Gear ratios

[Windjammer]

I am curious about the effect of say 4:10 or 3:73 or 3:55 gears have on the KPH reading of a standard uncorrected speedo How much can the difference be between what it shows and what the gps shows?

[ZR]

Higher the gear ratio (from ratio speedo was calculated with) the higher your RPM. Best way to confirm how far off is via your gps. Depending on yr of Mustang, corrected via speedo gear change or electric speedos via SpeedCal or Tuner / chip.

[Windjammer]

About 10 to 12 KPH high vs GPS. Trying to figure if it has gears and what they might be if so. Seems to be it is similar to difference on my 93 that had 3:73 This car is 2002 GT

Higher the gear ratio (from ratio speedo was calculated with) the higher your RPM. Best way to confirm how far off is via your gps. Depending on yr of Mustang, corrected via speedo gear change or electric speedos via SpeedCal or Tuner / chip.

[ZR]

Not difficult to count if it's on a hoist.

[ZR]

Look here.

http://www.how-to-build-hotrods.com/gear-ratio.html

[Windjammer]

Ah good to know that. next time on a hoist I can do that

[tulowd]

don't forget that the tires real world circumference (actually the spec is revolutions per mile) also affects the speedo, especially if you are running non stock tires and or wheels.

[juvehab]

speaking of gear ratios what gear is recommended for an automatic i was considering 3.55 or 3.73?

[ZR]

What yr you working on?

[NickD]

4.88 or bust

Sent from my Nexus 6P using Tapatalk

[juvehab]

What yr you working on?

92 automatic with a shift kit. my gears now are 3.08's

[ZR]

Great combo of city / hwy fun = 373.
Max effort with ok hwy manners = 410