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  Project CJ-7
Jeep Project CJ-7

An ongoing Budgeted Rebuild/Build up of a Rock Crawling Machine.

Jeep Central
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Jeep Technical Info
Engine Swaps

Installing 23,000 Volt Offroad Lights

What are HID Lights?

Onboard Air
Converting a York
AC Compressor
to Pump Air

Warn 9500i Winch Installation

HEI Ignition
Installation & Review

Lockers, Limited Slips &
other Differentials Explained

Jeep Dana 300 TeraLow - 4:1 Gearset for the Dana 300 Transfer Case


Smoke rises out of the ground, the smell of sulfur is in the air, the ground collapses as homes are destroyed.
Science fiction?
Think again.


2007 Jeep Wrangler JK
Jeep Wrangler JK Specs

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Hummer H3

Jeep Commander Articles and Reviews

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Nissan XTerra Articles and Reviews

Jeep Grand Cherokee Articles & Reviews

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Jeep Rubicon Unlimited Articles and Reviews

Suspension Lift Installations and Reviews







Offset: The distance from the centerline of the wheel to the face of the mounting surface of the wheel that contacts the hub.

Negative offset: Indicates the mounting pad is behind (or inboard) the centerline of the rim. This is often found on standard rear-wheel-drive vehicles and on so-called reversed rims.

Positive offset: Refers to wheel s that have the mounting pad in front (or outboard) of the centerline of the rim. Most often found on front-drive applications.

Centerline: The exact center of the rim width. The width is measured between where the tires rest.

Bolt circle size: The bolt circle represents the diameter of an imaginary circle that goes through the center of the bolt holes (A). On a four-lug wheel, this is determined by measuring the distance between opposite holes (B). For a five-lug application, measure the center-to-center distance between two adjacent wheel studs (C) and reference the table below,

2.645 in. = 4 ½ in. circle

2.792 in. = 4 3/4 in. circle

2.939 in. = 5 in. circle

3.233 in. = 5 ½ circle

Moving up to a larger tire and wheel requires planning, considering the effects on gearing. The most important factor is the actual rolling height and width of the tire. Actual height often differs from nominal heights, so measuring the actual rolling radius of the tire would be the ideal way to know the exact effect on gearing, speedometer, etc. But measuring rolling tires, which may "grow" a little at speed, is impractical, so tires are measured as they sit.

There is no more practical method for sizing new tires than to simply tape measure the old against the (proposed) new rubber. For most calculations, this measurement is accurate enough. However understanding tire-size nomenclature is important, and will help immensely in getting the most tire with the least hassle.

Many types of high-performance specialty-tread truck tires are sized according to height, width, and wheel diameter. A tire listed as a 33/12.50R-15 is a 33-inch-tall radial (R), 12.50 inches wide and built for a 15-inch wheel. If there is no R in the designation, you can assume it is a bias-ply tire. Keep in mind, this 33-inch diameter is a nominal number which could vary by as much as seven percent (in this case, more than two full inches) according to industry standards.

Today, more and more tires built for light trucks and SUVs carry metric designations, which can be very helpful when figuring your tire and wheel upgrade. First, a few terms:

Diameter: The actual height of the tire measured through the center, in inches. Not always marked on the tire.

Section height: The vertical distance between the edge of the wheel rim and the top of the tire tread. Expressed in millimeters, this number is not usually marked on the tire.

Section width: The horizontal distance between the tire’s sidewalls. Expressed in millimeters, this number is usually the first number in a metric designation.

Aspect ratio: The relationship between section height and section width. The higher the aspect ratio number, the skinnier the tire, relative to its height. An aspect ratio of 75 means that section height is 75 percent of section width. A tire with a lower aspect ratio of 60 will have a "lower profile" than a 75, and a fatter look. This is normally the second number listed on a metric-sized tire.

LT : Metric tire designation a light truck tire.

ST : Designation for a trailer tire.

P : Designation for a passenger-car tire.

Looking at a tire marked LT305/85R16, the buyer knows that it is a 16-inch radial tire built for light trucks with an 85-percent aspect ratio and 305 millimeters of section width. To determine the height of the tire, you must calculate its section height in inches, dividing by 25.4, the number of millimeters in an inch (see equivalency chart). Next, convert the aspect ratio to a decimal by dividing by 100. Multiply the quotients of these two numbers to find the section height in inches. Double that figure and add the wheel diameter, and you will have the tire’s height. Using a 305/85R tire as an example, the equation works out as:

2 x section width x aspect ratio x aspect ratio + wheel size
25.4 100


2 x 305 x 85         + 16     = 36.4 inches
25.4         100

Some of the most popular tire sizes, and their approximate metric equivalents, can be found in the chart below.

