Ari’s 39T cogs for SRAM XX1/X01 could be a cyclocross rider’s dream come true

44t and 42t replacements are good news for extending cassette life, too

Using the XD-Driver standard, SRAM’s 10-42t cassettes have found immense popularity in mountain biking. Both the XX1 and X01 cassettes feature ten steel cogs, with the largest 42t made of a lighter (but faster-wearing) aluminium. Given the 11-speed cassettes are one of the more expensive transmission items, aftermarket big cog options have arisen to extend the life of these parts.


To our knowledge, Italian component manufacturer Ari were the first to offer such a replacement, and they now have 39, 42 and 44t options for those grinding away their granny cogs.

Fitting one of these cogs requires you prying the stock 42t cog off your XX1 or X01 cassette with a flat blade screwdriver. It’s the same procedure as using similar aftermarket cogs from the likes of OneUp or Wolf Tooth. Cheaper X1 or GX cassettes are pinned together, and so cannot be used with any of these upgrade cogs.

A smaller 39t cog: perfect for cyclocross?

SRAM introduced its Rival 1 and Force 1 groupsets earlier in the year, and many 2016 cyclocross bikes are showing the group’s popularity. However, cassette choice remains limited, with either a 11-36t or 10-42t to choose from.

While many seek a wider range than 11-36t, the 10-42t is perhaps a little too wide for many racing cyclocross or gravel riding, especially given the jump from 36t to 42t between the first and second gear. With this, Ari recently released a 39t aftermarket cog.

Ari offers its cogs and chainrings in a wide variety of colours – although black is also available :

While black is available, you can go wild on colour too

Like the 42 and 44t Ari cogs, the 39t is made in Italy of hard-anodized ‘Ergal’ 7075-T6 alloy. The cogs are all available in a choice of 13 colours.

The 39T cog is claimed to save only 5g from the cassette’s stock 82g cog. The 44t upgrade is said to weigh 90g (8g addition).

For those living outside of Italy, each Ari Cog for SRAM XX1/X01 sells for 75 plus postage.

Enormous range of XX1 chainrings

The new oval mtb rings do appear to be quite ovalized. we’re yet to use one from ari, so cannot provide an opinion :

Round and oval XX1 rings in a wide range of sizes and colours

Ari has one of the largest ranges of 76mm BCD XX1-compatabile chainrings that we’ve seen. With this, the brand offers wide-narrow round rings in two tooth increments from 28 through to 42t. Ari also has wide-narrow Oval rings to fit a growing trend toward ‘traction-based’ chainrings, these are also available in two tooth increments from 30 through to 40t.

All chainrings (and optional bolts) are available in the same wide choice of colours as the rear cogs.  


Products are available direct from Ari, although we’ve found the website difficult to navigate.