Here are some screen shots of what the DR Pulley sliders do differently from rollers. This is actually a very nifty invention and has been patented. Good for them.
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The only draw back seems to be the possibility of the low ratio going below the design threshold and allowing the belt to go slack on some bikes which causes a shudder on take off until the weights swing out to take up the slack. Some people have had to add a shim to stop the travel of the variator.
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I think it would be pretty easy to make the sliders heavier with my triple beam scale which could easily tune them all back into balance within a couple 1/100 of a gram after adding some epoxy putty to the center of each one. The 30 mph cruise rpms are up to about 6,000? The sliders are much more responsive than the rollers. Less friction? The revs jump right to 7,800 when cracking the throttle and it is pulling at 8,000 by 40mph but the revs drop straight back down 2,000 rpm when reaching a cruise.
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Top speed is back up to 68 mph so there is a slight gain in the gearing there from using the sliders. I had been stuck at 66 for the last few weeks with .5mm wear on the belt already at 2,000 miles. I am hopeful that I can still see more top speed gains by tuning with a file the control edge of the slider that is responsible for the high stop as I still have 2 mm of unused pulley with the stock rollers. And I may take them up to 13 gm, the stock rollers were 18 gm, to see what that does. The epoxy will be very easy to drill back down if I want to lower the mass again. Surprisingly, my weighted hill climb trial was unchanged in top speed even though the rpms were running 8,000 at 45 mph instead of 7,000 which is right at the power peak of 8,000 and is using a gearing advantage to increase the revs. Fuel economy was unchanged so far so I don't see any need to add mass to the 12 grams that I have in there now.