If you’re looking to put together an expanded range 1×10 system from your current setup, this provides a good alternative to single cog adapters that make a big jump at the top of the cassette. This one provides a smoother transition onto the larger cogs and a more subtle change between the top four cogs, too.
And, it’s a fairly reasonably priced way to do it. The SRAM 1050 cassette retails for $85 and the AbsoluteBlack adapter for $122, putting you all in at $207. Your alternatives for bumping up to a 40T or 42T cassette are either Shimano XTR or SRAM XX1/X01/X1. With Shimano, the cassette is about $300, and it’s 11-speed only, which requires new chain and chainrings, too. SRAM’s is also 11-speed only and requires a new freehub body, chain and chainrings. Either way, it’s going to cost you a lot more.
As for the range only being 40T and not 42T, you could just opt for a slightly smaller single chainring to compensate, which makes even more sense if you’re dropping the 11T cog off the bottom of the cassette as I did. I found the new range to be very good for our local trails, keeping me mostly in the middle of the cassette.
Another benefit? It can add up to a lighter system than the stock cassette…