18" on AWD?

[FordMachET]

It's getting colder and colder and it's time to get some winter tires. Does anyone know if the original 18" fits the AWD model? What I've seen is the brakes the same size on the AWD as it is on the RWD.

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[OlaviK]

I certainly hope so !
I ordered original 18" (winter) tires for my AWD from my dealer and on the phone it was ok.
Have not gotten official quotation yet though.

 

[RMoore]

Does the width of a tire typically scale with the diameter, in other words, will tires for an 18" rim usually be narrower than those for 19 and 20 inch rims? Is this really only valid when comparing sizes for the same car (e.g. when switching to snow tires with a smaller rim)? My understanding is that using a more narrow tire for snow provides better "drivability" compared to a thicker tire (I realize using a dedicated snow tire makes the biggest difference). In order to use less wide tires, do you typically have to use smaller rims?

 

[Davedough]

Does the width of a tire typically scale with the diameter, in other words, will tires for an 18" rim usually be narrower than those for 19 and 20 inch rims? Is this really only valid when comparing sizes for the same car (e.g. when switching to snow tires with a smaller rim)? My understanding is that using a more narrow tire for snow provides better "drivability" compared to a thicker tire (I realize using a dedicated snow tire makes the biggest difference). In order to use less wide tires, do you typically have to use smaller rims?

The width of the tire is measured from top of the rim lip, up the sidewall, across the tread, down the other sidewall to the other rim lip. So a 255/40/18 for instance, the 255 is the measurement as I just stated. The 40 is the sidewall height. Sidewall height plays a part in the width of the tire too. If there is less sidewall to traverse, the tread is wider. Rim size has only a minor effect on this

 

[BMT1071]

The width of the tire is measured from top of the rim lip, up the sidewall, across the tread, down the other sidewall to the other rim lip. So a 255/40/18 for instance, the 255 is the measurement as I just stated. The 40 is the sidewall height. Sidewall height plays a part in the width of the tire too. If there is less sidewall to traverse, the tread is wider. Rim size has only a minor effect on this

That is incorrect. The 255mm width does not include the sidewall. It is measured across the tread area. The sidewall height is 40% of 255, or 102mm.

 

[RMoore]

The width of the tire is measured from top of the rim lip, up the sidewall, across the tread, down the other sidewall to the other rim lip. So a 255/40/18 for instance, the 255 is the measurement as I just stated. The 40 is the sidewall height. Sidewall height plays a part in the width of the tire too. If there is less sidewall to traverse, the tread is wider. Rim size has only a minor effect on this

Thanks, this is helpful. Just curious why, when folks want to use dedicated snow tires on their own set of rims, they often size down the rim diameter. I've put snows on the same rims I've used for my all seasons, but I've also seen on TireRack's site for example that they offer up options for using smaller diameter rims.

 

[Mathington]

It's getting colder and colder and it's time to get some winter tires. Does anyone know if the original 18" fits the AWD model? What I've seen is the brakes the same size on the AWD as it is on the RWD.

I just ended up getting 19” Michelin X-ice snow for my AWD premium. I thought about getting 18” tires for winter but would have to spend extra for wheels and it wasn’t really worth it. What is it that makes you want the 18’s?

 

[buzznwood]

I certainly hope so !
I ordered original 18" (winter) tires for my AWD from my dealer and on the phone it was ok.
Have not gotten official quotation yet though.

Ford have been using a funky minimum wheel size when it comes to the brake specifications, rather than the actual size of the disc. It has 18" for the select and 18" for the AWD premium so a 18" wheel package should fit wheel width / offset permitting.

 

[Davedough]

That is incorrect. The 255mm width does not include the sidewall. It is measured across the tread area. The sidewall height is 40% of 255, or 102mm.

I stand corrected. You’re right

 

[Pushrods&Capacitors]

That is incorrect. The 255mm width does not include the sidewall. It is measured across the tread area. The sidewall height is 40% of 255, or 102mm.

Correct. Tire terminology for this is Section Width. And, to calculate overall diameter without the tire spec sheet handy you can use the above info. like this:

40% (the sidewall profile) * 255mm (section width) = 102mm sidewall height * 2 (sidewall height at bottom and top of wheel) = 204mm, then 204mm / 25mm (25mm in an inch) = 8.16”

Now, add the 8.16” in combined sidewall height to the 18” wheel diameter and you get an overall tire diameter of 26.16”, or approximately 1.6-1.7” smaller diameter than the stock 225/55-18 Select tires, which are 27.8-27.9”.

 

[phidauex]

One reason a lot of people downsize to 18” wheels for winter is that winter roads are rougher from ice, so having a taller sidewall can help prevent damage. Smaller wheels are only smaller in diameter - you can have 18” tires that are very wide or very narrow, it doesn’t have anything to do with the rim size.

