Best gear ratio for 31" tires?

[cbxer55]

More of a race truck than mine for sure. My performance mods currently consist of a K&N air filter. Hopefully that will change in the future. Thats interesting you get such good gas mileage. Does the JET Chip help you run at higher RPM?

Yes, it changes the shift points to higher up the rpm band. Also changes the short term fuel trims and the timing, hence the need to run 93 octane. It's an old, old chip. Been on the truck many years. Considering getting a handheld tuning device, such as a SCT X4. Those are the best, plus they come with a bracket to allow it to be dash mounted. It also has gauge functions for any of the items the OBD II system covers.

I've taken the chip off and re-installed it a few times. I can tell it's there. Same with the cai. Some here insist they do nothing. Yet when I remove mine and put the stock system back on, I'm like :where's the beef?" I can tell the difference. I also tried running the stock box with the three inch tube from the MAF to the TB. Didn't do a damn thing. Tried running the stock pinched down tube with the open filter, didn't do a damn thing. Put the cai back on, back to the way I love it. So the stock system went the round-open-top-file route, so I'll never be tempted to put it on, ever again.

Yeah, the 20.03 surprised me, as it came after the 4.10 install. Only thing I can assume is the 3.0 is mucho happier revving higher. Also the good mileage came after a nice shift kit was installed in the transmission along with the 4.10 gears. And with the 4.10 gears, the truck shifts into OD at a lower speed than it did before, and the torque converter clutch locks up at a lower speed than it did before. All that may help. Truck also doesn't shift out of OD as often as it used to, and that includes going uphill. Doesn't hunt around between Drive and OD like it used to between 40 and 45. Goes into OD solid and stays there.

 

[Roert42]

Yes, it changes the shift points to higher up the rpm band. Also changes the short term fuel trims and the timing, hence the need to run 93 octane. It's an old, old chip. Been on the truck many years. Considering getting a handheld tuning device, such as a SCT X4. Those are the best, plus they come with a bracket to allow it to be dash mounted. It also has gauge functions for any of the items the OBD II system covers.

I've taken the chip off and re-installed it a few times. I can tell it's there. Same with the cai. Some here insist they do nothing. Yet when I remove mine and put the stock system back on, I'm like :where's the beef?" I can tell the difference. I also tried running the stock box with the three inch tube from the MAF to the TB. Didn't do a damn thing. Tried running the stock pinched down tube with the open filter, didn't do a damn thing. Put the cai back on, back to the way I love it. So the stock system went the round-open-top-file route, so I'll never be tempted to put it on, ever again.

Yeah, the 20.03 surprised me, as it came after the 4.10 install. Only thing I can assume is the 3.0 is mucho happier revving higher. Also the good mileage came after a nice shift kit was installed in the transmission along with the 4.10 gears. And with the 4.10 gears, the truck shifts into OD at a lower speed than it did before, and the torque converter clutch locks up at a lower speed than it did before. All that may help. Truck also doesn't shift out of OD as often as it used to, and that includes going uphill. Doesn't hunt around between Drive and OD like it used to between 40 and 45. Goes into OD solid and stays there.

I know you said you don’t live far from work, shorter gears are nice for shorter, lower speed drives.

I went from 3.08s in my f150 w/ a 300 and m5r2 at 15mpg no matter what (loaded, unloaded, highway, stop and go) to 3.55s. Truck was WAY better to drive under 50mph, so much more torque, and I started getting 18mpg on the way to work. A long drive but kept in under 55mpg all the way. Wouldn’t get over 80mph with the old gears, so I’m sure it was garbage on the highway after.

I miss that truck so much. :,(

 

[cbxer55]

I live seven miles from where I work. But I rarely drive seven miles. I typically take the long way, which can be anywhere from 15 to 30 miles. Depending on how much time I allow myself. The shortest way has so damn many traffic lights, 14 to 17 in that seven miles. Even the 30 mile route, I can get there at about the same time as the seven mile, just because of all the lights. I live in Stop Light City, USA. And choose to go around it, rather than through it, as much as possible. I live right on the northern edge of Stop Light City.

