The Mercury classic headset features a simple solution to extend the life of your head tube…simple but effective.

Deep insertion (22mm) headsets provide superior support to the headtube. However, they require a very deep ream of the head tube…so, deep insertion headsets are only used on special-built super heavy-duty bikes.

The Mercury Semi-Deep Cups increase the headset cup insertion to 12mm, compared to standard headsets . This may not seem like much, but it increases by 25% the insertion depth and contact area with the the head tube!

But, unlike deep-cups, Mercury fits in most frames that use classic headsets.

The Table and Illustration below shows the difference: