Cooper ST's - 255/85/16

[Redline]

jim65wagon:

I have not expended any effort comparing the heights of different 255/85R16 treads. I agree with madizell, there would not be enough difference to really measure or care about. Too many variables and not all the tires have been new at the same time. Most of the specifications I have seen for 255/85s have the tires listed around 33.0-33.5”.

255/85R16 tires I have owned (still have the bottom four sets):

Les Schwab Wild Country TXR (Private label made by Multi-Mile/TBC), 3-sets
Toyo M55
Dean SXT Mud Terrain (similar void to Cooper ST, sold by Les Schwab in the west)
BFG MT
Maxxis Bighorn
Maxxis Bravo AT
Cooper ST

Though I have not compared the height of these tires to each other, I have occasionally measured 255/85 height to other sizes, checking the static radius clearance of one tire to another on a specific platform (currently 4Runner). I have some decent data on a coupe of recent comparisons. I apologize in advance because I don't know how to make the formatting post correctly in the thread.

For these measurements I was using the lower right/rear shock mount on my 4Runner. The numbers/clearance doesn't really matter, just the difference between the two tires at different PSI, but the height from the floor is what is listed. Clearance matters at full PSI mostly for ‘street' looks, but depending on how much air we let out, clearance at lowered pressures matters more on the trail. Some tires can run higher pressures and still grip & flex while others are stiffer and must be aired down even more to get the tire to ride and conform well. The Toyo MT is an example of a stiff tire that I preferred to run at very low pressures.

1) Static height/clearance test Maxxis Bravo 761 AT 255/85R16 vs. BFG MT 265/75R16

Maxxis Bravo AT 255/85 (with 16/32, 17/32 when new)
PSI 33.5 10 12/16”
PSI 20 10 8/16
PSI 15 10 4/16
PSI 10 9 12/16

BFG MT 265/65R16 (new w/ 19/32 tread)
PSI 33.5 10 9/16
PSI 20 10 4/16
PSI 15 10 0/16
PSI 10 9 9/16

2) Static clearance test Maxxis Bighorn MT 255/85R16 vs. Toyo MT 265/75R16 (tread depth within 1/32, but tires have very different sidewall construction, Toyo is STIFF)

Maxxis Bighorn MT 255/85 (with 17/32 tread from 19/32 when new)
PSI 35 10 15/16
PSI 33.5 10 14/16
PSI 25 10 12/16
PSI 20 10 10/16
PSI 15 10 6/16
PSI 10 10 0/16
PSI 8 9 10/16
PSI 5 9 0/16

Toyo MT 265/75 (16/32 tread remaining)
PSI 35 10 6/16
PSI 33.5 10 5/16
PSI 25 10 4/16
PSI 20 10 2/16
PSI 15 9 14/16
PSI 10 9 9/16
PSI 8 9 5/16
PSI 5 8 15/16

On test 2: both the Bighorns & Toyo MTs had been siped. On my smooth, sealed concrete garage floor the Maxxis Bighorns made squeaking noises as the tire started to elongate while being deflated. It appeared that the softer, more flexible Bighorns and the sipes were gripping the floor well and could be heard working, fighting the spread. This started at 20-PSI with the Bighorns but did not occur with the Toyo MTs.

.............

James; just to satisfy my never ending curiosity of tire figures; how much difference in height is there between all these 255s? Is any one of them significantly taller or shorter than the others?

 

[Redline]

Is it easy/safe to add studs to tires that were not designed to take them?

If studs are all that keep you from using BFG MT, get them studded.

 

[Hilux_Max]

Redline,

May I please ask you on your thoughts of the 255/85x16 Bighorns, as I intend to purchase these next time when my 285/75x16 Buckshots wear out.

Can you tell me your thoughts and views on their wear both on and offroad?

Where they may seem to excel (if at all) and what their flaws are (if any) ?

Their ability to perform offroad in a fully loaded vehicle over various terrain?

and how well they mould around and over obstacles when deflated?

If there is anything else you may wish to add to help me out, feel free.

