Speed calculation

[Ramcharger90]

I'm no Marthamatition..... but im just curious how fast in theory I would be going in 5th gear at 5 thousand rpm.

Tire size 215/75R15
M5ODR2
3.73 lsd

Any smartly pants out there wanna chime in.

 

[Dirtman]

139.8 mph

Spicer Transmission Ratio RPM Calculator

Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.

spicerparts.com

 

[Uncle Gump]

I think what dirtman said is... too fast!!

 

[Dirtman]

27.7 inch tire
3.73 final gear ratio
0.79 overdrive 5th gear
5,000 rpm
139.8 mph.

No ranger could actually do this... but that's what the math says.

2,500 rpm (an actual cruising rpm would be 69mph)

 

[Ramcharger90]

No ranger could actually do this...

Lol maybe....

https://imgur.com/a/VeMH2yo

my speedometer only goes to 85mph so I guess we will never know.....

Makes weird wind noises though....

And the needle allegedly was resting against the post. In Mexico of course.

 

[Dirtman]

I believe there is still a speed limiter on the 90' (I think it cuts off at 100mph). But the driveline itself simply isnt rated for those speeds. If you actually got it to 140 it would start breaking apart in a pretty spectacular fashion. And without Z rated tires they would also be at risk of blowing apart.

 

[G8orFord]

I'm pretty close to what @Dirtman comes up with. I wrote this spreadsheet more for tire size calcs and rear end ratios than for figuring RPM or speed, but it working it backwards comes out to this.

 

[Snoranger]

‘90 supercab 4.0l. On my way to Carlisle, I was bouncing off the speed limiter for about 2 hours. (IIRC the speed limiter was 90-92 mph. @Dirtman )All of the sudden I just stopped hitting the speed limiter and was free to go as fast as I wanted... The speed limiter never worked again!

 

[pjtoledo]

get it up to 2500 rpms in 5th. look at the speed-o-meter. double what it indicates.