Re-Gear 4 sp w/ 315-70-17's

[Eric P]

Doing a 3.5 RC Lift with 315-70-17's on my 07 ssv Tahoe w 4sp, planning on some serious overlanding and looking for recommendations for the optimal gear ratio..... I'm thinking a 4:56 gear....

 

[swathdiver]

Doing a 3.5 RC Lift with 315-70-17's on my 07 ssv Tahoe w 4sp, planning on some serious overlanding and looking for recommendations for the optimal gear ratio..... I'm thinking a 4:56 gear....

That's a lot of gear for a 4-speed car. That'll have the motor turning about 2238 rpms mathematically at 70 mph. 1st gear ratio in 4LO will be 37.91:1.

@Tozan

 

[Eric P]

That's a lot of gear for a 4-speed car. That'll have the motor turning about 2238 rpms mathematically at 70 mph. 1st gear ratio in 4LO will be 37.91:1.

@Tozan

Do you think I would be able to do what I want (within the constraints of stock diffs) off roading with the 4:11's ?

 

[Geotrash]

Do you think I would be able to do what I want (within the constraints of stock diffs) off roading with the 4:11's ?

I do. Especially because you have a 2-speed transfer case. And I agree with James that the downsides of the lower gears will be significant.

 

[Tozan]

Do you think I would be able to do what I want (within the constraints of stock diffs) off roading with the 4:11's ?

I run 4:11's on mine with the 6 speed and they work pretty good. I have a 4 inch lift with 35's I started out going way to far with 4:88 (Pay the shipping I ll send them to you) and that was a terrible idea. Trans was shifting way to early, I was running around in town in 6th gear doing 35 mph. It was getting 10 mpg at best and accelerated really slow.

I think 4:56 would be too much as well, unless you plan on doing a lot of rock crawling. If you plan to crawl I think you picked the wrong vehicle for that.

 

[Eric P]

I run 4:11's on mine with the 6 speed and they work pretty good. I have a 4 inch lift with 35's I started out going way to far with 4:88 (Pay the shipping I ll send them to you) and that was a terrible idea. Trans was shifting way to early, I was running around in town in 6th gear doing 35 mph. It was getting 10 mpg at best and accelerated really slow.

I think 4:56 would be too much as well, unless you plan on doing a lot of rock crawling. If you plan to crawl I think you picked the wrong vehicle for that.

Do you feel that you can do what you want off road with the 4.11's ? (up to the limitations of the diffs of course)

 

[Tozan]

Do you feel that you can do what you want off road with the 4.11's ? (up to the limitations of the diffs of course)

Easily. I did over 2800 miles off road last year. It pulls just fine in high range and if anything is that bad I just drop it in to low range.

This shot was taken running up hill in 4H.


I pulled out a stuck Jeep with ease.

 

[Tozan]

It is deceiving but, there is almost 3 feet from the bumper to the ground here.




Here we have a Tahoe above Lake Tahoe..


Having fun in the high country in Nevada.

 

[Eric P]

That's a lot of gear for a 4-speed car. That'll have the motor turning about 2238 rpms mathematically at 70 mph. 1st gear ratio in 4LO will be 37.91:1.

@Tozan

I do. Especially because you have a 2-speed transfer case. And I agree with James that the downsides of the lower gears will be significant.

Easily. I did over 2800 miles off road last year. It pulls just fine in high range and if anything is that bad I just drop it in to low range.

This shot was taken running up hill in 4H.
View attachment 379727

I pulled out a stuck Jeep with ease.
View attachment 379728

 

[Eric P]

Well I certainly appreciate the feedback guys !, looks like 4:11's it is..... Tozan I read through your build thread a cpl of time and I am inspired for sure... I will create a build thread for mine as well.