max tire size
Grand Champion
Joined: Nov 2004
Posts: 6,099
Likes: 6
From: Colorado
RE: max tire size
ORIGINAL: 1969roadrunner
I'm not sure how you can say that they are usually considered a 33" tire.
Ok, let's look at my tires... 275/60R20
The 275 is the width in mm.
The 60 is the heigth as a percentage of the width, also in mm...
R20 is the rim diameter in inches.
So, that means that my tires are 275mm wide and 165mm (60% of 275) in heigth.
Now, since a tire is a circle, that means that you need to double this heigth measurement to accomodate the tire that is "below" and "above" the rim when you are measuring the diameter.
In other words:: 165mm + 20" + 165mm = Total Tire Diameter
There are 2.54 cm per inch, so that's 25.4mm per inch.
165mm * 2 = 330mm
330mm / 25.4mm per inch = 12.99" (We'll call it 13)
13" of rubberplus 20" of steel equals a total of 33"
I should correct myself, earlier I said I thought I had 34" wheels. I was thinking of the new, larger all-terrain wheels I just bought but have yet to put on the truck...
With these calculations you can also determine how your speedometer will be affected... Since for some reason you can't program the computer on mine, I have to just compensate for the difference. These 33" wheels are 12.5% larger than the factory wheels, so that means that the speedo is off by 12.5% as well. What it calculates to to is 62.5mph on the gauge equaling 70mph on the road and the 102 in my picture equaling 115...
ORIGINAL: hometheaterman
285's are usually considered a 33" tire. I like the 305's better but they are the same height only wider. I'm not sure if you will be able to fit them stock though. On my 01 with a 3" lift, 305's, and my 16x10 wheels they rub at full lock when you hit a bump at the same time. I like them but am not sure how they would work on a stock truck. I would be fine with mine though if I had differn't rims. I think. My wheels just stick out fairly far so make them rub on the plastic fender lining.
285's are usually considered a 33" tire. I like the 305's better but they are the same height only wider. I'm not sure if you will be able to fit them stock though. On my 01 with a 3" lift, 305's, and my 16x10 wheels they rub at full lock when you hit a bump at the same time. I like them but am not sure how they would work on a stock truck. I would be fine with mine though if I had differn't rims. I think. My wheels just stick out fairly far so make them rub on the plastic fender lining.
I'm not sure how you can say that they are usually considered a 33" tire.
Ok, let's look at my tires... 275/60R20
The 275 is the width in mm.
The 60 is the heigth as a percentage of the width, also in mm...
R20 is the rim diameter in inches.
So, that means that my tires are 275mm wide and 165mm (60% of 275) in heigth.
Now, since a tire is a circle, that means that you need to double this heigth measurement to accomodate the tire that is "below" and "above" the rim when you are measuring the diameter.
In other words:: 165mm + 20" + 165mm = Total Tire Diameter
There are 2.54 cm per inch, so that's 25.4mm per inch.
165mm * 2 = 330mm
330mm / 25.4mm per inch = 12.99" (We'll call it 13)
13" of rubberplus 20" of steel equals a total of 33"
I should correct myself, earlier I said I thought I had 34" wheels. I was thinking of the new, larger all-terrain wheels I just bought but have yet to put on the truck...
With these calculations you can also determine how your speedometer will be affected... Since for some reason you can't program the computer on mine, I have to just compensate for the difference. These 33" wheels are 12.5% larger than the factory wheels, so that means that the speedo is off by 12.5% as well. What it calculates to to is 62.5mph on the gauge equaling 70mph on the road and the 102 in my picture equaling 115...
A 275/16/20 is a 32.99" diameter tire, not 34". And your example is not really relevant because the original question is not about 20" rims, it'a about 285/75/16's. A 285/75/16 is considered a 33" by most people because the diameter listed by most manufactures for a 285/75/16 is 32.8". Most tires once mounted (whether 285/75/16 or 33-12.50R16) are actually less then 33" inches once you get the weight of the engine and truck pushing down on them. But people generally us the manaufuacteres size when discussing their tire size though.
And, if his stock tire is 245/75/16 (like most 2nd Rams had stock), and you want to go to a 285/75/16, that is a diameter difference of only 7.22%. If he had stock tires of 265/75/16 (like some Rams had), it is a diameter difference of 3.63%
I definetly agree with dhvaughan about the gears. These trucks are so heavy that even with stock tire size, 3.55 is barely the right gear. For 33's, you should really consider 4.10's.
