I went looking for the rated capacity of the shelves and found this: https://www.ikea.com/us/en/newsroom/corporate-news/safety-announcement-hemnes-bookcases-an

I went looking for the rated capacity of the shelves and found this: https://www.ikea.com/us/en/newsroom/corporate-news/safety-announcement-hemnes-bookcases-and-glass-cabinets-pubd05feb07 https://www.ikea.com/us/en/newsroom/corporate-news/safety-an... Ikea is providing longer, presumably stronger, pins free of charge. In any case the 48 cm wide unit is listed as having a 15 kg limit per shelf, the 89 cm wide units are rated at 30 kg. Fifteen kilos of hardback books is potentially a lot less than one might expect.