Tachometer App

Ford1931

Senior Member
I found a $.99 cent app for a tachometer that works pretty good. It is called "Remote Tach". It has a speedometer also. You put in the tire diameter, rear end ratio and the final drive. The final drive would be one without overdrive. 26 percent overdrive would be .74. It works off the car's speed and is not accurate in first and second gear. It is very handy to check what rpm the engine is turning at different highway speeds. I am going to buy a suction cup phone holder for the windshield. I have checked it against other vehicles with a tachometer and it is right on.
 
I bought it and it works fine. Gives elevation, gps coordinates, speed, mph, rpm, & compass. Fill in the setting page. My wheel diameter is 28.8 inches. Put 1 in the axle field and your rear end ratio in trans field. Mine is 3.78. If I want rpm iwith my 26% OD I put 3.0 in trans field.
 
I would measure from the road to the center of the hubcap, then double that for the "true rolling diameter". It'll be a little more accurate to find the true RPM.
 
Tom, you are correct. That is important for accuracy. I just did not want to use my fat finger on my iPhone to type all that. I would also have my tires inflated properly.
 
As noted in a related post...

In Ryan's "'I've had enough" post, many responders balked at the notion of using real names on this forum, citing privacy concerns.

Users should be aware that most apps - especially the free ones - are mining your device for data, sending info back to the developer and who knows who else. The flashlight apps are notorious for this.

Not saying this app does or doesn't, just be aware.
 
I found an online calculator

http://www.crawlpedia.com/rpm_gear_calculator.htm

With my 4:11 rear end and 29.25 tire size and 40 mph I get about 1890 rpm....that seems excessive!

At 50 it gives me 2361 rpm....but this is using the speedo...I need to try it using a GPS...

And as a bonus when measuring the wheels as Tom suggested, from the floor to the hub cap center, I learned that I have a complete matching set of five "Bool" hub caps..:eek:
 

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