Can I use just one spacer if I only remove one wheel?

Yes — use one spacer per calliper that has its wheel removed. The 2-piece set provides one for front and one for rear so you can handle both simultaneously.

Do I need these for mechanical disc brakes?

Mechanical disc brakes are less sensitive to piston push-out than hydraulics, but using spacers is still good practice to prevent pad contamination and misalignment.

Birzman

Birzman Dummy Rotor (Disc Brake Pad Spacer) (2Pcs)

Name: Birzman Dummy Rotor (Disc Brake Pad Spacer) (2Pcs)
Brand: Birzman
SKU: CMB_WOW_BM24-DBPS_Std
Price: 1550.00 INR
Availability: InStock
Author: InstaSport Editorial

₹1550.00

Description

Features: Material : High Polymer / Steel (bolts) Weight : 30 g Size : 100 x 70 x 25 mm