Metric Tire Conversion Calculator

Use this calculator to convert metric tire sizes (ie 265/75R16) to standard tire sizes (ie 31.6x10.40R15) and metric sizes to standard sizes.

Metric to Standard Conversion Enter the tire size below (ex 265/75/16) / R	Standard to Metric Conversion Enter the tire size below (ex 31x10.50/15) x R

Wheel Terminology:

Axle Pad or Hub Flange: The area of a wheel where it contacts a car.

Bolt pattern or lug pattern or bolt circle: These refer to the number of fasteners (lug studs) and diameter of the circle on which they are positioned. (5x4.5” would be “five by four and one-half.”)

Barrel: The outermost part of a wheel. It is the area where a tire is mounted.

Center Cap: The wheel part that covers the center bore of the wheel on the outer face of the wheel.

Center Disc: The portion of a wheel that consists of the axle mounting pad and the spokes.

Drop Center: Is the smallest inside diameter area of the outer barrel of a wheel. It is used to facilitate the installation of a tire onto a wheel. Additionally, it is used as an area for placing a center disc for some 2-piece wheels during the manufacturing process.

Back Space or Rear Space: The distance from the axle pad to the inner edge plane (inboard flange).

Front Space: The distance from the axle pad to the outer edge plane (outboard flange).

Hub Diameter or Center Bore: This is the size of the hole in the center of a wheel.

Offset: The distance +/- from wheel centerline, indicated in millimeters.

Negative Offset: When the axle pad of the wheel is closer to the inner (car underside) edge plane.

Positive Offset: When the axle pad of the wheel is closer to the outer (street side) edge plane.

Zero Offset: A situation when both the back spacing and front spacing are equal. The axle flange is centered between the outer edge plane and inner edge plane.

Wheel Stud or Lug Stud or Axle Bolt: The “BOLT” portion of the wheel-fastening device. It is what the “lug nut” threads onto.

Lug Nut or Wheel Nut: The “NUT” portion of the wheel-fastening device. It treads onto a lug stud.

Tire Mounting Size: The potion of the wheel that reflects what size tire it can accomidate. Not the overall size of the wheel. Usually used when talking about a wheel size. (15x7”, 16x8”, 17x7”, Etc.)

1.Vacuum boosters put out between 700-1,000lbs of pressure. That's the amount of pressure added to your braking capabilities (how much more pressure you can put on the brake pedal compared to manual brakes.). 2.Hydroboosts put out between 2,400-2,700lbs of pressure. This gives you 2-3 times the power of a vacuum booster. This is enough power to stop you in almost any circumstance, including towing. This system will only put out as much pressure as you demand. Step on it easy to come to a slow stop, hard to lock up all 4 tires. The hydroboost can start leaking fluid, but even so you won't lose power. Worse case scenario is you'll need to add fluid to your pump. So where a vacuum booster totally fails the hydroboost will still work even if it starts to leak. The smaller the master cylinder bore the less foot pressure it takes to stop your vehicle, but the more stroke (how far you have to press down) it takes to actually stop it. The bigger the bore the more pressure it takes but the less stroke needed. For example, if you put a 5/8 bore master cylinder on it would feel like power brakes, but you wouldn't have the stroke to actually stop. If you put a 2 inch bore you'd stop in half an inch, but it would be so hard you'd never actually be able to get the vehicle to stop (it would feel like stopping a tank with your feet). 1.Most Jeeps take a master cylinder that is 15/16-1 inch bore. This is fine with stock brakes and tires. But when you put on bigger axles/brakes or tires it's just too small. So we put a 1 &1/8th master cylinder to give you the fluid pressure you need. The end result with this master and the hydroboost is you stop in 1 inch travel. The hydroboost puts out so much power even with this master cylinder you stop on a dime. 2.If you used a vacuum booster with the 1 inch bore your brakes can almost reach the floor before stopping if you have updated your axles or brakes to a bigger system. 1.To get the 1,000-1,100 level of vacuum boosters you need to use duel-diaphragm units. The sizes of these units are 9 and 1-inch diameter. Thats' a lot of space to use in your typical cramped engine compartment. It's impossible to use if you added a blower or have a hydraulic clutch. If you went with a bigger cam and still had room you'd still have a vacuum problem. Bigger cams use more vacuum that directly takes away from the vacuum booster. 2.The hydroboost measures 4.5 inches in diameter. That's the same size of your master cylinder. Obviously all vehicles have a master so it fits in any vehicle. The total length is 14.5 inches so it's comparable to vacuum booster's length. It works off your power steering unit, so bigger cams don't affect this whatsoever. Stock power steering units put out 1,100lbs of pressure. When you add this hydroboost you need a pump that puts out 1,500lbs to be able to use both the steering and the brake unit. This is an upgrade many people have already done to get better steering. When you add the pump you're actually increasing both your brakes and your steering, it's a dual upgrade. The pumps we use are the exact same pumps that came on your vehicle. There's no bracket or pulley change to do. The upgrade is inside the pump so you won't see a difference, but you'll sure feel it. The kits come complete. There's no drilling or cutting involved. We sell the kits both with the pump and without the pump if you already have a pump that meets the standards. Typical installation time is 2 hours from start to finish, adding whatever time it takes to replace the pump. All you'll need to supply is fluids and in some cases you may need to reflare a line. This system works with any vehicle out there, not just Off-Road. We have made custom built kits for many different vehicles. These include, 57 Buick, 63 Corvette, 72 Chevelle, many Ford trucks and cars, the list is huge. With the power and size of this system it solves many problems. We build the booster and master cylinder to your car specs. We include fittings to convert your gearbox, power steering pump and Hydroboost to 3/8ths male flare. This is the fitting all hose makers use to make custom hoses. We do this because where our system will fit and work perfectly on your vehicle, we can't supply the different hoses each vehicle would need like we do with our Jeep® kits. Hoses typically cost $25.00-35.00 each to have made. As with the Jeeps® and some other vehicles we can also supply you the steering pump.

