This jumped around a lot.
Think like a long-form magazine article that starts out with the exciting subject matter and brings that discussion towards a climax, then abruptly cuts to tell the story of when the person of interest was growing up. For example, "and so, John took the last few precarious steps towards the top of the mountain. <cut> When John was 5, he was interested in many thing." And then maybe 50% of the article's length is spent on this not very interesting backstory, until it cuts back to John reaching the top of the mountain and everyone's reactions afterwards to finish out the article.
Now imagine that for 8-10 characters--that is this book, and I found it annoying. There are even some points where the author explicitly says thing like, "remember x, who had done this and that? Now they are..." Like, maybe if he had told me their story in a continuous segment I wouldn't have to be pulled back and forth.
The wording is a bit pretentious in many places, trying too hard to convey the author's awe of things like the conditions or the racers' determination.
The content overall is good. The descriptions of the challenges that the racers faced are great and did give me an appreciation of them. And it was a good way to learn about the subject matter.