Cooper ST's - 255/85/16
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KevinNY
Adventurer
I used to run the ST in 235/85-16 before I went up to bigger SSRs. That tire impressed the hell out of me and is incredibly under rated. It is way beter that the MTR in mud and I dare say batter than a BFG MT too. I am convinced a tire with a good center channel is a huge performance plus in soft stuff. Another club member ran them for a long time on his D90 in 255/85 with a 7" rim too. His truck is in the middle of the second pic, the yellow 90.
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Backwoods Rambler
Explorer
I drive my XJ daily 60 miles round trip for work. I also travel a lot in the summer for wheeling and camping towing a 2500# pop-up camper and some other gear. So I'm looking for a good all around tire.
These tires look pretty mild in all online pics I've seen, especially considering the good reviews they appear to be getting online. I decided to head down to the local tire shop and check 'em out in person. They happened to have a set of BFG AT-KO's, Cooper STT's and Cooper ST's all near eachother so I was able to make a good comparison. The STT's are the epitome of a Mud Terrain; Great aggressive pattern. The AT's...well they work well, but we all know they're not the best in the Mud or occasional deep snow that Colorado sees. The ST's on the other hand have a wider center tread void than the AT's and a narrower tread void than the STT's; A nice comprimise. The Edge tread, again the ST's were a bit wider than the AT's and a bit narrower than the STT's. I also liked that the ST's were siped which is surprisingly uncommon in agressive AT's and most MT's. Plus they can accept studs if your winter conditions are extreme. Not much sidewall tread carryover like the STT's which is a bummer, but to be expected with a less agressive tire.
Overall it seems like a GREAT tire and with reviews saying anywhere from 40-45k miles to be expected, I think I've found my next set of tires.
I am a bit bummed that they don't come in a 33x10.5x15 though
but most don't, so what's new. I'll just get them in the 12.5's and be happy I'm on 33's and not 237/75/15's anymore :wings:
These tires look pretty mild in all online pics I've seen, especially considering the good reviews they appear to be getting online. I decided to head down to the local tire shop and check 'em out in person. They happened to have a set of BFG AT-KO's, Cooper STT's and Cooper ST's all near eachother so I was able to make a good comparison. The STT's are the epitome of a Mud Terrain; Great aggressive pattern. The AT's...well they work well, but we all know they're not the best in the Mud or occasional deep snow that Colorado sees. The ST's on the other hand have a wider center tread void than the AT's and a narrower tread void than the STT's; A nice comprimise. The Edge tread, again the ST's were a bit wider than the AT's and a bit narrower than the STT's. I also liked that the ST's were siped which is surprisingly uncommon in agressive AT's and most MT's. Plus they can accept studs if your winter conditions are extreme. Not much sidewall tread carryover like the STT's which is a bummer, but to be expected with a less agressive tire.
Overall it seems like a GREAT tire and with reviews saying anywhere from 40-45k miles to be expected, I think I've found my next set of tires.
I am a bit bummed that they don't come in a 33x10.5x15 though
but most don't, so what's new. I'll just get them in the 12.5's and be happy I'm on 33's and not 237/75/15's anymore :wings:
Redline
Likes to Drive and Ride
Nice observations and comments. You and the previous poster both mentioned the narrow, open center section of the tread. I also noticed this when I inspected the ST in person for the first time a few weeks ago. It sure looks like water, snow, slush, and mud can escape via that open channel better than many other tires. Even many more aggressive 'mud' tires don't have an open channel in the middle like this to allow the muck an easy exit.
Backwoods Rambler said:I drive my XJ daily 60 miles round trip for work. I also travel a lot in the summer for wheeling and camping towing a 2500# pop-up camper and some other gear. So I'm looking for a good all around tire.
These tires look pretty mild in all online pics I've seen, especially considering the good reviews they appear to be getting online. I decided to head down to the local tire shop and check 'em out in person. They happened to have a set of BFG AT-KO's, Cooper STT's and Cooper ST's all near eachother so I was able to make a good comparison. The STT's are the epitome of a Mud Terrain; Great aggressive pattern. The AT's...well they work well, but we all know they're not the best in the Mud or occasional deep snow that Colorado sees. The ST's on the other hand have a wider center tread void than the AT's and a narrower tread void than the STT's; A nice comprimise. The Edge tread, again the ST's were a bit wider than the AT's and a bit narrower than the STT's. I also liked that the ST's were siped which is surprisingly uncommon in agressive AT's and most MT's. Plus they can accept studs if your winter conditions are extreme. Not much sidewall tread carryover like the STT's which is a bummer, but to be expected with a less agressive tire.
