Cooper ST MAXX thread

Hey guys, so I got the maxx's E load 255/80/17 and was wondering what I should have the PSI set at. I have a four wheel camper on the back right now weighing in at around 1300 lbs. Thanks!

 

chalk test recommended! different pressures for different loads. chalk tells the truth of how your tires distribute the weight, no substitute and takes 10 minutes.

I'm unloaded, no extra weight, and run 30psi F/27psi R warm. but I'm also on 265/65-17's (st maxx E's) so i can get away with super low pressures.

 

36 psi will get you back to load carrying capacity or GVWR.

Since your'e over GVWR by at least 150lb...
For your size and load rating, 1 PSI=38 lbs load capacity at each tire.
1 PSI @ 38 lbs load capacity x 4 wheels = 152 lbs additional load capacity.
So at least 37 PSI.

I'd go weigh it as you intend to have it fully loaded, and add 1 PSI(to 36 PSI) at each tire for every 150 lbs above GVWR.

 

I run 32 psi front and 30 psi rear on the road empty. Air down to 22/20 in the dirt.

 

Same here, it works.

 

Means nothing for comparison without knowing weight and tire size.

 

I ran the chalk test (using a sharpie was easier) with the following load in my 3rd Gen DCSB:

Alu-Cab Canopy: 140lbs
James Baroud RTT with Sleeping Gear: 170lbs
Other gear in bed: 200lbs
Rock sliders 100lbs
OME Shocks and HD Dakars
ST MAXX 255/85/16s on OEM TRD OR 16x7.5 wheels

28 fronts; 30 rears for even wear

Also called Cooper customer service directly; their recommended PSI was 30 and he acknowledged that the 255/85/16s will ride on the centers if inflated to 30+ PSI, but will even out after that. With the E-rated sidewalls it seems these tires are completely fine in the 20s if thats what it takes with a particular (light) load for even wear.

 

Here's a pic of mine. 255 80 r17.

 

about the same here.

 

What rims, lift? Any rubbing?

 

Got mine on today 255/85r16

 

Ive had my tires on stock offroad wheels down to 8 psi when off roading. I keep my tires are 36-38 in the summer, 32-35 in the winter

 

Anyone have 265/70R16 stmaxx on a stock trd offroad? If so what's your mpg? Thanks!

 

If you want a good off road tire, pull the trigger. If you want MPG info, go to Costco and get the lightest tire you can get

I have 265/75/16 StMaxx and love them. Have pinched, pulled, stretched them over High SierrA granit, death valley tire shredding rocks, snow and sand with 0 issues

 

Are these good in mud and clay? Trying to decide between these and falken at3w.

With my topper I am already averaging 18.7 combined. I really dont want to be below 17 mpg combined

 

Although my tires are a different size then you are asking about, I ve found that the St maxx have excelled at everything ive thrown at them. I off road in clay, water and rock. (and some mud)

 

I think the most you'll lose is 1 mpg. For reference, I just put on the ST MAXXs in 275/70r17 which are close to a 33 inch tire and I'm getting about 16.5-17 in the mountains in PA.

I just got done with a 900 mile trip hauling a 1700 pound trailer and averaged almost 15mpg. So lift, bigger tires, roof rack, and trailer and still wasn't too bad all things considered

 

Looks great! Do you have any pics of the truck in action with these new tires?

 

I know this is a year old thread, but what do you think of these tires after a year and a half? Do they seem as stiff as some people say? How is your MPG and what do keep for PSI? Any info would be great. I am not sure whether or not to get C load tires like the Grabber X3 or Toyo AT2 to keep the ride a little less stiff. Thanks for any info!

 

That sounds fantastic. I'm between 13.5-15 average with 275/70R17. Missing the good old stock tire days... but then you hit the dirt and...