Flotation Diameter (in.) Metric size
27x8.50R14 26.5 225/75R14
27.5 215/75R15
29x9.50R15 28.5 235/75R15
30x9.50R15 29.5 245/75R15
31x10.50R15 30.5 265/75R15
32x11.50R15 31.5 295/75R15
33x12.50R15 32.5 315/70R15
33x12.50R16 32.8 285/75-16

Offroad Tire Reviews
Read Tire Reviews and Post Your Own Review of Offroad Tires


Offroad Tire Info
P-Metric Tire Sizes Conversion to Inches
Tire Terminology
Wheel Terminology
How to Pick the Right
Tires for your Truck
Truck Tire Info
Tire Sizes Clearance Chart
Tires - What Hits What Fits
All Terrain  Mud Terrain
Tire Reviews & Info
Mud Terrain MT Tire Reviews
All Terrain AT Tire Reviews
Super Swamper Bogger
Super Swamper SSR
Super Swamper SX
Super Swamper Vortrac
Interco IROK TSL
Super Swamper LTB
Super Swamper TSL
Super Swamper TSL Radial
Super Swamper Narrow
Interco SS-M16 Swamper
Thornbird TSl Radial
Thornbird TSl Bias
Thornbird TSL
Parnelli Jone Dirt Grip
BFGoodrich Krawler
BFGoodrich MT T/A KM
BFGoodrich MT T/A KM2
BFGoodrich AT TA KO
BFGoodrich Mud King XT
Bridgestone Dueler MT
Cooper Discoverer ST
Cooper Discoverer STT
Cooper Discoverer ST/C
Federal Couragia MT
Firestone Destination AT
Firestone Destination MT
General Grabber MT
General Grabber AT2
Green Diamond Icelander
Ground Hawg Mud Tire
Hankook Dynapro MT
Hankook Dynamic MT RT01
Hercules Terra Trac MT
Hercules Trail Digger MT
Kelly-Springfield Safari DTR
Kelly-Springfield Safari MSR
Kumho Road Venture MT
Kumho Road Venture KL71
Kumho Road Venture AT
Dick Cepek Mud Country
Dick Cepek F-C II
Dick Cepek Fun Country II
Dick Cepek Fun Country Nylon
Dick Cepek Fun Country Kevlar
Mastercraft Courser MT
Mastercraft Courser HTR
Mastercraft Courser HTR Plus
Maxxis BigHorn Radial
Maxxis Creepy Crawler
Maxxis Trepador
Maxxis Buckshot Mudder
Maxxis MA-SW
Maxxis M-8080 Mudzilla
Maxxis MT-754 Buckshot
Maxxis MT-753 Bravo
Maxxis MA-751 Bravo
Maxxis MA-S2 Marauder II
Maxxis MA-S1 Marauder
Maxxis MT-762 BigHorn
Nitto Mud Grappler
Nitto Trail Grappler MT
Nitto Terra Grappler
Nitto Dura Grappler
Nitto Dune Grappler
Nokian Vatiiva MT
Pit Bull Rocker Extreme
Pit Bull Maddog
Pit Bull Growler
Goodyear Wrangler MT/R
Pro Comp Xterrain
Pro Comp All Terrain
Pro Comp Mud Terrain
Pro Comp Xtreme AT
Pro Comp Xtreme MT
Toyo Open Country AT
Toyo Open Country MT
TrXus Mud Terrain
TrXus STS All Terrain
Michelin LTX A/T²
Michelin LTX AT2 Press
Michelin LTX AT2
Mickey Thompson MTZ
Mickey Thompson MTX
Mickey Thompson Baja Claw Radial
Mickey Thompson Baja Claw Bias
Mickey Thompson Baja Crusher
Mickey Thompson Baja ATZ Radial SLT
Competition Claw
Dunlop Mud Rover
Federal Couragia M/T
Nitto Dura Grappler
Yokohama Geolandar
Dick Cepek's 2008 F-250 Super Duty Project Vehicle – Project CRUSHER
Mud Tire Reviews

FJ Cruiser

Engine Specs
Drivetrain Specs
Photo Gallery
FJ Cruiser Tires
Press Releases & Specs
FJ Cruiser Reviews

Paragon Adventure Park
Rock Krawl

Thousands more
photos here..»


Off-Road Lights
by LightForce Product Review / Installation.
from Off-Road Lights


Black Diamond Suspension Lift instal

 for CJ-7

Ramp Travel Index
RTI / Ramp Travel Index What it is and how to calculate it, with and without the ramp.

Offroaders Guide to Gearing up for Offroad
From Basic Equipment to Well Equipped.  An extensive list guide to help you prepare your vehicle for the offroad.

Do it Yourself
Detriot EZ Locker Install  in a 92 Toyota 8" rear

For all the Jeep
Fans out there!

Department of Cheap Tricks and Useful Tips
Ultra-Cool Hand Throttle for Free!

Jeep V8 Swap Tips

The Exploding Clutch

Radiator Protection using 6 bucks worth of material

Cracked Under Pressure - Fixing a smashed fingernail

A Cheap, effective alternative to undercoating

Home-built Saginaw Gearbox Brace for the cost of lunch!

Ammo Box Storage - Mounting Them for Quick Disconnect

Home-built Serious Skid-Plate protection for the Oil Pan for under 20 bucks!


Building a Garage?
Need a Garage Plan?
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Knoebels Amusement Park