I don't know if this "tip" is applicable, but I had to purchase a number of these (the desired style from the author) before finding one that would actually slip over the retaining flange. 90% of the ones I ordered were too small, even though it was sold as a 930 boot. Before I found what I could use, I tried to stretched the boot over a wood disc (over several days) to try and get the large-end diameter big enough to slip onto the flange. It was a frustrating ordeal, but these shorter (pyramid) boots were the only ones I could use to prevent interference with other components. The aero boots are better for that IF you have have a small CV angle, and the $$$ for 4 of them.