Max Tire Size

[Jesse1981]

good morning all. New to this forum and have a question. My 2017 sport calls for 255/50r20. I can get my hands on some 275/55r20 for about $250 dollars less for all 4. Will they fit without any rubbing on the inside wheel well?

 

[peterk9]

Your thread was merged with this existing one. As will see, there are several posts on the size you are considering along with the warning that they will exceed the generally accepted maximum diameter variance of 3% rule by double at 6.2%.
255/50-R20 vs 275/55-R20 Tire Comparison - Tire Size Calculator | Tacoma World

Peter

 

[Ntrain]

Your thread was merged with this existing one. As will see, there are several posts on the size you are considering along with the warning that they will exceed the generally accepted maximum diameter variance of 3% rule by double at 6.2%.

Peter

Yea, that's a huge difference. Nearly 2" in height off of the top of my head.

 

[doug625]

I'm running 8.5% variance with no issues except the speedo being off....but I'm dealing with a 3rd gen.

 

[KayGee]

I'm running 8.5% variance with no issues except the speedo being off....but I'm dealing with a 3rd gen.

You have been reported to the authorities...

 

[mmwelchman]

good morning all. New to this forum and have a question. My 2017 sport calls for 255/50r20. I can get my hands on some 275/55r20 for about $250 dollars less for all 4. Will they fit without any rubbing on the inside wheel well?

I have a 2014 Explorer sport and looking to put on the 275/55/r20s as well. Alot more tire choices Has anyone had these on 11-15 explorer sport and if so any problems? Obviously theres a risk putting larger tires on vehicles, but people have been putting larger tires on there vehicles for a long time.

 

[peterk9]

.........Obviously theres a risk putting larger tires on vehicles, but people have been putting larger tires on their vehicles for a long time.

Welcome to the Forum.
What you say is true, but the newer ones have many more electronic features than the older ones that can be negatively affected. Oversized tires will affect the performance of the ABS, Traction Control and the braking system not to mention the suspension.

Peter

 

[JAP42]

My wife just got a 2013 Explorer Limited. Our local tire shop is going to test fit a 275/55-R20 duratrac. Larger tires do cause extra brake wear, they will not cause your brakes to magically fail. Your ABS can be updated with forscan to work with just about any tire size. You will change the geometry, ride and handling. You will not go screaming off the road, it will just be different.

Height wise looks good, I am mostly worried about rubbing on the inside rear at a full turn.

 

[peterk9]

Welcome to the Forum.
I don't use FORScan but I haven't heard of anyone using it for that purpose so I can't really comment on that. I do know that the size indicated is twice the 'recommended' variance. If I recall correctly a member using that size did indicate there was some rubbing on the inner fender. Good luck. Will FORScan allow you to adjust the speed as well?

Peter

 

[JAP42]

Yep, there is a few bits in the BCM module, There is a calculator here: Ford As-Built Tire Calculator v3.0

 

[KayGee]

Just wanted to post again for folks looking to go with different size tires. The size marked on the sidewall is not the exact width of the tire. It just provides nominal guidance as to size. Rim width can also impact actual width once installed. You should understand the manufacturers actual published section width for a given rim width and how to estimate the impact if you have a different width rim (the claimed industry rule of thumb is that every + or - 1/2" change in rim width affects section width by a corresponding + or - 1/5").

Here is a thread from another forum with a good example of two marked 255 width tires mounted to the same width rim. There is ~ 1/2" difference in the actual width of the tires.
255 tires - Not all created equal! - AudiWorld Forums

Two tires of different brands marked as 255 width, mounted to same width rim, yet actual width is physically ~ 1/2" different.
https://cimg4.ibsrv.net/gimg/www.audiworld.com-vbulletin/1147x763
/picture_php_pictureid_242629_42770caf0bd49415419d10eb34d8b8a5b5a4c48a.jpg

Some manufacturers publish that their width and height variances are up to 3-4% or more. Online tire calculators will only tell you so much and they shouldn't be relied on for anything more than anecdotal/directional estimating. If you want to know for sure, you will need to mount and measure (or compare to your current mounted tire), and test fit the tires on your vehicle.

It is theoretically possible to find a 255 marked tire that is almost the same installed width as a 275 marked tire (if the 255 was on the high side of variance and the 275 on the low side). Stop relying on an online calculator that says warning variance exceeds 3% when it may not really be the case. Do your homework...

Also, for those concerned about their AWD systems getting messed up by having different size tires on the same axle or different size tires on FR vs RR axle, this is also why you must verify that replacement tires are actually the same size. If you were to put 2 different brand tires marked with the same size on the same axle, they may have a size/circumference difference. Same thing if you have one brand on the front axle and a different brand of the same marked size on the rear axle - they may not be the same actual size/circumference and could cause damage to your driveline if the variance is large enough. I know no one here runs mismatched tires, so feel free to disregard.

 

[JAP42]

Try almost 3/4. The duratrac tires have a tread pattern on the sidewall It raises up about 3/8 of an inch on top of the 3/8 the sidewall bulges out. That rubbed a little. I decided to stick with the stock size weather ready.

 

[narcanony18Platinum]

Try almost 3/4. The duratrac tires have a tread pattern on the sidewall It raises up about 3/8 of an inch on top of the 3/8 the sidewall bulges out. That rubbed a little. I decided to stick with the stock size weather ready.

Ive been toying with the idea of ridge grapplers in this size for a while and you seem to be the only person who has actually tried this so hoping you’d be able to answer whether in your opinion 265/65R18 would fit. Calculating the difference between 275/55R20 these are -0.9% in circumference and diameter. 31.6” diameter opposed to the 31.9” diameter you tried. Basically, looking to find out just how close the fit was in your opinion. Would 7mm solve the rub?