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CeramicSpeed Oversized Pulley Wheel System

Handmade in Denmark, the Oversized Pulley Wheel System comes with two giant (70mm diameter) machined-alloy 17-tooth pulley wheels and a price tag to match. They large pulley wheels certainly add an exclusive and high performance look to the bike, and they’ll definitely turn heads out on the road.

There are two variants, a standard and a coated low-friction ceramic bearing option that marks the difference in price whilst the cage and pulley wheels themselves remain the same.

At a touch over $700AUD, the standard low-friction bearing system is compatible with mechanical and electronic Shimano Ultegra and Dura Ace 10 or 11 speed components and offers enough clearance for a 28-tooth cassette. It will only add about 10 grams to an existing Dura Ace rear derailleur, and though figures aren’t readily available, according to CeramicSpeed, it does not create any aerodynamic drag.

The simple installation requires just a few tools (including a 1.5mm allen key), a longer chain and half an hour. The carbon-reinforced polyamide plastic cage fits to the upper half of the Shimano derailleur body the same way the standard lower pulley cage does.

With three tension settings built into the cage you can choose between L (low), M (medium) or H (high) spring tensions. A low spring tension will result in slightly compromised shifting performance but reduced chain friction. The opposite is the case for the high tension setting. CeramicSpeed recommend the medium and high tension for mechanical groupsets and the low and medium tension for electronic groupsets. We installed the OSPW system on a 9070 Dura Ace Di2 groupset and chose the medium tension setting.

One of the concepts behind the OSPW system is to increase the diameter of curves the chain follows as it passes through the two pulleys—requiring less energy than the tighter bends of smaller conventional pulleys. Combined with the Grade 3 low-friction ceramic bearings, this reduces the friction on the pulleys by 60%, according to the CeramicSpeed website. This makes it more efficient than the stock Shimano pulley system with a rider’s power savings beginning at approximately 2.4 watts (noting that such marginal gains would be relative to each individual rider).

How exactly do you measure a power saving of 2.4 watts? The test equipment CeramicSpeed uses is apparently accurate down to +/- 0.001 watts. But when out on the bike a more aero body position or even the weight of the rider after sweat-loss could outweigh the 2.4W. I found the most noticeable real-world benefit didn’t come from the claimed reduction in friction per se, though we don’t dispute CeramicSpeed’s test results, but rather a perceptible improvement in smoothness of shifting and a reduced level of noise from the drivetrain. Those 2.4 watts would equate to somewhere below 1% of my average power output, and as with any marginal gains, they must be worth some level of speed. But at what cost?

We asked CeramicSpeed specifically why the OSPW cost so much. Their explanation for the hefty price tag comes down to the extensive R&D that they conduct. According to CeramicSpeed spokesperson Venlig Hilsen, everything from the bearings to the system’s cage and the size of the pulleys was intensively developed until the optimal OSPW system was achieved. The grade of the bearing relates to how round and smooth the surface is, as well as the purity of the materials used and the density of the ball. At Grade 3 the ball is round to 3/1,000,000 inch; the best achievable grade for this sized bearing. There is an extensive certification process each ball must go through to attain certification, so you can rest assured these bearings are as pure and efficient as you can get.

Extensive testing has shown the Oversized Pulley Wheel System does reduce friction and increase shift efficiency and therefore, the low-friction bearings should save you watts. But so should having a professional bike fit to dial your riding position, or shaving your legs and losing 5 kilos.

This product is specifically aimed at those who are pushing the ultimate limits in speed and power and are looking for those marginal gains where no gains can possibly be made from anything else. Or those who are willing to pay for improved performance rather than working harder to achieve the same result. Or both.

I don’t doubt the benefits of having an entire CeramicSpeed bearing upgrade where the almost friction-less set up begins to really work its magic. These are some of the highest quality bearings in cycling and they will deliver a measurable level of improvement in speed. They’ll also last you considerably longer than any normal steel bearing with the correct care and servicing.

But while the OSPW certainly looks outstanding and does deliver power savings, there will likely be lower cost, higher benefit actions available and the asking price is likely to be beyond the average cyclist’s budget.

RRP: North of $700


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