QUICK MEASUREMENT HELP: 295's real world diameter

[KlausVanWinkle]

To be clear, these measurements were taken with the tires mounted on the truck. On my 295/75/16 NTG spare with the nubs still on the tread, it measures 32.75" on OEM 16" alloy rim while NOT on the axle.

This is what I was worried about. The 285 Nittos were smaller and heavier than the manufacturer specs. I was worried that the 295s were also smaller to the point that it wasn't worth the expense to switch.

For example, the 295 Terra Grappler is supposed to be 33.27in diameter when not mounted. Not 32.75"

 

[re_guderian]

This is what I was worried about. The 285 Nittos were smaller and heavier than the manufacturer specs. I was worried that the 295s were also smaller to the point that it wasn't worth the expense to switch.

"Smaller" than what?

 

[no-pistons]

Nothing on Mojave road needs 33s or 35s.

If the tire manufacturer's spec are right, which I noted above they're usually not, then a 295 would be .5-.75in larger. Trying to find out if that's accurate.

I have nittos in 285 so I can't calculate the percentage of error for BFGs.

I think you are confusing the "size" of the tire which is written on the sidewall with the actuall specs. If you go by the size of the tire, then yes you are correct, it can be somewhat inaccurate. However, I have no real reason to believe the the specifications on the website are inacurrate.

Specs from the website:

295/75-16D are: 33.2" in diameter

285/75-16D are: 32.8"

285/75-16E are: 33"


If I was just calculating the sidewall size you get these diameters:

295/75-16D = 295 x .75 / 25.4 x 2 + 16 = 33.42"

285/75-16 = 285 x .75 / 25.4 x 2 + 16 = 32.83"

 

[SanDiegoCruiser]

Adam, is it worth all of the expense to get .5'' lift?

 

[KlausVanWinkle]

Just measured my 285/75/16 Nitto Terra Grapplers at 39 and 42psi. Both 31.5"

Nitto Terra Grappler 295's. Prolly 20K-ish miles at 37 psi on stock alloys are measuring at 32.25". Plus or minus about half an inch in my measurement error. Yes, I double checked 'em...

Okay, great. This is all I wanted to know. That means switching to 295s would give me a real world gain of .75" in diameter.

All 295/75/16s [or any tire size for that matter] are not created equal. The actual diameter is brand dependent. For example, the BFG AT is 33.2" overall dia but the General Grabber AT2 is 33.6". You need the diameter of the tire you are actually using. 0.4" may not seem like much, but it can mean the difference between rubbing and not.

Thank you for understanding what I'm talking about.

 

[elkaholic]

This is why I blow off everyone's MPG numbers that they "correct" for based on either nominal, or mfg spec, tire diameter. It's all BS.

This is why I utilize the Revs/Mile or RPM/Mile that most manufacturers print on their specs. This is measured mounted on a wheel and loaded and accounts for tread squirm, rolling radius, and a few others and is usually a better measure than diameter. Perusing spec charts, you will find differing revs/mile for tires with the same OD ...

<hijack mode off>

 

[no-pistons]

Adam, is it worth all of the expense to get .5'' lift?

A difference in .4-.5 in tire diameter will not give you that much in lift. More like .2-.25".

 

[larryt]

is the angle straight so that 32.5 is what I am reading there? I will measure mine when I get home. I have to take one of the truck anyways. I can lower the spare and compare it as well.

I held the camera part of my phone as close to level with the top of the side lug as possible.

I'd be interested to see how your spare measures with no load.

 

[KlausVanWinkle]

I held the camera part of my phone as close to level with the top of the side lug as possible.

I'd be interested to see how your spare measures with no load.

That's pretty much how I measured mine. Looks like yours is 1" taller than mine when loaded.

.5" of ground clearance isn't nothing to sneeze at.

So the 295/75/16 BFG is a true 33" tire. Much more so than the 285.

 

[SanDiegoCruiser]

.5" of ground clearance isn't nothing to sneeze at.....

I wonder if it would be worth getting a hold of some 18'' Tundra rims... You end up with a taller tire that is not as wide as the 295's. I've seen them on Craig's list going for $100 for a set of 5.

 

[KlausVanWinkle]

I wonder if it would be worth getting a hold of some 18'' Tundra rims... You end up with a taller tire that is not as wide as the 295's. I've seen them on Craig's list going for $100 for a set of 5.

Yeah the 285/75/18s? I think Spressmon runs those and likes them. The tundra 18's are heavier. I'd like the LC 18 to do that.

 

[SanDiegoCruiser]

Yep, 285/75/18. LC 18's are hard to come by and probably more $$ than the Tundra's...

 

[Socal Cruiser]

I wonder if it would be worth getting a hold of some 18'' Tundra rims... You end up with a taller tire that is not as wide as the 295's. I've seen them on Craig's list going for $100 for a set of 5.

ill be mounting my tires soon, ill post pics. Finally decided on the Toyo OC MT 285/70/18... may help you decide

 

[hoser]

(I'f you must know why, I'm debating trading tires with someone and want to know how much actual ground clearance/ improved angles I'd gain).

Perhaps what you really want is a measurement from the wheel's centerline to the ground (loaded radius) when the tires are aired down to 15 or 20psi?

 

[KlausVanWinkle]

Perhaps what you really want is a measurement from the wheel's centerline to the ground (loaded radius) when the tires are aired down to 15 or 20psi?

That'd be interesting to know but not as concerned about that since it'll probably be proportional to the fully inflated diameter. And it'll be full most of the time.

Thanks for the info so far everyone. Im trading my NTG 285s for some stock LTX's on the same rims + cash this weekend. Trying to figure out what new tire to get.

Anyone have the 285/75/16 E rated GY Duratracs? I'd be interested to know if they're a true 33". In which case they'd be the same size as the 295 NTGs.

 

[kazisaki]

Just measured my 285/75/16 LT Dueler D694's at around 70% useful treadlife and it only comes up to around 31.5-6 inches. Disappointed and sad hahaha. Small tires!
I wonder how the other brands such as Mickey Thompson and BFG measure in actual, real-world overall diameter.

 

[mcgaskins]

That'd be interesting to know but not as concerned about that since it'll probably be proportional to the fully inflated diameter. And it'll be full most of the time.

Thanks for the info so far everyone. Im trading my NTG 285s for some stock LTX's on the same rims + cash this weekend. Trying to figure out what new tire to get.

Anyone have the 285/75/16 E rated GY Duratracs? I'd be interested to know if they're a true 33". In which case they'd be the same size as the 295 NTGs.

Not sure if you already got an answer on this one, but my duratracs measured 33.2" with about 10k wear on them aired to 38psi on factory rims mounted on the truck.

 

[KlausVanWinkle]

A more accurate way to compare real world diameters seems to be with the Revolutions per minute listed on tire rack. You can reverse the math to figure out the real world, inflated diameter.

I'd recommend anyone go with 295s over 285s. It's the tallest you can go before entering the slipper slope of 35s (most of which are more like 34s).

 

[MrGreenJeans]

Can I piggy back onto this - if the heights are slightly shorter than advertised on the truck, is it fair to assume there is a proportional increase in tire width?


TIA

 

[BullElk]

295 mm X 75% = 221.25 mm / 25.4 (1") = 8.7" x 2 = 17.42 + 16" wheel = 33.42 inch diameter