Gearing Your Challenger for the Right Task

Challengers are rear wheel drive cars which places the differential out between the rear wheels. Power is sent from the transmission through the driveshaft and to the ring and pinion in the differential. The pinion is directly connected to the driveshaft and is turned by it. The pinion spins the ring gear which then spins the carrier that sends the power through the axles.

Challenger GT: On a Challenger GT you will find that there is an active transfer case that sends power to the front axle. Because of this if you plan on altering the gear ratio in the rear differential you will need to do exactly the same to the front. This will keep the drivetrain moving at the same rate and no binding up will occur.

The ring and pinion are a set of gears that directly impact the acceleration characteristics of the Challenger. You will often find that the ring and pinion gear ratio is listed as the final drive of the Challenger. 

When you are looking to manipulate top speed, throttle response, and acceleration, you can alter these gears to make your Challenger drive as you need it to.

Learning to read gear ratios can be a bit of a trick to get used to but once you have it down there’s no forgetting it. A typical final drive ratio in a Challenger is 3.92:1.

This means for every time the driveshaft spins 3.92 times, the tires rotate once. 
By moving to a lower gear ratio (higher numerically) you will increase throttle response but lower top speed.

By moving to a higher gear ratio (lower numerically) you will reduce throttle response but increase top speed. A lower gear ratio than 3.92:1 would be a 4.10:1 and a higher gear ratio would be 3.64:1.

Even if you have a rough idea of what you’re looking to do with your Challenger and what you would like to improve you need to understand what you have to work with out of the line. For instance, you might want more throttle response by throwing a lower ring gear in.

Without reading into what your car has, you can purchase a 3.92:1 ring and pinion kit only to come to find that’s what your car already has. So before you go shopping you should check the list below to see what you’ve got.

Factory Challenger Gear Ratios

• SE w/17" wheels = 215mm 3.64:1
• SE w/18" wheels = 215mm 3.64:1
• R/T A/T = 215mm 3.06:1 
• R/T 6-speed w/18" wheels = 226mm 3.73:1 
• R/T 6-speed w/20" wheels = 226mm 3.92:1 
• SRT = 215mm 3.06:1 open 
• SRT A/T = 226mm 3.06:1 
• SRT 6-speed = 226mm 3.92:1 
• GT AWD= 3.07:1
• Hellcat = 3.70:1
• Demon = 3.09:1

Choosing the right gear ratio needs to be balanced with the type of performance you are looking to improve. With Challengers, you have a number of races to compete in. Before you go buying gears you need to think about the obstacles ahead to ensure the best performance.

Road Racing: Road races have a lot of wide-open segments where top speed is of concern and some tight turns where throttle response will be demanded. If you plan on road racing you’re going to want to try to find a gear that’s got enough to fling you out of the turn, but allows you to climb to that redline with confidence. You don’t want something too high or too low, you want something that’s in the middle.

Quarter Mile: The quarter mile is a short run that allows you to build up some significant speed. Still, for this type of race, you’re going to look at something on the lower end of gear ratios. Something like a 3.73:1-3.92:1 would work just fine. 

Eighth Mile: As one of the shortest types of drag racing you’re going to want to make every second at the bottom end count. For this type of ratio you will be looking for something extremely low. Many drivers will rub up against or surpass a 5.0:1 gear ratio. 

Half Mile: The half-mile drag is super long in comparison to other drags and requires as much top end performance as possible. For this type of racing you wouldn’t want to go super high because you still want to give yourself something that will give you some extra bite at the end. Remember that the third generation of Challengers have overdrive gears which allows you to milk a lower ring gear for all it’s got.

To install a ring and pinion in your Challenger’s differential you will need an installation kit and some specialty tools. 

This process can be approached by an experienced mechanic but without the proper tools and shop settings, this is something that is best left to the pros.