DanW
Well-Known Member
- Thread starter
- #1
I'm going to re-gear my Jeep. I went up very slightly in tire size from 34.6" diameter KO2's to 34.9" Grabber X3's. The slight increase in diameter and higher rolling resistance of the mud tread hit the tipping point for me with 6th gear. On the KO2's, I'd shift into 6th at 60mph and it was ok. Now I feel like 65 is the shift point and it will hold it, but it just bugs me. 1st through 5th is fine, really. And finally, reverse was and is just too tall, with either tire.
So, I've done the math and see the rpm differences. On paper, I very slightly favor 4.88's. But after driving around knowing what the RPM's would be at different speeds, it pushed me back to 4.56, which would give me slightly more rpm than the original stock 33's and the current 4.10 gearing gives. The short time I ran the 33's, 6th was perfectly fine and the engine could pull hills pretty well in that gear.
So the final phase of the decision is at hand. I need to hear from Jeep drivers with manual transmissions, 35" tires, and either 4.56 or 4.88's to see how you like them after living with them. I know it is very subjective, so I'm probably looking more for someone who says something like 4.56 turned out not to be enough, or 4.88's went too far. I have a feeling that either is actually fine in the real world and that both groups will be very happy.
@chevymitchell , whose advise I highly respect, said 4.88's were perfect with 37's. One thing I know for sure is that I won't be going to 37's on this Jeep. There are too many reasons to go into here, but getting 4.88's to keep that option open is just not part of the consideration. If hell froze over or aliens landed at the White House, and I did change my mind, I think 4.56's could pull 37's ok and would leave me no worse off than I am right now, which is liveable. I'm doing this just to fine tune the Jeep, not because it is a dog or not fun to drive. I'd be fine leaving it alone. I just want to make it a little better.
Final thought: Low range is no issue. It is fine now and a final drive change to either choice won't make a huge difference there, for me. Either would only improve on what is already good.
My two areas of concern are 6th, which I've already explained, and 1st. I don't want first to be too short. The difference right now, according to the caclulation, is that redline currently occurs at about 30 right now and would drop to about 25 or 26 with 4.88's, and 28 or so with 4.56.
So help a Jeep brother out and let me know your experiences and thoughts with your re-geared Jeeps! I'd be in your debt for the feedback and help in making the decision. If I don't hear from anyone, I'll make the decision tomorrow and I'm pretty sure I'll be happy either way.
So, I've done the math and see the rpm differences. On paper, I very slightly favor 4.88's. But after driving around knowing what the RPM's would be at different speeds, it pushed me back to 4.56, which would give me slightly more rpm than the original stock 33's and the current 4.10 gearing gives. The short time I ran the 33's, 6th was perfectly fine and the engine could pull hills pretty well in that gear.
So the final phase of the decision is at hand. I need to hear from Jeep drivers with manual transmissions, 35" tires, and either 4.56 or 4.88's to see how you like them after living with them. I know it is very subjective, so I'm probably looking more for someone who says something like 4.56 turned out not to be enough, or 4.88's went too far. I have a feeling that either is actually fine in the real world and that both groups will be very happy.
@chevymitchell , whose advise I highly respect, said 4.88's were perfect with 37's. One thing I know for sure is that I won't be going to 37's on this Jeep. There are too many reasons to go into here, but getting 4.88's to keep that option open is just not part of the consideration. If hell froze over or aliens landed at the White House, and I did change my mind, I think 4.56's could pull 37's ok and would leave me no worse off than I am right now, which is liveable. I'm doing this just to fine tune the Jeep, not because it is a dog or not fun to drive. I'd be fine leaving it alone. I just want to make it a little better.
Final thought: Low range is no issue. It is fine now and a final drive change to either choice won't make a huge difference there, for me. Either would only improve on what is already good.
My two areas of concern are 6th, which I've already explained, and 1st. I don't want first to be too short. The difference right now, according to the caclulation, is that redline currently occurs at about 30 right now and would drop to about 25 or 26 with 4.88's, and 28 or so with 4.56.
So help a Jeep brother out and let me know your experiences and thoughts with your re-geared Jeeps! I'd be in your debt for the feedback and help in making the decision. If I don't hear from anyone, I'll make the decision tomorrow and I'm pretty sure I'll be happy either way.
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