Odometer and Speedometer Compensation for 33''s?

[Empty V]

So now that I've got 33's I really need some way of compensating for the larger tire. Does anyone know how this can be done as my speedo and odo are waaaaaaay off.

Thanks!

Billy

[01silvapathy]

Mine just seems to be off by about 5-6mph so once I get above 40mph I just go 5 under what the speedo says. So if its a 70 zone, then I set the cruise at 65. As for the odemeter I dont know what to say about that, why do you need the odo anyways?

[Empty V]

Mine just seems to be off by about 5-6mph so once I get above 40mph I just go 5 under what the speedo says. So if its a 70 zone, then I set the cruise at 65. As for the odemeter I dont know what to say about that, why do you need the odo anyways?

I plan on pacing a buddy to see what the actual difference is. I'd really like everything to be correct so I can calculate MPG and have a correct odo. I've heard that you can install these specific gears somewhere on the trans which will fix the problem but to be honest I know nothing about them. I called 4 Wheel Parts and they said they don't have anything for R50's.

Billy

[Pwnin O'Brien]

Supposedly the best way to accurately calculate your speed is to use GPS. I'm not sure if that's true though. If you have a portable GPS unit it should give you a speed readout.

[Empty V]

Supposedly the best way to accurately calculate your speed is to use GPS. I'm not sure if that's true though. If you have a portable GPS unit it should give you a speed readout.

Ahhh I never thought about that. I've got a speedometer built into my in-dash nav so I'll check that today. Thanks dude!

Billy

[01silvapathy]

Yeah I know on Jeeps and such you can replace the spedo gear it is based off of your R&P gear and tire size. You can buy them cheap for jeeps obviously and its an easy swap. I use a buddies Garmin Nuvi GPS and it has a spedo on it. To help figure out the speed difference and like I said its off by about 5-6mph once you go over 40mph. So ya getting a GPS is probably the best solution for it, to get an accurate speed, it also has an odo feature that whenever the gps is on, it tracks how far you went.

[KyooX4]

Yeah, I have a Garmin Nuvi that shows current speeds.

[Pwnin O'Brien]

Supposedly the best way to accurately calculate your speed is to use GPS. I'm not sure if that's true though. If you have a portable GPS unit it should give you a speed readout.

Ahhh I never thought about that. I've got a speedometer built into my in-dash nav so I'll check that today. Thanks dude!

Billy

No good, you have a Pioneer Z3 right? That uses the speed sensor instead of GPS (unless you left the speed sensor wire disconnected).

[Empty V]

No good, you have a Pioneer Z3 right? That uses the speed sensor instead of GPS (unless you left the speed sensor wire disconnected).

Ohh that's right, damn you Ryan and your infinite wealth of dream crushing knowledge!

Billy

[KyooX4]

Hahaha, seriously dude, how do you know so much?!

[Empty V]

Well I just set my cruise to 68 on the deck and the speedo on the cluster showed 62, hmmmm.

Billy

[alexf20c]

don't listen to anything 01silvapathy says. the speedometer/odometer is not only off after 40mph. the difference is a percentage of your advertised speed. on my pathfinder it's about 8% difference. so at 30mph i'm doing 32.4mph and at 70mph i'm doing 75.6mph. i've checked it with my Garmin standalone GPS and 8% is about exact. i just round up to 10% to make it easier. there is a percentage error AT ALL SPEEDS.

also, our pathfinders do not use a speedo gear on the differential like 01silvapathy suggested. the speedo gear is inside the transmission. there is no off-the-shelf speedo gear designed specifically for oversize tires, but there is a relatively easy fix. if you have the 4.3 R/P you can install a speedo gear from a 4.6 R/P-equipped pathfinder. it's about 7% shorter ratio and almost a perfect match for the upgrade to ~33in tires. likewise, if you have a 4.6 R/P you can use a speedo gear from a 4.9 R/P-equipped Xterra or Frontier.

