Recently purchased 2000_255 85 16 Cooper S/T

[perk]

I recently installed the 255 Cooper S/T's (I'll get pics up later). They are definetely more aggressive than the BFG AT's and the Nitto Terra Grapplers I've ran on vehicles in the past. The ride is fine and I think the handling is better than the worn out stockish tires that were on it. They made my last desert run alot of fun and I think they did very well handling high speed desert driving.

They do have noticably more road noise than the others. I was expecting to actually have an MPG gain with them as they are lighter and narrower than stock, however this has not beern the case.

I recently purchased the vehicle (with worn out stockish tires) and cruising it back from LA at 60 mph I actually got 19.9 mpg The next few fill ups from mixed driving were 16-17. I was very pleased. I've been using 91 oct.

Since the S/T's I've gotten 11-13 from mixed driving. What gives???

It runs VERY smooth. It has 96K on the clock and had the full 90K service including timing belt and water pump done at 91K. The drop in mileage has me wondering if it could be something other than the tires???

I am absolutely LOVING the new cruiser, got it for $12,600 off Ebay. I finally bit the bullet and replaced my 95 80 series. I am thrilled with the power, comfort, and handling of the new ride. I got the running boards off right away and picked up the Coopers, which weren't easy to get locally. I really like them, hopefully none of the Aussie problems will pop up. I went back and forth between the Cooper S/Ts or the BFG KM2s in the 255 size. I went with the S/T's because I thought they would be quieter, slightly better mpg, and generally better on road than the BFGs, but now I wonder...

Anyways, any insights into my drop in mileage would be appreciated,

Ted

 

[1loudLX]

dead kittens inside the tire, or maybe its the fact they have more rolling resistance then stock. Also have you accounted for your speedo being off?

 

[mtnracer]

Remember to multiply your miles driven by 1.067 to account for the 6.7% diameter increase from stock 31" tire to 33.1" on the 255/85/16.

You can check it yourself here:

Tire size calculator

 

[hks3sgte]

Bigger tires = less MPG... no way around it

 

[uzj100]

Please post pics. I am still deciding if I will get 255s or 285s.

 

[scottm]

On my 80 I went from stock 275 to S/T 265. Same diameter, pretty much same width footprint, a little more noise, and same mileage. I don't think it's the agressive tread pattern giving you bad mileage. My wife is making noises about wanting a different vehicle, so I may have the 100 on S/T tires soon as my daily driver.

 

[highonpottery]

Please post pics. I am still deciding if I will get 255s or 285s.

255s are 10.03" wide and the 285s are 11.22" wide (depending on brand) = more contact with ground = more friction + weight, comparatively speaking

perk - like everyone's already stated: larger diameter tires increase rolling resistance. if you were to stay with the same sidewall profile as the stock tire in the 255 width (maybe a 255/75/16), then you MIGHT see less rolling resistance because it's a skinnier tire - but probably not enough to notice outside of a controlled lab test.

i like this tire calculator: Tire Size Calculator - tire & wheel plus sizing

 

[uzj100]

I am not sure how 255s will look with factory fender flares.

 

[perk]

I'll get picks up when I get a chance. They are slightly tucked in looking. I think they will look great with spacers.

 

[macneill]

Ttifuwop!

 

[uzj100]

iftawmp!

 

[BendFJ]

Can we see 'em yet?

iftawmp!

 

[hks3sgte]

this is a set on my '04


click---->

 

[perk]

Here are some pics of the tires with OME 860's and cranked OEM Torsion bars.

 

[bigskyguy]

I'm running 285/65 r18 cooper st's on my 99 right now in the 6ply and couldn't be happier. I've got about 30,000 miles on em' now and still have about half tread life left. Almost all the plow trucks here run em' and they do really well on the snow and ice here. Been to Moab several times and they grip the rock well (what doesn't ?). We have some pretty bad clay here in the valleys and they do pretty well in the sloppy stuff . I had a set of bfg AT's previously and they performed well too, but were a pain to balance and were down to the treadware inds. at about 40,000 miles. The coopers will surpass them for sure. I had a set of load range E's that I picked up cheap on my 05 tacoma 4x4 but they were way too stiff and did terrible on the packed snow and ice. When my wrangler AT's wear out I'll be putting ST's on the tacoma just in the 6ply not the 10's.

 

[fish2live]

nice! That's my next tire in 275/70/18 (33.1") on my 2003

 

[nicholas]

Bigger tires = less MPG... no way around it

I actually noticed a slight increase with the 315 cooper stt vs the 285 (stock gears in both situations). This has been verified using my SGII and GPS corrected for tire size. However this only holds true to semi-flat roads. If I am climbing steep grades the mpg drops. I rarely get below 14mpg even in the city, but I drive like a senior citizen (slow acceleration and rarely exceed 65MH).


I run them at 42PSI, so that prolly helps a bit too.

 

[scottm]

like everyone's already stated: larger diameter tires increase rolling resistance.

Larger diameter tires decrease rolling resistance, but it's negligible on smooth surfaces. On rough surfaces, larger tires decrease rolling resistance dramatially by bridging surface irregularities. Tractors, land-speed record cars, bicycles, and off-road trucks have used relatively large diameter tires/wheels for this reason. Newer road bikes and land-speed record cars have gone to smaller wheels because the surfaces they travel on are more predictable. Larger wheels have more wind resistance and required compromises in design elsewhere.