Renthal Ultralight™ Aluminum Chainwheel: 2WheelTimes Review

By Michael Hannas

Renthal Chainwheels, which apparently means sprocket in England where they are made, are a staple product on most factory and privateer race machines world wide on the Motocross/Supercross tours. Used by Champion riders James Stewart and Ryan Villopoto to dominate both the 2008 AMA Motocross and Motocross Lites Championships, Renthal has proven over the years to build the best sprockets in the motocross business; they are the industry standard.

While Renthal has been the first choice of many motocrossers for years, their Ultralight™ aluminum sprockets has been viewed by many in the off-road world as not durable enough for extreme conditions and terrain. Renthal has finally given in and developed a longer-lasting twin-ring steel/aluminum combo design targeted directly at the off-road market, but I noticed US Trophy Team rider Ricky Dietrich was running the all aluminum version instead on his KX250F in Greece during the ISDE this year. It made me think- If RD had enough faith in durability of the Renthal aluminum sprocket to use it in the grueling Six Days, perhaps it was worth another look for off-road abuse after all.

Just like Dietrich runs, I chose the sweet-looking black anodized Ultralight™ aluminum version for my KX. According to Renthal, it is constructed with a specially enhanced 7075 T6 aluminum alloy with excellent resistance to wear and a very high tensile strength. All I know is that it looked totally sick with the brand new green chain I put on at the same time, almost too nice to go trash in the mud. Nevertheless, inquiring minds wanted to know how it holds up, so I had no choice but to go get her dirty. As far as performance, the lightweight sprocket doesn’t sap up any power whatsoever like a heavier but longer-lasting steel sprocket does. Not such a big deal with a 450 but definitely something to think about for 250F or 125-200 riders. Also, the little grooves in between the teeth really do help to clear mud and muck as they are claimed to, keeping the sprocket light and your chain free of grime.

But, the real question is how long did it last?

Well, it is still on my bike after eight rides and probably around 500 miles, all off-road.  Most of the riding was in muddy or wet conditions with creek crossings and the like, with a little hard-pack and dust thrown in the mix for good measure. The teeth are just starting to show some wear and rounding on the top but I’ll probably leave it on for a few more rides. The black anodizing has held up pretty well on the sprocket face itself but wore off the teeth pretty quickly, which does make the sprocket not look quite as factory as when it is new. Of course it hasn’t lasted as long as a super long-lasting steel sprocket like an Ironman or Sidewinder, but it has lasted much longer than the stock aluminum sprocket and longer than I expected it to.

If, a fraction of a second, a few grams, and couple of millimeters make the difference for you or you ride a 250F or smaller and want every ounce of horsepower you can get to the ground, the Renthal Ultralight™ aluminum sprocket is a perfect choice. If you could care less about looking cool and and saving a few ounces or ride a 450cc or bigger machine with more than enough power for you and you just want to put a sprocket on and leave it on through three chain replacements (please don't), then you would be better off looking towards Renthal’s new Twinring or something else like a Sidewinder that is designed more with durability in mind rather than all out performance. 

For motocross the Ultralight would be my number one choice for any bike, for off-road, it would depend. A true big-bore off-road only machine that gets hammered on the trail more than loved on in the garage, I would rather opt for a longer-lasting design like the Twinring. However, if we were racing a 250F or two-stroke 125 or 200 in hare scrambles or enduros, the Renthal Ultralight™ aluminum rear sprocket would definitely be on our bike. For a machine that is used for moto as well as off-road like my KX, the Renthal Ultralight™ aluminum is a solid choice for the $65 retail price, sick looks, and its relatively long lifespan considering the high level of performance it offers. Winning 142 World Titles and 111 US Titles pretty much sums it up!

Go to www.renthal.com for more info.

Report Card: Renthal Ultralight™ Aluminum Chainwheel