Office Chair Base Adjustment

Office chair base adjustment mainly includes backrest tension or resistance adjustment, regular three-function base adjustment, and advanced adjustment functions. Here are the details:

Backrest Tension or Resistance Adjustment

The cylindrical knob on the base is the key device for adjusting the backrest tension or resistance of an office chair. When rotated clockwise, the tension of the backrest increases, meaning the resistance becomes stronger. In this case, leaning back becomes more strenuous, which is suitable for users with a heavier weight or those who prefer firmer support. Conversely, rotating the knob counterclockwise reduces the tension, making the resistance weaker and allowing for easier leaning back. This adjustment can meet the needs of different users based on their weight and personal preferences.

Regular Three-Function Base Adjustment

Many office chairs adopt a regular three-function base that integrates the three most commonly used adjustment functions, usually operated in coordination with a control lever and a knob.

• Backrest Locking: By pulling out or inserting the control lever on the right side below the seat, you can unlock or lock the current backrest recline angle. When you need to fix the backrest angle, insert the control lever; if you want to adjust the recline angle, first pull out the control lever, adjust to the desired angle, and then insert it to lock.
• Seat Cushion Height Adjustment: By rotating the control lever clockwise or counterclockwise (some chairs use lifting or pressing operations), you can adjust the seat height. This adjustment relies on the working principle of the gas spring. Some office stools have height adjustment functions below the chair. When sitting on it, find the corresponding wiggling or button device and press it to perform the height adjustment.
• Backrest Tension Adjustment: This is the same as the separate backrest tension or resistance adjustment mentioned above, operated via the cylindrical knob on the base. The backrest recline angle of this type of base is usually between 125° and 130°.

Advanced Adjustment Functions

Some more precisely designed ergonomic chairs have more complex knob adjustment functions.

• Multi-Position Backrest Recline Angle Adjustment: Using the knob on the left side below, you can switch between two to three preset positions (such as upright sitting, mild recline, and maximum recline) to meet usage needs in different scenarios.
• Forward Tilt Function Adjustment: This function is usually controlled by two knobs (an inner knob and an outer knob). Generally, you need to first unlock the inner knob, move the backrest forward to the forward tilt position, and then tighten the outer knob to activate it. Note that this function usually needs to be initiated in the reclined state.
• Lumbar Support Intensity Adjustment: The knob located on the backrest can adjust the protrusion degree of the lumbar support pad, thereby changing the support intensity for the lumbar region and providing more personalized lumbar support for the user.