RE: max tire size
ORIGINAL: Silver_Dodge
A 275/16/20 is a 32.99" diameter tire, not 34". And your example is not really relevant because the original question is not about 20" rims, it'a about 285/75/16's. A 285/75/16 is considered a 33" by most people because the diameter listed by most manufactures for a 285/75/16 is 32.8". Most tires once mounted (whether 285/75/16 or 33-12.50R16) are actually less then 33" inches once you get the weight of the engine and truck pushing down on them. But people generally us the manaufuacteres size when discussing their tire size though.
And, if his stock tire is 245/75/16 (like most 2nd Rams had stock), and you want to go to a 285/75/16, that is a diameter difference of only 7.22%. If he had stock tires of 265/75/16 (like some Rams had), it is a diameter difference of 3.63%
I definetly agree with dhvaughan about the gears. These trucks are so heavy that even with stock tire size, 3.55 is barely the right gear. For 33's, you should really consider 4.10's.
ORIGINAL: 1969roadrunner
I'm not sure how you can say that they are usually considered a 33" tire.
Ok, let's look at my tires... 275/60R20
The 275 is the width in mm.
The 60 is the heigth as a percentage of the width, also in mm...
R20 is the rim diameter in inches.
So, that means that my tires are 275mm wide and 165mm (60% of 275) in heigth.
Now, since a tire is a circle, that means that you need to double this heigth measurement to accomodate the tire that is "below" and "above" the rim when you are measuring the diameter.
In other words:: 165mm + 20" + 165mm = Total Tire Diameter
There are 2.54 cm per inch, so that's 25.4mm per inch.
165mm * 2 = 330mm
330mm / 25.4mm per inch = 12.99" (We'll call it 13)
13" of rubberplus 20" of steel equals a total of 33"
I should correct myself, earlier I said I thought I had 34" wheels. I was thinking of the new, larger all-terrain wheels I just bought but have yet to put on the truck...
With these calculations you can also determine how your speedometer will be affected... Since for some reason you can't program the computer on mine, I have to just compensate for the difference. These 33" wheels are 12.5% larger than the factory wheels, so that means that the speedo is off by 12.5% as well. What it calculates to to is 62.5mph on the gauge equaling 70mph on the road and the 102 in my picture equaling 115...
ORIGINAL: hometheaterman
285's are usually considered a 33" tire. I like the 305's better but they are the same height only wider. I'm not sure if you will be able to fit them stock though. On my 01 with a 3" lift, 305's, and my 16x10 wheels they rub at full lock when you hit a bump at the same time. I like them but am not sure how they would work on a stock truck. I would be fine with mine though if I had differn't rims. I think. My wheels just stick out fairly far so make them rub on the plastic fender lining.
285's are usually considered a 33" tire. I like the 305's better but they are the same height only wider. I'm not sure if you will be able to fit them stock though. On my 01 with a 3" lift, 305's, and my 16x10 wheels they rub at full lock when you hit a bump at the same time. I like them but am not sure how they would work on a stock truck. I would be fine with mine though if I had differn't rims. I think. My wheels just stick out fairly far so make them rub on the plastic fender lining.
I'm not sure how you can say that they are usually considered a 33" tire.
Ok, let's look at my tires... 275/60R20
The 275 is the width in mm.
The 60 is the heigth as a percentage of the width, also in mm...
R20 is the rim diameter in inches.
So, that means that my tires are 275mm wide and 165mm (60% of 275) in heigth.
Now, since a tire is a circle, that means that you need to double this heigth measurement to accomodate the tire that is "below" and "above" the rim when you are measuring the diameter.
In other words:: 165mm + 20" + 165mm = Total Tire Diameter
There are 2.54 cm per inch, so that's 25.4mm per inch.
165mm * 2 = 330mm
330mm / 25.4mm per inch = 12.99" (We'll call it 13)
13" of rubberplus 20" of steel equals a total of 33"
I should correct myself, earlier I said I thought I had 34" wheels. I was thinking of the new, larger all-terrain wheels I just bought but have yet to put on the truck...
With these calculations you can also determine how your speedometer will be affected... Since for some reason you can't program the computer on mine, I have to just compensate for the difference. These 33" wheels are 12.5% larger than the factory wheels, so that means that the speedo is off by 12.5% as well. What it calculates to to is 62.5mph on the gauge equaling 70mph on the road and the 102 in my picture equaling 115...