 

[gaz]

Pod,

Not all 4x4's come with a specific gear set, one of mine came with 4:10, the other with 3:43. It is worth the time and effort to establish what you have.

When my Ranger was new with a fresh tune up on premium with 3:43's on 25.7" rubber, it would net 20/25 (city/hwy). That set up was a little doggy on the steep stuff but did well at the fuel Depot.

Getting the same or more efficient performance on larger rubber is math to begin with, simple cross multiplication and then doing what is necessary to turn them with less fuel.

 

[85_Ranger4x4]

I like my 3.73’s with the 31’s.

 

[racsan]

what motor you have plays a big part, a 302 V8 or 4.0 litre V6 is usually fine with 31’s and 3.73’s, a 2.3 4cyl however wouldnt be, 4.10’s with a 4cyl and 31’s would be ok on flat ground but would struggle on hills and not like pulling a trailer. I personally run 4.10’s with my 94 lima 2.3 and tires are 225/70/15’s winter- 235/75/15’s summer. the 235’s are almost too much, especially if I try to tow anything. the 225’s are much better for towing and It does accelerate better with them. fuel mileage is about 21 mpg, speedometer is dead-on with the 235’s but is off by about 3mph with the 225’s. But either setup is better than the original it came with: 22570/14’s with 3.45’s

 

[Pod]

Pod,

Not all 4x4's come with a specific gear set, one of mine came with 4:10, the other with 3:43. It is worth the time and effort to establish what you have.

When my Ranger was new with a fresh tune up on premium with 3:43's on 25.7" rubber, it would net 20/25 (city/hwy). That set up was a little doggy on the steep stuff but did well at the fuel Depot.

Getting the same or more efficient performance on larger rubber is math to begin with, simple cross multiplication and then doing what is necessary to turn them with less fuel.

Oh that's interesting. I'll check out what gears I have tomorrow. I will also talk to the guy that does the re gears and see what he thinks as he's done a couple hundred and can give me some specifics on how different gears will affect the driving.

 

[Pod]

Yes, it changes the shift points to higher up the rpm band. Also changes the short term fuel trims and the timing, hence the need to run 93 octane. It's an old, old chip. Been on the truck many years. Considering getting a handheld tuning device, such as a SCT X4. Those are the best, plus they come with a bracket to allow it to be dash mounted. It also has gauge functions for any of the items the OBD II system covers.

I've taken the chip off and re-installed it a few times. I can tell it's there. Same with the cai. Some here insist they do nothing. Yet when I remove mine and put the stock system back on, I'm like :where's the beef?" I can tell the difference. I also tried running the stock box with the three inch tube from the MAF to the TB. Didn't do a damn thing. Tried running the stock pinched down tube with the open filter, didn't do a damn thing. Put the cai back on, back to the way I love it. So the stock system went the round-open-top-file route, so I'll never be tempted to put it on, ever again.

Yeah, the 20.03 surprised me, as it came after the 4.10 install. Only thing I can assume is the 3.0 is mucho happier revving higher. Also the good mileage came after a nice shift kit was installed in the transmission along with the 4.10 gears. And with the 4.10 gears, the truck shifts into OD at a lower speed than it did before, and the torque converter clutch locks up at a lower speed than it did before. All that may help. Truck also doesn't shift out of OD as often as it used to, and that includes going uphill. Doesn't hunt around between Drive and OD like it used to between 40 and 45. Goes into OD solid and stays there.

That sounds nice but 93 octane gas is about $6 a gallon out here so that's just not going to happen unfortunately.

 

[Rimjam]

My vote is: 4:10 with 31" tires ( '88 4x4 w/ 2.9 & auto ).

 

[cbxer55]

That sounds nice but 93 octane gas is about $6 a gallon out here so that's just not going to happen unfortunately.

93 octane here is $4.299. Anyhow, I get 93 octane another way sometimes. 15 gallons of 91 octane and two gallons of E85. Comes out to a perfect 10% and 92.7 octane. Truck runs great on it as well.