Originally Posted by Tofer

you'll want 5.29s

Originally Posted by camo31"10.50"

yep..5.29's..if you were SAS'd then you could run 5.71's but no 5.71's are made for the ifs 7.5in. front diff

Originally Posted by dark_fairytales

So here I go explaining the relationship between engine torque and your final drive gearing. I'm going to try to keep this as simple as possible using the 22re and the W56 tranny as the example.

To start with, the 22re has about 140 ft/lbs of torque at an rpm of 2800. On the W56 manual tranny, fourth gear is 1:1, which means the input shaft in the front of the tranny rotates at the exact same rate as the out put shaft at the rear. The final drive (also known as the ring and pinion gears) has a ratio of 4.10:1. To help understand the relationship between the ring and pinion gear and the ratio that represents them, I will explain. In the designation 4.10:1, the 1 represents the ring gear. We only need to know that the ring gear only rotates one full rotation. On the other hand, the 4.10 represents the pinion gear, which completes 4 full rotations plus a 10th to rotate the ring gear one full rotation.

Lets have some fun with some numbers so you can grasp the the concepts and relationship between the ring and pinion gears. For example, if you wanted to know how many turns are required of the pinion gear to turn the ring gear twice or three times you would simply multiply the designation 4.10 by 2 or 3. By doing so, you would end up with an answer of 8.2:2 if twice or 12.3:3 if three times. Just like fractions, ratios are typically taken to the lowest common denominator in order to keep ratios standard and simple. ( I do apologize for explaining all of this, but there are those in the world who may come across this info for the first time. We were all noobs at one point)

Now lets look at tire size. The stock size tire for a Toyota pickup was 28”. I do know 30” was an option, but the standard is 28” and we will use that for reference. The tire is directly related to the ring gear by one fact: the tire will rotate once for every rotation of the ring gear, due to the way the tire and ring gear are locked in a 1:1 ratio. On some vehicles this is not true, but we will just stick with the Toyota, which is similar to 90% of all vehicles in the world. Next is forward movement, which is dictated by the diameter of the tire its self. For example, a 28” tire making one rotation will move a vehicle forward 87.92 inches. In order to determine the forward movement you only need the circumference of the tire, which we all know is 28”, multiplied by 3.14 and you get 87.92 inches.

So now, with the stock numbers represented above, we can mess around with some ratios to get a base line. For simplicity, we will be sticking with fourth gear on the tranny, which (as stated before) has a 1:1 ratio. At 2800 rpms, 140ft/lbs go through the tranny and out the back end to the drive shaft at 1:1, still producing 140 ft/lbs on to the differential.(Yes. We all know that only in a perfect world is this entirely true, as you do lose some power down the drive train due to friction, but that is a constant and is currently an unnecessary variable) Due to the relationship between the pinion and ring gear, the rpms change and end up with 682.92 rpms at the wheels. This can be calculated by taking your initial rpms and dividing them by the ring and pinion, which is 4.10. This not only changes the rpms, but also changes the force of torque that is applied at the axle. To determine the force changes, you take your 140 ft/lbs and multiply it by your 4.10 number again and you end up with 574 ft/lb of torque. All of this takes place within 87.92 inches of forward motion. (again this is only in a perfect world, but for basic purpose it is fine) The final step is to make a new ratio, describing the relationship between the torque at the wheel, to one inch traveled. So now we take 574 ft/lbs and divide by 87.92 and get 6.5 (rounding to the nearest 10th), we also divide 87.92 by 87.92 and get 1. The new ratio is 6.5:1. This is the number we are wanting to match to the new tire and gear ratio.

There will be many numbers listed to avoid unnecessary typing to show the changes between 35” tires and the assorted gear ratios:

35inch tire X 3.14 = 109.9 inches traveled
4.10gear ratio X 140ft/lb = 574ft/lb

4.88gear ratio X 140ft/lb = 683.2ft/lb

5.29gear ratio X 140ft/lb = 740.6ft/lb

5.71gear ratio X 140ft/lb = 799.4ft/lb

We can now use the figures listed above to determine the ratios for each gear set vs. the 109.9 inches traveled per gear set.