A 275/16/20 is a 32.99" diameter tire, not 34". And your example is not really relevant because the original question is not about 20" rims, it'a about 285/75/16's. A 285/75/16 is considered a 33" by most people because the diameter listed by most manufactures for a 285/75/16 is 32.8". Most tires once mounted (whether 285/75/16 or 33-12.50R16) are actually less then 33" inches once you get the weight of the engine and truck pushing down on them. But people generally us the manaufuacteres size when discussing their tire size though.
And, if his stock tire is 245/75/16 (like most 2nd Rams had stock), and you want to go to a 285/75/16, that is a diameter difference of only 7.22%. If he had stock tires of 265/75/16 (like some Rams had), it is a diameter difference of 3.63%
I definetly agree with dhvaughan about the gears. These trucks are so heavy that even with stock tire size, 3.55 is barely the right gear. For 33's, you should really consider 4.10's.
I know that the question was not about 20" wheels, but I did that to demonstrate the calculations... And yes, I realized that I goofed on the 33"~ 34" thing... I was thinking of the newer tires I just bought which are 34"...
Anyway, the calculations are still relevant. Using the same formulas you can determine that the 285/75R16s are almost a33.5" tire and therefore very similar in overall diameter to mine, making my first post relevant to this thread...
(By the Way, my stockers were the puny 225/45s or somethin' like that - Idon't feel like runnin' outside just to check the fender tag...They barely filled up the wheel wells... It just didn't look right... That's why with mine the percentage is so large... And I'm still runnin' 3.55s too. It's not bad like everyone claims. If you do alot of highway driving, you should keep the higher gears... Better MPG!
)
Captain
Joined: Feb 2007
Posts: 504
Likes: 0
From: Spokane WA
RE: max tire size
my friend as a 98 dodge ram qc 4x4 and heput on 33x12.5x15. the rims were offset as well, don't remember how much. But he rubb a little on the front bumper. He then put on a 3 inch front coil spacer which fixed his problem but looked like **** cuz the front sat higher then the rear. i doubt you will be able to fit 33s ona stock 2wd
RE: max tire size
All this about the 2nd or third most asked question in the world of Dodge trucks. (sigh) Can't we be friends?
I've had 285/16 tires on my ram since I bought it. I added leveling spacers and nothing changed as far as rubbing.Using 16x7 chrome rims (factory) they have never rubbed. Oh...FYI...Factory rims run 5 inches of backspacing.
The all terrains when I ran them (bigfoot and generals) ran about 33.1 when new. Thats not my specs, but the manufacturers. I'd hazard thats a fair measurement.
The TRUXSswampers, and now my Dakota mud terrains run around 32.7-8 ish. Its probably the tread pattern/carcass that determines diameter.
It's also my experience that tells me that going to a wider rim will spread the tire a tad, and cost you some heigth. Not much, but if your concerned about clearences, you may want to use a 7 or 8 inch rim.
BTW, running a 33 inch tire will tend to kill your off the line performance with 3:55 gearing. Worse, it plays funk with your overdrive as well. Beefing your tranny's coolingis a very good idea.
I've had 285/16 tires on my ram since I bought it. I added leveling spacers and nothing changed as far as rubbing.Using 16x7 chrome rims (factory) they have never rubbed. Oh...FYI...Factory rims run 5 inches of backspacing.
The all terrains when I ran them (bigfoot and generals) ran about 33.1 when new. Thats not my specs, but the manufacturers. I'd hazard thats a fair measurement.
The TRUXSswampers, and now my Dakota mud terrains run around 32.7-8 ish. Its probably the tread pattern/carcass that determines diameter.
It's also my experience that tells me that going to a wider rim will spread the tire a tad, and cost you some heigth. Not much, but if your concerned about clearences, you may want to use a 7 or 8 inch rim.
BTW, running a 33 inch tire will tend to kill your off the line performance with 3:55 gearing. Worse, it plays funk with your overdrive as well. Beefing your tranny's coolingis a very good idea.
Champion
Joined: Jan 2005
Posts: 4,268
Likes: 1
From:
RE: max tire size
I'm not saying they are a true 33" tire I'm just saying I've heard lots of people call them 33"s so I'm saying that when he has people say he can fit 33"s that may be why. I'm not sure if a 305 will fit stock or not. I know with my rims I don't think they would. I've often heard 285's called 33"s thats why I said commonly reffered to. I guess some people round up. They technically are a 32.8" by 11.2" tire so I'd assume people just round up. It isn't that much of a difference between that and 33".
Champion
Joined: Jan 2005
Posts: 4,268
Likes: 1
From:
RE: max tire size
ORIGINAL: Cereal Killer
So are they or aren't they? [sm=WTFsgign.gif]
So are they or aren't they? [sm=WTFsgign.gif]