RPM vs.MPH Graph?
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Professor Fate
Topic author - Posts: 755
- Joined: Tue Jan 08, 2019 12:39 am
- First Name: Dan
- Last Name: S
- * REQUIRED* Type and Year of Model Ts owned: '23 and '26
- Location: Taxachusetts
- Board Member Since: 2015
RPM vs.MPH Graph?
Does anyone have a graph depicting rpm vs. mph? Is 50 mph 2000 rpm in high gear? (TT truck, ruckstel, and warford excluded. Stone stock car only)
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**FATE**
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**FATE**
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Mark Nunn
- Posts: 1241
- Joined: Mon Jan 07, 2019 8:01 am
- First Name: Mark
- Last Name: Nunn
- * REQUIRED* Type and Year of Model Ts owned: 1926 Runabout
- Location: Bennington, NE
- Board Member Since: 2017
Re: RPM vs.MPH Graph?
You have not provided enough information. Is this for your speedster? What is:
Tire rolling radius?
rear axle gear ratio?
Aux trans?
My runabout with my tires, 40/11 ring and pinion would turn 2054 rpm at 50 mph. But, it will only see that speed on a trailer.
Tire rolling radius?
rear axle gear ratio?
Aux trans?
My runabout with my tires, 40/11 ring and pinion would turn 2054 rpm at 50 mph. But, it will only see that speed on a trailer.
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TXGOAT2
- Posts: 7391
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: RPM vs.MPH Graph?
2000 RPM will give about 50 MPH in high gear with standard gearing. Actual tire diameter will affect actual speed.
200 RPM = about 5 MPH, 1000 RPM = about 25 MPH, etc
My car shows about 48 MPH @ 2000 RPM according to a Garmin device. The error may be due to an inaccurate tach or tire size or the Garmin device or even the set up of the ring & pinion or tire slippage.
FWIW, the Garmin device appears to be fairly accurate as to speed and location. It is not consistent with elevation readings.
I have 4.40/4.50 X 21 tires running at 24 PSI cold. Tread is well-worn on rear tires.
200 RPM = about 5 MPH, 1000 RPM = about 25 MPH, etc
My car shows about 48 MPH @ 2000 RPM according to a Garmin device. The error may be due to an inaccurate tach or tire size or the Garmin device or even the set up of the ring & pinion or tire slippage.
FWIW, the Garmin device appears to be fairly accurate as to speed and location. It is not consistent with elevation readings.
I have 4.40/4.50 X 21 tires running at 24 PSI cold. Tread is well-worn on rear tires.
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Craig Leach
- Posts: 1906
- Joined: Tue Jan 08, 2019 12:22 am
- First Name: craig
- Last Name: leach
- * REQUIRED* Type and Year of Model Ts owned: 1919 Firetruck/1922 Speedster
- Location: Laveen Az
Re: RPM vs.MPH Graph?
I found this on the Forum.
Craig.
- RPM vs Speed.jpg (53.73 KiB) Viewed 1255 times
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Norman Kling
- Posts: 4634
- Joined: Tue Jan 08, 2019 1:39 pm
- First Name: Norman
- Last Name: Kling
- Location: Alpine California
Re: RPM vs.MPH Graph?
I don't think they are directly related. MPG will also be affected by the grade uphill, downhill, level. And it will be affected by the wind speed and direction. Also the weight of the vehicle and load. And will be affected by the condition of the engine. Too many variables.
Norm
Norm