4.30 or 4.88 gears

[tpruitt]

Well these are my two choices. Which one should i choose? I want something that would be equivalent to the 4. 10 with stock tires. I have a 3. 54 now and i am running 37 inch tires and i wanted to get my truck back to about 2000 -2200 rpm's running at 70mph. The 4. 88 and the 4. 30 are the only two that i have an option for. i wanted a 4. 56 but its not offered in the Dana 80. So with This information what gear would you pick. I also should say i have a 6 speed.



Thanks

Trey

 

[onesloryd]

Run the 4. 88 if you want it similar to the 4. 10 or run a 4. 56 if you want something close to a 3. 73.

 

[KLockliear]

The 4. 88's are the closest to a 4. 10 geared stock tire'd truck. However, the 4. 30's give you an effective ratio of 3. 66, so not too far off from your 3. 54/stock tire setup.

 

[tpruitt]

hey keith how did you come up with that 3. 66 number. can you do the same for the 4. 88 and let me know how close it would be to a 4. 10



Thanks

Trey

 

[KLockliear]

4. 15 ratio with the 4. 88's.



Simple: old tire / new tire * new ratio

31. 5 / 37 = . 851 * 4. 88 = 4. 15 effective ratio.

 

[C. Harlan]

4.30's!

my friend's dad just sold his 550 with 4. 88's... could pull anything, but never could go over 75. Keep this in mind... I realize you are getting bigger tires, but still... from experience, go with the 4. 30's.



-Chris-

 

[tpruitt]

i aready have 37 inch tires. I really dont need speed i want power but i want it not to run over 2250 at 70 mph in 6th gear. If anything i will end up putting bigger tires on eventually. Bigger is better. I am now running about 1550rpm in 6th gear at 65mph.

 

[Cooker]

Originally posted by tpruitt

If anything i will end up putting bigger tires on eventually. Bigger is better.

I think you answered your own question. If you are going to a larger tire I would opt for the 4. 88's If you are going to stick with the 37's I might opt for the 4. 30's.

 

[SS]

Trey,



My own experience with 4. 10's and 36. 4" tires: I'm always looking for 7th gear! Mine is a daily driver with moderate off-road use, but unless you *really* need the torque multiplication, I would suggest the 4. 30's. I'm just over 2000 RPM at 70 mph - I figure it would be about 2125 with 4. 30's and 2400 with 4. 88's. You can always downshift or add more power (or both! )

 

[tpruitt]

are the torque numbers really going to be that different between 4. 30 and 4. 88. I always like the idea of more torque but i am driving the truck back and forth from college alot and i dont think a 5 hour trip at 2400 rpms would be fun, if that what its going to be at. I have done some figuring my self because i only want to do this once. From what Keith said earlier its basically 4. 15 vs 3. 66. I guess any way i look at it it will be an improvement. For those out there running stock tires with 4. 10 what rpm's are you seeing at 65 mph.

 

[onesloryd]

I am currently running 4. 10 with a 235/85 and the rpm's are around 2200.

 

[CUMMINZ]

TP you have 3.01 ratio now with 3.54s. If you want about 4.10 finals you need 4.88s. This website will make the numbers work for you. I think the tire sizes are backwards.

I went to 4.30s with 19.5s. http://www.rocky-road.com/calculator.html