Replace it with a 17T Chinese Big Pulley

I heard that replacing it with a big pulley would improve drive efficiency in exchange for shifting performance, so I looked for a Chinese pulley. ・ By increasing the pulley, the R of the chain → tension pulley → guide pulley to sploke becomes loose, so resistance is reduced. ・ By increasing the pulley, the rotational speed of the pulley is reduced and resistance is reduced. It seems to be two points. It is said that the drive efficiency will be improved by a few watts, but I think that I probably do not understand the difference, so it looks alone … (^_^;) And, I bought it immediately and arrived.
Kactus is a mystery maker, both tension pulleys and guide pulleys are 17T. Although it is Chinese, it seems that ceramic bearings are used in carbon gauges. If you look at the contents of the bearing, it was certainly ceramic. Artegra and Dura Ace have the same shape in the part where the gauge is attached to the delayer, and it seems to be a different standard below 105. I took a video of how much it turns. Size comparison with genuine arte pulley. Big. Before replacement. After replacement. In the photo, the big pulley seems to have a chain bent. Unlike the top side, if it is a low side, will the chain bend on the contrary? A little while ago I replaced Sproke with a 32T maiden gear, but when it was 32T, the guide pulley interfered with the sproche, so I returned it to the 28T sproqué. regret. The shifting performance you care about is a spa spa shifting if it is genuine, but if it is a big pulley, it may certainly be a little satid. Well, if it is not Chinese, this area may be more good … If you increase the guide pulley, the shifting performance will fall, so it seems that there is a product that increases only the tension pulley without changing the size of the guide pulley By the way, the price of the Chinese big pulley is 15,000 yen.