Overall it seems like a GREAT tire and with reviews saying anywhere from 40-45k miles to be expected, I think I've found my next set of tires.
I am a bit bummed that they don't come in a 33x10.5x15 though
Redline
Likes to Drive and Ride
There are some very powerful endorsements here for these treads. I really like an aggressive all-terrian/mild mud-terrain as an all-around ‘do most things’ tire. I've had very good luck with tires with a similar void ratio.
I was going to purchase a set of 255/85 from
http://www.custom-wheels-car-rims.com/Tires.cfm
which I read about in this thread. They are $137.00 plus $15.00 shipping to reach me (no tax out of state). But they only had three in stock and were going to order the fourth from Cooper, said it would only take a couple days.
I decided to call a couple more local stores and found a very small tire shop on the 'wrong side of the tracks' part of town (low overhead
who could order the tires. My 'carry out' price is $143.00 plus tax, four tires it will cost me about $5.00 more to buy them local. They are supposed to be here in a few days.
Now I just need to decide which tires are being removed from which set of wheels, but I think I'm going to dismount the Maxxis Bravo 761 ATs. I'm hoping the STs are not too loud and I won't mind running them as my 'everyday' tire, at least in the winter. Though I'm a fan of aftermarket siping, I'm going to try these first without any additional cuts.
I was going to purchase a set of 255/85 from
http://www.custom-wheels-car-rims.com/Tires.cfm
which I read about in this thread. They are $137.00 plus $15.00 shipping to reach me (no tax out of state). But they only had three in stock and were going to order the fourth from Cooper, said it would only take a couple days.
I decided to call a couple more local stores and found a very small tire shop on the 'wrong side of the tracks' part of town (low overhead
who could order the tires. My 'carry out' price is $143.00 plus tax, four tires it will cost me about $5.00 more to buy them local. They are supposed to be here in a few days. Now I just need to decide which tires are being removed from which set of wheels, but I think I'm going to dismount the Maxxis Bravo 761 ATs. I'm hoping the STs are not too loud and I won't mind running them as my 'everyday' tire, at least in the winter. Though I'm a fan of aftermarket siping, I'm going to try these first without any additional cuts.
KevinNY said:
Redline said:
No doubt the tires in question work as well as everyone so far has said, but I doubt that the ability to work, particularly in deep mud, has any thing to do with the center channel. Volumetrically, the center channel is too small a void to carry much displacement, and if you think about it, anything displaced to the center of the tire constitutes something that the tire necessarily has to roll over to get ahead. A displacement tire, which most mud tires are, needs to displace to the outside of the tread if any serious degree of displacement is to take place.
Center channels are generally a design feature of wet weather tires, not mud tires, and I would expect that the channel in this case is there to allow for displacement of surface water to reduce hydroplanning. The tiny ribbon of mud that the center channel could carry would not make a significant difference in providing traction in mud.
A more important feature in providing mud traction is block shape and siping, and the Cooper ST is reasonably well designed in this regard. There are so many variables in tire traction that it is not easy to make direct comparisons, and frequently, small changes in design can have a dramatic effect.
The Interco Swamper has a long standing reputation for being a good mud tire, largely because it is a high-void tire with aggressive lugs. However, a bit of custom grooving and siping can make even the Swamper an extremely effective tire, to the extent that I have seen them outperform Boggers in slippery mud conditions, and the Bogger is a dedicated mud tire.
A comparison was made to Goodrich MTs, and it may well be that the Cooper is a "better" mud tire, at least under many conditions. It must be noted though that the BFG MT is not siped. If it were siped to the degree that the Cooper tire is, there could be less of a difference between them, until you find yourself in conditions that require a high-void tire. At that point, there is really no substitute for the void and block design.
I like the looks of the Cooper tire, and I have a pair of Coopers on my off-road trailer. From a design perspective, however, I don't think the center channel has much to do with off road traction.
Redline
Likes to Drive and Ride
Well stated and point taken regarding the center channel and mud.
The higher void ratio BFG is one reason that if I get another set of tires soon to test (some 285/75 muds might be in the works) I may dismount the Maxxis Bighorn MTs instead of the BFG MT.
The higher void ratio BFG is one reason that if I get another set of tires soon to test (some 285/75 muds might be in the works) I may dismount the Maxxis Bighorn MTs instead of the BFG MT.
