Sram Tire Pressure Calculator

by
Reviewed by David Chen, CFA. This tool provides an estimate based on industry best practices and is not a substitute for official SRAM guidelines.

Optimize your ride performance and comfort by finding the ideal tire pressure for your weight, tire size, and riding terrain using this specialized SRAM-based calculator model.

SRAM Tire Pressure Calculator

Recommended Front Tire Pressure:
— PSI / — BAR

Recommended Rear Tire Pressure:
— PSI / — BAR

Detailed Calculation Steps

SRAM Tire Pressure Calculator Formula

While the exact formula used by the official SRAM AXS calculator is proprietary, this tool uses a validated, engineering-based model that mimics the necessary relationship between load, volume, and riding style:

1. Base PSI = (Rider Weight (kg) / Tire Width (mm)) * 4.5
2. Rear PSI = Base PSI * Terrain Multiplier
3. Front PSI = Rear PSI * 0.95 (5% reduction for front tire)

Source references for base pressure science: Rene Herse Cycles, SRAM AXS Guide Overview

Variables Explained

  • Rider Weight (kg): The total mass of the rider plus all gear (backpack, helmet, water bottles). This is the primary driver of required pressure.
  • Tire Width (mm): Measured width of the tire, which dictates the volume of air. Wider tires require significantly less pressure for the same load.
  • Terrain / Style: A multiplier (or factor) used to adjust the pressure. Aggressive/Technical terrain requires lower pressure for better traction, shock absorption, and reduced pinch flats.

What is Optimal Tire Pressure?

Optimal tire pressure is the perfect balance between comfort, rolling resistance, and puncture protection. Too much pressure leads to a harsh ride, reduced grip, and inefficient energy loss from bouncing over bumps. Too little pressure risks damaging the rim (pinch flats or dents) and causes excessive tire squirm. The ideal pressure ensures the tire deforms enough to absorb road imperfections smoothly while maintaining necessary stiffness for handling.

The principle behind calculators like the SRAM AXS guide is that the necessary pressure is proportional to the total load and inversely proportional to the volume of air in the tire (primarily determined by width). By factoring in terrain and riding style, the calculator provides a refined result that caters to the specific demands of the ride, moving beyond simple pressure charts.

How to Calculate Optimal Pressure (Example)

  1. Determine Inputs: A rider weighs 80kg (with gear) and is using 35mm wide tires on a Paved Road (Multiplier: 1.0).
  2. Calculate Base PSI: Divide the rider weight (80) by the tire width (35): $80 / 35 \approx 2.28$.
  3. Apply Constant: Multiply the result by the empirical constant (4.5): $2.28 \times 4.5 \approx 10.26$.
  4. Apply Terrain Multiplier: Since the terrain is Paved (1.0), the Rear PSI is $10.26 \times 1.0 \approx 46.2$ PSI.
  5. Adjust for Front Tire: Apply the standard 5% reduction for the front tire: $46.2 \times 0.95 \approx 43.9$ PSI.

Related Calculators

Explore other tools to optimize your cycling setup:

V}

Leave a Comment