Somebody 'plain this.....

[bobmbx]

Was crawling around under the '17 Expy XLT yesterday and noticed the tread design on the spare was different than the the other 4. Sure enough, my spare is a Goodyear Wrangler while the original tires are the Hankooks.

While typing this, it occurred to me that I need to look again to make sure its the same size (in diameter, any way).

 

[Black]

Was crawling around under the '17 Expy XLT yesterday and noticed the tread design on the spare was different than the the other 4. Sure enough, my spare is a Goodyear Wrangler while the original tires are the Hankooks.

While typing this, it occurred to me that I need to look again to make sure its the same size (in diameter, any way).

I am guessing you have the 20” wheel upgrade?

The Goodyear Wrangler were OEM for 18” wheels. You likely have an 18” spare but similar overal diameter.

I have 18” wheels and a 17” spare.

 

[Gary Waugh]

As stated above, you probably have the 20" upgraded wheels (they came standard on my limited), but the spare is a cheap pressed steel 18" with wrangler tyre, at least its a full size spare not those horrible skinny things!!

Gary

 

[powerboatr]

I am guessing you have the 20” wheel upgrade?

The Goodyear Wrangler were OEM for 18” wheels. You likely have an 18” spare but similar overal diameter.

I have 18” wheels and a 17” spare.

yep thats the deal a standard 18" wheel and tire

 

[1955moose]

Wouldn't lose any sleep over it. Just don't leave it on more than 25 miles if you can help it. 4 wheel and all wheel drive vehicles can have differential problems if you have one or more different sized tires. On some even a different tread pattern can throw off the differential. Has to do with the computer, I believe. Maybe one of the others can elaborate on this. Just make sure your tire pressure is up on spare. I check mine about once a year, and pump it to the max on tire.

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[LokiWolf]

Wouldn't lose any sleep over it. Just don't leave it on more than 25 miles if you can help it. 4 wheel and all wheel drive vehicles can have differential problems if you have one or more different sized tires. On some even a different tread pattern can throw off the differential. Has to do with the computer, I believe. Maybe one of the others can elaborate on this. Just make sure your tire pressure is up on spare. I check mine about once a year, and pump it to the max on tire.

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The 18 Spare has the same rolling diameter as the 20 inch combo. Absolutely 0 issues running it. Ran ours on our 15 for 300+ miles while the dealer was repairing one of the 20’s they messed up.


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[chuck s]

Yep, and our trucks are not full time 4x4 (like a Subaru) if you keep it in 2H. Rarely any need to run other than 2H anyway.

-- Chuck

 

[Plati]

Yep, and our trucks are not full time 4x4 (like a Subaru) if you keep it in 2H. Rarely any need to run other than 2H anyway.

-- Chuck

I guess you're saying they aren't fulltime 4x4 if you keep it in 2H because if you keep it in 2H they are never 4x4?

 

[chuck s]

Our trucks aren't fulltime 4x4 by any definition. They're selective 4x4 at best. Full time 4x4 vehicles, like Subarus, don't offer any options. They're always 4x4 -- AKA full time 4x4.

Having matched tires on all 4 corners is vital on a full time 4x4 vehicle like a Subaru. Get a flat on one of these cars you buy four (4) new tires, not 3 like our trucks.

-- Chuck

 

[JExpedition07]

A crossover like Subaru isn’t 4x4 like an Expedition as it doesn’t have a Transfer Case that mechanically locks the front and rear driveshafts with a 50/50 constant torque split. It’s AWD and has a power transfer unit like a Ford Edge or Explorer. By definition 4x4 is selectable and controlled by the driver via shifter or switch.

Big difference, hop under a 4WD Expedition and look at the large 2-speed BorgWarner T-case and then hop under an Explorer and it’s got a little PTU instead.

 

[chuck s]

Expeditions are not full time 4x4 and you don't need to panic if you have a slightly mismatched tire.

-- Chuck

 

[LokiWolf]

Subraru’s DO have a Center Diff. They DO NOT have a PTU. They are AWD or what some people more accurately call Full Time 4WD. All 4 wheels have power, and that Torque can be moved around based on multiple clutches and brake application techniques. All of Subaru’s systems are Symmetrical, but there are a few variations on how Torque is managed...

https://www.subaru-global.com/technology/performance/drivetrain_awd.html


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[JExpedition07]

I do not believe any Subaru is offered with a selectable 2 speed locking transfer case. Interesting info on their awd though and looks to be a better system than fords AWD PTU solutions.

 

[LokiWolf]

I do not believe any Subaru is offered with a selectable 2 speed locking transfer case. Interesting info on their awd though and looks to be a better system than fords AWD PTU solutions.

Much better system!!! Trust me! Have owned both. My DD is the Edge, and PTU has to be seriously taken care of if you are launching hard regularly, because it is meant as a part time system.

Having a Center Diff, and a 2 Speed transfer case are 2 different things. Transfer case and Center Diff can be all in one, but having one does not mean the other. Many of the 18+ Expys have 4WD but do not have a Low Range. They still have a Center Diff.

A PTU is more of an add on. The Edge for example is primarily FWD, and the AWD is bolted on(PTU).


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