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Redline
Likes to Drive and Ride
A very nice UP-grade
dnellans said:Here are some comparison pics of my old 265/75 R16 BFG AT's to the new 255/85 R16 ST's
bah, how can i get these to insert inline?!? this is the 2nd time i've tried to post pics and it just shows a link. if anyone can help i'll post quite a few more comparison pics
I have never seen mud that was of a consistent nature throughout. Slick greasy mud on top of dry base, or deep bog without a reachable bottom, each situation offers a broad spectrum of materials. In liquidy situations, the siping may do very little because there is no surface against which the siping can work, but unless you are trying to float across a lake, pure liquid is rarely an issue. By siping an otherwise strictly displacement-type tire, you reach for the best of both worlds, and in my opinion, you will increase the potential performance of the tire. Since I have seen this actually work in the real world, I base the opinion on experience.
The situation where I saw the siping of a Swamper outperform Boggers was in Alaska. I had destroyed a front axle u-joint way out on a trail on top of the Talkeetna Mountains (Purches Creek trail in case you know where that one is), and at the mid-point of the trail, decided to return the way I had come rather than exit through the lower, bog trail because I preferred the trail behind me in my crippled state. One of the group was the fellow who was our teammate for the 2003 Outback Challenge, Eddie Angel, in his 1997 TJ. Our vehicles, other than suspension, are incredibly similar. They weigh the same within about 100 pounds, have the same peak power, same Currie axles, Altas II T-case, etc. The only real difference between us was my leaf spring rear suspension, and I was using custom cut and siped 36x12.5x15 Swampers with 50 percent of available tread, and Eddie was using 37x13x15 nearly new Boggers. He has a Detroit in the rear, and I have ARB. We both use 4.88 gears.
On the way out, I had only rear wheel drive. Eddie chose to use rear wheel drive to keep things even, and to assist in finding usable lines and predicting results in getting me out of a very hard spot. Climbing out of the Purches Creek valley, the trail is rocky, muddy, twisting, and steep, sometimes all at the same time. With the cut and siped Swampers, I climbed that slick trail without issue, while Eddie slipped all over the place wherever conditions were not purely deep mud.
The trail condition was probably closer to what you might find in the lower 48 and eastern woods trails -- greasy 2 inches to 4 inches on top of firm, wet dirt with scattered rock and boulders and lots of steep climbs thrown in. Under those conditions, I simply outclimbed Eddie with his Boggers. I was also displacing and throwing more and larger chunks of the trail than his Boggers were doing, even though I had a lot less tread depth and a lower void ratio. I can only attribute this to the block cutting and siping I had done which turned a non-directional Swamper into a nearly directional pattern with lots of extra traction edges.
All I can say is that traction is where you find it, and that unless you are paddling your way through bottomless goo, siping will help.
The situation where I saw the siping of a Swamper outperform Boggers was in Alaska. I had destroyed a front axle u-joint way out on a trail on top of the Talkeetna Mountains (Purches Creek trail in case you know where that one is), and at the mid-point of the trail, decided to return the way I had come rather than exit through the lower, bog trail because I preferred the trail behind me in my crippled state. One of the group was the fellow who was our teammate for the 2003 Outback Challenge, Eddie Angel, in his 1997 TJ. Our vehicles, other than suspension, are incredibly similar. They weigh the same within about 100 pounds, have the same peak power, same Currie axles, Altas II T-case, etc. The only real difference between us was my leaf spring rear suspension, and I was using custom cut and siped 36x12.5x15 Swampers with 50 percent of available tread, and Eddie was using 37x13x15 nearly new Boggers. He has a Detroit in the rear, and I have ARB. We both use 4.88 gears.
On the way out, I had only rear wheel drive. Eddie chose to use rear wheel drive to keep things even, and to assist in finding usable lines and predicting results in getting me out of a very hard spot. Climbing out of the Purches Creek valley, the trail is rocky, muddy, twisting, and steep, sometimes all at the same time. With the cut and siped Swampers, I climbed that slick trail without issue, while Eddie slipped all over the place wherever conditions were not purely deep mud.
The trail condition was probably closer to what you might find in the lower 48 and eastern woods trails -- greasy 2 inches to 4 inches on top of firm, wet dirt with scattered rock and boulders and lots of steep climbs thrown in. Under those conditions, I simply outclimbed Eddie with his Boggers. I was also displacing and throwing more and larger chunks of the trail than his Boggers were doing, even though I had a lot less tread depth and a lower void ratio. I can only attribute this to the block cutting and siping I had done which turned a non-directional Swamper into a nearly directional pattern with lots of extra traction edges.
All I can say is that traction is where you find it, and that unless you are paddling your way through bottomless goo, siping will help.
Redline
Likes to Drive and Ride
Interesting story, I believe it. Like I said, I'm a fan of siping. My dilemma was if I was going to add aftermarket siping to the Coopers immediately, or wait and see how the tires performed (w/ factory sipes), and possibly add siping later.
After much thought, I decided to wait on the siping. I made this decision partially on the depth of some of the the factory siping (from 10-15/32) and the direction of some of the sipes (inline with the circumference). I think siping these tires in the traditional method across the tread might compromise some side-hill performance of the factory sipes and severely increase the likelihood of ‘chunking'. In the past with similar void ratio treads with factory siping I ran them to about half their depth them added sipes. I can always add sipes but driving lots of miles is the only way to take them off.
James
After much thought, I decided to wait on the siping. I made this decision partially on the depth of some of the the factory siping (from 10-15/32) and the direction of some of the sipes (inline with the circumference). I think siping these tires in the traditional method across the tread might compromise some side-hill performance of the factory sipes and severely increase the likelihood of ‘chunking'. In the past with similar void ratio treads with factory siping I ran them to about half their depth them added sipes. I can always add sipes but driving lots of miles is the only way to take them off.
James
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Redline
Likes to Drive and Ride
Initial Impressions
I mounted the tires last night, went for a short late night test drive, then ran a few errands today. Some freeway, some street.
Surprisingly loud, just like Pierre reported. Not as loud as my Maxxis Bighorns (which I think are a little on the loud side), but louder than I thought they would be. About as loud as a Toyo MT. Need to see if BFG MT is similar? Noise gets a little quieter around 65-75 but this is also where there is a bit more wind noise. Still forming an opinion. The 4Runner is a nice quiet car, and it's easy to hear tire noise. Even my conservative Maxxis Bravo 761 ATs had a little audible whine to them on the freeway. Despite the perceived volume, the lugs don't meet the ground as forcefully as my Bighorns, and the tires run very smoothly.
Well balanced. I was worried that the tires were taking too much wheel-weight, even had one tire spun on the wheel and rebalanced before leaving the tire shop. Single point ("static") balancing method with tape weights, 3-oz or a bit less on three, one with 5-oz, which I put on the right-rear. Flexible (thin?) sidewalls help the tires ride softly over bumps with my normal 32-psi. Very nice road tire with the possible exception of the noise. Narrow tires drive nice on the road, and these skinny girls (almost as narrow as many 235/85R16) may truly deserve the designation of ‘pizza cutters' The tires weigh about 48.5-lbs each.
Narrower tread makes the 4Runner's slightly heavy steering lighter and a bit more responsive.
I mounted the tires last night, went for a short late night test drive, then ran a few errands today. Some freeway, some street.
Surprisingly loud, just like Pierre reported. Not as loud as my Maxxis Bighorns (which I think are a little on the loud side), but louder than I thought they would be. About as loud as a Toyo MT. Need to see if BFG MT is similar? Noise gets a little quieter around 65-75 but this is also where there is a bit more wind noise. Still forming an opinion. The 4Runner is a nice quiet car, and it's easy to hear tire noise. Even my conservative Maxxis Bravo 761 ATs had a little audible whine to them on the freeway. Despite the perceived volume, the lugs don't meet the ground as forcefully as my Bighorns, and the tires run very smoothly.
Well balanced. I was worried that the tires were taking too much wheel-weight, even had one tire spun on the wheel and rebalanced before leaving the tire shop. Single point ("static") balancing method with tape weights, 3-oz or a bit less on three, one with 5-oz, which I put on the right-rear. Flexible (thin?) sidewalls help the tires ride softly over bumps with my normal 32-psi. Very nice road tire with the possible exception of the noise. Narrow tires drive nice on the road, and these skinny girls (almost as narrow as many 235/85R16) may truly deserve the designation of ‘pizza cutters'
The tires weigh about 48.5-lbs each. Narrower tread makes the 4Runner's slightly heavy steering lighter and a bit more responsive.
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Backwoods Rambler
Explorer
Great review/comparison. I'm very interested in how the stack up against the BFG MT's.
Keep it coming :wings:
Keep it coming :wings:
