gears

[yota 91]

I have a 91 yota with 410 gears and running 31s.  I drive it back and forth to work and have some hills to climb and have to downshift to make it up them.  What gears would you recommend running and still have good gas mileage?

[Goldrush]

4.88s and 31s are gonna be a little steep for you. 4.56 will be a little better but still hurt your gas mileage. Your best bet is going to prolly stay will 4.11s for daily driving to keep your current fuel mileage.

[Snowtoy]

The 4.56 gear set is the factory gear set for 31's and a 5-spd transmission(need 4.88's if you have an auto), they will improve your mpg, as they will return your '91 to stock performance.  You can usually find the oem 4.56 set up rear 3rd and the front IFS section for around $150-200 each, if you go with new gears expect it to run anywhere from $700-2000 for parts plus bench labor or drive-in-drive out route labor.

[yota 91]

I would like to thank yall for the info.  I will have to look into getting a set and see if it will help cause i dont have any pulling power.

[Snowtoy]

There is about a 10% difference between the stock 28" tire and the 31's, which basically amounts to a 10% loss in performance/power.  The 4.56 gears and 31's should allow you to pass on the highway without having to downshift, depending on terrain and speed of course.  Also with a proper tire/gear combo, any performance upgrades to the exhaust or intake will have an actual effect on performance.  If the 31's are close to needing replacing, or will be when you get to the gears, 32's and 4.88 gears would be a pretty good combo, a little over geared, but not enough to be an mpg/heat problem.

If you want to experiment with different tire/gear combo's and their effect on mph/rpm's, these Drivetrain Calculators will give you the info needed, and you can find the transmission gears here Marlin's Transmission Gear chart.

[emsvitil]

I can live with 4.10s and 31s on my 86.

If I was to regear, I'd go with 4.88s.

That way they'd work with the 31s, or 33s if I get a bigger tire.............

[Tim]

to give you an example of actual mileage I have a 1980 20r 4 speed with 35's.  at 55 MPH I am running nearly 3k and would expect to be at or around 2.8k if I had a 5th gear.  Per tank I get roughly 220-240 highway miles which in a 15 gallon tank is not the best but I am practically half throttle sucking fuel faster than it can fuel up in a carb'd motor.

I would say go for the 5.29's due to the fact you would have a fifth gear which would keep the RPM's lower and also allow you to use less throttle in doing so which means less fuel and would have better options in the future for larger tires. You would have better pulling power too.  If you had a V-6 it would be best to stick with 4.88's

[Snowtoy]

From your statement about how much throttle you are using makes me think your poor mpg's have more to do with engine or fuel delivery issues, than it is a lack of 5th gear.  What is the state of the engine, i.e, mileage, compression, carb or exhaust modifications?

[dropzone]

Bossnote-
Stock tank?
Thought the shortbed tank was 13.5 gal and the longbed tank was 16 on 1st gens..
Have you tracked your actual mileage with a GPS?
mine with 35's and 5.29's is getting about 16-17mpg around town...which is about comparable to yours w/ a 13.5 gallon tank

[Tim]

From your statement about how much throttle you are using makes me think your poor mpg's have more to do with engine or fuel delivery issues, than it is a lack of 5th gear.  What is the state of the engine, i.e, mileage, compression, carb or exhaust modifications?

Yeah maybe so but driving a 34 year old Toyota 20r on 35's with 5.29's going 55-60 down the road  half throttle is about right.  its no 22re we are talking about.

It may be a 16 gallon tank I was just trying to remember the amount of fuel I put in last fill up.  so its around 13-14 mpg

[BigMike]

I would say go for the 5.29's due to the fact you would have a fifth gear which would keep the RPM's lower and also allow you to use less throttle

This might be nice if he only drove in the hills and his top speed was no more than 65-70 mph. Really the OP should specify what type of roads the majority of his daily driving sees. "Some hills" ... How steep are they, are you downshifting into 3rd? What is your average cruising speed?

According to our old speed calculator, 31" tires in 5th gear with 4.10s sees 70 MPH at about 2,650 RPM.  To do this same speed with 5.29s he'll be almost 800 RPM higher. Also this is assuming his 31" tires actually measure "thirty-one-inches" tall. They may only measure 29.5" or 30" which would push his RPM closer to 3,600 RPM just to gently cruise at 70 MPH. A constant 3,500 RPM wouldn't be the end of the world but carb'd 22Rs that I've experienced start to run out of steam just over the 4k mark .... so you'd basically be near the peak power band all the time just cruising around which does seems excessive.

When I first built my rig, knowing I would eventually have 37s, I installed 5.29s. The problem however was that at the time I only had bald 33" tires. My first ever wheeling trip was at the Hammers and I was more than an hour behind my group on the highway and was literally running 4,000 RPM at just above 80 MPH to catch up to them. This was a six hour road trip and it took all of that to catch the group. Six hours of that high a RPM was horrible: Loud, vibrations all over, could barely hear myself talking to myself. Poor, poor engine.

BigMike