Aftermarket wheels

[CDW6212R]

Hi everyone! Great thread with tons of helpful info.

For the Explorer Sport owners, I’m curious to know why you didn’t go with 295/40/20 tires as they are a smaller variance to the stock sport tires of 265/45/20.

Thanks!

That tire is 1/2" taller than the 265 tire you mention, but the same height as the 255/50/20 tire Peter referred to.

 

[No3Putts]

Hmm. That’s odd. The calculators I use show it’s smaller in diameter by about 2.5mm.

 

[peterk9]

Hmm. That’s odd. The calculators I use show it’s smaller in diameter by about 2.5mm.

It seems that each calculator is slightly different but then the tire sizes are actually a 'nominal' value as the tires themselves may vary slightly from their stated size.

Peter

 

[CDW6212R]

Ditto, brands have varying tread depths and each model can differ slightly from other brands etc.

I learned a rule of thumb about tire sizes many years ago. Each series step(50 or 40, or 45 etc) is about 1" of diameter change, and each section width change being 10mm between, is about 1/2" of diameter change.

So your tire example was easy to compare diameters. The 30mm gain is 1.5" gain of diameter, and the one step(45 to 40) down is a drop of 1" diameter. So most tire calculators will show about a 1/2" change in diameter, larger.

 

[Ls2Bait]

Tire sizes are both standard and metric, however pretty easy to determine size.

-Width is the first number in mm. Converted to inches. 255 / 25.4 = 10.04

-Aspect ratio is a percentage of the width. So a 255/50R20 means the height of the sidewall is 50% of the width. In this case. 5.02. Multiply that by two (side wall on either side of the rim) takes you back to 10.04.

-Add the rim size to that number. So 20 + 10.04 = 30.04” stock tire height.

A 295/40R20 would be 29.3”
A 295/45R20 would be 30.4”

 

[CDW6212R]

Tire sizes are both standard and metric, however pretty easy to determine size.
...
A 295/40R20 would be 29.3”
A 295/45R20 would be 30.4”

Yes, a one inch difference, no need for a calculator.


The last example is also as simple, changing from a 265/45/20 to a 295/40/20 tire is not hard to do in your head(no calculator needed).

The 265mm to 295mm adds 1.5", and the 45 series to 40 series loses one inch. Together, that's a 1/2" change/gain in diameter, easy. It's close enough to accurate, no need for a calculator, or a link online to a tire calculator. The margin for error is within acceptable limits for a speedometer. If you match the sizes this way, the speedometer will be very very close.

Note OEM speedometers are not accurate when new, some are but most are not. Ford likes to error on the slow side, 1991-2001 Explorers read slow on all 15" tire models. 16" tires didn't become options until 1998, and those were rare to begin with. The speedometers didn't change when the tire size did, even though there is a 1" difference in diameters of 15 and 16" tires back then. The optimum size for the speedometer for all of those years was a 30" tire.

So if the speedometer accuracy concerns you, first check it yourself by a GPS device, or a roadside speed display etc. Then you can make a wise decision about the needed tire diameter, or what effect a tire size will have for your truck.

 

[No3Putts]

Thanks everyone! Really helpful information.

I was unaware that the stock tires were 255/50/20. Based on this new info I’m leaning towards the 285/45/20.

 

[peterk9]

..............................So if the speedometer accuracy concerns you, first check it yourself by a GPS device, or a roadside speed display etc.........

I've found that those displays don't always display the same numbers when I've passed them with ACC locked on.

Peter

 

[CDW6212R]

Thanks everyone! Really helpful information.

I was unaware that the stock tires were 255/50/20. Based on this new info I’m leaning towards the 285/45/20.

That's a half inch taller than stock.

 

[No3Putts]

According to the rule of thumb calculation, yes you are correct.

I used these links which show the 285/45/20 are about 1.5mm to 3mm taller than stock.

255/50-R20 vs 285/45-R20 Tire Comparison - Tire Size Calculator | Tacoma World

Tire Size Calculator - Compare Two Sizes

 

[Ls2Bait]

That's a half inch taller than stock.

Not if the stock tires are the 255/50R20. It’s a .06” difference.

 

[CDW6212R]

Not if the stock tires are the 255/50R20. It’s a .06” difference.

