1. What is Portal Gear Reduction?

Portal gear reduction is a mechanism used in vehicles and machinery to reduce rotational speed (RPM) while increasing torque. The portal ratio determines how much the input RPM is reduced at the output.

2. How Does the Calculator Work?

The calculator uses the portal gear reduction formula:

Where:

• Input RPM — Rotational speed of the input shaft (revolutions per minute)
• Portal Ratio — Gear reduction ratio (e.g., 2.0 means 2:1 reduction)

Explanation: The output RPM is simply the input RPM divided by the portal ratio. A higher ratio results in greater reduction of output RPM.

3. Importance of RPM Calculation

Details: Calculating output RPM is crucial for proper gear selection, performance tuning, and ensuring components operate within their designed speed ranges.

4. Using the Calculator

Tips: Enter input RPM (must be > 0) and portal ratio (must be > 0). The calculator will compute the output RPM after gear reduction.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical portal ratio for off-road vehicles?
A: Common ratios range from 1.5:1 to 3:1, with 2:1 being a popular choice for many applications.

Q2: Does this affect torque output?
A: Yes, while RPM decreases, torque increases proportionally to the portal ratio (minus efficiency losses).

Q3: Can I use this for other gear reduction calculations?
A: Yes, this formula works for any simple gear reduction system where you know the input RPM and reduction ratio.

Q4: What if my portal ratio is less than 1?
A: Ratios < 1 would increase RPM (speed increase rather than reduction), but most portal axles use ratios > 1 for reduction.

Q5: How precise are these calculations?
A: The calculation is mathematically precise, but real-world results may vary slightly due to efficiency losses in the gear system.