rgds,

Michael...

 

[michaelgroves]

For the record, the 4Runner does have a moderate OME lift of about 2.5-3-inches. It also has FJ TRD wheels which have less backspacing and are 7.5-inches wide, giving the vehicle a slightly wider track width. But the wheels are not much wider and the tires/wheels are well under the fenders with all 255/85 tires I have tired. The vehicle feels very stable in normal on/off-highway conditions, though these super narrow Coopers are a new additions. Past treads were 8-inch wide tread 255s. My seat-of-the-pants opinion is that this platform is relatively wide, low, and long (wheelbase) and is quite stable. But would the platform be significantly more stable on side hills if a much wider tire like a 285/75R16 was used?

I'd have thought much wider tyres would only be more stable to the extent that the overall track of the vehicle is then wider. So narrow tyres mounted offset should surely be just as stable? Not that I am a fan of offset wheels (or spacers), but that's for reasons of steering and wheel bearings etc.

That is an excellent addition to this thread and this forum Mr. Groves.

Thank you

 

[Redline]

The question I was trying to pose was:

Is it simply the overall track width that matters for stability?

Does it matter if the width comes from wheels or tires?

Given the TRD wheels I'm using would a wider tire on theses wheels (a 285 instead of a 255) add stability?

My sense is that yes, overall width, regardless if it comes from wheels and/or tires, helps stability.

I'd have thought much wider tyres would only be more stable to the extent that the overall track of the vehicle is then wider. So narrow tyres mounted offset should surely be just as stable? Not that I am a fan of offset wheels (or spacers), but that's for reasons of steering and wheel bearings etc.



Thank you

 

[Pskhaat]

Is it simply the overall track width that matters for stability?

Not trying to hijack the thread here, but I just did some extraordinarily elementary statics comparisons from numbers off the top of my head. I assumed my LC80 (with fictional 33" tires) at ~61" track width and a COG transversely centered at ~36" off the ground (nothing empirical).

This puts a really rough tipping point at ~40 degrees.

Add 2" to track width and I'm at ~41 degrees. Bigger delta than expected.

BUT is a degree in fungible lateral stability noticable as a driver? really?

 

[Redline]

You have the science and math on your side, I'm weak in this area...

One degree doesn't sound like much, but I would guess that some rigs with much wider tires/wheel might be more like 4-inches wider overall (or more) compared to stock?

Not trying to hijack the thread here, but I just did some extraordinarily elementary statics comparisons from numbers off the top of my head. I assumed my LC80 (with fictional 33" tires) at ~61" track width and a COG transversely centered at ~36" off the ground (nothing empirical).

This puts a really rough tipping point at ~40 degrees.

Add 2" to track width and I'm at ~41 degrees. Bigger delta than expected.

BUT is a degree in fungible lateral stability noticable as a driver? really?

 

[madizell]

You have the science and math on your side, I'm weak in this area...

One degree doesn't sound like much, but I would guess that some rigs with much wider tires/wheel might be more like 4-inches wider overall (or more) compared to stock?

Mine is approximately 12 inches wider than stock in total, 3 inches attributable to additional axle width, and the rest attributable to wider wheels but with stock backspacing, so that all of the additional wheel width is found outboard of the stock outer rim location. On the other hand, the vehicle is also about 9 inches taller than stock (5 to 6 due to SOA and new spring pack height, 2 1/2 suspension lift, one inch body lift), at least 1,000 pounds heavier than stock, and more suspension travel than stock (9 rear, 12 front) so I wouldn't say that it is necessarily more stable than stock in off camber situations. It seems that just modifying the wheels is never really enough. Lots of other things get done, too, which muddies the sense of whether wider wheels result in more stability. But, all other things being equal, a wider track width will increase cross hill stability.

 

[R_Lefebvre]

Wow, excellent discussion guys. Very refreshing to see this level of debate occuring regarding off-road vehicles... usually discussions are much less civilized in other forums.

I just had a comment about the excellent white paper that was written:

I believe the assumption that the coefficient of friction, between rubber and a tactile surface like concrete or asphalt, remains constant for a given pressure is not valid.

In fact, as the pressure decreases, the coefficient of friction increases. It's non linear. This fact throws high school physics professors into fits, but it's a fact. I believe it has been pointed out by Milliken in his excellent book.

