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Upgrading to Rubi 33s.

Mkcagle

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I am upgrading this weekend to a set of Rubi 33s MT take offs. Currently running 245/74R17. Should I expect my speedometer to need recalibration and if so what is the most economical way?
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primethios

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I just made this exact upgrade Sunday on my overland. I am seeing no difference in the speedo. Every day I drive past "this is your speed" signs and everything looks spot on. The rubi setup is slightly taller. You have to remember that the rubi has 17 inch rims and the overland has 18 inch rims.

I was partially concerned of the same thing but when I put the overland rims/tires next to the rubi it is a slight difference in height and a bit wider.
 
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Mkcagle

Mkcagle

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I just made this exact upgrade Sunday on my overland. I am seeing no difference in the speedo. Every day I drive past "this is your speed" signs and everything looks spot on. The rubi setup is slightly taller. You have to remember that the rubi has 17 inch rims and the overland has 18 inch rims.

I was partially concerned of the same thing but when I put the overland rims/tires next to the rubi it is a slight difference in height and a bit wider.
I currently have a Sport S with 17 inch wheels.
 

primethios

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Gotcha, I saw overland in your vehicle heading. I am no tire expert by any means (they confuse the crap out of me with the sizing). I have the AT tires but I assume they are the same size as the MT and the height is about 1.4 inches taller. I assume this will cause some variance but not a huge swing. As a test you can use a GPS that reports current speed (I believe waze does this) to compare against your speedometer to see if there is a noticeable difference. I met someone with 37 inch tires on his gladiator and he was using waze until he re-calibrates and he said at 55 he saw about an 8 mph difference from the rubi takeoffs I bought off him. As far as recalibration you can buy one of these programmer chips they talk about on the forums or take it into the dealership. It is all electronic control and jeep sent out a calibration chart to dealers so they hook up a computer and put in a new code. If you look around on the forum you will probably find a copy of the chart as I recall seeing one a week or two ago.
 
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Mkcagle

Mkcagle

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Gotcha, I saw overland in your vehicle heading. I am no tire expert by any means (they confuse the crap out of me with the sizing). I have the AT tires but I assume they are the same size as the MT and the height is about 1.4 inches taller. I assume this will cause some variance but not a huge swing. As a test you can use a GPS that reports current speed (I believe waze does this) to compare against your speedometer to see if there is a noticeable difference. I met someone with 37 inch tires on his gladiator and he was using waze until he re-calibrates and he said at 55 he saw about an 8 mph difference from the rubi takeoffs I bought off him. As far as recalibration you can buy one of these programmer chips they talk about on the forums or take it into the dealership. It is all electronic control and jeep sent out a calibration chart to dealers so they hook up a computer and put in a new code. If you look around on the forum you will probably find a copy of the chart as I recall seeing one a week or two ago.

Good catch on the vehicle type. That was my previous Jeep. Updated now.
 

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Good catch on the vehicle type. That was my previous Jeep. Updated now.
Just wondering how you made out, I was contemplating doing the same thing. I came across a set of Rubi take offs 17 inch rims with a Falken 285/70/17 tire. My sport S came with 17 inch rims and a 245/75/17 tire. The Falken have an OD of 32.8 while the Bridgestone Duelers are 31.5. I see no reason why this should be an issue.
 
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Mkcagle

Mkcagle

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Just wondering how you made out, I was contemplating doing the same thing. I came across a set of Rubi take offs 17 inch rims with a Falken 285/70/17 tire. My sport S came with 17 inch rims and a 245/75/17 tire. The Falken have an OD of 32.8 while the Bridgestone Duelers are 31.5. I see no reason why this should be an issue.
Turned out good. At 70 MPH speedo was reading 4 off. Corrected by the RC correction unit. Speedo now matches two independent GPS units. Had to use 32.5 inches as the new tire height. Truck now feels much better on the highway and around town. Very solid feel.

0B50F737-C4B1-4332-900B-1B7B096D1DCB.jpeg
 

Campo

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Turned out good. At 70 MPH speedo was reading 4 off. Corrected by the RC correction unit. Speedo now matches two independent GPS units. Had to use 32.5 inches as the new tire height. Truck now feels much better on the highway and around town. Very solid feel.

0B50F737-C4B1-4332-900B-1B7B096D1DCB.jpeg
Thanks! BTW. what the RC correction?
 
 



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