As for tire sizing numbers, it can be mysterious. As people have said, the 225 is the section width of the tire in mm, the 55 is the aspect ratio between the sidewall and the tread width, and then the last number is the rim diameter in inches (at the tire bead, so if you measure your rims now you’ll see a bigger number than you think).

When people drop to 18” wheels, they aren’t getting a smaller tire - the trick is that you go to a smaller wheel, but then a higher aspect ratio, putting you back at the original tire diameter (or within a percent or so).

The stock 19” tires are 225/55-R19. To get the same diameter on an 18” wheel you would get a 225/60-R18.

To the OP’s actual question, most 18” wheels with the right bolt pattern, offset and center bore will fit on all Selects and Premiums, RWD and AWD, since they all have the same size brakes.

Here is a calculator pre-loaded with those two options which can help you visualize tire sizes: https://www.wheel-size.com/calc/?wh...60-18X7ET48&fcl=20mm&scl=35mm&wcl=70mm&sr=0mm

 

[MMJ]

One reason a lot of people downsize to 18” wheels for winter is that winter roads are rougher from ice, so having a taller sidewall can help prevent damage. Smaller wheels are only smaller in diameter - you can have 18” tires that are very wide or very narrow, it doesn’t have anything to do with the rim size.

As for tire sizing numbers, it can be mysterious. As people have said, the 225 is the section width of the tire in mm, the 55 is the aspect ratio between the sidewall and the tread width, and then the last number is the rim diameter in inches (at the tire bead, so if you measure your rims now you’ll see a bigger number than you think).

When people drop to 18” wheels, they aren’t getting a smaller tire - the trick is that you go to a smaller wheel, but then a higher aspect ratio, putting you back at the original tire diameter (or within a percent or so).

The stock 19” tires are 225/55-R19. To get the same diameter on an 18” wheel you would get a 225/60-R18.

To the OP’s actual question, most 18” wheels with the right bolt pattern, offset and center bore will fit on all Selects and Premiums, RWD and AWD, since they all have the same size brakes.

Here is a calculator pre-loaded with those two options which can help you visualize tire sizes: https://www.wheel-size.com/calc/?wh...60-18X7ET48&fcl=20mm&scl=35mm&wcl=70mm&sr=0mm

Another reason that people often down size rim size for winter tires is because additional side wall results in a longer longitudinal foot print that provides in additional traction in the snow. It is the counter argument against wide tires with narrow side side walls that have a narrow horizontal foot print. The width of the tire is often reduced as wide tires tend to push more snow. However MME factory 18" and 19" tires are the same width and fairly narrow anyway.

 

[FordMachET]

One reason a lot of people downsize to 18” wheels for winter is that winter roads are rougher from ice, so having a taller sidewall can help prevent damage. Smaller wheels are only smaller in diameter - you can have 18” tires that are very wide or very narrow, it doesn’t have anything to do with the rim size.

As for tire sizing numbers, it can be mysterious. As people have said, the 225 is the section width of the tire in mm, the 55 is the aspect ratio between the sidewall and the tread width, and then the last number is the rim diameter in inches (at the tire bead, so if you measure your rims now you’ll see a bigger number than you think).

When people drop to 18” wheels, they aren’t getting a smaller tire - the trick is that you go to a smaller wheel, but then a higher aspect ratio, putting you back at the original tire diameter (or within a percent or so).

The stock 19” tires are 225/55-R19. To get the same diameter on an 18” wheel you would get a 225/60-R18.

To the OP’s actual question, most 18” wheels with the right bolt pattern, offset and center bore will fit on all Selects and Premiums, RWD and AWD, since they all have the same size brakes.

Here is a calculator pre-loaded with those two options which can help you visualize tire sizes: https://www.wheel-size.com/calc/?wh...60-18X7ET48&fcl=20mm&scl=35mm&wcl=70mm&sr=0mm

Correct!

But correct me if I'm wrong - the red calipers and the discs on the AWD is exactly the samze size as the RWD?

So, the 18" original will fit the AWD just fine? Because I thought that the fitments were different and the brakes/discs would be too big for the 18".

 

[FordMachET]

 

[tuminatr]

Nice I also went and bought 18" wheels for winter tires. The tires I went with are the factory 18" size 225/60/18 104v XL. As some other members stated they downsize because of the roads being rough and that is true by mid-February it's a pothole city here in MN. Also, I went with 18" TSW wheels and the wheel tire combo is 13lbs per wheel or 52lbs total less than my factory 19" wheels. One myth I would like to dispel is narrow tires provide more traction in snow that's actually false although it was true before modern tire building techniques (ie before 1990 or so) The Bridgestone Blizzak being one of the first modern winter tires. Before it, winter tires were like M/T truck tires and state-of-the-art thinking was a winter tire works like paddle and snow is like sand or mud. Modern winter tires use sipes for biting edges they pick up snow with the biting edges snow in the sipes provides grip with snow on the ground so more biting edges = more traction

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