4.88 dif, 265-75R16, ECT, Shift Sense Pro

My truck a 2016 TRD Off Road.

So we know the engine trans combo sucks. For me I live in the hills and tow a RZR frequently.
The ECT helps and so does the Shift Sense pro to bring the rpm up to the power band.
But I went backwards a little with a larger diameter tire by 1".
Now I am considering installing the 4.88 dif gear set, Stock is 3.909.

Does anyone have the same set up. I am looking to hear your results.

By the numbers using calculations it looks like at 2000 rpm with the larger tire and stock dif I get 83 mph in 6 the gear. Changing to the 4.88 it will be 67 mph. That's about a 12% reduction.

I am wondering what the new ft lb torque value would be for the same given speed. Can't find a calculator for that.

 

Look into an ECU tune..

 

I considered that, but Gears get the HP to the ground. I don't need a truck that can 100mph

 

Did you go with a heavier tire?

 

Yes, load range E, They are BFG K2 but that should not affect performance.

 

Wow. Tire/wheel weight increases are probably the most well-known wheel weight factor that impacts how ANY car performs. Yes, heavier tires affect performance, and there is no debating it.

 

You would need to know torque at 2,000...

 

Subbed. I'm looking to regear with 4.88's

 

Gears get more torque to ground. Not horsepower. Horsepower determines how fast you go with that gearing. Simple look at torque rating at 2000 rpms. Gears make torque come on faster. But would limit top speed.

 

wrong, tires can greatly affect performance.


4.88 is a huge jump for that tire size. Many running 4.88 are on 33s or larger. Doing the math even at a 33 thats too much.

 

Some things I've wondered about regears:
Is only the rear diff changed or do they do the front too?
If only the rear is done, how does that affect 4WD operation?
It seems that if you only did the rear, when you engage 4x4 the front and rear drive shafts would rotate at the same rate from the transfer case, but the different final drive ratio would cause the rear tires to spin faster or slower depending on which way you went.

 

I'm not sure but think.u do both front and rear

 

Yes they do both front and rear.
BTW cost is $1325 for parts, labor another $1100 and speedometer recalibrator is $229

 

Running 265/75/16s now... moving to 33"s as soon as these tires are done.

Are 4:88 Nitro gears too much for this tire size?

 

Truthfully, I think 4.88 may be too much.

the new JL rubicon is 4.10 with I believe 33s.

I currently have 265/75/16 with the e rated KO2s and I have no issues at all.
I do live in flat Illinois so that has a lot to do with my lack of frustration.

But with everything being said, I believe 4.88 might be a tad bit much. I am basing that off of a JL rubicons numbers.

Personally I would do a ecu tune, once you open up a diff it’s never gonna hold up as well as the factory diff.

 

Thanks. I put my order in at East Coast gear... it’s about a month out. I can still cancel.

waiting on bumper to arrive.

feeling hesitant and that 4:88s are going to be too much.