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MOJAVE; Turns out I do not need to adjust/recalibrate speedometer running 37s.

jeepit

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Mojave running 37s with -12 offset wheel, no lift, full turns are perfectly clear.
also turns out I do not need to adjust/recalibrate speedometer jumping from 32s to 37s.
Comparison I made was with waze and other speedo apps before and after and it is still accurate without any adjustment.
Looking at 2" AEV spacer lift but it seems 1" all-around would be good enough for my level of off-roading if available.
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AzRob

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I went from 33's to 35's and was like 5-6 mph off..... I agree with above....Its just not possible.
 

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Mojave running 37s with -12 offset wheel, no lift, full turns are perfectly clear.
also turns out I do not need to adjust/recalibrate speedometer jumping from 32s to 37s.
Comparison I made was with waze and other speedo apps before and after and it is still accurate without any adjustment.
Looking at 2" AEV spacer lift but it seems 1" all-around would be good enough for my level of off-roading if available.

View attachment 111973

View attachment 111981
Can't happen. Larger tires mean fewer rotations per mile, meaning the speedometer will read low and slow compared to smaller tires spinning faster for the same ground speed.

The ONLY way it would be possible is if Jeep is using GPS to give you ground speed- and they ditched the VSS type reading.
 

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ShadowsPapa

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Was your phone plugged into the usb on the dash when taking your measurements? If so, it will read the Jeep’s speedometer rather than actual gps speed.
How can that be since the GPS of the phone is what it displayed. My phone doesn't display anything from the Jeep but the Jeep can access my phone.

An app on the phone reads the phone's GPS. Can prove that by turning off the location services, etc. - and it will stop working on the phone.
 

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How can that be since the GPS of the phone is what it displayed. My phone doesn't display anything from the Jeep but the Jeep can access my phone.

An app on the phone reads the phone's GPS. Can prove that by turning off the location services, etc. - and it will stop working on the phone.
My phone’s speed app would vary depending on if it was plugged in or not until I reprogrammed my Jeep for the current tire size. Before reprogramming for tire size, I could hold a steady speed with it plugged in and it would read the same as my speedometer. As soon as I unplugged it it would increase by about 10%. Maybe it depends on the app which is used?
 

ShadowsPapa

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My phone’s speed app would vary depending on if it was plugged in or not until I reprogrammed my Jeep for the current tire size. Maybe it depends on the app which is used?
It must - android wants to read from the phone's location services/GPS - if you turn that off, none of the apps I have will work.

In any case - as long as the speedometer is reading either wheel sensors for speed, or a VSS type device like they used to - you must recalibrate for tire size differences. No way around it.
Even my dealer told me that - well the dealer's accessories guy did.
Words along the lines of - 'Change tires - recalibrate, we can do it or we'll sell you a device for you to do it'
 

TrainMan

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I agree that's impossible. I highly recommend this app. Super accurate and fast to respond. I was off by about 7mph at like 50mph.
Jeep Gladiator MOJAVE; Turns out I do not need to adjust/recalibrate speedometer running 37s. Screenshot_20201024-011819_Google Play Store


Jeep Gladiator MOJAVE; Turns out I do not need to adjust/recalibrate speedometer running 37s. Screenshot_20201024-011844_Google Play Store
 

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It must - android wants to read from the phone's location services/GPS - if you turn that off, none of the apps I have will work.

In any case - as long as the speedometer is reading either wheel sensors for speed, or a VSS type device like they used to - you must recalibrate for tire size differences. No way around it.
Even my dealer told me that - well the dealer's accessories guy did.
Words along the lines of - 'Change tires - recalibrate, we can do it or we'll sell you a device for you to do it'
My iPhone stays plugged into the USB and I use WAZE all the time with my business driving. I can say without a doubt that it does not go by the Jeep speedometer. The Jeep's speedo is calibrated to read a little slower than the GPS. It's about 1 mph difference at 60, and the difference increases with speed.
 

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Well in any event, if your GPS is correct or not, some bit of information is missing here.

It's not possible.

Either it was wrong before, or there is a wrong reading now, or it was reprogrammed and you are unaware, or your phone is wrong, or the computer somehow sensed it and changed itself.

Or something else.

This is massive change. There is simply no way that it is "close enough" that reprogramming isn't required.
 

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My iPhone stays plugged into the USB and I use WAZE all the time with my business driving. I can say without a doubt that it does not go by the Jeep speedometer. The Jeep's speedo is calibrated to read a little slower than the GPS. It's about 1 mph difference at 60, and the difference increases with speed.
WAZE is a lot more complex than what I use for speed, which is this app, on an iPhone. This one varies.

Jeep Gladiator MOJAVE; Turns out I do not need to adjust/recalibrate speedometer running 37s. 74F56361-EFE0-465C-921A-8F6E90D39067
 

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Jeep looks great! My identical 37s arrived yesterday for my Mojave. Still a few more weeks until my wheels are built. I'm tempted to just install them on the stock wheels for now.
 
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jeepit

jeepit

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thanks ya’all
will be trying some of these suggestions today ya’all
will keep ya’all posted
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