Quick Answer

Question: What gear ratio is a 12 bolt rear end?

Probably the easiest 12-bolt differentials to find are the type 2 units. These are found primarily in standard-performance Chevrolet passenger cars. Type 2 ratios were somewhere between 2.29:1 and 2.73:1.

How do you find the gear ratio on a 12 bolt?

Count the number of teeth on the pinion gear and count the number of teeth on the ring gear. Divide the ring gear teeth number by the number of teeth on the pinion. The result is your gear ratio.

What ring gear size is a GM 12 Bolt diff?

12-Bolts to Glory The GM 12-bolt debuted in 1965 and was mass-produced until 1972. It features an 8.875-inch ring-gear carrier held in place with two internal main caps. The pinion gearshaft measures 1.625 inches in diameter and is shimmed to achieve the proper pinion depth.

What’s better 10 bolt or 12 bolt rear end?

First, the 10-bolt’s pinion shaft diameter is 1.438 (25 splines) while the 12-bolt is 1.625 (30 splines) which makes the 12-bolt 13 percent larger in diameter and therefore stronger.

What does a 12 bolt rear end mean?

In actuality, the term 12-bolt is due to the 12 bolts holding the ring gear to the differential. The coil spring mounts and the mounts for the upper trailing arms on the differential identify this as a Chevelle or Monte Carlo rearend, not one from a full-size car like an Impala.

What size is a GM 12 bolt rear end?

The GM 8.875-inch, 12-bolt positraction came in many 1965 to ’72 passenger cars. The pinion shaft on passenger cars’ differentials was 1.625 inches in diameter, and the cover was oval, measuring 10.9375 inches wide by 10.625 inches tall.

How many teeth does 4.10 gears have?

Example: 4.09 / 4.10 / 4.11 Gear Ratios

Axle Ring Gear Teeth Final Ratio
Toyota 8″ 37 4.11
Dana 44 45 4.09
Dana 60 41 4.10
GM 10.5″ 14 Bolt 45 4.09

How do I know my diff ratio?

Rotate the marked tire one revolution while counting how many times the driveshaft rotates. eg, If your driveshaft made 3 3/4 revolutions, that would determine a 3.73 gear ratio. If you get approximately 2 3/4 revolutions, you have a 2.76 gear ratio.

How do I choose the right gear ratio?


The conventional procedure for selecting gear ratios is to pick ratios that run the engine rpm to redline at the end of the medium and longest straights, and pick the lower gear ratios to minimize the rev drop at each shift. This method minimizes the number of shifts per lap.

How many quarts is a 12 gauge bolt?

Registered. A 12 bolt should only take around 3 quarts until it comes out the fill hole.

What is the difference between a car and truck 12 bolt rear end?

They are two different rear ends, and the car is better in nearly every way. If I am not mistaken the 8.5 10 bolt is stronger in more ways too then the truck 12 bolt. The only things that make’s the 8.5″ &amp
the Car 12-bolt stronger is the larger pinion stem diameter &amp
only seen one break.

Did Pontiac make a 12 bolt rear end?

Although Buick, Pontiac and pre-’67 Oldsmobiles used the same basic 8.2-inch 10-bolt differential (1967-’70 Oldsmobiles used the Olds-specific 12-bolt 8.5-inch differential), these are different from the Chevrolet 8.2 10-bolt offerings.

Is posi traction the same as limited slip?

Despite the fact that a lot of folks confuse the terms “posi” or “Positraction” with “limited slip,” the fact is that the two are basically one and the same. Today, all positive traction systems are referred to as limited slip systems.

How much horsepower can a 8.2 10 bolt handle?

Roughly 550 to 600 HP total. No slicks, drag radials. No problems with the 8.2 at all. I used the stock diff., the Auburn would be better.

How do I know my Chevy ring gear size?

The ring gear diameter is measured across the face of the gear. To obtain the ring gear diameter, simply place a tape measurer across the gear. This can be tricky if the ring gear &amp
carrier are still in the housing. In some cases, a differential can be identified by the number of cover bolts is has.

What is the strongest rear end?

Dana 60 Rear End Assemblies

If you want a big brute of a rear end under your car, look no further than a Dana 60. Even in the heyday of muscle cars, Dana 60 rear differentials were renowned for their strength, along with their difficulty to locate.

What size is a #12 bolt?

The number “12” is used as a size designator with no numerical meaning. “24” references the 24 threads per inch. You can identify a 12-24 screw by measuring the diameter with a ruler at slightly less than 7/32 inches (5.6mm).

How do you find the gear ratio on a Chevy Silverado?

Identify your GMC or Chevrolet rear end gear ratio by the RPO Codes, usually located on the placard labeled “Service Parts Identification” inside the drivers door panel or glove box.

What rear end came in a 57 Chevy?

Automatic 57 cars (both 6 and V8) came with 14inch tires and 3:36 rear gears. Stick shift 57 cars came with 14 inch tires and 3:55 gears.

How many teeth does 3.55 gears have?

39-11 Teeth

Manufacturer ‎Motive Gear
Brand ‎Motive Gear
Model ‎Motive Gear D35-355 Rack and Pinion, 39-11 Teeth, 3.55 Ratio
Item Weight ‎11.44 pounds
Product Dimensions ‎15.5 x 11 x 5.25 inches

Are 3.73 or 4.10 gears better?

4.10 is the typical gear ratio for a high-performance vehicle like a sports car or SUV because it provides better acceleration than 3.73 because of the faster second and third gears, which provide more torque at lower speeds to accelerate from a stop.

Are 4.10 and 4.11 gears the same?

4.10 will have 41/10 teeth so more, but smaller for the same diameter ring. 4.11 will have 37/9 teeth which will be larger. The 4.10 is a stronger pinion.

What is the best gear ratio for torque?

indeed Does gear ratio affect horsepower? A higher numeric axle ratio (4.11:1) keeps the engine running in the higher horsepower range, thus improving performance.Are 3.73 or 4.10 gears better?

3.73 Ratio 4.10 Ratio
Lower Torque Higher Torque
Better Gas Mileage Decreased Gas Mileage
Higher Top Speed Lower Top Speed

What gear ratio do I have f150?

Write down the number in the lower left-hand corner of the tag. It will look like “3.23” or “3.50.” This is the gear ratio.

How do I know my rear gear ratio?

Turn the wheel TWO revolutions and count the number of driveshaft turns. The number of driveshaft rotations will help you determine your rear axle ratio. For example, if it turned 3 and a half times, it’s a 3.50:1 ratio. If it turned 4 and a quarter times, it’s a 4.25:1 ratio.

What are 3.55 gears good for?

PERFORMANCE: The larger the axle ratio number, the quicker the truck will accelerate. For example, a truck equipped with 3.55:1 axle gearing will accelerate faster than one equipped with a 3.31 axle ratio.

Which gear ratio is faster?

A lower (taller) gear ratio provides a higher top speed, and a higher (shorter) gear ratio provides faster acceleration. . Besides the gears in the transmission, there is also a gear in the rear differential. This is known as the final drive, differential gear, Crown Wheel Pinion (CWP) or ring and pinion.

What is the best gear ratio for crankbaits?

Low gear ratio reel | 5.1:1 thru 5.4:1

A lower fishing gear ratio reel is ideal for big baits that pull a lot, such as deep crankbaits. These reels have the highest amount of torque, allowing you to put less effort into retrieving the bait and more energy towards finding the fish.