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Discussion Starter #1
Five-speed manual
Gear Ratios
First 3.62:1
Second 2.05:1
Third 1.37:1
Fourth 1.03:1
Fifth 0.84:1
Reverse 3.58:1
Final-drive ratio 4.06:1

Four-speed automatic
Gear Ratios
First 2.85:1
Second 1.58:1
Third 1.00:1
Fourth 0.69:1
Reverse 2.18:1
Final-drive ratio 4.04:1

Any mechanics here? Has anyone ever heard of someone changing the final drive ratio in a manual trans. Accent? Is it possible and what would it take? I'm talking taller to reduce RPMs for better FE.
 

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and by easier, he means possible. and you've got your gear ratio thinking backwards. Taller gearing or Smaller tires produce more acceleration, great for city driving. Shorter gearing or Taller tires will give you more top end cruising. Can't have both, not in the Accent with the short geared transmission.
 

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Discussion Starter #5
QUOTE (TwitchAutoSystems @ Feb 23 2010, 11:19 PM) index.php?act=findpost&pid=299729
and by easier, he means possible. and you've got your gear ratio thinking backwards. Taller gearing or Smaller tires produce more acceleration, great for city driving. Shorter gearing or Taller tires will give you more top end cruising. Can't have both, not in the Accent with the short geared transmission.

I'm not sure who you were replying to but, a taller final gear ratio will result in LESS engine rpm at a given speed. Look it up if you don't believe me.
 

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QUOTE (Kuripot @ Feb 24 2010, 09:22 AM) index.php?act=findpost&pid=299810
I'm not sure who you were replying to but, a taller final gear ratio will result in LESS engine rpm at a given speed. Look it up if you don't believe me.
a taller gear, if its anything like a bicycle will result in more revolutions than a shorter gear. But more engine load at lower speeds (referring to tire size). More engine load at lower speeds = crappy city mpgs
 

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A short gear is one with a low gear ratio, and a tall gear is one with a high gear ratio. A 4.11 gear is shorter than a 3.23 gear.

All else being the same (engine,transmission ratios) a 4.11 (shorter gear) will turn more RPM and produce more torque to the wheels than a 3.23 (taller gear)

Another example is to look at an 18 wheeler truck. Ever notice them shifting what seems like 7 gears by the time they reach 40MPH? A car might just be dropping into 2nd or 3rd gear by then. The truck has very short gearing to gain torque multiplication. Every gear change produces less torque to the wheels but more speed. Same with anything really. Start off your ten speed in 10th gear (tall gear). Kind of hard to get moving right? Once moving you can travel pretty fast though at a low RPM. Start off in first gear (short gear). Plenty easy to get going but now the speed is gone. You'd have to pedal like a mad man (more RPM)

So...

Short gear = more torque/more RPM/higher numerical number(4.11)
Tall gear = less torque/less RPM/lower numerical number(3.23)
 

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http://www.chevyhiperformance.com/techarti...ting/index.html

QUOTE
The Numbers Game
Gear Ratio Calculating
February, 2009
By Bob Mehlhoff
148 0208 Gear Lead Z

Hot rodding is largely about relationships. No, we're not talking about the kind that your girlfriend or wife loves to discuss, but the optimal mechanical relationships for your car's performance. A few simple math formulas can help you select the right gear ratio and tire diameter to optimize your vehicle's performance. Because performance cars are often used for both street and track use, gearing a car to do both usually demands a compromise. Vehicle speed, engine rpm, overall gear ratio, and tire diameter are all related to a acceleration. For track use, an engine needs to operate within the rpm range where it makes the most power. For street use, optimal fuel economy and engine life warrant lower engine rpm. The good news is that, armed with some basic information, you can have a car that clocks impressive e.t.'s at the dragstrip and achieves plenty of low-rpm driveability on the freeway. Who said math was no fun?

What's in a Ratio?

An automobile uses gear ratios in both the transmission and the drive axle to multiply power. The two ratios multiplied together equal the final drive ratio. Spend a few minutes in any bench-racing session and soon you'll hear rear axle gear ratios discussed. For many performance cars, 3.73s and 4.10s are common gear choices. The rearend gear ratio refers to the relationship between the ring gear and the pinion gear. By simply dividing the ring gear tooth count by the pinion gear tooth count, the ratio is determined. For example, if we divide a ring gear with 41 teeth by a pinion gear with 10 teeth we find that the gear ratio is 4.10:1 (41/10 = 4.10).

Tire diameter will also have an effect on a vehicle's final drive ratio. As tire diameter changes, so will engine rpm at a given speed. We can demonstrate this with the simplified formula: rpm = (mph x final gear ratio x 336*) / tire diameter (*see "Formulas for Success" sidebar). For example, given 65 mph, a tire diameter of 30 inches, and a final gear ratio of 4.10, the engine speed will be approximately 2,984 rpm--(65 mph x 4.10 final gear ratio x 336) / 30-inch diameter tire. If we reduce the tire diameter to 25 inches, the engine speed increases to 3,581 rpm. By installing shorter tires, the vehicle will accelerate as though it has a 4.73 (higher numerically) gear without the expense of gear swapping.