[01silvapathy]

don't listen to anything 01silvapathy says. the speedometer/odometer is not only off after 40mph. the difference is a percentage of your advertised speed. on my pathfinder it's about 8% difference. so at 30mph i'm doing 32.4mph and at 70mph i'm doing 75.6mph. i've checked it with my Garmin standalone GPS and 8% is about exact. i just round up to 10% to make it easier. there is a percentage error AT ALL SPEEDS.

also, our pathfinders do not use a speedo gear on the differential like 01silvapathy suggested. the speedo gear is inside the transmission. there is no off-the-shelf speedo gear designed specifically for oversize tires, but there is a relatively easy fix. if you have the 4.3 R/P you can install a speedo gear from a 4.6 R/P-equipped pathfinder. it's about 7% shorter ratio and almost a perfect match for the upgrade to ~33in tires. likewise, if you have a 4.6 R/P you can use a speedo gear from a 4.9 R/P-equipped Xterra or Frontier.

Alex, if you hate stupid people and idiots you must hate yourself. When did I ever suggest that we had a speedo gear? Perhaps you should go back and read aloud to yourself my post. The speedo gear is not even on the diff of a Jeep its in the transfercase. And of course all of our readings are going to be different all of our tires are different sizes. You really need to think before you type.

[Pwnin O'Brien]

Stop fighting in every thread. This is a warning for both of you, no more warnings herein, just banning.

[alexf20c]

I'm still waiting for NICO to add an Ignore List to the userCP.

[01silvapathy]

Stop fighting in every thread. This is a warning for both of you, no more warnings herein, just banning.

Really? Im pretty sure that most people here would agree with me in the fact that im not the instigator in this matter

[Pwnin O'Brien]

Stop fighting in every thread. This is a warning for both of you, no more warnings herein, just banning.

Really? Im pretty sure that most people here would agree with me in the fact that im not the instigator in this matter

It doesn't matter who instigated it, you guys are consuming all of the threads with your arguments. Now get along, please.

[infiniti97qx4]

dissregard arguments boy will be boys no metter what ,back to thread,
Stock Tire - 255/65R16 - 33x12.50R16
Section Width: 10.03 in 255 mm
Section Width: 12.51 in 318 mm

Rim Diameter: 16 in 406.4 mm
Rim Diameter: 16 in 406.4 mm

Rim Width Range: 7 - 9 in
Rim Width Range: 8.5 - 11 in

Overall Diameter: 29.05 in 737.87 mm
Overall Diameter: 34.02 in 864.10 mm

Sidewall Height: 6.52 in 165.60 mm
Sidewall Height: 9.01 in 228.85 mm

Radius: 14.52 in 368.80 mm
Radius: 17.01 in 432.05 mm

Circumference: 91.26 in 2318.0 mm
Circumference: 106.8 in 2712.7 mm

Revs per Mile: 716.0
Revs per Mile: 611.4

Actual Speed: 60 mph 100 km/h
Speedometer1: 51.2 mph 85.3 km/h

Speedometer Difference: - Speedometer Difference: 17.10% too slow
Diameter Difference: - Diameter Difference: 14.61%

I was thinking that ecu will learn new spedo after remove battery over night,but aint case here.
Use gps and you will se actual speed lock car on cruise and see if transsmissino downshifting /upshifting on the weird way.
also watch for stability and safty ,ccheck if you are rubbing inside wheel base if you do not have lifting kit or spacers installed.


my opinion that is too big tires for this suv and your ball joints and tire rods ends especially outside tire rod ends will suffer a lot.

[Empty V]

did you fail basic math in grade school?

Were you not hugged as a child? Seriously you need to grow up and stop insulting everyone or GTFO. You're begging to get banned from ANOTHER forum for being a prick. It's really a shame because you have the ability to help but it's covered up by all that hate.

[Pwnin O'Brien]

That's it Alex, I think I've been more than nice when it comes to your improprieties. You have really got to learn some respect and learn how to not be so rude to others. When you come on here and start bashing other members it just makes you look bad, especially when you start bashing new members. Until you can learn how to be a productive member of this forum without being extremely rude and condescending to other members you can take a vacation from NICO.

Bye.