When choosing a Rod End for a Specific Application, consider the following information. Most rod ends or heim joints are engineered for the ultimate in strength. When deciding which rod end or heim joint is best for your application look at the load ratings so that you don't under spend or over spend for your need. ECT Offroad carries all the Rod Ends that your project may need. From race rod ends to simple linkage rod ends, there is a rod end that will fit your application best for strength and longevity.

Radial Load - A load applied normal to the bearing bore axis and parallel to the shank axis. Axial Load - A load applied along the bearing bore axis. Static Radial  Limit  Load That static load required to produce a specific permanent set in the bearing structure. It will vary for a given size as a function of configuration. It may also be PIN limited as a function of body restraints as in the case of rod ends bearings. Static Radial Ultimate Load That load that can be applied to a bearing without fracturing the ball, race, or rod end eye. The ultimate load rating is usually, but not always 1.5 times the limit load. Static  Axial   Limit  Load That load that can be applied to a bearing to produce a specified permanent set in the bearing structure. Static  Axial  Ultimate  Load That load that can be applied to a bearing without separating the ball from the race. The ultimate load rating is usually, but not always 1.5 times the limit load. ANGLE OF MISALIGNMENT

We have had many customers ask what shocks are best when it comes to there project vehicle, trail rig or the simple daily driver. We have broken down the shocks into a few basic categories followed with a brief description of the need to know information, when choosing the shocks that is right for you. 

 Things to remember when choosing a certain type of shock for your application.

• Each type of shock absorber serves a specific purpose.

• When selecting the shock that provides the features and functionality most important to you.

• The cost of a shock generally coensides with its level of performance. (You get what you pay for when it comes to shocks)

• Consider the over all weight of the vehicle

• What type of terrain will the vehcile travel most

• Will there be ample space to mount the shocks on your vehicle

SHOCK TYPE:

Non-coil shocks: Higher performance shocks allow the ability to customize suspension dampening to suit  street, race, and  recreation applications. Non-coil shocks are available for several types of high performance automotive applications that are suitable for universal-fit shock absorbers.

Coil-over shocks: feature a threaded body and dual-stage spring mounting hardware. When optional coil springs are installed, you can adjust vehicle ride height, suspension preload and travel.

OE replacement shocks: provide the quality and performance of a professional racing shock in a convenient factory-fit, bolt-on design. Perfect for upgrading aftermarket lift kits or factory shocks.

Bypass shocks: offer the highest level of damping customization for the most demanding off-road racing conditions. Damping performance can be externally adjusted in a matter of seconds for immediate results.

Air shocks: are an economical coil-over alternative that not only dampens, but also suspends your lightweight off-road vehicle without the need for additional springs.

Hydraulic bump stops: are compact, secondary shocks that soften harsh suspension impacts caused by bottoming out.

RESERVOIR:

The style of reservoir should  be determined by the terrain and driving conditions that the vehicle will encounter. For optimal performance reservoir shocks  contain the highest volume of oil, external reservoir shocks dissipate heat more efficiently than internal reservoir shocks. This prevents overheating and ensures consistent performance when driving for extended periods in harsh terrain.

Emulsion: shocks utilize a combination of oil and Nitrogen gas contained within the shock body. They are more economical than external reservoir shocks due to the simplicity of design. Emulsion shocks are ideal for light-duty or street applications, although not recommended for high speed driving in off-road conditions. They should be mounted as close to vertical as possible.

Internal floating piston: shocks are identical to emulsion shocks with one exception. A floating piston located within the shock body keeps the oil and Nitrogen gas separated. This allows the shock to be mounted at an angle, and to perform more efficiently than emulsion shocks.

Piggy back: shocks feature a fixed external reservoir for increased oil volume. An internal floating piston separates the oil from the Nitrogen gas, allowing the shock to be mounted at any angle with no detrimental effect on performance. Piggy back shocks are well suited for both street applications and off-road use.

Remote reservoir: shocks benefit from a large external reservoir that offers the greatest oil volume. The fluids are separated by a floating piston which allows the shock to be mounted at any angle. Oil flows freely between the shock body and reservoir through a flexible high pressure hose, providing excellent heat dissipation.

Remote reservoir and piggy back shocks are the best choice for off-road vehicles that are frequently exposed to sustained high-speed driving in harsh conditions.

PISTON ROD:

The piston rod diameter should be matched to the desired duty rating. A larger diameter rod will provide greater resistance to compression forces, although cost and weight will also increase. 5/8" Diameter rods are the standard size for most 2.0" shocks, and recommended for light-duty and street applications. 7/8" Diameter rods are optional for most 2.0" shocks and standard for all 2.5" designs excluding air shocks. The 7/8" rod is best suited for street and medium-duty off-road applications. 1" Diameter rods are standard on all 3.0" and 3.75" shocks, and ideal for heavy-duty off-road applications and extreme terrain. 1-1/4" Diameter rods are only available on 2.0" air shocks and hydraulic bump stops. 1-5/8" Diameter rods are only available on 2.5" air shocks.