Gear ratio vs axle ratio

[jnabird333]

What am I missing?

Willing to learn....

:beer:

You are missing that the tire doesn't go down the road unloaded. It goes down the road with a load and "squish" that lowers the effective diameter. This is why the loaded diameter is needed for an accurate speed.

 

[wayoflife]

You are missing that the tire doesn't go down the road unloaded. It goes down the road with a load and "squish" that lowers the effective diameter. This is why the loaded diameter is needed for an accurate speed.

This ^^^ :yup:

 

[BlackHawk08jk]

You are missing that the tire doesn't go down the road unloaded. It goes down the road with a load and "squish" that lowers the effective diameter. This is why the loaded diameter is needed for an accurate speed.

I agree if you take it off and measure and put that in the computer it will think the tire is bigger than what it is it only cares how it is goin down the road.

 

[OverlanderJK]

My thinking is this, if you took your tire off with no load and measured it, you would get the same reading regardless if you measured from top or bottom. No change in diameter from load. Round is round. Once you put a load on the tire (bulge) you will get a different reading from the bottom as you would the top ( no bulge ) think of a ball that is round then you add pressure and it's no longer round, correct?

What am I missing?

Willing to learn....

:beer:

I understand but when you drive your jeep there is weight on it. Unless you are in the movie back to the future and have a flying car, measure the way you described is wrong.

 

[AncientTrail]

I understand but when you drive your jeep there is weight on it. Unless you are in the movie back to the future and have a flying car, measure the way you described is wrong.

Thanks guys! I'll recalibrate using the correct way.

There was a time back in the day when I thought I had a flying car but thank god I gave that stuff up...

:beer:

 

[trailless]

My thinking is this, if you took your tire off with no load and measured it, you would get the same reading regardless if you measured from top or bottom. No change in diameter from load. Round is round. Once you put a load on the tire (bulge) you will get a different reading from the bottom as you would the top ( no bulge ) think of a ball that is round then you add pressure and it's no longer round, correct?

What am I missing?

Willing to learn....

:beer:

I'm with you on this thinking. If you measure from the tire from the ground to the axle wouldn't that measurement be different from the measurement from the top of the tire to the axle? The load of the Jeep squishes only the bottom of part of the tire. A good image is a tire that's aired down to 10psi. Only the bottom half of the tire is "squished" by the weight.

What am I missing?

Sent from my SCH-I545 using WAYALIFE mobile app

 

[noroad]

I'm with you on this thinking. If you measure from the tire from the ground to the axle wouldn't that measurement be different from the measurement from the top of the tire to the axle? The load of the Jeep squishes only the bottom of part of the tire. A good image is a tire that's aired down to 10psi. Only the bottom half of the tire is "squished" by the weight.

What am I missing?

Sent from my SCH-I545 using WAYALIFE mobile app

gravity :cheesy:

 

[silversurfer575]

gravity :cheesy:

:cheesy::cheesy::cheesy::cheesy::cheesy::cheesy::cheesy::cheesy:

 

[AncientTrail]

wrong as said above measure with a good tape measure and a level on top of the wheel to get an accurate reading.....and check the tire pressures before (get your mean pressure!!!)

Because I have a Pro Cal, I just now called AEV and they said measure from the floor to the top of the tire using a level on top of the tire. Maybe because of their programmer this is their method of measurement?

Anyway, that's the way I'll go and thanks to all who chimed in :beer:

 

[wayoflife]

Because I have a Pro Cal, I just now called AEV and they said measure from the floor to the top of the tire using a level on top of the tire. Maybe because of their programmer this is their method of measurement?

Anyway, that's the way I'll go and thanks to all who chimed in :beer:

LOL!! So, do it like they say to do it and I guarantee you that you will get a measurement that is TALLER than you need. 7-8 years ago, I used to recommend that same method until I found that it was wrong. But, you don't have to take my word for it. Input that number anyway and check your speedometer against a radar speed trap or GPS or have a friend with a stock Jeep pace you and verify how fast you are really going. Then, measure your tire like I've stated and do the test again. Believe whoever you want but facts won't lie.

 

[cozdude]

Because I have a Pro Cal, I just now called AEV and they said measure from the floor to the top of the tire using a level on top of the tire. Maybe because of their programmer this is their method of measurement?

