A Quality Chain Roller Kit from All Balls Racing. Hi-performance rollers for replacement of OE chain rollers. The universal 34mm and 38mm Polyurethane chain rollers have a 98A Durometer hardness for long life and feature sealed precision bearings with two additional outer seals to prevent water and dirt from contaminating the bearings. They are the longest lasting chain roller in the industry. The OE replacement chain rollers that mount directly to a frame boss are made from hi-performance self lubricating nylon.