Math Question

[vynn23]

Okay, my Dart originally had a 2.92 axle ratio. I've since swapped to 3.23's, but haven't changed the speedo gear yet. I believe that this means my speedo and odometer are approximately 10% off.

My question is this: When calculating MPG's, would I add 10% to the result to correct, or subtract 10% from the result? My tiny brain can't figure it out...

 

[Murray]

Why don't you just replace the gear with the correct one?

 

[vynn23]

I eventually will. Just haven't done so yet.

 

[68BarracudaTT]

Your odometer will think you are going farther than you actually are, so take 90% of your odometer reading when calculating MPG.

 

[vynn23]

Thanks!

 

[CudaFactHackJob]

Check your odometer against mile markers.

 

[66fs]

Check your odometer against mile markers.

over a distance of 10 to 100 miles

 

[forphorty]

If you have taller tires on the back than the the car was originally equipped with, your current speedo gear might not be too far off. Calculate GEAR, RPM, MPH, TIRE DIAMETER

 

[Vertex_Jeff]

I have one of these in my Barracuda. Cheap, accurate, and plugs into cigarette lighter.
Amazon product ASIN B07FNHGRZ9
Well- i was trying to post a hyper link to a $37 digital GPS speedometer that is small and can sit on your dash. plugs into your cig lighter. Cant figure out how to pist the link.

 

[33IMP]

I have one of these in my Barracuda. Cheap, accurate, and plugs into cigarette lighter.
Amazon product ASIN B07FNHGRZ9
Well- i was trying to post a hyper link to a $37 digital GPS speedometer that is small and can sit on your dash. plugs into your cig lighter. Cant figure out how to pist the link.

I just clicked on the picture and it came up. THANKS! I need one for my 62. That'll be perfect, I'll wire it direct with a switch (no lighter socket, lol)