Thankyou in advance for your time. :bowdown:

 

[Redline]

This thread already has lots of tire info not specific only to the Cooper STs, but maybe it would be better to direct you to this thread? I don't have answers to all your questions, but some of them may have already been answered here. Others have put more miles on their Bighorns that I.

http://www.expeditionportal.com/forum/showthread.php?t=2350&highlight=maxxis+bighorns+255/85

Redline,

May I please ask you on your thoughts of the 255/85x16 Bighorns, as I intend to purchase these next time when my 285/75x16 Buckshots wear out.

Can you tell me your thoughts and views on their wear both on and offroad?

Where they may seem to excel (if at all) and what their flaws are (if any) ?

Their ability to perform offroad in a fully loaded vehicle over various terrain?

and how well they mould around and over obstacles when deflated?

If there is anything else you may wish to add to help me out, feel free.

Thankyou in advance for your time. :bowdown:

 

[Pskhaat]

If studs are all that keep you from using BFG MT

Nope, $ and TCO

 

[Pskhaat]

as a snow tire I think all of these have it over the BFG...as well as the Toyo M55...

In my experience, which despite amateur I make up in volume , for winter time you just can't beat studs. A skipping LP, previously I've said that. I know compounds have come leaps and bounds, but can not say how often enough I believe I've been saved or made it up/down from a wintry trail with 'em.

 

[Redline]

I'm sure you are correct, and these tire that take studs (Maxxis, Cooper, M55) are cool and offer great traction on snow/ice. I have never owned a set of studded snow tires, though I have driven in lots of snow both with and without chains. I might be tempted to buy a set of tires to have studded in the future, though we typically have lots of very intermittent snow/ice with lots of dry roads mixed in. The noise and the reduced traction on dry surfaces are a couple negatives I see with studded tires.

In my experience, which despite amateur I make up in volume , for winter time you just can't beat studs. A skipping LP, previously I've said that. I know compounds have come leaps and bounds, but can not say how often enough I believe I've been saved or made it up/down from a wintry trail with 'em.

 

[madizell]

Is it easy/safe to add studs to tires that were not designed to take them?

The biggest problem in studding tires is finding someone with the tools to do it. Not all tire installers are willing or able. Custom studding has been used for years, and results in a tire just as safe as one which comes pinned from the manufacturer.

BFG MT's are a good candidate because they have fairly meaty blocks and the compound is on the firm side. Each tread block can take one or two studs. Traditionally, the outer blocks get the studs leaving the inner blocks clear, or even better, free to be siped. The process is simple enough. Drill hole or proper size to the correct depth for the stud being used, insert stud with stud gun.

I have seen on trails in Alaska several different tires studded for winter use. BFG MT's are one of them. Others included Swampers, Boggers, and Cepek (I think Fun Country's). All worked well enough, studs giving them perhaps 10% more traction than they otherwise would have.

Custom studding also allows you to place studs where they otherwise might not be placed by a manufacturer (inner blocks), and to use more or less of them than a standard winter tire. If you plan to do this often, you can buy the tool for home use, as it is a small hand held pneumatic gun which will insert or extract studs, and the studs are available in different lengths, ostensibly so that you can stud new or used tires.

For highway use, a dedicated ice/snow radial will provide more traction than a standard studded winter tire. I stopped using studs on the road 8 years ago because I purchased 1) an Audi A6 Quattro, and 2) Bridgestone Blizzak tires. The combination beats any studded tire I ever used, and I used studded tires for more than 20 years in Alaska. For trail use, choose the tire that provides the best all around traction for the terrain and season in hand, and if you feel the need for studs, get studs. I don't favor chains on trails regardless of the time of year. They tear things up too much, including fenders and other car parts, and if you really need chains to get somewhere on a trail, it is time to rethink why you are going there.

 

[SOAZ]

to be a little more accurate. I have about 20k miles on these. Check out the chunkiness. Good tread depth still... st-c maybe nex time,but I hate getting 285's
Still love them though.

