I'm thinking of swapping my current 4.30 gears for 4.88's for better towing and offroading. What kind of rpms could I expect at 60 mph, 70, 80 in 5th gear?

I have a 1999 4Runner, V6, 4x4, 5 speed, 285's.


I think that a gear ratio of 4.56 would be almost exactly back to stock, but that the 4.88's would yield better towing. So, what rpms are you guys running? Keisur has told me about 3100 at 70 mph, who's next?



What does a stock 4Runner, V6, 5spd, 4x4, run at 70, 80 mph?

Yes, I have searched.

 

I think I am close to 3000RPM at 80 (not sure though)

Edit: 265/70/16, I don't know my stock ratio (maybe 4.10?)

 

Is that stock? Do you have 3.90's or 4.10's? What size tires?

 

Mine runs at 3000 RPM at 80 mph. 265/75/16 tires and 4.10 gears.

George

 

I ran my 265/75-16 BFG's for quite a while before switching over to my MTR's on 4.88's, but I can't remember the rpm's it ran at. On 315/75-16's @ 3000 rpm - 74mph GPS checked.

 

Nolan has some useful info on his website:

http://members.cox.net/nolanlh/4runner_drivetrain.htm

 

When mine was stock (4.10, 265/70, 5sp) at 70 mph I was running about 2700 rpm. Now with 265/75's I'm running about 2500 at 70 mph.

I did all the calculations a while back when I was deciding on what size tires and gears I wanted to get. So based on my calculations, with 285's and 4.56's it came out to be about 100 rpm's higher than stock between about 70-80mph. With 285's and 4.88's it came out to be about 200 rpm's highter than stock between 70 and 80 mph. Hope that helps.

 

Did you search a 6th grade math textbook?

Here, to make it easy- forget about speedo error and all that - ballpark is good enough unless you're an engineer and need it to 3 decimal places...

Pick any speed, say 60 mph. Note your rpms.
Now multiply that rpm by the new gear ratio, then divide by the existing ratio.

For example: Lets say you have 4.30s and you think you might want 4.56s. And lets say you turn 2500 rpm at 60mph.

2500*4.56/4.30=2651rpm
2500*4.88/4.30=2837rpm
etc

 

Yep, I've got to do that.

 

I believe that will put me at about 3400rpm at 78 mph. Yikes, a lot higher than stock.

 

FYI, All 3rd gen V6 5 spd 4Runners have 4.10 gears from the factory.

 

I believe the 3rd gens with e-locker have 4.30 gears .

George

 

I think Brett's e-locker was a retrofit, not OEM.

 

Don't think so. I think 5sp with 31x10.50 (or 265s or whatever they started using) option had 4.56 gears.

 

No, it really isn't. Stock (dont' forget STock Tires too) would put your rpms 'somewhere' around 2600 at 60, right smack where the horsepower and torque curves cross where it belongs. That calculates to 3380 at 78 mph stock. You want to push that much frontal area with the rolling resistance of big tires and the aerodynamics of brick at that speed with that little horsepower you're gonna need some rpms, a bit more than stock is better since you have more drag to overcome.

 

My 1999 V6 5spd 4x4 4Runner came with 3.90's, the e-locker 4Runners came with 4.10's and the auto w/e-locker had 4.30's.

The 4.30's and e-locker that I have were diff's swapped over from a wrecked 4Runner.

 

Are you sure that is for a 3.4 V6? Those sound more like the number for the 4 cylinder 4Runners to me.

 

I guess another option to regearing the diffs is to regear the transmission.

I could go with a 4.31 (3.83 stock) first gear from a turbo tranny and increase my crawl ratio to 47.6, fom the 42 I'm at now with 4.30 gears. If I kept the stock tranny and went to 4.88 gears in the diffs my crawl ratio would be 48. Or I could go and get the Marlin aftermarket gear set in the tranny with a 5.15 first gear and have a crawl ratio of 57.6.

If I regear it will be to mainly improve my towing (thinking about a bigger camper) and to improve my offroad crawling ability. The dual cases would be cool offroad but would not help at all with the towing so it's not an option.

 

Ok I know its long after last post but I was bored on the way back from lunch. Here are my reads:
80 at 3000rpm
75 at 2800
70 at 2600
65 at 2400
60 at 2200
50 at 2000
so 200 rpm for each 5mph increase, 265/70/16 tires.
C

 

don't think so. mine came stock with 265/70/16's, 5speed and had 4.10s.