The M525 version of the Shimano SPD pedals is marketed for use with the Deore DX and LX parts, though they can be used with any crank and drivetrain. The body of the pedal is made of cast aluminum, with two tapped holes on the bottom and top to hold the cleat saddle. The interior of the body is tapped with threads for the spindle with all the bearing parts to thread in as a single unit. The M525 is reversible, so both the top and bottom can be "clipped" into without searching for an "up" side. The rear clamp is spring loaded, the front clamp is a part of the saddle structure and therefore rigid. A main difference from the M737 is that you must entr the M525 toe first, while the M737 can be entered with merely downward pressure. The rear clamp has no aluminum housing, as in the M737, and the clamp itself is larger and made of steel. There is the same 3mm allen wrench adjustment for each rear clamp, with the red dot as a visual indicator to show approximate spring tension and to help set the two retention systems (the same or not as you choose). The spindle is made of forged Cro-moly steel and uses the same style of threaded plastic lock nut to load and tighten the bearing assembly that the M737 has.
The M525 again uses twelve 2.2mm steel ball bearings for the inner and outer bearing works and uses a steel tube with cupped ends to form the cup races. The bearing tension is adjustable. The gross size of the M525 pedal is slightly smaller than the M737 and the spindle is therefore slightly shorter, they are not interchangeable. These have most of the features of the M737 and weigh slightly less. The M525 pedal set comes with SM-SH50 cleats and the mounting hardware required for them, also included is the TL-PD40 spindle/bearing removal tool. The pedals are Black with Silver saddles and retaining clips, the pair weighs 487 grams, and the Black cleat set, with hardware weighs 63 grams. These are no longer made and have been replaced by the M535 which will be reviewed by mid-summer 1995. We sold these for $84.99 a pair. Their successor is the M535