Cooper ST's - 255/85/16

[madizell]

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’.

I would agree that because the siping on the S/T's is somewhat longitudinal on the blocks, siping across the tread might lead to some chunking. However, you could sipe parallel to the siping already there, at least on the large outer blocks. You could also do it more or less across the tread, parallel to the inner block voids, but nor cut very deeply which would probably avoid the chunking. Not sure, but from reading the literature on the Coopers, the S/T-C has some sort of different compound which resists chunking, and might make a better candidate for siping

If you have the tool and want to experiment, sipe one or two blocks on each tire and drive them for a while to see if they do chunk.

 

[Redline]

Yep, I agree. Recently I have been siping my other
tires 9/32” deep. I was considering siping these STs 7 or only 5/32 (still might). I don't have a siping tool, not even sure I want to spend that much time working on the treads... I pay Les Schwab Tires to do it on their machine.

The ST-C uses a chip resistant compound, but they are only available in a few sizes, and not 255/85R16. Even if they were, I'm a little torn ☺, not sure I want a chip resistant compound right now. I think chip resistant tires are usually made with a harder compound and traction can suffer. [Edit- I was not correct. I talked to a Cooper Tire engineer and he stated that chip resistant tires are 'softer'.]

This is not to say that chip resistant isn't helpful. When I had a set of the ST's little brothers two years ago on my Rubicon, Dean SXT from Les Schwab, I got into some loose rocks on a hill and did some slow speed tire spinning with the lockers ON to get going again. The tires were not siped but were pretty chewed-up from that experience (probably lots of tires would have been, chip resistant or not). My intended use for the ST is primarily as my 'street/winter'. I'm hoping the tread is a little on the soft side and has lots of grip. Having said that, if the tires are as good off-highway as I have been reading in this tread, then they may see some back-country use as well.

 

[madizell]

I used a common tire groover for siping. The tool was borrowed, but I believe it is readily available for under $100. It uses a U-shaped blade for grooving, but if you turn the blade upside down and leave the two legs projecting, it sipes two lines at a time, and it is adjustable as to depth. Once fully heated, the tool cuts tires like butter (well, maybe hard butter).

 

[p1michaud]

New tires.

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 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 48.5-lbs each.

Narrower tread makes the 4Runner’s slightly heavy steering lighter and a bit more responsive.

Glad to read you finally pulled the trigger. :gunt:
I've had them on for approximately one month now and am very happy with their performance. I've had them in the snow both packed and fresh. They do really well. I was running arround 18 psi off road and the tires seem to conform to obstacles very well. The only word of caution I would give potential buyers is the road noise. I don't mind because I was used to the MTR noise going down the road.

 

[Redline]

I agree with you Pierre, the noise is more than I expected. But I was noticing this evening that they seem noticeably louder at 30-mph than at 60-75 which makes me happy. They are quieter at freeway speeds than my Maxxis Bighorns, but I really need to do a back-to-back test one of these days when I have the time.

I prefer not to listen to loud tires on a long highway trip, but want the traction when I get there. I think I’m going to keep them on for the trip to Death Valley this weekend.

 

[p1michaud]

Trip/tire report.

I prefer not to listen to loud tires on a long highway trip, but want the traction when I get there. I think I’m going to keep them on for the trip to Death Valley this weekend.

I hear you, but it's all about compromise with the changes we make. The weekend trip should be a great test. Will look forward to the report.
Cheers,
P

 

[MoGas]

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

In the icons of the reply box, click the "insert image" icon it looks like a small post card. then put the image URL in the box that pops up and away you go.

Dave

 

[MoGas]

In the icons of the reply box, click the "insert image" icon it looks like a small post card. then put the image URL in the box that pops up and away you go.

Dave

That's strange, it didn't work for me either

 

[Redline]

Last week I put about 850-miles on the Cooper STs on the ExPo LA Death Valley trip. Mostly dry highway down there with just a little snow/ice on the return trip home. Off-highway they performed well but there was nothing very challenging to help me to form a strong opinion. I didn't run them as low as I will in other conditions (rock crawling) or if I didn't have my Chaser on the hook. I set the fronts to 20-psi and rears to 25-psi. With this size ST and it's very narrow tread width to section width ratio [compared to other 255/85s] I will be careful not to air-down too much and expose the sidewalls to sharp sticks and rocks. I still plan to routinely use 15-psi. The tires don't seem like they will need very low pressures to perform as the sidewalls are flexible.

If there is anything about the Cooper STs that I don't care for so far it's the noise. They are not crazy loud, I had just hoped that they would be a little quieter. They are closer to a mild MT than an AT for noise. If they were on my noisy F350 diesel I would probably say they aren't so loud, but the 4Runner is quiet. As Pierre said above, it's all about compromises, and generally if you want traction and void you are going to get some noise.

DISCLAIMER: I'm not trying to bash the BFG MT, I have a set and know they are very popular. I also have a set of Maxxis Bighorns. Almost everything I say in critique about the BFG MT could be applied to the Bighorns. This is just my Apples & Pears very short opinion.

A couple days ago I pulled my BFG MTs from my Chaser, which have never been on the 4Runner, and put them on for a short 60-mile test. I drove up to the Sierras where there was some snow/ice. The spied BFGs did well but not as well as the Coopers (no surprise there). Also, though the noise of the STs is noteworthy, they are still quieter than the BFG MTs, which are close/similar to the Maxxis Bighorns [if it wasn't winter and I had the time I would like to try a back to back noise test of these tires]. It had been a while since I had a set of MTs on the 4Runner and I thought if the BFG MT (or Bighorns) were as loud as the Coopers I would just run the full MT treads and the Cooper STs could be removed and used on my F350. However, the Coopers are quieter than the BFG MTs and I decided to change back to the Coopers immediately (after only 60-miles).

Additionally, at the same PSI (32) the BFG MTs are firmer (3-ply sidewalls) and are rougher on the pavement, meaning that the lugs can be felt meeting the pavement like my Bighorns where this is not the case on the cross-over Cooper ST tread. I love the ride of the Coopers as they seem very well balanced, smooth & true. The flexible sidewalls ride nice at all pressures.

The BFGs certainly look better, they are about 3/4-in. wider at the tread, and they have sidewall lugs/tread. If I need a full on mud tire surely this is the choice.

The STs are my current everyday treads. If I get tired of the noise I will put my Maxxis Bravo ATs back on. The driving continues. :smiley_drive:

Great review/comparison. I'm very interested in how the stack up against the BFG MT's.

Keep it coming :wings:

 

[jim65wagon]

Bring on the noise! You know, I never had anything to compare them to except the BFG AT. Guess what? At 26,000 they are louder yet; but I knew that would happen. Never met a tire that got quieter. Glad to know they aren't MT loud; very glad to know they work in snow; if we ever get any snow they will come in handy.

Looking forward to more Redline Reviews as my wheeling experiences is a little more dirt track/muddytrack/gravelroad; curious to see how they fare on real rocks...

 

[michaelgroves]

I'm considering the Cooper 225/85-16s for my Defender 130 here in the UK. The tread patteren is very much like the BFG Trac Edge, which was the best all-rounder I have ever owned. (Unfortunately it was never available in 255/85, and even more unfortunately, it is now discontinued. Replaced by the BFG Commercial A/T, I believe).

One reason I'm reluctant to put another set of MT's on my vehicle is that in my experience, the second half of an MT tyre's life gives me the worst of both worlds - all the disadvantages of a specialised mud tyre, but increasingly mediocre performance in mud.

 

[p1michaud]

Road test.

The driving continues. :smiley_drive:

Great report Redline. I continue to be happy with my decision to purchase the Cooper S/T tires.

Cheers,
P

 

[Redline]

I admired the BFG Trac Edge a few times in a tire showroom, attracted to the all-around traction tread design. I have also recently looked at the new BFG Commercial TA Traction (I think that is the correct name) and think it is a fine tread too if available in the size you prefer.

From one of the reviews above where the gentleman running the ST in 235/85 said the ST is a very underrated tire (his friend also ran the ST in 255/85, both on Rovers I believe) as well as the other input here and from just looking at the tire, I think it is a very fine traction tire. Good wear, traction, and noise are often not compatible but my past experience with similar void tires was very positive for several years. Hopefully these Cooper STs will prove to be as good.

Half worn tires are half worn tires, and their ability to provide the traction in sloppy terrain is usually greatly reduced. I like deep tread depth and I agree with BajaTaco, deeper tread for off-highway use is much better.

I'm considering the Cooper 225/85-16s for my Defender 130 here in the UK. The tread patteren is very much like the BFG Trac Edge, which was the best all-rounder I have ever owned. (Unfortunately it was never available in 255/85, and even more unfortunately, it is now discontinued. Replaced by the BFG Commercial A/T, I believe).

One reason I'm reluctant to put another set of MT's on my vehicle is that in my experience, the second half of an MT tyre's life gives me the worst of both worlds - all the disadvantages of a specialised mud tyre, but increasingly mediocre performance in mud.

 

[Desertdude]

I've been quietly following this thread. I don't think I have ever read a more concise report on these tires. The choices are slim in this tire size (255/85/16) Thanks for the detailed testing and reports.

I have been through two sets of the BFG MT on the Tacoma and one set on the 80 series. I am finally going to switch brands.(and have to Toyos on the 80) With my driving schedule this year, I will be on the highway more than off - I was looking for a quieter tire and something less aggressive.

At less than 50% thread wear the BFG MT have really not worn evenly... Now at 60% they are past the point of comfort and traction.

I am out on the road and will have to locate a dealer and get new Cooper meats. ASAP.:victory:

Thanks for the awesome info

 

[p1michaud]

The Dude will ride on Cooper Tires!

I am out on the road and will have to locate a dealer and get new Cooper meats. ASAP.:victory:

DesertDude,
I'm confident you won't be dissapointed with your decisions to give the Cooper S/T tires a try. If you see Mr. BajaTaco one of these days, you can ask him to see the Australian 4WD Monthly tire comparisson if he still has it. The Cooper S/T took first place in their test for puncture resistance. Big bonus IMO... Happy tire shopping!

Cheers :beer:,
P