This is why you see race cars using the widest practical tire. Tire temperature and wear life are a factor. But using wider tires allows a larger contact patch, which reduces pressure and increases the coefficient of friction.

I don't think the point is really relevant to the discussion about off-road tires running on loose surfaces, but I just wanted to make the point to complete the argument.

I might argue that in pure rock-crawling situations, the same could be true. A wider tire with lower pressure and a correspondingly bigger contact patch may grip a clean rock face better than a narrow tires. I know the argument has been made that narrow and wide tires both achieve the same contact patch area at a given load and pressure. But I think one variable that has thus far been ignored is the fact that I believe wider tires can be run with less pressure than narrower tires without completely flattening the tire.

I know that is the case with road race tires. Wide tires can be run with relatively less pressure than narrower tires while still keeping the wheel rim off the road. The wider, lower pressure tire has a correspondingly bigger contact patch, and thusly higher coefficient of friction.

Edit, thinking about it more, I think it becomes evident when one considers the geometries involved. Lets's assume equal wheel diameter, tire diameter, and assume the contact patch is nicely square. I'm going to assume a 255/75/16 compared to a 295/65/16. Both 31" tall with 7.5" tall sidewalls. At 25psi, they would both necessarily have 60 sq.in. footprint assuming a 6000lb truck. Difference is, the 255 footprint would be 6" long. The 295 footprint would have a 5.2" long footprint. At 15 psi however, the 255 would have a 10" wide footprint. The 295 would be 8.62".

One can see that from a side view, as the footprint is lengthened, the sidewall hight becomes shorter. The vertical height of the contact patch moves up until the tire is flat and the weight is resting on the rim. A wider tire can run lower pressure until you get to this point. A wider tire will place less strain on the sidewall of the tire at a given low pressure than a narrower tire. Now, we all know that there is more to it than this. You need to worry about the bead retention on the rim, etc. There will be a point where you can't go any lower. That's why beadlocks were invented.

I think the point stands that, for most practical purposes, we are better off with skinnier tires as long as we plan to run reasonable pressures like 25psi. But for a very dedicated mud bogger, rock crawler or Greenland traveller, very wide tires with beadlock rims allow the use of VERY low pressures with massive contact patches for floatation or in the case of the rock crawler, potentially better coefficient of friction.

 

[madizell]

In fact, as the pressure decreases, the coefficient of friction increases. It's non linear. This fact throws high school physics professors into fits, but it's a fact.

Most experiments depend on control of all variables but one in order to isolate and verify results. In your statement I believe there are more than one variable at work, so that a conclusion can not be simply drawn that decreased tire pressures change (increase or decrease) coefficient of friction. I believe the phenomenon you are witnessing is an increase in available traction, not a change in coefficients.

I would expect the coefficient of friction to be a function of (principally) tire compound, friction surface, and the load on the tire. None of these are impacted by tire pressure. Available traction, on the other hand, can be impacted by footprint size, tread design, and by carcass and tread stability, which features can be manipulated by tire pressure. Decreasing tire pressure increases the footprint (which decreases the psi load on the tire as well as increasing contact surface.) The net result of decreasing tire pressure frequently increases available traction, but I don't believe it does this by changing the coefficient of friction, which I would expect to be a constant for a given surface to surface combination.

 

[dieselcruiserhead]

I also agree, excellent info here. And sorry for the long post...

I have long long wanted tall and narrow tires that would be completely functional in the taller sizes, and have experimented with most of the currently available options...

I personally dislike swampers for the most part but I used to run 34x9.5 pizza cutter Swampers back east. The traction was amazing but aired down there was some loss of lateral stability and most annoyingly, it was easy to pop a bead for some reason. With higher air pressures though they were mostly OK. The best part is they would go right to the bottom of a mud hole and stick like glue. These were probably the best tall and skinnies I have run. But of course, they were fairly aweful on the street especially once they began to wear down and the massive side lugs would then make contact with the street. The next best option that is also very popular back east are the 35 x 10.5 Swampers and these would be decent too but again are such and off road tire they are not useable by most... But these are the big popular option on older trucks there and they work unbelievably well and are also stable as a rock...


I also ran the 33 x 9.5 BFG tires quite often too, these were also great but aired down they did not feel very stable at all. This and their relatively thin sidewalls made them feel very vulnerable. This also sounds a little cheezy but they also only cosmetically look decent on a small assortment of vehicles. On smaller lighter trucks and 40 series they felt fine but on larger vehicles like a FJ60 Land Cruiser they felt a little sloppy laterally. The good news was they fit the stock rims and fit in the wheel wells fine with little or minimal lift unlike most larger tires...

And my final experimentation with tall and skinny was a set of Michelin XZL 9.00x16 military tires that were also awesome but in the end too much tire for my Land Cruiser, even my big heavy diesel powered FJ55. These were stable, incredibly smooth on the road and surprizingly quiet. But aweful in bad weather (rain/snow) like most military tires. The other issue with these, as well as the Swampers, is the thickness of hte tires is so extreme... The XZLs were like 16" big rig tires that just happened to have off road lugs. The weight rating for each tire is close to the entire weight of the vehicle. So they also weigh a ton. On side hills/off-camber though for some reason (my guess is also the lack of lateral stabiliy) they felt downright dangerous though. Probably because the vehicle was so tall with them but again because the tread is so narrow. I put my vehicle over on my side once, and a couple other close calls, but by far the worst/closest was a slightly off camber where one of the rear tires slipped off a rock and the whole thing almost went over and it would have been a very dangerous/massive roll. This was also a hill I have driven a million times with other vehicles. I chose to sell them immediately... And finally, they also did not match the vehicle well. They looked goofy and odd and too big which is how I anticipate they will work for most people. They came out to about 36"-37" which is way way too much tire for me and for most people. They are nice in the smaller narrower size but they are only 9" wide and they are about 32" I think, too small for me...

The best match I ever saw these on (which made me want to get them) was a very well built D90 with a 4.6 higher horsepower engine, gearing, and about 4-5" of lift... But, even with aftermarket axles, he kept blowing them mostly related to the added weight of the tires.

IMO unfortunately these are the best skinny off-road tires on the US market today.


And in the end, despite the mileage loss I have gone back to regular old 12.5 width common American tires on off-road vehicles. I think the BFG 33 x 10.5 is a good tire for the average user. But to me it is also small, I am looking for a 34" ideally so I compromise and run 35" tires in that common 12.5 width. In the Southwest, I literally have no complaints. We do get sand so I like the floatation. It is stable, laterally, even with smaller rims like a 15" that still expose a lot of side wall. Both 35" and 33" tires in 7" and 8" wide rims are incredibly stable and do not pop beads. 8" wide rims are literally perfect, they wear well and are perfectly stable and do not pop beads.

And I have actually never noticed a particular lack of traction other than on the road in bad weather with slush and such (tires are wide so they catch a lot). But the heavier the vehicle with this though, the better, and they will power through most things... A Hummer H2 for example uses 35 x 12.5 tires stock (which is unbelievable, but testiment to the streetability of these tires).

My truck with 35 x 12.5 and adequate suspension lift and engine power/gearing, basically stuck like glue anywhere I pointed them out here. So "some" loss of traction I suppose but very little actual drawback that I ever really noticed. On severe off road terrain like the Pritchett Canyon trail they were amazing, and my vehicle could hang with much more built vehicles and even buggies and such as long as I took it slow. It is similar to the situation a lot of you guys have but with 31-32" tires versus the vehicles with 35" tires, but on much harder terrain/bigger boulders.... And you really learn how to drive..

Mud terrains, particularly, are bad in snow and some rain, and they make noise. So my best solution now is a set of 35 x 12.5 R17 BFG all terrains. After seeing them on some of my friend's rigs from back east who have recently moved out here (I have friends with them on 40, 80, and 100 series) I am very impressed... With their manners and noise and wear and traction and about a million other reasons... Ideally if there was a 34x11.5 or possibly 35 x 11.5 something like that, I would be all over it. But since it doesn't exist such is like.

I have also had great luck with buying spare tires and Hummer H2 take off from some of the guys who put big rims on their trucks. I have bought three complete brand new tires with wheels for $80, $100, and $100, and have sold two of those rims on ebay for $80 and $129 before shipping so I have not paid a whole lot for them...