I have read that proper break in period is to avoid longs trips, take it easy for the first 500 miles and change the diff oil. My question is does the tire size matter during the break in period? Should I break in the new gears while running the factory 32s or can I go ahead and run the aftermarket 35s? Thanks...

 

I'd say go ahead and run your bigger tires. Just be easy on the gears for a while and don't do anything which will overheat them.

 

I talked to the shop that did mine I bit before the install. They said they didn't usually do anything after the install, but I told them what had been done on my regears of the past and included it in the price. When they did the install they put in valvoline gear oil. (dino oil not synthetic) then after 500 miles of "break in" style driving (my choice not their recomendation) they popped off the covers. Then they cleaned out all the shavings and oil, then they checked the pattern in the paint again, squirted royal purple in the sealed up diff covers.

 

OK, maybe I'm on the wrong thread, but I'm wondering what kind of results I would get if I were to put 5.13's in my JK. I have a Rubicon Unlimited, and I'm running 33's. I do a lot of highway driving, so I'm wanting increased power AND fuel economy. I've already done the exhaust, CAI, and programmer, but I'd still like a little more power and fuel economy. Are 5.13's the right thing to do, or am I going to hurt my economy?

 

unless you increase tires size, 5.13s are going to kill your mpg. The power would be great, nut the mpg would suck. that rubi comes stock with 32s and 4.10s. to have that same ratio with 5.13s you would need 37" tires.

 

Hmmmm...so, if I go with 37" tires, my MPG and power will increase with the 5.13's?
What is my best bet for keeping the 33's (or maybe going with 35"s)? Keep the gears I have? or should I regear to some other ratio?

 

If you go with 5:13 and 37 power might increase , your MPG will decrease BIGGER tire more frictiion on the road. (ITS A JEEP face it your MPG SUCK! ) Once you add bigger tires its sucks even more..

 

5.13s seem to be majority's choice for the auto and 35's, even 5:38s for non Rubis.


I am going with the 5.13s this week. Currently with the 3.73s I cruise around 2000 RPM which just sucks. I picked the ratio by choosing the RPM range I want to cruise in on the highway (2400-2700 at ~70-80 MPH) and the RPM I can tolerate when my JK drops out of overdrive (3100-3400). That is about as high as I want to tack while cruising, the 5.38 increase that RPM range by 100-200 rpm.


An interesting observation is that I get 1-2 MPG better when I drive aggresively and keep my closer to RPM ~2500 than when I take it easy on the gas pedal and hardly ever go beyond 2100 RPM.

 

i got my 513s today and it is so much better but im hoping to have the break in period in before saturday

 

The 500 mile just came up with the 5.13 gears that was recently installed in my JK. I started with changing the rear gear oil and notice the usual grayish color of the oil as it was draining. However, when it came time to change the front, the gear oil coming out seemed to be untouched (had the usual caramel color). My question is, does the front gearing (R&P) move/spin when not in 4wheel? or does the jeep have to be locked in 4 wheel? So is proper break in the front axle just as important as the rear..(duh..Yes......)? If so I guess I would have to drive in 4wheel at some dirt/sand trails couple of times a week..Thanks...