Metric / Inch Tire Size Converter

Enter your tire size information into one side of the tire size converter below to convert metric tire sizes to inches or inch tire sizes to their metric equivalents.

Metric Tire Size

 /   R 
(Example: 315 / 75 R 16)

Inch Tire Size

 x   - 
(Example: 35 x 12.50 - 16)

( Full Calculator: Metric To Inch Tire Size Converter )


Ring and Pinion Gear Finder

Enter your original tire size and gear ratio into the form below along with your new tire size to find your recommended ring and pinion gear ratio.

OEM Tire Diameter:

OEM Gear Ratio:

New Tire Diameter:

New Gear Ratio:

( Full Calculator: Ring and Pinon Gear Set Calculator )


Gear Ratio Calculator

Enter the number of teeth found on your ring gear as well as your pinion gear in the boxes below to calculate their combined ring and pinion gear ratio.

Ring Gear Teeth:

Pinion Gear Teeth:

Gear Ratio:

( Full Calculator: Ring and Pinon Gear Ratio Calculator )


Crawl Ratio Calculator

Enter your transmission, transfer case, and axle gear ratios into the left side of the form below and press the calculate button to find your final crawl ratio.

Transmission Ratio:

 : 1

Transfer Case Ratio:

 : 1

Axle Gear Ratio:

 : 1

Final Crawl Ratio:
 : 1

( Full Calculator: Drivetrain Crawl Ratio Calculator )


MPH Offset / Corrected MPH

Enter your original and new tire sizes into the table below and select a base speed to calculate your speedometer's offset and your vehicles actual speed.

New Tire Diameter:

OEM Tire Diameter:

Speedometer (MPH):

Actual Speed:


Speed Offset:


( Full Calculator: Vehicle Speed Offset Calculator )


Engine RPM Calculator

Enter your axle gear ratio, tire diameter, vehicle speed, and transmission gear ratio in the blue fields and click the calculate button to find your engine RPM.

Axle Gear Ratio:

 : 1

Tire Diameter:


Vehicle Speed:


Transmission Ratio:

 : 1


Engine Speed:


( Full Calculator: Engine RPM Calculator )

Choosing our company as your transportation partner you invest into success of your business. Our reliable service and competitive rates are called to deliver you unmatched customer experience. Just provide us with the information about your cargo, pickup and delivery details, time frame, and budget, - and our specialist will find you a solution with the best performance/price ratio.

services overview


Our first choice is to do the service at your location.  This is the most convenient and preferred way for most of our customers.  Because this opotion is the most popular we strive to make it also the most effective.


You always get the VIP Service you deserve at Premier West Gears!


We strive to make our services affordable for everybody.  For your conveneince we also accept all major credit cards.


Whether you are relaxing at your place or enjoying our lobby, it's always convenient to get service at Premier West Gears.

our services

Welcome to West Coast Differentials. We are here to help you with your Differential / Gear Needs. If you aren't sure about what we can do, just contact us.