Two different ways of transmitting power – which to choose? chain vs belt in the world of Harley-Davidson

WHAT DO THOSE NUMBERS MEAN? 24T48T, 25T54T, ETC.

You’ve likely come across part codes like 24T48T, 22T54T, or 25T51T.
Here’s what they actually mean:

• First number (T) = front engine sprocket tooth count

• Second number (T) = rear wheel sprocket tooth count

From these two values, we calculate the transmission ratio, which defines how the engine torque is transferred to the wheel and how that impacts speed, torque, acceleration, and gear efficiency.

HOW THE GEARING RATIO WORKS

The formula is simple:

A lower ratio = higher top speed, less torque
A higher ratio = more torque and acceleration, but lower top speed

COMPARISON TABLE – RATIO CALCULATIONS:

• 22T54T: 0.41
• 22T51T: 0.43
• 22T48T: 0.46
• 24T51T: 0.47
• 24T48T: 0.50
• 24T54T: 0.44
• 25T48T: 0.52
• 25T51T: 0.49
• 25T54T: 0.46

WHICH GEARING WORKS BEST DEPENDING ON THE TRACK?

✔️ Twisty circuits with many corners:

Choose a higher ratio like 25T48T (0.521) – better exit speed from corners, higher torque

✔️ High-speed tracks with long straights:

Choose a lower ratio like 22T54T (0.407) – maximize top-end speed, better RPM utilization

✔️ Balanced riding or daily use:

Choose a middle-ground like 24T51T (0.471) – offers good versatility for mixed conditions

A REAL-WORLD TEST: 24T48T vs 24T51T

I decided to dig into two setups: 24T48T and 24T51T.
To make things real, I used actual data from my own Performance Bagger build.

• Wheel size: R17 (radius = 0.215 m)

• Bike weight: 320 kg

• Rider weight: 95 kg

• Total mass: 415 kg

• Engine torque: 163 Nm

• Max RPM: 7000

• 6-speed Harley gearbox ratios:
  1st – 3.34 / 2nd – 2.30 / 3rd – 1.71 / 4th – 1.41 / 5th – 1.18 / 6th – 1.00

• Efficiency (η): 0.9

Using standard dynamics formulas, I calculated:

• Acceleration

• Speed

• Torque delivery

• Time to complete various distances

Results:

• 24T48T delivers quicker acceleration, better corner exits, but slightly lower top speed

• 24T51T allows higher top speed, better RPM spread on highways, but loses some traction in corners

Depending on the track layout (I tested against "Nemuno žiedas" and "Cremona Circuit"), the choice matters — and after testing, I personally went with 24T48T.

WHAT IF WE REDUCE WEIGHT?

Let’s not forget that performance isn’t just gearing – it’s power-to-weight ratio.

When your Harley drops from 385 kg to 320 kg, and you keep the 24T48T ratio — acceleration improves dramatically.

A lighter bike:

• Responds faster

• Feels more agile

• Needs less torque to move

• Feels alive through every gear

While the 24T48T may reduce your maximum top speed a little, it gets you there faster, especially when paired with a lightweight chassis.

BOTTOM LINE: MATH MATTERS, BUT SO DOES REALITY

Of course, math is helpful — but racing outcomes are never decided on paper.
Track surface, weather, rider skill, tire grip, and mechanical condition all play a role.

So here’s what I recommend:

• Try both setups on your own machine, in your own conditions

• Use apps or gear calculators tailored to Harley-Davidson models

• Decide based on your riding style, not just data

Theoretical performance doesn’t always match real-life results.
But understanding how gear ratios change your ride will help you make smarter tuning decisions going forward.

At LORD’S Performance, we provide both 24T48T and 24T51T kits tailored for Performance Bagger builds, whether you're racing, riding hard, or tuning for the perfect setup.

Choose torque or speed — and we’ll help you build the rest.

LORD’S Performance Team
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