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If some of you experts would look at the tag attached to my differential can you help me decipher if my gear ratio has been changed? according to the door sticker it is 3.70. Thanks for the help
Pretty sure you are missing a number and possible a letter in front of 73. Should be like 3L73 witch is 3:73 ratio and limited slip. The 10.5 means sterling 10.5. Not sure about the other numbers. Lots of time gears get changed and the tag never gets updated so it's possible that you have a different ratio.
Tire size only matters if the speedo is corrected though.
The way I understand it and have experienced it is that a gear ratio change will not affect the speedo readings due to the sensor reading off the ring gear. But a taller or shorter tire than stock will throw the speedo farther off than it was from from the factory. My speedo read exactly the same verified by GPS with my 32" tire with both my stock 3.73 gears and my swapped in 4.88 gears, but the speedo was thrown off by the swap up to 35" tires.
Well have been installing Ride Rite airbags and Helliwig ASB. I was dodging rain showers as I did those jobs. Tires are not stock 305/80R20. will these tires affect the speedo?
If they are maybe 305/60R20 tires like the Toyo Open Country at 34.3" tall I doubt that they would fit on a stock suspension also without some rubbing.
A 305/55R20 at 33.5" may fit without rubbing.
Is this EX a 4X4 model? What motor? All diesel EXs came with 3.73 gears from the factory. Pictures will help to judge if it has a lift on it as well as a good set of measurements from the CENTER of the hubs to the bottom of the top center of the wheel wells both front and rear. This measured distance will determine the suspension ONLY distance removing any tire size variables from the equation.
Many EX owners have found their speedos to be slightly off (as verified by GPS) with stock sized (265/75R16) tires but upgrades to a 285/75R16 (33-ish) seems to bring the speedo to the correct accuracy.
The way I understand it and have experienced it is that a gear ratio change will not affect the speedo readings due to the sensor reading off the ring gear. But a taller or shorter tire than stock will throw the speedo farther off than it was from from the factory. My speedo read exactly the same verified by GPS with my 32" tire with both my stock 3.73 gears and my swapped in 4.88 gears, but the speedo was thrown off by the swap up to 35" tires.
You are correct. I was referring to the speedo accuracy difference between different tire diameters, wasn't even taking a gear swap into account. I think we just got a crossed communication line. If you change tire diameter, your speedo will be off a bit, that amount being a percentage that goes up with the difference in diameter from stock, and also with increase in speed.
sorry for the delay. . .nothing like work to get in the way of things. I checked and yes I had my tire size wrong. I have 305/50R20 tires. Cooper Discoverer HT Plus to be exact. Seem to have good reviews. My rear is a 3.73 from the door sticker and tag. thanks everyone for the help.
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If you change tire diameter, your speedo will be off a bit, that amount being a percentage that goes up with the difference in diameter from stock, and also with increase in speed.