Renthal 520 Final Drive Conversion | Ducati Monster Project Bike
Chain, Sprockets and Carrier Upgrade
Performance and quality components continue to be our main theme as we upgrade our Ducati Monster 1100S motorcycle project bike. Maximizing the power delivery from our air-cooled v-twin through to the final drive was our next task. Again, we surveyed the market to find proven bolt-on parts that would meet our objectives and inventively we again found a company with a storied motocross legacy; one with 142 World Titles and 111 US Titles.
Founded in 1969, Renthal is a global motorcycle parts company headquartered in Manchester, UK. In October 2000, a fire destroyed the factory and the original factory was replaced by a new, state of the art facility. Today, Renthal manufactures high-quality handlebars, chainwheels, chains, grips, levers and brake pads and sells their products in 42 countries.
Based on our riding preferences, we decided to stay with the stock gearing. Our replacement parts list from Renthal included their 520 RR4 Road Race Chain, rear Ducati Carrier and their front and rear 520 chainwheels. The two-piece Renthal Carrier /Chaiwheel replaces the one-piece OEM sprocket. The two-piece allows you to more easily swap out gearing later by not having to remove the entire carrier each time. Also, the Renthal is CNC machined from billet 6082 T6 aluminum where as the OEM is made from steel.
The rear chainwheel is precision CNC machined to tight tolerances from 7075 T6 aluminum alloy. The surface is hard anodized for increased longevity but we suspect no aluminum sprocket will last as long as steel. But for performance applications, the 7075 T6 is lighter and more eye-catching than the stock sprocket. While the front chainwheel is case hardened 655M13 Nickel-Chrome-Molybdenum alloy steel to maximize durability yet drilled to reduce weight.
The lightweight RR4 Self Regulating Seal (SRS) 520 chain was developed for racing applications and ultimate performance. The chain is made from alloy steel plates and pins, solid bushings and rollers, and shot-peened gold side plates. Standard chain tools may not compress the solid-pin master link so make sure you have the right tool if you attempt this on your own. The chain is pre-stretched from the factory and has not required any adjustments during our two-month testing period.
The Renthal final drive system has operated very smoothly and quietly since inspection. We used WD-40 to clean the factory white chain lube off and as our primary chain lubricant. The look is clean and the operation is just as quiet. With no chain lube it is essential to spray down the inside of the chain with fresh WD-40 after each ride for proper maintenance.
The finished assembly glimmers with racing appeal on the Monster. The 520 set-up is smaller in width, lighter in weight and sharper looking than the OEM 525. On the scale the OEM set-up weighs 8.0 pounds while the Renthal pieces are just 5.6; a 2.4 pound weight savings. This significant reduction of unsprung weight is quite noticeable as it helps deliver quicker acceleration. The Monster spins more freely and spins-up more quickly as we were hoping. And our average track lap times have improved slightly as well.
Stay tuned as we continue to upgrade our Ducati Monster before it appears in our print magazine at the end of this year.