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Thread: Real world rpms with 3:73's and 265's

  1. #1
    Join Date
    May 2007
    Location
    South Russell, Ohio
    Posts
    280

    Default Real world rpms with 3:73's and 265's

    I've combed using the search function as all TDP people should...... But I would like to know/hear some real world rpm's for 60, 65, 70 mph running 3:73's and a set of 265/16's.

    I need new tires now, and would like to upgrade from 245's and rims from standard stock steel to the polished alloys. I'm also looking to swap gears. currently have 4:10's and don't tow heavy enough. I need mileage. Also I don't drive this in the winter to keep it out of the salt, so Yes I plan on keeping her a very long time.

    Thanks
    1996 K2500 Suburban
    Second owner, Former Fire Dept Vehicle
    "F" Engine, 4:10's looking for 3:73's
    D-TECH Remote mounted PMD, HO water pump
    1998 air box with K&N filter
    Fluidampr
    17" GMC Alloy Wheels with 265 70 R17's
    RACOR 490 fuel filter with heater and 2 Micron Filter

  2. #2

    Default

    1985 Chevrolet suburban k10 4x4. 6.2 diesel. 700r4 3.73 gears

    1987 K5 blazer 6.2 diesel. 4x4 SM465 NP208 4.11 gears and 31" tires.

    "the cop asked me " Do you know why Im pulling you over"?
    I said "Yeah". The cop then asked "why"? I said " Because you have a gun, a faster car, a radio, lots of friends with radios, pepper spray and handcuffs". "

  3. #3
    Join Date
    Jan 2001
    Location
    New Hampshire - Live Free or Die
    Posts
    6,057

    Default

    I ran 245/75's, 255/85's and 265/75's on my '95 and didn't notice much change in mileage between them.
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  4. #4
    Join Date
    May 2007
    Location
    South Russell, Ohio
    Posts
    280

    Default

    Thanks guys. Ran some numbers in the calculator and it looks like 3.73's with 265/16's will get my highway rpm's down at 2079 for 70mph with 65mph at 1930, pretty close to the sweet spot.

    I just need to locate front and rear gear sets and get the project rolling.
    1996 K2500 Suburban
    Second owner, Former Fire Dept Vehicle
    "F" Engine, 4:10's looking for 3:73's
    D-TECH Remote mounted PMD, HO water pump
    1998 air box with K&N filter
    Fluidampr
    17" GMC Alloy Wheels with 265 70 R17's
    RACOR 490 fuel filter with heater and 2 Micron Filter

  5. #5
    Join Date
    Sep 2002
    Location
    Fort Wayne, IN
    Posts
    39

    Default

    I went from the 245's to the 265's. The family vacation to Florida we averaged around 19 mpg round trip (2400 miles). We routinely kept the cruise set at around 78 mph. After the 265's wore out (Dunlop) I changed to 235/85R16 in the BFG All-Terrains. My mileage went down to around 16-17 mpg for the same trip the next time we went. I now have BFG commercial TAs on the Suburban, and now I get between 18 and 19 MPG. Haven't taken the Sub to Florida since putting the new tires on, but I do notice a difference. The All-Terrains had a more aggressive tread, and must have had more rolling resistance.

    HTH
    Bill

    1996 K2500 Suburban - Purchased in Sept. 2002 - 297K miles
    Only mods - K&N filter, Greg's Oil Cooler Lines, Home-made FSD heatsink, Kennedy quick heat glow plugs, LED interior lights, Kenwood stereo, 2001 GMC aluminum rims. AutoMeter Guages (boost, EGT, TransTemp)
    2007 GMC Acadia SLE - wifes car.
    1987 Buick GN totally stock - 48K miles

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