Because transmissions are comprised of several gear choices, the transmission allows the vehicle to accelerate quickly with lower gears and to maintain a cruising rpm using higher gears. In the '60s and '70s, most transmissions offered three or four gears with a 1:1 high gear. Using a TH400 as an example, First gear is 2.48:1, Second gear is 1.48:1, and Third gear is 1:1. Multiplying the 2.48 First gear by the 4.10 rear axle results in a final drive ratio of 10.16:1 (2.48 x 4.10 = 10.16). For most street performance applications, a 10:1 final First gear ratio is usually considered optimal. The disadvantage of operating a 4.10:1 axle ratio on the street with a 1:1 high gear is excessive freeway engine speed.

Fortunately, today's transmissions frequently utilize Overdrive high gears in the neighborhood of 0.70:1, which allow reduced engine speeds. Combine these overdrive transmissions with a 4.10 axle ratio and you have a fuel-friendly final drive ratio of 2.87:1 (4.10 x 0.70 = 2.87) in high gear. A TH200-4R overdrive automatic utilizes a First gear of 2.74, a Second of 1.57, a Third of 1.00, and a 0.67 Overdrive. With this transmission's First gear ratio of 2.74 combined with a 3.73 axle ratio, the final drive ratio >> yields a 10.22 (2.74 x 3.73 = 10.22). In overdrive, the final drive ratio equates to a Bonneville-ready 2.49:1.

Making Torque Multiply

Acceleration is all about torque. One way to accelerate more quickly is to multiply the torque at low speeds to help move the vehicle forward. That's what a torque converter does. The torque converter features a component called a stator. The stator changes the direction of oil flow to the pump impeller's rotating direction and also incorporates a one-way clutch assembly. This redirection of fluid increases torque by applying the energy remaining in the oil.

By applying the basics of gear ratios and power leverage, you can easily improve acceleration without paying too steep a price in highway rpm. It's all in the ratios.
 

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Discussion Starter #13
I got this email from Hyundai today. I had requested the gear ratios for the Accent Blue a couple of months ago.


Thank you for contacting Hyundai Motor America. We appreciate the opportunity to address your question regarding the gear ratios for the 2010 Accent Blue.

The gear ratios for the 2010 Accent blue are as follows:

- 1st (3.615)
- 2nd (1.950)
- 3rd (1.286)
- 4th (0.886)
- 5th (0.733)
- Reverse (3.583)

We have documented your inquiry in case # _______. Please reference this case if you require any further assistance from us.

Thank you for contacting Hyundai Consumer Affairs.

This is from my first post in this thread and represents the old gear ratios:

Five-speed manual
Gear Ratios
First 3.62:1
Second 2.05:1
Third 1.37:1
Fourth 1.03:1
Fifth 0.84:1
Reverse 3.58:1
Final-drive ratio 4.06:1

Four-speed automatic
Gear Ratios
First 2.85:1
Second 1.58:1
Third 1.00:1
Fourth 0.69:1
Reverse 2.18:1
Final-drive ratio 4.04:1

It seems the old automatic still has the mpg. advantage on the highway unless there is a lot more parasitic loss from the auto trans.

Thoughts?
 

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My guess for the fifth gear ratio was pretty **** close.

QUOTE (burnitwithfire @ Feb 26 2010, 04:46 PM) index.php?act=findpost&pid=300395
After some quick calculations with an online gear ratio calculator, it seems the fifth gear in the 2010 is a .72 instead of a .837. That's if the final drive ratio is the same as the earlier models.
Nice to see the ACTUAL ratios. Even on HMA they didn't have the right ratios.
 

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A short gear is one with a low gear ratio, and a tall gear is one with a high gear ratio. A 4.11 gear is shorter than a 3.23 gear.

All else being the same (engine,transmission ratios) a 4.11 (shorter gear) will turn more RPM and produce more torque to the wheels than a 3.23 (taller gear)

Another example is to look at an 18 wheeler truck. Ever notice them shifting what seems like 7 gears by the time they reach 40MPH? A car might just be dropping into 2nd or 3rd gear by then. The truck has very short gearing to gain torque multiplication. Every gear change produces less torque to the wheels but more speed. Same with anything really. Start off your ten speed in 10th gear (tall gear). Kind of hard to get moving right? Once moving you can travel pretty fast though at a low RPM. Start off in first gear (short gear). Plenty easy to get going but now the speed is gone. You'd have to pedal like a mad man (more RPM)

So...

Short gear = more torque/more RPM/higher numerical number(4.11)
Tall gear = less torque/less RPM/lower numerical number(3.23)
 
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