Now that 12-speed road bike groupsets exist, cassettes can have a larger range and the jumps between each gear can be relatively small. If you wanted to use an 11-34 cassette, as well as buying the relevant cassette, you would need to buy a compatible rear derailleur. In this example, it would be an Ultegra R8050-GS or 105 R7000-GS rear derailleur. The GS denotes that these are ‘medium cage’ derailleurs. The same rule applies to Shimano Di2 derailleurs.

On the mountain bike side, Shimano uses its Microspline freehub standard for its 12-speed Deore, SLX, XT and XTR groupsets. Unless you’re running a triple crankset, it’s unlikely you’ll want to use a road bike cassette on a mountain bike. Dave Caudery / Immediate Media Gravel bikes are best viewed as a crossover between a road and mountain bike. As such, it’s normal to see them specced with either a road or mountain bike cassette.

Cassette gear ratios

These days, it is increasingly common to see higher-spec road bikes with 12-speed gearing, Shimano having joined SRAM and Campagnolo with 12-speed groupsets in 2021 with the release of its Dura-Ace Di2 R9200 groupset. In case you're not sure whether your bike has a cassette Freehub or a thread-on freewheel, we have a separate illustrated article explaining how to tell them apart. Beyond weight, there’s not much difference in performance between a Dura-Ace 11-28 cassette and one from a Shimano Ultegra or a Shimano 105 groupset, so you can save yourself considerable expense by down-speccing.

You need to ensure you’re using a compatible rear derailleur if you’re using the 10-52 option, because the previous-generation Eagle mechanical rear derailleur’s cage is slightly too short.Well, the smallest cog is a 10-tooth, and the largest cog is 52-tooth, which is 520 per cent larger than the 10-tooth cog, thus giving a 520 per cent range. Where an 11-28 cassette would have once been considered a large training cassette, it now sits at the lower end of the typical range for road. Simon Bromley / Immediate Media SRAM eTap AXS rear derailleurs can take up to a 33t for road, and this is denoted by the ‘Max 33t’ written on the inside of the derailleur cage. There is also a ‘Max 36t’ option to pair with the 10-36 cassette, as well as an XPLR rear derailleur, which can take up to a 44t.