Let me preface this for a moment. I am not a wheel/tire expert. I am simply writing this part to answer some of the most basic questions. With that said... If you find any of the information here incorrect or unclear, please PM me and I will either fix it or try to make it more clear for you. If you still have questions or this post doesn't help you.. Post a reply and someone (or myself) will answer it!

There are a lot of questions posted about which size to use, and how wide of a wheel to use. So, here is an easy guide to refer to when looking for replacement tires. First, let's breakdown what the size numbers/letters mean:

P245/50R17 93V

P = Passenger Tire (does not appear always) // LT = Light Truck
245 = Section width (in millimeters)
50 = Section height or aspect ratio (ie. sidewall is 50% of section width)
R = Radial construction
17 = Rim diameter (in inches)
93 = Load Index
V = Speed symbol

All of the components of your tire size are important, but when choosing a replacement or plus size, many of those numbers will change. You may have a wider tire with lower aspect ratio and a larger wheel. However, the last two characters are the most important.

Standard Tire Sizing:

1500 4WD
Stock height: 265/75R16 (this is the stock tire size).
Probably OK: 285/75R16, 235/85R16, 255/85R16, 32/11.50-16.5
With a 2-3" lift: 33/12.5-16.5, 315/75R16
With a 4" Lift: 35/12.5-16.5

2500 4WD

6.5x16" steel wheels - 1994-2000 ST/SLT, 2001 ST

LT255/85R16D fits the stock rim, 33+" tall, spare fits in frame, 3000 Pound capacity (many reports)
33-11.50-16 thornbirds on stock rim
8x16" Forged Aluminum heels - 2001 SLT

LT295/75R16 on stock rim 33.5" tall - no rub
315/75R16 on stock rim and it only rub lightly at full lock.
Aftermarket Wheels and/or lifts:

LT285/75R16D fits with aftermarket rim, 33" tall. no lift needed (many reports)
33/12.50-16.5 - no problems
35/12.50-16.5 - Tires rub plastic inner fender when the steering is locked.
305/70R16 - Light rubbing at full lock of the wheel.
305/85R16 - ( 36" tall, 10.5" wide) with just a front leveling kit.

3500 2WD, 4WD

LT235/85R16E is generally agreed to bew the maximum size without spacers between the wheel rims, but brands vary in width - max section width is 9.4".


Bolt Pattern
The bolt pattern or bolt circle is the diameter of an imaginary circle formed by the centers of the wheel lugs. Bolt patterns can be 4, 5, 6, or 8 lug holes. A bolt circle of 4x100 would indicate a 4 lug pattern on a circle with a diameter of 100mm.

The bolt pattern for the Dodge Ram is 5 x 5.5” (inch)





Offset

What is an offset and how does it play into my wheel choice? First let's answer what an offset is. The offset is the distance from it's hub mounting surface to the centerline of the wheel. You have a positive, zero, or negative offset.

A simple picture...


Zero: The hub mounting is even with the centerline of the wheel. I rarely see a zero offset...

Positive: The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative: The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset. Mostly found in alot of RWD cars.

As a side note...

If the offset of the wheel is not correct for the car, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won't work correctly.

Offset also becomes important if you are thinking about lowering your ride. If the offset is to not correct, you will have rubbing against the fenders. To get rid of this you will have to perfrom what has been popularly called "Fender-rolling", rolling the fenders out/in to give clearance for the new wheel/tire combination.

Backspacing

The distance from the hub to the back of the rim. This determines with how far the tire reaches into the wheelwell. If you get wide wheels and keep stock offset, the wheel will increase backspace toward the inside. If you want to keep stock backspacing, then you need a lot of offset (NOT desirable).
A wide wheel, with less backspacing puts extra stress on the bearings and seals, etc, etc because the center of the tire is farther away from the hub. A wide wheel with less backspacing can also cause more rubbing on the control arms and a reduced turning radius.

Ram Rim Dimensions

1994-1999 1500 2WD/4WD Aluminum Wheels
• Lug Pattern - 5 on 5.5", 1/2" bolt
• Rim Size - 16x7.0"
• Offset - +13.97mm
• Backspace - 5"
• Max Tire Size -
• 15x8.0 rims with 3.5" backspace will fit, but they stick out of the wheel wells.

