Shimano's ultra light, high end Road Racing headset. The DA headset has cast aluminum upper, lower cups and head lock nut. Each of these parts, after being cast, is machined to their exquisite light weight final shape. The cup bottoms and tops, the seats for the steel races, and the threads for the head lock nut, are finished to the measured precision that a professional racer would want. The steel races are ground to the same precision. The fork cone race, which is subject to so much stress is titanium plated to add a harder surface. It uses twenty 4mm steel ball bearings in both steel retainers. This headset is triple sealed. There are seals between the cone and cup race surrounding the bearings to protect it from road contaminants and there is a stem seal in the head lock nut. This headset's stack height is 37mm and weighs 114 grams. It is made in the 1" size, with the English/Italian thread pattern, in Silver only. This headset was replaced by the 7410. We sold it for $79.99
This headset weighs just 99 grams! The fork cone race is cast of stainless steel with a smoothly ground bearing surface. The bearing cups are made of cast, then machined aluminum, with precisely ground steel races pressed into them. The upper cone race is cast of steel lightly machined then colored Black. The Ultegra head key washer is stamped of steel and recesses into the upper cup, to help prevent the upper cup from backing off. The head lock nut is forged aluminum, octagonally shaped, 32mm across. Twenty 4mm steel ball bearings are held in a steel retainer for both bearing sets. This is a triple sealed headset, featuring plastic seals between the cup and cone race with a stem seal (rubber washer) mounted on the head lock nut. This 1" headset is for Road Racing use, has a stack height of 33.5mm, and uses a 32mm headset wrench to tighten both the upper cup and head lock nut. This was replaced by the 6500 model. We sold it for $29.99
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