Navigating C10 Lowering Spindles: Importance of Brake Rotor Measurement
Posted by Trekline Motorsports on May 6th 2026
Updated April 2026
Before ordering C10 lowering spindles, make sure you know which front rotor thickness your truck uses. On 1973-1987 Chevrolet C10 and GMC C15/C1500 2WD trucks, the common front rotor choices are 1.00-inch and 1.25-inch thick rotors. Ordering the wrong spindle can create fitment problems with the bearing, hub, brake, and rotor setup.
Quick answer: Measure the rotor thickness with calipers. A rotor that measures around 1.25 inches is the heavy-duty/thick rotor setup. A rotor that measures around 1.00 inch is the standard/thin rotor setup. A worn 1.25-inch rotor may measure slightly less than new, so do not assume 1.15 inches is a 1.00-inch rotor.
How to Measure
- Park safely, support the truck, and remove the front wheel.
- Use calipers to measure the rotor thickness across the braking surface.
- Measure in a clean area away from heavy rust, lips, or grooves.
- Compare the measurement to the spindle fitment notes before ordering.
Which Trekline Spindle Fits?
For 1973-1987 Chevrolet C10 / GMC C15 2WD trucks with 1.25-inch thick rotors, review SKU 8000100 3-inch drop spindles for 1.25-inch thick rotors.
For 1973-1987 Chevrolet C10 / GMC C15 2WD trucks with 1.00-inch thick rotors, review SKU 8000101 3-inch drop spindles for 1.00-inch thick rotors.
Helpful Related Guides
If you are planning the full drop, read our complete truck lowering guide, drop spindle installation guide, and truck lowering cost guide. You can also browse all lowering spindles.
Still unsure - Email info@treklinemotorsports.com with your truck year, rotor thickness measurement, cab style, and photos of the front brake setup.