Riders and mechanics replacing a worn 40 x 52 x 7 mm 45/45° lower headset bearing.
The Black Bearing D2 is a 40 x 52 x 7 mm headset bearing with 45° / 45° contact angles, designed for the lower bearing of a 1 1/2 inch tapered steerer. It's one of the most common lower headset bearings around.
It's built from SAE52100 chrome steel balls and rings with an angular contact design, good seals and quality grease, and it's made to replace the original bearing from FSA, Stronglight, Cane Creek, Acros and Ritchey.
It's sold individually, and the top bearing on a tapered headset is usually a different size, so check it separately.
40 x 52 x 7 mm
45/45° angular contact.
1 1/2" lower
Suits tapered steerers.
Chrome steel
SAE52100 balls and rings.
Wide fit
Replaces FSA, Cane Creek, Acros, Ritchey and Stronglight.
Bearing
In the box
Angular contact
The 45° faces carry both the downward and sideways loads through the headset for smooth, precise steering.
Great for
Maybe not for
Match your old bearing exactly: 40 mm inner, 52 mm outer, 7 mm tall and 45° on both faces. Sold as a single bearing.
Check the crown race
A pitted crown race will ruin a new bearing quickly. While the fork is out, check the race for marks and replace it if it's worn.
Set the preload right
After refitting, tighten the top cap just enough to remove play, then tighten the stem bolts. Too tight and the new bearing will feel notchy and wear early.
