Another gear question...

[NKlekas]

I live in Nevada, and for those who don't know, Nevada has A LOT of hills and grades. It's the most mountainous state in the U.S. Nevada is also very empty, after Reno and Las Vegas, there isn't much. Due to both of these details, I drive a lot on interstates and highways to get to places. I like to use my jeep to camp/overland so I do a good amount of long-distance driving.

I currently have 33x15x12.5 with the stock 4.10 gears in the Rubicon. I recently put on a Roof Top Tent and drove on I-80 over to Utah with gear loaded down in the back as well. So the RTT and the back of the jeep loaded down is my normal set-up. It really performed well with the 4.10's but I could tell the tent had an impact. I don't go any faster than 75 with everything on the jeep. I was getting around 13.5 MPG at about 75MPH (ish) I was running around 2700 RPMs (ish). However, for ANY, and I mean ANY kind of uphill grade, I had to downshift into 4th to maintain just 70MPH.

I know Jeeps aren't speed demons nor have the excess power to flaunt around. So, my question is, given my current setup should I re-gear to 4.56's? I've also highly considered going to 35's and in that case...would 4.88's be the best for my setup? Anything helps!

 

[JMT]

4.88's for 33's

5.13 for 35's

 

[NKlekas]

4.88's for 33's

5.13 for 35's

That low with 35's? I'm not the biggest brain when it comes to gears but that surprising

 

[L J]

That low with 35's? I'm not the biggest brain when it comes to gears but that surprising

I have an '06 on 35s with the 6 speed. 5.13s were my choice and I don't regret it. My LJ probably runs a fair bit lighter than your TJ(?).

 

[JMT]

That low with 35's? I'm not the biggest brain when it comes to gears but that surprising

You have a 5-speed. That's the ratios I would go with, and probably the recommendation of 75% on the forum.

Check http://www.grimmjeeper.com/gears.html

You want to hold your 5th gear on hills? Higher RPM's aren't going to hurt your 4.0 one bit. They aren't going to affect your MPG either.

I have the 6-speed with 33's and 456 gears. I'm going to 35's and wish I had 513's.

 

[NKlekas]

I have an '06 on 35s with the 6 speed. 5.13s were my choice and I don't regret it. My LJ probably runs a fair bit lighter than your TJ(?).

Yea TJ! Sorry, should have specified. Thank you!

 

[NKlekas]

You have a 5-speed. That's the ratios I would go with, and probably the recommendation of 75% on the forum.

Check http://www.grimmjeeper.com/gears.html

You want to hold your 5th gear on hills? Higher RPM's aren't going to hurt your 4.0 one bit. They aren't going to affect your MPG either.

I have the 6-speed with 33's and 456 gears. I'm going to 35's and wish I had 513's.

Yea I have the 5 speed. Thanks for your help JMT, I appreciate it.

 

[TheBoogieman]

4.56 from 4.10 would be a waste of money IMO.

 

[JMT]

4.56 from 4.10 would be a waste of money IMO.

Agree 100%

 

[jjvw]

5.13 for 35s

 

[mrblaine]

4.56 from 4.10 would be a waste of money IMO.

Have you ever actually paid to have a re-gear done?

 

[TheBoogieman]

Have you ever actually paid to have a re-gear done?

Yes.

 

[mrblaine]

Yes.

Of the 19 rigs you have owned, how many did you pay to re-gear?

 

[TheBoogieman]

Of the 19 rigs you have owned, how many did you pay to re-gear?

Three.

 

[mrblaine]

Three.

I have single rigs that I have geared more times than that.

 

[TheBoogieman]

I have single rigs that I have geared more times than that.

I'm poor though.

 

[NKlekas]

4.56 from 4.10 would be a waste of money IMO.

Ah I see. So for my interstate driving at 33's, 4.88's would be best?

 

[L J]

So for my interstate driving at 33's...

You need the gearing for the mountainous terrain as well as the increased load you're hauling around.

4.88's would be best?

It depends on how realistic/timely the following is:

I've also highly considered going to 35's ...

If you're sticking with 33s long-term, 4.88s are a great choice.

 

[jjvw]

Ah I see. So for my interstate driving at 33's, 4.88's would be best?

I thought so. Better than 4.88 pushing 35s.

 

[Steel City 06]

For the 6 speed, the only reason I wouldn't do 4.88 with 33s or 5.13 with 35s is because 4th gear becomes less useful at freeway speeds.

For the NSG370, 4th gear is the power gear between 70-80 mph. You want to climb a steeper grade and hold speed or pass some elderly driver, 4th gear is what you want.

With 4.88 and 35s, 4th gear turns 4300 at 70, 4600 at 75, and 4900 at 80. Thus it is right in the power band at about 75 mph, and delivers far more torque to the ground than 5th or 6th gears at those speeds.

Go up to 5.13 and 4th turns 4500 at 70, 4850 at 75, and 5200 at 80. At that point you are past the powerband once you are above 70 mph. And 5th is still only turning 3600-4100, so even though you still get more torque to the ground than in 5th, it is significantly less than you would get with 4th and 4.88.

With the 5 speed I would absolutely go with those deeper gears, as 3rd becomes useless by around 70 regardless and you have to rely on 4th.