[01silvapathy]

Oh wow, guess I missed when Alex finally got banned....oh well moving on! Here is that thing I was talking about Billy its called the scanguage, it is like a really smart brain. It tells you max speed, mph, trip odo, miles to empty all sorts of stuff, here is a link to the website. I know that it plugs into your ecu but you might want to email the company and ask if you can compensate for bigger tires ect, at this point its worth a try. I know over on another big forum, Expedition Portal (pretty cool site yall should check it out) they rant and rave about this little gadget so I figured id pass it along

Edit: Forgot the link

http://www.scangauge.com/features/

[Empty V]

Oh wow, guess I missed when Alex finally got banned....oh well moving on! Here is that thing I was talking about Billy its called the scanguage, it is like a really smart brain. It tells you max speed, mph, trip odo, miles to empty all sorts of stuff, here is a link to the website. I know that it plugs into your ecu but you might want to email the company and ask if you can compensate for bigger tires ect, at this point its worth a try. I know over on another big forum, Expedition Portal (pretty cool site yall should check it out) they rant and rave about this little gadget so I figured id pass it along

Edit: Forgot the link

http://www.scangauge.com/features/

This loks similar to something a buddy has in one of his cobras. I'll email them and see if they have any way of doing the recalibration, thanks!

[fleurys]

Oh wow, guess I missed when Alex finally got banned....oh well moving on! Here is that thing I was talking about Billy its called the scanguage, it is like a really smart brain. It tells you max speed, mph, trip odo, miles to empty all sorts of stuff, here is a link to the website. I know that it plugs into your ecu but you might want to email the company and ask if you can compensate for bigger tires ect, at this point its worth a try. I know over on another big forum, Expedition Portal (pretty cool site yall should check it out) they rant and rave about this little gadget so I figured id pass it along

Edit: Forgot the link

http://www.scangauge.com/features/

This loks similar to something a buddy has in one of his cobras. I'll email them and see if they have any way of doing the recalibration, thanks!

This was in the userguide....:

MORE>SETUP>SPEED
Both speed and distance can be adjusted to compensate for changes in
tire size, gears, tire wear, etc..
The setting can be changed at any time. If SAVE is not used, the entered
value will be lost when the ScanGaugeII is disconnected. This may be
the desired operation if the vehicle is not to have the ScanGaugeII
regularly used on it.
< 0% >
0=> 0 SAVE>
The right and left upper buttons can be used to increase/decrease the
selected adjustment in 1% steps. The lower left number is the speed
reported by the vehicle. The lower right number is the speed which will
be shown by the ScanGaugeII by applying this correction. Positive
values of % will increase the displayed speed. Negative values of % will
decrease the displayed speed. The approximate % to use for a tire size
change can be computed by dividing the diameter of the original
equipment tire by the diameter of the new tire, subtract this from 1 and
multiply by 100. For instance, if the diameter of the original tires was 24
inches and the size of the new tire is 30 inches, 100x(1-(24/30)) = 20.
Setting the value to 20% will compensate for the tire size change.
For gear changes, the formula would be 100x(1-(new ratio/old ratio)).
For instance if the old ratio was 3.55 and the new ratio was 4.10,
100x(1-(4.10/3.55)) = -15%.
One accurate way to set the speed is to use a handheld GPS. With one
person driving, the other person observes the speed on the GPS and
adjusts the % until the lower right value agrees with the GPS speed
indication. Setting both the GPS and the ScanGaugeII to display KPH
while making the adjustment will allow a more accurate adjustment to
be made.
Another way would be to have the driver drive at a ScanGaugeII
indicated speed of 60 MPH and measure the time between mile marker
posts on a highway. For every second more than 60 it takes to go 1 mile,
subtract 1% from the adjustment. It may be necessary to repeat this a
few times until it takes 60 seconds plus or minus a second to go 1 mile.
Distance measurements can also be used to adjust the ScanGaugeII.
Highway mile markers can be used to verify the correct setting. Use
CURRENT TRIP DISTANCE and RESET when passing a mile
marker. After a few miles see that the Miles changes as you pass the
mile marker. Adjust the Speed up or down to adjust the indicated
distance.


So the bottom line, is that it can be adjusted to show the real speed...

[Fisherdude]

Supposedly the best way to accurately calculate your speed is to use GPS. I'm not sure if that's true though. If you have a portable GPS unit it should give you a speed readout.

This is what I use in my other jacked up trucks and it works great. The garmin also tells you average speed, exact distance and other useful stats. I would look into it if i was you.

[Empty V]

I thought I had linked to it but I guess not. Here's what I'm looking at 12 O'clock Labs It ties into the ECU and corrects your OEM gauges. The Scangauge II looks amazing and the price is outstanding. I almost want to do both so I can have an accurate reading on my stock speedo and have the scangauge for the extra functions.