Cooper Discoverer Rugged Trek

I'm thinking to go with Dobinson, trying to decide between IMS or MMR. with one you installed and how do you like it? I have KDSS

 

Sorry, just now saw this. I went with IMS because after a lot of research I came to the conclusion that reservoirs are not needed unless you do higher speed offroading (from what I read at least). I don't live anywhere near the desert or those types of trails so I didn't want to pay extra for something I wouldn't get any usefulness from.

I have KDSS as well and love the IMS suspension so far. It's been on a few months but I haven't exercised it offroad (haven't gotten around to putting new skids on yet and the front skid is still off - as long as nothing else comes up ill get them on this weekend). On road, I like the ride. Dobinsons also gives you lots of options to get the right height based on your added weight. @Crikeymike answered all my questions about Dobinsons and if you go with them you can order from him at Exit Offroad. My experience was great and I'm happy with my decision!

 

Almost forgot about this thread. So I ended up dropping my PSI to 28 cold and they warm up to about 31 on the interstate, although I don't do a ton of highway driving anymore. For reference, online tire pressure calculator said 26 but that seemed too low for warm PSI so I started here.

The ride is SO much better. 38 PSI cold made them feel like bricks (they aren't C or E load). The IMS feels a lot better with the lower pressure and I love it. Took it on some light forest roads (green ridge state forest) and I have zero complaints. The feel as if they stick to the road much better now, but not a soft squishy feeling as if they are underinflated.

Best part is I now see even "wear" (the dirt chalk test) across the entire tire now, not just the crown in the center. I will keep checking them each rotation to make sure I don't get cupping or uneven wear. About 10k on them now (with 5 tire rotation).

 

Glad you figured the PSI out. I'm considering these tires for mine (though disappointed the 255/80 is so damn heavy) so I'll keep this in mind.

Reading through the thread till now, I was really thinking the outer tread not contacting the road was a design feature. A few years back it came out this was the case with the Milestars, people were running super low pressure to get a good chalk test, but the tire was designed to have just the center pattern running on pavement.

Just curious though, how has your mpg been with the lower pressure?

 

I actually didn't see much difference. With the lift, heavier tires, and all the other weight I've added I'm still averaging 16-17 mpg (per the computer) even with PSI change. With the cooler weather dropping in between slightly warmer, they've been down to 25-26 cold but warm up to 28-29. I hand calculated a few times based on GPS miles and was within about 0.5 mpg of the computer. Although everyone says the stock size cause speedo to run high (and it did but they were quite worn when replaced), these do have a little of the opposite affect. Up until about 45 mph they are dead on, above that (according to GPS) they are 1-2 mph off. I only see 2 mph occasionally when I'm up to about 80.

I think these run a bit large for a 285/70 and are close to a true 33" tire when new. I think I'm getting about 0.25-0.5 mpg better than what the computer shows as a result. I'm still about 16.5 average though and it's weird because it doesn't matter if it's around town or mostly cruising at 70 (up to 80) - it's always the same. Maybe cruising at 55-60 would increase it slightly but probably not by much.

 

I will say, too, that I'm impressed with the noise and wet traction given how aggressive they are. They do make noise but about as much as any other AT I've run in the past. Since I dropped PSI, I can still break them loose on wet pavement when it's raining but I have to try. I did try a couple of weeks ago and got the traction control system to kick in but I intentionally accelerated hard while making a 90 degree turn from a stop, up a hill. I've never had them break loose or even hydroplane yet in quite a bit of water when driving normally (carefully because it's raining). But because they only have about 8k miles on them and I did a 5 tire rotation (so one only has about 3k on it), they're still really chunky with a lot of tread depth and siping so the water has plenty of places to go

 

I am again impressed with the traction on these tires. Went back up to GRSF last Friday to do some "leaf looking". Turned out to be a terrible day for seeing the leaves because it rained off and on all day and there were low clouds but it was a great day for offroading.

I knew it was going to be a good day when I put it in 4lo, turned up the first side trail, and as I started up the wet rocks my wife asks "can we even make it up this?". These tires handled the wet rocks like the first time I went up that trail in the dry. What were a few scattered puddles the first time I went through had turned into 75-100 foot long ponds on the trail, although not deep.

I would say that it was all 4runner but I have to give the tires credit too. Even in 4hi (where traction control is still on) I didn't feel a single tire slip or the traction control kick going up a few really steep areas. Had one really steep downhill area (finally used the front camera for its intended purpose) where I rode the brakes because I was in 4hi and it wasn't that far down and again, no slipping. Felt like driving a gecko.

 

These tires are absolutely amazing off road. I would HIGHLY recommend them to anyone that off roads. I ran MTRs on my Rubicon for years and these are just as grippy.