Welcome to OnlineConversion.com

Convert just about anything to anything else.


If you have, or plan to, increase or decrease your car's tire size, you may want to check out these conversions.

These calculators brought to you by Mark Medina of 4Lo.com

Ever wonder how far off your speedometer is with your new bigger tires? I'm using a simple ratio calculation, so this info will only approximate your corrected speed and depends on the accuracy of tire size diameters (assumimg nothing but tire size has changed).

  Speedo converter 
Original Tire Diameter:  
New Tire Diameter:  
Speedometer Reading (MPH):  Corrected Speed (MPH): 

Now that you have your truck lifted, you want bigger meats. They look cool and have the potential of being very functional, but they may also be robbing you of power/gas mileage. This calculator will get you back to a ratio that's closer to your original. Enter the values on the left and press Compute.

  Find new Gear Ratio with new tire size 
New Tire Diameter:  
Old Tire Diameter:  
Current Gear Ratio:  New Gear Ratio: 

Ever wonder what your low-low-low gear ratio is, your "crawl ratio"? You'll need to do a little research by finding out the transfer case and transmission ratios first. Enter your values on the left side, press Compute and your answer will be on the right.

  Find Overall Crawl Ratio 
Transmis Ratio: TransCase Ratio: Axle Ratio:  Overall Ratio: 

I've spend a bunch of time trying to WAG (wild ass guess) my actual MPH when going down the road. By knowing your gear ratios and tire size you'll get a more accurate idea here. Enter the value on the left, press Compute.

  Find MPH 
RPM:  Tire Diameter:  
Axle Ratio: Transmis Ratio: TransCas Ratio: 

I suppose if you don't have a tachometer you could use this form, otherwise it's only useful to find out how accurate your Tach is. Enter the values on the left, press Compute.

  Find RPM 
MPH: Axle Ratio: Transmis Ratio: TransCas Ratio:  
Tire Diameter:  

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