Tires are not created with such accurate dimensions to match your assumption of tire calculator sizing. They vary a ton, way more than .06", so stop quoting decimal points, those are not significant digits. The error is so great that different brands of the same size could be 1/2" or more different.

That's the rub, there are multiple tire calculators, plus various "stock" tire sizes. I don't know the available stock tire sizes for all Explorer models. But as I pointed out before, Ford put 29" stock tires(235/75/15) on virtually all 1991 to 1998 Explorers, and then 30" tires(255/70/16) on a high percentage of 98-01's.

What matters is not what the stock tire was, but what the speedometer is calibrated for. Older Explorers were all the most accurate with 30" tires. Newer models will be different than that, no doubt.

So find out what the accuracy of your individual vehicle is, before changing tire sizes. You can do calculations to figure out what diameter is best for your truck, and then look at available options.

 

[peterk9]

Tires are not created with such accurate dimensions to match your assumption of tire calculator sizing. They vary a ton, way more than .06", so stop quoting decimal points, those are not significant digits. The error is so great that different brands of the same size could be 1/2" or more different.......................................

That's what I've been trying to get across.

Peter

 

[CDW6212R]

That's what I've been trying to get across.

Peter

Exactly. When I began trying Cooper tires for my work truck, the models have deeper tread than the prior Michelin and similar tire with "passenger car" tread designs. I didn't worry about speedometer error, knowing I was already using a tire in between the 15's and 16's in diameter. As I passed by some random speed display, I began to notice my actual speed was barely slower than indicated.

I use 245/70/16's because they are a hair cheaper than the stock 255/70's, and being slightly shorter, that brings me down a little to help with mailboxes that are too low(95% of them). So I save a few dollars a tire for a "29.5" size, but the actual diameter is very close to 30", if I did the math on true speed versus speedometer indicated. Right now the set I have is 2/3rds worn, and I saw 49mph two days ago, when the speedometer said 50. So these tires are very good given my needs, and very close to accurate on the speedometer.

Tires change size as they wear, so the accuracy varies from new, to when you replace them. A 12/32" new tread worn down to 3/32", loses 18/32"(9/16") of tire diameter.

 

[Ls2Bait]

Lol ok dude. You probably torque your wheels to “good and tight” too continue on.

 

[jkintn]

Sent you an e-mail. I'm in west ky.

reply sent

 

[CDW6212R]

Lol ok dude. You probably torque your wheels to “good and tight” too continue on.

105lbft. every time.

 

[KaroSatan]

Hi I'm new here and my first post.
I am a member if other forums for my other cars and found them to be very helpful at times.
Time for input.
So I have a 2015 sport and want a more aggressive off-road look. I'm looking into 17 inch wheels with meatier tires but don't want to lift the vehicle.was would dering if anyone has done this and what size tires you would recommend. I would like the side walls to poke out a bit but maybe not the tread if that makes sense. Tia.

I'm running 265/60/18 Hankook Dynapro ATMs on +10mm 18x8.5 Wheels. Definitely a more aggressive off road look, performed well so far for me. I've done an insane amount of research regarding all terrain tires for the Explorer and what are the best options, Max size you can go without a lift is 265/60/18 or 265/65/17. My 265/60/18 with a 8.5 wide rim with +10MM offset REQUIRED TRIMMING on the driver side wheel well to prevent rub at a certain turning point. This trimming was a plastic piece that was slightly out of position on my model, YMMV. It still was about 3 inches of a simple plastic cut. With my current setup I have a " stanced " approach because of the offset. If you would like some pictures to see I can upload some and link them here.

What kind of off roading do you plan to do or are you just going for the look? I've done a lot of research regarding pretty much every tire option for 17" 18" & 20" wheels. I maybe could give some useful insight but if not ¯\_(ツ)_/¯

 

[ecoboost_xsport]

For all the people *****in about specs. Here's the facts. I posted 2015 as it's a "middle of the road MY for 5th Gen, but probably more info than anyone cares to know.

 

[Supergus1]

Looking to change the wheels on my '17 Sport. I'd like to run 20"×10.5" but I'm not sure if that's doable without rubbing. Anyone running 20"×10.5" w/o rubbing, and if so what offset did you use?