Why We Make It We build bearings, so we build bottom brackets. T47 is a standard we helped develop, an answer to the imprecise and often loud press fit bottom brackets that appeared on the market a few years ago. T47 offers the benefits of larger bottom bracket shells, mainly frame stiffness, with the upsides of traditional, threaded bottom brackets, precision and quietness. Why You Want It ThreadFit T47 30i will fit 68mm, 73mm, 83mm, 86mm, and 92mm shell widths with 30mm spindles. All our bottom brackets come with King's legendary, angular-contact bearings, either steel or ceramic. These are the best bearings in the industry, and actually get faster over time, as their contact surfaces wear. You want this bottom bracket because it offers super low drag. You want this bottom bracket, because it can be opened, cleaned and repacked for years of faithful service. You want this bottom bracket, because you don't want to think an awful lot about your bottom bracket. - Steel Bearings - King Lifetime Warranty - Legendary made-in-house bearings - Ceramic bearing upgrade available - Threaded security with PressFit 30 shell stiffness - A Fit Kit is required for use and included in the purchase price - Engineered, manufactured and assembled in Portland, Oregon USA - Uses Chris King bottom bracket cup tool for installation