Okiespaniel
Senior Member
- Joined
- Dec 18, 2011
- Posts
- 1,645
- Reaction score
- 898
- Location
- Work, Shop, Computer
- Ram Year
- 2000
- Engine
- magnum, 5.9
Benefits to gears...ok let me explain what happens why you need them first.
When you add lift components and larger heavier tires, along with other mods you create three issues.
First, you increase the overall weight of the truck.
Second, you destroy the aerodynamics of the vehicle. Yes... your truck was designed from the factory to have less drag than its predecesors.
Lastly, the larger tires increase the "unsprung weight" This is one of the most crucial parts of the power loss you'll experience when you innstall them them. More on that in a moment
The obvious is you need to add more "power" to the truck. So everyone starts out with simple bolt on engine components. You know. air intakes, exhaust, throttle bodies, iintakes manifolds, tuners... and they see some gain but not much. So they believe the truck's a piece of crap and trade up. Some guys go all out and build a bigger motor, supercharge it, and again this makes a difference, but for $ spent, you could have had more for less.
You see, horsepower doesn't get your truck moving, especially from a dead stop. It takes torque, and the taller, heavier and bigger tired a truck is, the more it takes. Even Hemi guys had to learn this. The Cummins owners smile and tweak some knobs on thier tuner. Dirty biggers!
The unsprung weight of larger tires sucks up torque big time. And it's in exponential amounts. So a 33 inch tire might take 50% more applied torque to rotate it at the same speed as a 31 inch tire. A 35 inch tire might take as much as 150 % (or more) more applied torque to turn it at the same rate! The effort required to turn those big ol' meats ballons the torque converter and makes for clutch plate slippage increasing heat and wear. Well guess what?
Gears are torqure increasers! YAY gears! Gears take the suppled torque from the transmission/motor and multiply it many times to overcome the weight of your vehicle and it's tires. The benefits down low are increased acceleration and many times depending on how the vehicle is driven a slight mileage increase. It's not a big one, becasue the faster you go the more the reduced drag of your lifted truck takes over. Another advantage is on the downlow, gears reduce tranmission heat.
And that brings me to the downside of gearing. Gears increase torque where you need it, but suck up horsepower and gas on the other end. Driving fast will raise your rpms, lowering mileage and increasing engine wear. If you neeed speed to go with your acceleration, you'll need motor upgrades. Most of you guys don't need that much. Been there done that.
Here's the deal...if you want to speed away from the stop sign like your truck did stock, and don't try to drive NASCAR on the highway (which will kill you and your truck someday) you'll love the benefit to gears, and you'll want them. A quick rule of thumb is 3:92s/4:10s for 33 inch tires, 4:56 for 35s, 4:88s for 37's and 2500/3500 axles with 5:38s for larger. This assumes you use the truck for on and off road use and need a good crawl speed in 4 low.
Some guys who run the highway use 3:82s with 35's but in talking to them I find most have done motor mods which also increased torque. 3:92s with supercharger is a good combo.
Gear installation varies figure anywhere from 1300 to 1800 for a reputable shop (unless he's your best bud) to do a proper job. . Believe me it's worth it.
When you add lift components and larger heavier tires, along with other mods you create three issues.
First, you increase the overall weight of the truck.
Second, you destroy the aerodynamics of the vehicle. Yes... your truck was designed from the factory to have less drag than its predecesors.
Lastly, the larger tires increase the "unsprung weight" This is one of the most crucial parts of the power loss you'll experience when you innstall them them. More on that in a moment
The obvious is you need to add more "power" to the truck. So everyone starts out with simple bolt on engine components. You know. air intakes, exhaust, throttle bodies, iintakes manifolds, tuners... and they see some gain but not much. So they believe the truck's a piece of crap and trade up. Some guys go all out and build a bigger motor, supercharge it, and again this makes a difference, but for $ spent, you could have had more for less.
You see, horsepower doesn't get your truck moving, especially from a dead stop. It takes torque, and the taller, heavier and bigger tired a truck is, the more it takes. Even Hemi guys had to learn this. The Cummins owners smile and tweak some knobs on thier tuner. Dirty biggers!
The unsprung weight of larger tires sucks up torque big time. And it's in exponential amounts. So a 33 inch tire might take 50% more applied torque to rotate it at the same speed as a 31 inch tire. A 35 inch tire might take as much as 150 % (or more) more applied torque to turn it at the same rate! The effort required to turn those big ol' meats ballons the torque converter and makes for clutch plate slippage increasing heat and wear. Well guess what?
Gears are torqure increasers! YAY gears! Gears take the suppled torque from the transmission/motor and multiply it many times to overcome the weight of your vehicle and it's tires. The benefits down low are increased acceleration and many times depending on how the vehicle is driven a slight mileage increase. It's not a big one, becasue the faster you go the more the reduced drag of your lifted truck takes over. Another advantage is on the downlow, gears reduce tranmission heat.
And that brings me to the downside of gearing. Gears increase torque where you need it, but suck up horsepower and gas on the other end. Driving fast will raise your rpms, lowering mileage and increasing engine wear. If you neeed speed to go with your acceleration, you'll need motor upgrades. Most of you guys don't need that much.
Been there done that.Here's the deal...if you want to speed away from the stop sign like your truck did stock, and don't try to drive NASCAR on the highway (which will kill you and your truck someday) you'll love the benefit to gears, and you'll want them. A quick rule of thumb is 3:92s/4:10s for 33 inch tires, 4:56 for 35s, 4:88s for 37's and 2500/3500 axles with 5:38s for larger. This assumes you use the truck for on and off road use and need a good crawl speed in 4 low.
Some guys who run the highway use 3:82s with 35's but in talking to them I find most have done motor mods which also increased torque. 3:92s with supercharger is a good combo.
Gear installation varies figure anywhere from 1300 to 1800 for a reputable shop (unless he's your best bud) to do a proper job. . Believe me it's worth it.
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