Forum Discussion

drillagent's avatar
drillagent
Explorer
Oct 28, 2014

16" or 18" tires and how do I match rims

I currently have LT265/70R17 BF Goodrich Rugged Trail T/A tires with a max load of 3195lbs on my 2012 F250. I know it has the same axle as the F350 with 18" tires, so I can increase the payload capacity with higher max load tires. Not trying to overload the truck, just would like a little more buffer.

So which Cooper Discoverer HT3 tire should I replace them with, the 275/70R18 with max load 3640lbs at $180ea or 285/75R16 with max load 3750lbs at $162ea. I've used the Tire Size Comparison website, and the 285 is about 1/2" shorter than the 275, but it's also about 1/2" wider too. Both are almost a full inch taller than my current tires.

Either way, I'm going to have to replace the rim as well. How do I match the rim with the tire? Whenever I look up rims, I can match the diameter, but none of them give the width? Does it matter?

Thanks.
Tow Vehicles

9 Replies

  • BenK's avatar
    BenK
    Explorer
    Oct 28, 2014
    All tires have a recommended rim width *range*

    On the narrow side will provide better 'ride quality', but poorer handling

    On the wide side will provide better handling, but lower 'ride quality'

    All to do with the sidewall bendback (how much)

    Of course all with the same tire and same PSI/load
  • spud1957's avatar
    spud1957
    Explorer
    Oct 28, 2014
    I have OE 18s on my F250. They are 18x8. Bolt pattern is 8-170.

    Go to a reputable retailer if you buy after market wheels to ensure 1. they know what they are ordering and 2. make sure you dry fit them on your truck without the tires to ensure proper clearances. Once you mount the tires on them they will probably not take them back.

    Only an observation not a judgement but man that's a lot of 5th wheel for a 3/4 ton.
  • BenK's avatar
    BenK
    Explorer
    Oct 28, 2014
    Find the spec for the higher class truck's wheels...rim width (bead to bead),
    offset and load rating

    Toss in hub centric or not. Hard to find after market alloys with hub centric
    designs

    Best to just go out and buy some take offs from that bigger truck

    OEM's ratings are what the regulatory agencies go by. You can have it legally
    changed (a licensed firm with PE/ME's signing off on the modifications, etc)
    but that will cost more than just going out and buying a bigger truck

    My eyeballs aren't good enough to see the differences between them. Like the
    disc's are thicker, the pads are thicker, the caliper is bigger, the MC has
    larger bores, the proportioning valving is different (if they have a proportioning
    valve body), software is different (mainly temp and safeties) and whatever
    else is out there that I've not found on my GMT400
  • goducks10's avatar
    goducks10
    Explorer
    Oct 28, 2014
    I'm in the same boat. I have 245/70/17's on now. I plan on going to 18" rims and Bridgestone Dueler AT Revo 2 275/65/18 rated @3415lbs. 32.1" in dia. Won't change the door sticker, but I don't care. Common sense tells me that my truck will be better. Just like upgrading shocks or adding a rear stabilizer bar. I wouldn't go to a 16" rim unless you're sure you'll have the clearance.
  • boogie_4wheel's avatar
    boogie_4wheel
    Explorer
    Oct 28, 2014
    You will most likely have an issue running the smaller 16" wheel; the reason for the larger wheel is for brake clearance (the larger the rotor, the larger the wheel for caliper clearance).

    That pretty much sums it up, you should go to the 18" wheel. Nitto has a 17" tire with a 3450lb rating if you want to keep the wheels you have now (verify wheel weight capacity).
  • spud1957's avatar
    spud1957
    Explorer
    Oct 28, 2014
    Here is the link to your Cooper tire selection. Click on the Tire Size and Specifications button and you will find rim width sizes. For the 275/70s it looks like a rim 7"-8.5" wide will fit.

    Cooper Tires
  • spud1957's avatar
    spud1957
    Explorer
    Oct 28, 2014
    donn0128 wrote:
    That alone cannot alter your factory GVWR numbers. Does the axle assembly in deed have the same part number? How about the spring pack? Or the frame? Or heck even the front axle assembly? Think for a minute, why would Ford, or any manufacturer go through the huge expense of certification just to use different tires and wheels? Makes absolutely no sense.




    Nope, with the exception of the add'l overload spring and block on the F350 (optional on the F250 but doesn't change any numbers) There is no difference in model year 2011+.

    When you buy an F350 with 17" wheels, you get different axle ratings obviously.

    Agree that you can't change the "legal" (I use that term loosely) GVWR but you can upgrade to feel safer with the add'l weight capacity.

    It is a little bizarre but it is all a numbers game.

    Here is Ford's small print:

    Gross Axle Weight Rating is determined by the rated capacity of the minimum component of the axle system (axle, computer-selected springs,
    wheels, tires) of a specific vehicle. Front and rear GAWRs will, in all cases, sum to a number equal to or greater than the GVWR for the particular
    vehicle. Maximum loaded vehicle (including passengers, equipment and payload) cannot exceed the GVW rating or GAWR (front or rear).
  • spud1957's avatar
    spud1957
    Explorer
    Oct 28, 2014
    drillagent wrote:
    I currently have LT265/70R17 BF Goodrich Rugged Trail T/A tires with a max load of 3195lbs on my 2012 F250. I know it has the same axle as the F350 with 18" tires, so I can increase the payload capacity with higher max load tires. Not trying to overload the truck, just would like a little more buffer.

    So which Cooper Discoverer HT3 tire should I replace them with, the 275/70R18 with max load 3640lbs at $180ea or 285/75R16 with max load 3750lbs at $162ea. I've used the Tire Size Comparison website, and the 285 is about 1/2" shorter than the 275, but it's also about 1/2" wider too. Both are almost a full inch taller than my current tires.

    Either way, I'm going to have to replace the rim as well. How do I match the rim with the tire? Whenever I look up rims, I can match the diameter, but none of them give the width? Does it matter?

    Thanks.


    "If it were me" I would replace them with the OE size available which is the 275/70s. With the 1" difference your speedo will be off. For an hours labour charge, you can go onto Ford and have them reprogram the PCM to the correct size.
  • donn0128's avatar
    donn0128
    Explorer II
    Oct 28, 2014
    That alone cannot alter your factory GVWR numbers. Does the axle assembly in deed have the same part number? How about the spring pack? Or the frame? Or heck even the front axle assembly? Think for a minute, why would Ford, or any manufacturer go through the huge expense of certification just to use different tires and wheels? Makes absolutely no sense.

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