Anyway, that's the way I'll go and thanks to all who chimed in :beer:

once again they are wrong. that is not the correct way to measure. measure from the ground to the center of the wheel then multiply x2.

when the procal says to subtract 24 from that number its just for the programmers sake and how they have the nimbers plugged into it.

 

[wayoflife]

...when the procal says to subtract 24 from that number its just for the programmers sake and how they have the nimbers plugged into it.

This ^^^. The -24 is only for their programmer to work, nothing else. If the instructions that manufacturers provided were sacred, I wouldn't have gotten to where I am today.

 

[OverlanderJK]

once again they are wrong. that is not the correct way to measure. measure from the ground to the center of the wheel then multiply x2.

when the procal says to subtract 24 from that number its just for the programmers sake and how they have the nimbers plugged into it.

This ^^^. The -24 is only for their programmer to work, nothing else. If the instructions that manufacturers provided were sacred, I wouldn't have gotten to where I am today.

Just let this guy do it his way. Clearly he doesn't want to listen to us as this is more then a half a dozen posts with him saying he is going to measure from the ground to the top of the tire.

When he gets it wrong he will start a thread saying how the Procal sucks and his speedometer is wrong. Seen this before.

 

[AncientTrail]

LOL!! So, do it like they say to do it and I guarantee you that you will get a measurement that is TALLER than you need. 7-8 years ago, I used to recommend that same method until I found that it was wrong. But, you don't have to take my word for it. Input that number anyway and check your speedometer against a radar speed trap or GPS or have a friend with a stock Jeep pace you and verify how fast you are really going. Then, measure your tire like I've stated and do the test again. Believe whoever you want but facts won't lie.

I'm sure you can understand how frustrating it is to have AEV giving out info that contradicts with what you discovered. You would think they would have figured out what you have.

Ahhh, the journey...

:beer:

 

[TheStick]

LOL!! So, do it like they say to do it and I guarantee you that you will get a measurement that is TALLER than you need. 7-8 years ago, I used to recommend that same method until I found that it was wrong. But, you don't have to take my word for it. Input that number anyway and check your speedometer against a radar speed trap or GPS or have a friend with a stock Jeep pace you and verify how fast you are really going. Then, measure your tire like I've stated and do the test again. Believe whoever you want but facts won't lie.

Just to be clear, the pace car does not HAVE to be a Jeep, but it is always better if it is

 

[wayoflife]

I'm sure you can understand how frustrating it is to have AEV giving out info that contradicts with what you discovered. You would think they would have figured out what you have.

Ahhh, the journey...

:beer:

LOL!! Manufacturers SUCK when it comes to their OWN instructions and I wouldn't be where I am at today or have the contacts that I do if it weren't for that fact. Me testing their stuff out and re-writing their instructions in the form of my write-ups over the last 20 years is how I got to quit my day job and play with Jeeps for a living. :yup:

 

[AncientTrail]

Just let this guy do it his way. Clearly he doesn't want to listen to us as this is more then a half a dozen posts with him saying he is going to measure from the ground to the top of the tire.

When he gets it wrong he will start a thread saying how the Procal sucks and his speedometer is wrong. Seen this before.

As you can read in those posts there were different opinions on how to measure. We all are just trying to figure stuff out. When I get conflicting info I do my due diligence.

Now, I'll do it both ways and when I get the results I'll post back here. As Eddie stated ( and I didn't know this ) for seven years he advised the same measurement until he found it was wrong.

You don't know me from Adam and as you can read in my posts I'm not trying to start anything, contrary to your posts.

Go look for a fight somewhere else.

:beer:

 

[AncientTrail]

LOL!! Manufacturers SUCK when it comes to their OWN instructions and I wouldn't be where I am at today or have the contacts that I do if it weren't for that fact. Me testing their stuff out and re-writing their instructions in the form of my write-ups over the last 20 years is how I got to quit my day job and play with Jeeps for a living. :yup:

I hear ya and respect what you are saying.

Thanks again :beer:

 

[wayoflife]

Now, I'll do it both ways and when I get the results I'll post back here. As Eddie stated ( and I didn't know this ) for seven years he advised the same measurement until he found it was wrong.

To be clear, I didn't recommend this for seven years, I recommended it 7 years AGO. There is a difference :crazyeyes:

 

[AncientTrail]

Just to be clear, the pace car does not HAVE to be a Jeep, but it is always better if it is

LOL! I was going to use a vette

My problem is I never agree with myself for longer than 20 min. I guess that's been pretty obvious :idontknow:

:beer: