Change to 20" wheels on '13 PIU?

[Rattlecan]

Almost time for new tires on my 2013 PIU, and I'm considering changing from the stock 18" steel wheels Ford OEM 20" alloys.
I've read on the forum that others have done this, but I'd like to make sure there's not risk of damage to the AWD system.

I'll likely keep the 18" steel wheels and put dedicated winter/snow tires on them. We don't get a lot of snow here, but it is typically wet slushy stuff that stays for a week or so. This PIU may become my go-to ride for skiing as well, which would be 8-10 trips to the pass every winter.

Thanks,
Rattlecan

 

[peterk9]

What is the size you have now? 245/60R18? If so then it shouldn't be an issue. It has a maximum diameter variance of 1.6%. Well within the 3% maximum.

245/60-R18 vs 255/50-R20 Tire Comparison - Tire Size Calculator | Tacoma World
I actually would prefer the 18" since it has more sidewall height and less chance of getting 'curb rash'. I also use 18" in place of my 20s for Winter and find they have a slightly better ride because of the extra sidewall.

Peter​

 

[KayGee]

PIU comes with 245/55R18, so the 255/50R20 retail setup would not meet the arbitrary 3% rule.

I put 275/40R21 on my 16 PIU. They don't meet the 3% rule either, but I like to live on the edge.

 

[peterk9]

......I put 275/40R21 on my 16 PIU. They don't meet the 3% rule either, but I like to live on the edge.

That is only off by -0.5%. Really living dangerously. My Winters are off by -0.1%. With the 2020 possibly going to 22" I will be out of luck with the current Winter setup.

Peter

 

[KayGee]

That is only off by -0.5%. Really living dangerously. My Winters are off by -0.1%. With the 2020 possibly going to 22" I will be out of luck with the current Winter setup.

Peter

245/55R18 to 275/40R21 shows as 3.7% difference on the tire calculator.
245/55R18 to 255/50R20 shows as 5.0% difference on the tire calculator.

 

[Lightn95]

It shouldn't effect the AWD as long as all 4 tires are the same.
The 3% rule should only apply to the speedometer

 

[peterk9]

245/55R18 to 275/40R21 shows as 3.7% difference on the tire calculator.
245/55R18 to 255/50R20 shows as 5.0% difference on the tire calculator.

Right you are. Must have plugged in a wrong number. Thank you.

 

[peterk9]

It shouldn't effect the AWD as long as all 4 tires are the same.
The 3% rule should only apply to the speedometer

It also affects the ABS, Traction Control and other features programmed to the OEM size. On later models you can actually go in and change the size with Forscan to update those programs.

Peter

 

[Lightn95]

It also affects the ABS, Traction Control and other features programmed to the OEM size. On later models you can actually go in and change the size with Forscan to update those programs.

Peter

Correct...but his question was regarding possibly damaging the AWD system... which it won't as long as all 4 tires are the same size.....and the spare because you never know when you'll need it...