Speedometer reading fast 10+mph

MTB-BRUH

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Drove to work today and thought wow I’m flying down the road. Sure enough I came to a stop and my speedometer says I’m going about 11 mph. The digital speedometer is accurate at least. I didn’t know these used a speedometer cable. I’m assuming it jumped a tooth or something

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MTB-BRUH

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Update.. left work today and now it’s fine. What the heck!?! lol dealer is gonna look at it Friday just in case
 

P. A. Schilke

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Update.. left work today and now it’s fine. What the heck!?! lol dealer is gonna look at it Friday just in case
Hi Tyler,

We got rid of cables way back in 1985. We at the time a speed sensor that had a driven gear on it in the side of the tranmission that fed a signal to the speedo on the dash. Called a VSS.

Back Story,

Speedo errors were common on prototypes when the speedo was cable driven. Gears did not match the axle etc...they were so unreliable....Remember when you saw the fifth wheels on picutres of test vehicles....all the 5th wheels did was provide exact speed. We used to get a protortype with a cheater card taped to the dash... a list of indicated speeds relative to the actual speed...except it was unknow if the axle had been changed for example. The solution at the time was a measured mile at the test track. We drove the low speed track at an indicated 60 mph and hacked our stop watch and drove the mile and rehacked....If 1 minute...speedo correct, if not we back calculated what speedo gear we needed and delved in to the box of colored coded speedo gears for the closest one to correct. I recall the lowest gear teeth was 5 and the highest was 21 for the driven gear. Drive gears in the trans were 6, 7, or 8...and we had no clue how to determine what the prototype build transmission folks put in to the transmission. Vehicle speeds in that day were quite a PITA. Things are much better these days. And when is the last time you saw a 5th wheel.

fifth_wheel.jpg


Here is a couple pix of my Ford Issued Swiss stop watch which is now a antique and quite amazingly valuable... It got a lot of use....

minerva.jpg


minerva1.jpg


So how does this make me feel as this stop watch is an antique... I am also an antique???

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
 
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Toytec

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There's a thread on here on how to put your cluster into diagnostic mode. Something about press and hold the ok button 5sec.
 


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You can use a gps and some of the map apps will give you your MPH while driving. I dont know how scientifically accurate they are but it will be close enough for most people. Back in the day Dodge police cars had certified on their speedos. That ment that those speedos were better than the average. It used to be if you got a speeding ticket and went to a certified speedo repair facility, got a paper that your speedo was off then the Judge would let you slide. I dont think that works anymore. No speedo can be perfect as the tires get larger the faster you go. Many, many other variables.
 

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By federal law, a speedometer can read up to 10% faster than actual speed but can not read anything less than actual speed.

Motorcycle manufacturers are notorious for setting motorcycle speedometers anywhere from 8% to 10% faster than actual speed. And it doesn't matter which manufacturer either.

I haven't delved into all the settings yet but normally you need a tuner of FORSCAN to adjust the speedometer.
 

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Hi Tyler,

We got rid of cables way back in 1985. We at the time a speed sensor that had a driven gear on it in the side of the tranmission that fed a signal to the speedo on the dash. Called a VSS.

Back Story,

Speedo errors were common on prototypes when the speedo was cable driven. Gears did not match the axle etc...they were so unreliable....Remember when you saw the fifth wheels on picutres of test vehicles....all the 5th wheels did was provide exact speed. We used to get a protortype with a cheater card taped to the dash... a list of indicated speeds relative to the actual speed...except it was unknow if the axle had been changed for example. The solution at the time was a measured mile at the test track. We drove the low speed track at an indicated 60 mph and hacked our stop watch and drove the mile and rehacked....If 1 minute...speedo correct, if not we back calculated what speedo gear we needed and delved in to the box of colored coded speedo gears for the closest one to correct. I recall the lowest gear teeth was 5 and the highest was 21 for the driven gear. Drive gears in the trans were 6, 7, or 8...and we had no clue how to determine what the prototype build transmission folks put in to the transmission. Vehicle speeds in that day were quite a PITA. Things are much better these days. And when is the last time you saw a 5th wheel.

fifth_wheel.jpg


Here is a couple pix of my Ford Issued Swiss stop watch which is now a antique and quite amazingly valuable... It got a lot of use....

minerva.jpg


minerva1.jpg


So how does this make me feel as this stop watch is an antique... I am also an antique???

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
I am a watch wh**e, I would love to have one of those stopwatches. I have about 25 nice watches right now. ?
 

WOADKIL

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Hi Tyler,

We got rid of cables way back in 1985. We at the time a speed sensor that had a driven gear on it in the side of the tranmission that fed a signal to the speedo on the dash. Called a VSS.

Back Story,

Speedo errors were common on prototypes when the speedo was cable driven. Gears did not match the axle etc...they were so unreliable....Remember when you saw the fifth wheels on picutres of test vehicles....all the 5th wheels did was provide exact speed. We used to get a protortype with a cheater card taped to the dash... a list of indicated speeds relative to the actual speed...except it was unknow if the axle had been changed for example. The solution at the time was a measured mile at the test track. We drove the low speed track at an indicated 60 mph and hacked our stop watch and drove the mile and rehacked....If 1 minute...speedo correct, if not we back calculated what speedo gear we needed and delved in to the box of colored coded speedo gears for the closest one to correct. I recall the lowest gear teeth was 5 and the highest was 21 for the driven gear. Drive gears in the trans were 6, 7, or 8...and we had no clue how to determine what the prototype build transmission folks put in to the transmission. Vehicle speeds in that day were quite a PITA. Things are much better these days. And when is the last time you saw a 5th wheel.

fifth_wheel.jpg


Here is a couple pix of my Ford Issued Swiss stop watch which is now a antique and quite amazingly valuable... It got a lot of use....

minerva.jpg


minerva1.jpg


So how does this make me feel as this stop watch is an antique... I am also an antique???

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired
Phil, better be a calibration sticker on the back of your chrono device!

I remember switching the plastic speedo gears on the tranny tail stock!

Enjoy!
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