What are potential issues by re-gearing a Gen 3 to 4.88?

very true! I guess end of the day Automakers can be bullies and sometimes you can and need to push back. something like the MAF sensor or they once told me my roof rack was making my side mirror whistle (not worth the fight, but funny) fight them. My regear grenading my rearend, obviously not their fault. I was definitely outside the parameters of that rear end.

 

like this?:

4.88’s, I never get below 16.5 even when running fast (over 70mph)

 

The OP asks what will be affected, one thing not mentioned yet is the cruise control setting will have to be set to a different point to get a desired speed. My understanding thus far, as my Tacoma is less than a month old to me, is that the speedometer and odometer can be adjusted with a box behind the cluster. This box does nothing for the cruise control. Does this OVTune take care of the cruise control issue?

 

Look at what rpm you’re turning now @ 60 or 70 and use that as a baseline to choose your new gear set for the larger tire. Use an online gear calculator to see What you need to maintain at least the same rpm and a little more (500 or so) rpm would be great. Too much and you are going to hate it on the highway @ 75. Make sure you use the tire dia. The manufacturer states in their nomenclature, not just “33” because the size is commonly regarded as a 33. The lower gears are going to help you the most at take off, especially with larger dia., heavier tires. They will also take some strain off the trans and engine.

One downside is aftermarket gears tend to whine. In a truck you don’t notice it too much though. Make sure whoever does them is familiar with the setup for that axle so you don’t end up with a junk third member.

If you don’t have a locker, now is the time for it. I used Detroit Tru-Tracks front and rear on my old full size Ram and really liked them. Put 500 easy miles on the new gears, change the oil after a few thousand.

I’ve done a bunch of gear sets, but it’s all been Dana and Ford stuff so I don’t know if there is anything to watch for on the Toyota axles. For a DD, there will almost certainly be some compromise when choosing a ratio because you operate on the street and highway. Not enough gear and you are wasting you money, to much and it will become tedious to drive on the highway and drop your highway mpg.

Gears make a big difference with larger, heavier, tires.

 

I'm on stock gears and 33s and it's fine. Don't over think this. Get your 33s and then go from there

 

Gears have nothing to effect in regards to speed sensors. Only the change in tire size effects speed sensors as the sensors are at the wheels, not the trans.

 

Someone mentioned that at 75 mph, their truck was doing 2250 rpm with 33's and 4:88's.

Does anyone have that data for 5:29's and 33's?

 

Ok, I just answered my own question. After years of owning a Rubicon that I upgraded to 35 inch tires and was planning on going to 37's with it, I knew regearing it was a necessity. I did not realize how tall the gearing was in these 3rd gen Tacos. Upgrading tires size in a Rubi is fairly easy. With a 4 inch lift and flat fenders, I had the ability to hit 37's. I had 35's, but 37's were no problem. When I went from the factory 32's to 35's in my rubi, my mileage went from 16.6 to 12.6 with the same gears. Terrible. I had no power climbing up the colorado 10k to 11k foot passes. So I know that in this Taco, I will have to regear. What I just did was make a comparison at highway rpm of 2200 rpm in all gears and here is what I got. Did this for myself, hope this helps you:

 

I've got 4.88's, OVTune, and a lot of added weight. I'm very happy with it. I used to think I should have gone 5.29's, but now I'm happy I went 4.88. If you have any plans to do bigger tires in the future then do 5.29. You'll be fine with them with 33's, but I don't think they're necessary. I do think 5.29's would be necessary for anything above 33's though.

 

I'm in San Antonio. Would you recommend your mechanic for installation? If so, who did it?

 

Sorry did it in Colorado.

 

I have a hypertech speedocalibrator. It took a some number tweaking but my speedo, mpg, gps, and cruise is all in synch.

The op should know that 4:88 is a little much for 33’s. But that’s just not how this thread went.

 

Where would you get a OVTune done and how much is it?