285x70x17???

[DocDetonancour]

Local tire dealer tried to talk me into 285's. Have any of you guys got them? did they screw up your mileage with the 48re transmission. Are they worth the extra $$? Thanks, Doc

 

[nwjetboat]

I've got 285 BFG AT's on my 03. I like the way they fill the wheelwell. I think the diameter difference is 3%. The dealer can reflash the computer so that everything is correct. He told me they can go up one size, ie 265's to 285's.

The only issue I see is there is not much clearance between the tire and the rear wheel well liners. I may have to trim some away to put on a set of chains.





Here is a link to a tire size calculator:



Tire Calculator

 

[nickleinonen]

the 285's will fit with no problem at all... i have 315's under my truck and they fit just fine too... the dealer is right about the reflash to correct the speedo i think on the 285's. the 1500 series rams with the 20" wheels & 4x4 have 33" tires right from the factory [275/60/20's i had them on my red 1500] and the 285/70/17 is the same overall diameter as the lower profile 20"s... the dealer should be able to flash to that setting to correct the speedo. [the body computer that handles the dash display should have that size in it's memory]

 

[Moterhead]

Seems that I remember someone posting that the computer feature that allows speedo correction for tire size has a couple of sizes only and a line marked Other. If the tech clicks on the Other, he gets to select by rotations per mile.



Go here:



http://www.csgnetwork.com/tireinfo4calc.html



plug in your tire size to get rpms and all sorts of other measurements. Then the tech can set the computer to that rpm number.



I pugged in the two sizes your are asking about and came up with:



RPMs for the 265 is 638 and the 285 is 616.



That's a 3. 4% difference. IOW, at indicatated 60, you would actually be doing 62. 70 indicated is 72. 4. Hardly worth messing with!



BTW, the stock size on the 20s that come on the 1500s is 275/55/20, not 60 as someone posted. They is only . 30 difference in diameter between them and the 265/70/17s.

JOIBO!