2000-2001 1500 2WD/4WD 16" Aluminum Wheels• not posted yet

2000-2003 1500 2WD/4WD 17" Steel Wheels (Chrome or painted) • Lug Pattern: 5 on 5 1/2
• Rim Size: 17x7"
• Fits 94 and up 1500 trucks

2000-2003 1500 2WD/4WD 17" Aluminum Wheels:
• Lug Pattern: 5 on 5 1/2
• Weight: 23.5 pounds
• Rim Size: 17x8"
• Actual width edge to edge: 9 1/16"
• Backspacing: 5 9/16".
• The space from the outside edge to the mounting surface (against the rotor) is 3 1/2".
• offset calculate: 1 1/32"
• Fits 94 and up 1500 trucks

1994-2002 2500 2WD/4WD Steel Wheels:
• Lug Pattern - 8 on 6.5", 9/16" bolt
• Rim Size - 16x6.5"
• Offset - 4.75"
• Max Tire Size - 245/75R16, 255/85R16

2000-2002 2500 2WD/4WD Forged Aluminum Wheels:
• Lug Pattern - 8 on 6.5", 9/16" bolt
• Rim Size - 16x8"
• Offset - 6.25"
• Max Tire Size - ??
o Rear: Have a machine shop turn the widest part of the brake drum down by about 1/8.
o Front: If clearance is a problem, grind the steering components just enough to clear the wheel rim. The tie rod ends may need to be lightly touched with a peanut grinder. Make sure the front wheels are pushed all the way back to the rotor, or you could cinch up the lugs and bind the wheel in a bind/angle= wobbly wheel. It is a very close tolerance at the center circle in the wheel in front, but the wheels will fit.

Lug Nut Torque Specs:

• 80-110 ft lbs (108-150 Nm) on 5 stud wheels
• 120-150 ft lbs (163-203 NM) on 8 stud single wheels
• 130-160 ft lbs (176-217 NM) on 8 stud dual wheels


Useful Links:
Here is a wheel /tire size calculator: http://www.wheelsmaster.com/rt_specs.jsp
Most of the info found on this post is located here: http://dodgeram.org/tech/specs/Ramspecs.htm

 

Nice Post! This helps with a lot of the most common questions here.
Also use http://www.tirerack.com/a.jsp?a=AJ7&...echcenter.html to help with a ton of general tire and wheel info.

 

Thanks! Sorry for not including that tirerack link in my post, I meant to add it but when I was finishing up the post it was at the end of the day so I was in a hurry. Hope this offers a little help to some folks!

 

No worries, I have our tech center stickied at the top, so people can find it there too. Thanks for all the work you put in on this, I'm sure it'll help a lot of our members.

 

May I pose a question? Your article is very complete, however it is missing one set of numbers which I have been searching for desperately. I have a 2001 Dodge Ram 1500 with the 5x5.5 and 16" Rims. I need to buy some lug nuts and I don't know what the pitch and size should be. I know I use a 3/4" socket to take them off, and they are 1/2" studs from what your article has said. Now I just need one more number, pitch! If you can't get this, I supposed I can get out the old micrometer and count. Thanks for your great article!

 

Ben@tiererack

I posted a question today on this exact topic "Tire Sizes" I have a Ram 1500 5.2 Magnum RWD. I lean towards the Michelin Tire Brand, as I have had them on my Trucks since the early 70s. The stock size as on the ;abel on the door post, is 225 75 R 16. I don't do any off road driving, just interstate, and pull a Car Float. I currently have 235 75 R 16, tires on my truck, they are in need of replacement. I have over 100,000 miles on these at present. I wanted to move up to 245 75 R 16s, in an A/S. I have been buying my tires at the same place for years and they will not install these on my Truck, as there is a percentage increase that is in excess of their tolerance. From the Stock size which is 225 75 R 16, to 245 75 R 16, yet the scale which you probably have states that the 245s were optional. The speedo showing at 60 MPH, would actually be 62.5 MPH, with the 245s. Can you tell me if you might know why they won't install them, and the probable reason? for some reason I don't understand the reason. I just want a tire under my Truck that when I'm cruising at Interstate speeds to be a safe reliable one. Sure would be nice if you could get back to me with an explanation on this, and thanks in advance.

 

Hummer H-2 Wheels and tires on 2000 3/4 ton Ram 4x4:only needed to do minor mods to fit

Hummer factory standard, BF Goodrich All Terrians 315/70/17 load range D (Almost 35" tall and 11.5" wide)
Hummer factory standard, 17x8seven spoke alloy wheel "looks a little like old Hurricane wheels without center cap"

I'm on a tight budget, and my dry rotted 265/75/16's were to dinky for my taste and trails in Phoenix area, I did not want to pay $700-$1200 on just new tires on(factory alloys)rims I don't realy like anyway.

I did a little searching online and found the Hummer H2 Wheels have same 8 lug bolt pattern as the Dodge

(the main reason for checking on this is, I see sets of these H-2 wheels and tires at shops and in classifieds all the time as a lot of richer people then me replace them with a sets ofHigh $bling blings)

I found a set on craigslist asking $450 about a 1/2 hour away, the guy let me test fit one before i bought them for $260 (4 wheels, 50% tread tires, caps, lugs, lugs don't fit) Great deal!

depending on area you live, prices should be from $400 - $1200 a set, in my search I found alot, some that were brand new take offs, some with chrome plated wheels, etc. remember these tires new cost about $220 each
__________________________________________________ __________________________________________

What I needed to do for fitment: (your year 3/4 ton may vary, but install will be similer)

(if you are not mech. inclined or comfortable with a grinder, a shop could do this for you in an hour or less)

-The hub center hole on H-2 wheelis 1/16"-1/8" to small to fit over the rear hub (part that sticks out)on the factory Dana 60 rear and on the front unit bearing hub on factory Dana 60 front.