4.10:1 gears = 5.2:1

4.88:1 gears = 6.2:1

5.29:1 gears = 6.7:1

5.71:1 gears = 7.2:1

Remember we are trying to match as close as possible to 6.5:1 to maintain stock driving characteristics. 4.88 and the 5.29 gears are both very close to our 6.5:1 and the difference is 0.1 ft/lb per inch.

Now comes the time to involve the real world factor into our perfect world equation. The factor is tire weight. In order to keep this as simple as possible, and not too technical, I will state that (for absolute fact) the 35” tire will not want to accelerate as quickly as the 28” tire. We all know it takes more force to move more weight, and when it comes to cars and trucks that force is torque. Comparing the 4.88 and the 5.29 the 0.5 ft/lb of torque per inch is going to be more acceleration friendly to the added weight of the 35” tires and that 0.5 ft/lb comes from the 5.29 gears.

There are pros and cons to the choice of the 4.88 or the 5.29 and they have to do with your mpg. The 4.88 will give better highway mpg once you are up to speed and remain at a steady speed, but will kill your mpgs any time you have to accelerate. Both going up hill or trying to get on to the freeway will require much more involvement of the gas peddle. On the other hand, the 5.29 will deliver better mpgs under acceleration, but will not be as efficient as the 4.88 at high way cruising. So the choice would have to do with each individual depending on how they drive or where they drive. Over all, I believe the 5.29 will deliver better mpgs per tank of gas due to the demands of acceleration on a vehicle. It would be a cool experiment to test and see which gear set would bring the better mpgs as a whole. The final keynote to state here is the change in the odometer. With the 4.88 and 35” tires, you will have traveled 5% further than the odometer states and with 5.29 you will lose 3% of what the odometer reads, so you have to factor that in when calculating your mpgs.

We can now take this same idea and match it to different engines, such as the 5vz, 7m or the 4.0. So here is the torque list for each engine and the stock ring and pinion ratio related to the engine:

5vze-fe 3.4L 220ft/lb @3600 / ring and pinion 3.90:1 / stock tire size 30”

7mge 3.0L 196ft/lb @4800 / ring and pinion 3.73:1 / stock tire size 24”

1ger-fe 4.0L 278ft/lb @3700 / ring and pinion 3.73:1/ stock tire size 30”

With the info stated above, you can now apply the same formula to engine swaps. You have one of two options when considering matching gears to an engine swap. Option one would be to match the ring and pinion to the truck you are swapping the engine into. Option two would be to match the gears to the stock ratio to the new swapped engine. Most people would choose option one as they usually have already invested in gears before they ever did the engine swap, so that is what I'm going to choose for the example. I'm going to use the 5vze-fe as the example, since it is a very popular swap. So the 3.4L has 220ft/lbs. We multiply that by 4.10 and end up with 902 ft/lbs at the axle, then divide by 109.9 which is the circumference of the 35”tire, and we now get 8.2. Now, I can finally show you where this simple, pea brain formula can lead you. 8.2 is much higher then 6.5 but the problem is the peak torque on the 3.4L is at 3600 rpms, which will cause a huge error in this simple formula. To say the least, you would end up with bad acceleration and nasty free way behavior. This shows option two is the better way to go and takes the guess work out of all this. Running the formula again we multiply 220ft/lb to 3.90 and divide by 94.2 inches, which is the circumference of the stock 30” tire, we end up with 9.1. Lets try to match that newly swapped engine to some gears using 35”tires.

4.10gears = 8.2

4.30gears = 8.6

4.56gears = 9.1

4.88gears = 9.7

5.29gears = 10.5

5.71gears = 11.4

With luck, there is a gear set to match our stock 9.1 and that is the 4.56:1. Now, the choice from here would be yours: go with the 4.56, or go for a little more seat of your pants fun with the 4.88.

