bkg
Explorer
There are a lot of questions about gear ratios that pop up from time to time, especially when people change tire size. There's seems to be a presumption that choosing the ratio that gets the vehicle back to as close to stock as possible is the correct choice, but I think that presumption is faulty, especially on vehicles that are carrying more weight.
What is often forgotten is to compare the final drive ratio of the vehicle in question across both the automatic and manual versions available from the factory. I have three 5Vze vehicles, all with aftermarket gearing. One 3rd Gen 4Runner w/ 4.88's and 33" (equivalent) tires. 1st Gen doublecab, also with 4.88's and 33" tires. And my extracab which has 5.29's and 37's... is supercharged, SAS'd, etc but isn't daily driven.
When people hear 4.88's and 33's, there's an assumption that the vehicles are over geared, the engine is revving to high, speed is impacted, etc. But that isn't really accurate, especially when compared to their manual-equipped counterparts.
So using the RPM calculation: Axle Ratio x speed x trans ratio x 336.13 / tire diameter (where tire diameter is the nominal diameter in inches), the below charts tell a pretty good story, IMHO.
Taking a look at the data, doing a 33/4.88 combination is still geared higher than a stock R150-equipped truck. Now consider that my double cab is probably a good 600-800# heavier than stock (winch, bumpers, sliders, cap, skids, 5 full size tires) and the 5.29's start to look even more appealing as a way to help make up from the weight.
Similar for the 1GR equipped vehicles.
Point is that choosing gear ratios means more than just trying to get back to stock final drive ratio of the particular vehicle. Take a look at the other final drive ratios available via different packages and transmissions. Ideally, one would also take into account the engine's torque curve, driving habits, overall weight added, driving location... but that's adds more data points and offers more possibility for confusion, IMHO.
What is often forgotten is to compare the final drive ratio of the vehicle in question across both the automatic and manual versions available from the factory. I have three 5Vze vehicles, all with aftermarket gearing. One 3rd Gen 4Runner w/ 4.88's and 33" (equivalent) tires. 1st Gen doublecab, also with 4.88's and 33" tires. And my extracab which has 5.29's and 37's... is supercharged, SAS'd, etc but isn't daily driven.
When people hear 4.88's and 33's, there's an assumption that the vehicles are over geared, the engine is revving to high, speed is impacted, etc. But that isn't really accurate, especially when compared to their manual-equipped counterparts.
So using the RPM calculation: Axle Ratio x speed x trans ratio x 336.13 / tire diameter (where tire diameter is the nominal diameter in inches), the below charts tell a pretty good story, IMHO.
Taking a look at the data, doing a 33/4.88 combination is still geared higher than a stock R150-equipped truck. Now consider that my double cab is probably a good 600-800# heavier than stock (winch, bumpers, sliders, cap, skids, 5 full size tires) and the 5.29's start to look even more appealing as a way to help make up from the weight.
Similar for the 1GR equipped vehicles.
Point is that choosing gear ratios means more than just trying to get back to stock final drive ratio of the particular vehicle. Take a look at the other final drive ratios available via different packages and transmissions. Ideally, one would also take into account the engine's torque curve, driving habits, overall weight added, driving location... but that's adds more data points and offers more possibility for confusion, IMHO.