I took a 3 1/2" stone type grinding wheel on an angle grinder and just went to work around the hub circle on each wheel till I found what fit, the first one took about half hour of trial fitting and being carefull not to go to far but the rest took about 15 min. ea. once I new what was needed. (please note, this does not take anything away from the structure of the wheel) after therough grinding with the stone type wheel I cleaned it up with a sand paper flapper wheelwith same anglegrinder

**edit
I am somewhat of a SAFETY NUT and don't like wheels falling off, somethings of note, on every wheel i modified I went to the truck and mounted and torqued them down and used a mechanics mirror and flash light to make sure each wheel seated flush to drum or disk, I made sure the lug nut taper was the same, and checked the torque on all lugs about 4 times in 100 miles of mixed driving "all stayed tight".

I understand how hubcentric type wheels work and was a bit worried at first but they are smooth on the road.

I know this post may not apply to many out there, but if you have a 3/4 ton 4x4 and haven't invested money on custom after market wheels and tires yet this may be a good option for you, for me it saved me about $600 plus it looks much better than just new tires on Dodge rims.

I will copy this post to the main Ram section for it to be exposed more, delete if needed.

 

Hummer H-2 Wheels and tires on 2000 3/4 ton Ram 4x4:

Hummer factory standard, BF Goodrich All Terrians 315/70/17 load range D (almost 35" tall, aprox. 11.5" wide)
Hummer factory standard, 17x8 seven spoke alloy wheel
-----------------------------------------------------------------------
I just did this swap a couple days ago and have driven highway and serious dirt and rock offroad, only about 100mi. but this is what I found so far:

-to me, they look great, a very agressive tough look compared to the stock weenie donuts, they fill the wheel well (stock 3/4 ton 4x4 suspension) much better. the hummer center capswould work on the front but on back you would have to cut a hole for the dana 60 full floater hub

"I think it looks better with no caps, I cleaned up all the exposed hubs, lug nuts and painted them a gun metal grey"

-the ride: much better, these wheels are wider and offset more then stock so it feel like it handles more secure.
I'm still figuring on the best air pressure unloaded, but overall theseat of pants feelis good "for a 3/4 ton gas Ram"

-power: around town just fine, I can tell some power was lost do to the extra weight, rolling resistance and larger tire diam. (I weighed my stock 16" 265's alloy wheel & tire, they were 74lbs, the hummer combo 315 on 17'sis about 92lbs),on the highway you can tell a bit more (I live in a hilly mountain area) I had to drop out off overdrive a few times more then with old tires, I will likley swap to the stock rims and tires when I do any long distance towing of my jeep

you guys that have a diesel will not have this issue

I have factory 4.11 gears and a gas 360 with alot of miles

-speedometer: for me acording to GPS, at highway speeds (45-65)speedo is off about 5 MPH showing to fast

-OFFROAD: I have always thought BFG AT's are a great all around tire that is about as tough offroad as you can get without comprimising on road to much, on the Ram, Wow! I aired down to about 14 psi and this thing just went up and over places I never thought it would, great traction (I did disconnect the front anti-sway bar, BIG PLUS)

*for those that take there 1/2 or 3/4 tonRamsoff-road often.
If you haven't yet disconnected the frontanti-sway bar, give it a try, off road ride ismuch smoother and it willhelp keep all tires on the ground, its almost like adding a limited slip or locker on some stuff, its not bad on road, a little more sway and in a panic situation could bea problem so keep it connected for the street!

same goes for lowering tire air pressure off-road, try it, the difference is night and day and is often the difference between getting stuck or not, always have a on board source of air (portable compresor)
to get back to street pressure before you drive home


I have a fair amount of offroading under my belt with all sorts of trucks, jeeps, I have a TJ with air lockers and BFG CRAWLERS, so for the stock Ram with just bigger more aggressive tires and no front sway bar to impress me and others wheelers was a big deal!

-rubbing on-road: only front, when I do a tight U-Turn the outside edge of tire rubs the inner plastic fender liner (it only rubs a smooth surface towardsthe backand makes a light mark, veryslight)

-rubbing off-road: only front, same as above only a little more, and if you have the sway bar disconnected and have stock front bumper they rub that corner plastic lip/lower air dam on full stuff and turn, I will cut a little of this corner with hack saw or knife, its a common area of rub with bigger tires, the offset of the H-2 rims are somewere between the stock wheel and common aftermarket wheel, I havent measured but my track width has increased about 3"

Over all I am very happy with the swap, best $260 I spent in a while

 

will a 16.5" wheel fit on a 2002 dodge ram 1500 with the new body style? if so can someone let me know, thank you

 

I have been trying to figure out what off-set wheel I would need to run 35" tires on an aftermarket wheel for my 2005 2500 Big Horn.

Thanks for your time,
Mike