JUST REMEMBER TO MATCH THE GEARS TO THE ENGINES STOCK FACTOR WITH THIS FORMULA. THE REASON FOR THIS IS TO BE SIMPLE AND NOT TECHNICAL. SO, SORRY IN ADVANCE TO ALL THE MATHEMATICIANS AND PHYSICISTS.

Originally Posted by etan

5.29! 5.71s are weak

Originally Posted by etan

5.29! 5.71s are weak

Originally Posted by brian2sun

Huh? 5.71s will turn 38s much better than 5.29s. There's guys on here that run 5.29s and 33s with 3.4Ls and love it.

Originally Posted by ajoebob

might read up on it
http://www.gearinstalls.com/410suck.htm

Originally Posted by brian2sun

I guess it's personal preference but I would rather run lower gears and have more power. The guys that are running 5.29s and 33s (automatics particularly) are just hitting 3K rpms at 80. My rpms w/ an auto trans, 4.88s and 33s and are perfectly fine at high freeway speeds with a little room to spare even and I still get good gas mileage (17-18 average).

38s will drop those rpms way below stock and 5.71s would bring them back closer to the original stock range in 5th or O/D than 5.29s would. Not that 5.29s wouldn't be ok, but it's a lot of $$ to spend and it sure would suck to still be bogging down when you could have gone with lower gears for the same price. Either way, it'll be a lot better than 4.11s (or whatever he has now).

Originally Posted by toyota808

10" of lift and 38's isn't a crawling truck. sounds more like a mud truck to me so 5.71s aren't necessary. 5.29's are good enough. personally i wouldn't run 5.29s on 33s either unless anyone likes to redline just to hold 60mph. lol. if you wanted a better crawl ratio you shoulda put dual cases in it.



don't be so gullable. that guy only measured out the ring gear thoroughly and not the pinion. they work together and is only as strong as the weakest link. did you notice the size of the 5.71 pinion??? because that is where you're losing strength in 5.71. and even if so, why is it that most buggys run 4.10's or something similiar.

Originally Posted by etan

Theres no way 33's and 5.29's are going 80mph at 3k rpm. the speedo most likely wasn't corrected. it says 80mph, but road speed must be about 65-70mph. 5.29 is too much gear for 33's IMHO. you'll suffer at highway speeds.

4.88 puts 37" tires back to the stock ratio. strictly speaking ratio wise with tacoma/3rd gen 4runner drive train. miles per hour will match actual MPH. the problem will be the weight of the 37" tires, because rule of thumb for every 1 lb heavier is equal to 10lbs dead weight. strains motor and brakes.

lastly, in 1st gear on tacoma drive train:
4.10 and 31's have 40:1 ratio. (STOCK)
5.29 and 33's have a 52:1 low ratio.
4.88 and 37's have 48:1 ratio.
4.10 and 33's with the 2.28(stock) dual cases is 92:1.
4.10 and 33's with the 4.0 dual cases is 161:1.
4.10 and 33's with the 4.7 dual cases is 189:1

point is if you wanted good crawl ratio dual cases is something to look into.

Originally Posted by brian2sun

etan,
read this other thread - particularly the 2nd post:
https://www.yotatech.com/forums/f2/a...w-265s-194641/

That's where I got my info and I trust Dale because he's been on here for 7 years and has 8000+ posts.

Originally Posted by crolison

Hmm he said automatics, which have a hell of an overdrive...... I'm running 5.29's and 33's and its a tad much on the interstate, but in town and offroad its a dream.

5.29's and 37s put me at stock ratio....

Were also talking a 22re here, its got about 80hp less than your 3.4, and 38's................

It all depends on the person that set up your gears on how long they will last. As its been said before crappy gears + good setup will last sooo much longer than good gears with crappy setup.....

5.71's properly setup will do just great. I'd do 5.71's if I was him