The excellent Blackspire Twinty 2X chainguide combines secure chain management with quiet-running durability in a refreshingly easy-to-install unit.
Blackspire score points straight away for a full range of ISCG, ISCG 05, SRAM and standard BB mounts in 32-36T or 36-40T big ring sizes, plus red, blue, white or black colours. Included washers make spacing easy and the lower tensioning guide is a trough design, not so dependent on perfect alignment.
A lack of rollers means nothing to squeal or jam, but the ‘proprietary polymer’ has proved impressively tough and mud-proof so far. Chain noise is a minimal mumble with no obvious drag through the pedals.
It works with or without a bashguard, with only one chain loss incident so far, and the skid plate on the single-piece 6061 alloy frame shrugs off sumping incidents. The whole 164g unit is made in Canada, too, if that sort of thing interests you.