4 inch lift installed, almost. I am planning on putting 33 inch tires on and I have an Auto trans with a 2.5L, do you guy think that I should go with 4.88 or 4.56? This is my daily driver and I don't want to over do it, but I want the power. Is there any one with this setup? What kind of top speed will I get and will my RPM be to high?
4.56 or 4.88 auto 2.5L 33 tires
- Thread starter 4x4dave
- Start date
GaryMB
New member
Bounty__Hunter
Super Moderator
4k on a six cylinder, ouch. Not only is it hard on that engine, but I've never heard of it on stock gears. Stock gears for the 4.2L or 4.0L 5spd should be 3.07.
As for the 2.5L auto, your stock gears should be 3.73. Going to 4.56 will put your rpms right back to where they were stock at 65mph. 4.88 will add about 200 rpm at 65mph, not too bad at all.
If it were my, 4.88 all the way. Regearing is $$ and time intesive, and 3.73 to 4.56 isn't much of a change. Go to 4.88 to get your moneys worth and to help compensate for the added weight of the larger tires as well as the larger diameter.
As for the 2.5L auto, your stock gears should be 3.73. Going to 4.56 will put your rpms right back to where they were stock at 65mph. 4.88 will add about 200 rpm at 65mph, not too bad at all.
If it were my, 4.88 all the way. Regearing is $$ and time intesive, and 3.73 to 4.56 isn't much of a change. Go to 4.88 to get your moneys worth and to help compensate for the added weight of the larger tires as well as the larger diameter.
Bounty__Hunter
Super Moderator
www.4lo.com/calc/gearratio.htm and plug in 1:1 for your transmission and transfer case ratio to compare rpms at any given speed. I recommend comparing 27" tires with 3.73 axle ratio with 33" tires and either 4.56 or 4.88.
GaryMB
New member
Like Bounty said, 4.56 to go back to stock, 4.88 for more power but lower freeway speeds. You can plug in the model of your transmission at http://www.grimmjeeper.com/gears.html and compare different gear ratios side by side; it's the most detailed gear ratio calculator I've come accross. Plugging in 1:1 for the transmission would let you compare the differences in axle ratios, but if you have overdrive would not give you an accurate estimate of freeway rpm (you have overdrive, right?). While I still think 4.56 would be a viable option, I have to agree that 4.88 would be a better choice...those 4 angry squirls under the hood aren't putting out much power, and the big tires and lift are going to slow you down alot more than just the tire's increase in diameter. I doubt you will have enough power after the tires and lift to go fast enough to need 4.56 gearing. Now if you did an engine swap, that would open up some doors for you...
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Bounty__Hunter
Super Moderator
4x4dave, where in IL you located? I'm just a little south of St. Louis.
Most 2.5L auto trannies have no overdrive, straight 1:1 drive ratio.
200 additional rpm at 65mph is nothing to a 4banger, they like to spin up.
Most 2.5L auto trannies have no overdrive, straight 1:1 drive ratio.
200 additional rpm at 65mph is nothing to a 4banger, they like to spin up.
GaryMB
New member
I didn't realize that you didn't have overdrive; I see where you would be worried about the 4.88's on the highway. I would just compare max cruising rpm/speed you will be happy with and go from there. Both gear ratios will work well, only one will be better offroad and the other on the highway. Basicall you are looking at a 4mph difference on the highway.
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Bounty__Hunter
Super Moderator
4bangers generally have:TwistedCopper said:
3.73 with auto trans
4.10 with manual trans
Same applies to XJ's and MJ's. There's a reputed 4.56 from the factory in some early 4banger XJ's/MJ's, but it's myth until I see one in person
jfrabat
New member
I know this is reviving an old discussion, but I have a 94 YJ 2.5L Jeep. I currently have 31" tires, and it runs fine (although after 65mph, it feels like you hit a wall, and unles you downshift from 5th, you are NOT going to accelarate!). But I am thinking about doing a Spring Over Axle conversion and putting 33" tires, but I am not sure the 4 banger will be able to handle it. I dont want to spend big $$$ in regearing or swaping engines, but I do like the bigger tires better.
I have NO IDEA what my current ratio is, but I do have a manual 5 speed transmission. I posted a similar question in other discussions, so those that see the repeated question, please excuse it (it just seemed propper to include it here for future members' reference).
Felipe
I have NO IDEA what my current ratio is, but I do have a manual 5 speed transmission. I posted a similar question in other discussions, so those that see the repeated question, please excuse it (it just seemed propper to include it here for future members' reference).
Felipe
On my 89 YJ 4 banger i put 35" tires on it with the stock gearing (till the axel broke being stupid) it pulled 65-70 on the highways in 4th but it had to be flat or down hill, i slow down in 5th gear going down hill. It does put more stress on the clutch and what not starting out cause you have to feather it a little more so you dont stall.
Your 4 cyl with a 5speed is 4.10 ratio in the axels.
Your 4 cyl with a 5speed is 4.10 ratio in the axels.
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