 

[Redline]

Those are some pretty good chips/chunks there SoAz.

I agree, going to 285s to get the ST-C doesn't sound appealing to me either. A couple weeks ago I was thinking that 285s might be nice (didn't realize the ST-C were available in that size), and surely would look good. But I talked myself out of both another set of tires and 285s. At least for now.

 

[p1michaud]

Tire chunks

to be a little more accurate. I have about 20k miles on these. Check out the chunkiness. Good tread depth still... st-c maybe nex time,but I hate getting 285's
Still love them though.

Thanks for posting this, I'll have to keep an eye on mine to see how they hold up.

Cheers,
P

 

[Redline]

Excessive chunking was one of the big complaints I read about on some Australian forums but I still decided to buy these.

I wonder how much the soft/sticky tread compound is contributing to the chunking people are seeing?

Edit:I have learned that chip resistant tires are softer, harder tires are more susceptible to cutting/chipping.

Those are some pretty good chips/chunks there SoAz.

I agree, going to 285s to get the ST-C doesn't sound appealing to me either. A couple weeks ago I was thinking that 285s might be nice (didn't realize the ST-C were available in that size), and surely would look good. But I talked myself out of both another set of tires and 285s. At least for now.

 

[SOAZ]

Excessive chunking was one of the big complaints I read about on some Australian forums but I still decided to buy these.

I wonder how much the soft/sticky tread compound is contributing to the chunking people are seeing?

I have a feeling that has a lot to do with it. These tires are softer to the touch than any I've ever owner. The amazing part is that the tread depth is really great still. They seem like they will last for a long time as long as the chunking doesn't get too excessive.

p1michaud,
You're welcome. Most of the chunking seems to come from these sharp az rocks. :truck:

 

[jim65wagon]

1) Static height/clearance test Maxxis Bravo 761 AT 255/85R16 vs. BFG MT 265/75R16

Maxxis Bravo AT 255/85 (with 16/32, 17/32 when new)
PSI 33.5 10 12/16”
PSI 20 10 8/16
PSI 15 10 4/16
PSI 10 9 12/16

BFG MT 265/65R16 (new w/ 19/32 tread)
PSI 33.5 10 9/16
PSI 20 10 4/16
PSI 15 10 0/16
PSI 10 9 9/16

2) Static clearance test Maxxis Bighorn MT 255/85R16 vs. Toyo MT 265/75R16 (tread depth within 1/32, but tires have very different sidewall construction, Toyo is STIFF)

Maxxis Bighorn MT 255/85 (with 17/32 tread from 19/32 when new)
PSI 35 10 15/16
PSI 33.5 10 14/16
PSI 25 10 12/16
PSI 20 10 10/16
PSI 15 10 6/16
PSI 10 10 0/16
PSI 8 9 10/16
PSI 5 9 0/16

Toyo MT 265/75 (16/32 tread remaining)
PSI 35 10 6/16
PSI 33.5 10 5/16
PSI 25 10 4/16
PSI 20 10 2/16
PSI 15 9 14/16
PSI 10 9 9/16
PSI 8 9 5/16
PSI 5 8 15/16

On test 2: both the Bighorns & Toyo MTs had been siped. On my smooth, sealed concrete garage floor the Maxxis Bighorns made squeaking noises as the tire started to elongate while being deflated. It appeared that the softer, more flexible Bighorns and the sipes were gripping the floor well and could be heard working, fighting the spread. This started at 20-PSI with the Bighorns but did not occur with the Toyo MTs

.

:bowdown: Above and beyond, James!

 

[Redline]

Adding to the info in this thread, here are a couple shots of the supper narrow Cooper STs stacked next to Maxxis Bighorn MT. Both tires are 255/85R16 and both are mounted on Toyota TRD 16x7.5-inch wheels.

The Coopers are noticeably narrower, but mostly in the tread. The Cooper ST has a tread of about 7.2-inches while the Bighorns have about 7.75-inches of thread width. I like them both ☺ The Coopers were temporarily removed to run the quiet Maxxis Bravo ATs.