XTR Cassette Comparison: 11 Speed M9001 vs 12 Speed M9101

Following up on the previous introduction post on the XTR 10-51T CS-M9101 12 speed cassette, here is a comparison post that is related. Before XTR moved to 12 speed, it had a 11 speed cassette, the CS-M9001 cassette. Although both are XTR cassettes, the differences are much more than just adding one more gear.

XTR 12 speed cassette on the left has 8 riveted gears and 4 loose sprockets, while the 11 speed cassette on the right has 4 sets of riveted sprockets, and 3 loose sprockets.

XTR 12 speed cassette, CS-M9101 in the 10-51T specification.

This 12 speed cassette weighs 370 grams, which is lightweight for its size.

XTR 11 speed cassette, in the 11-40T specification, is lighter at 326 grams. Much smaller gear range though (510% vs 363%).

There are a lot more details on the XTR CS-M9001 11 speed cassette over at the other blog post, so check it out if you want to know more. This post will focus more on the comparison rather than the details of each cassette.

Lock rings are very different, but they do use the same lock ring tool which is great.

Microspline lock ring on the left has a much longer body and smaller thread diameter, to cater for the smaller 10T sprocket.

10T Microspline sprocket on the left, 11T HG sprocket on the right. The HG sprocket engages directly with the end of the HG freehub body, unlike the Microspline design.

XTR 12 speed cassette has 3 aluminium and 5 titanium sprockets, while the 11 speed version has 1 aluminium and 6 titanium sprockets (1 not shown).

11 speed cassette has many separate spiders, with just 2 sprockets on each. Two of the spiders are made of injection molded carbon fibre to save weight. However, they look very chunky.

Comparing the largest 8 sprockets of both cassettes. 12 speed cassette on left is much larger, while there is a steel sprocket on the 11 speed cassette on the right.

Weight of largest 8 sprockets on 12 speed cassette is 311 grams. All riveted onto a single aluminium spider.

Weight of largest 8 sprockets on 11 speed cassette is 283 grams. Separated into 4 spiders with 2 sprockets on each.

Rear view of the largest sprocket. 51T on the left, 40T on the right. Much more lightweight design and look on the 12 speed cassette.

The two carbon fibre spiders on the 11 speed cassette are overmolded onto an aluminium spline profile in the centre, so as to better resist torque and drive impact.

The construction of these two cassettes are very different, as the 12 speed cassette uses a giant spider to fix 8 sprockets together. This saves weight, but at the expense of modularity for replacement. Although the 11 speed cassette are split into more sub-modules that can be replaced individually, I believe the actual number that is replaced should be quite small.

If the 11 speed XTR cassette was built using the 12 speed construction with a giant spider in the middle, I think it might be even more lightweight! In any case, most of the weight savings of the XTR cassettes come from the liberal use of aluminum (1/3 weight of steel) and titanium (1/2 weight of steel). If you look at the next level of cassette, the Deore XT which does not use any titanium, the weight gain is quite a lot. About 90-100 grams of weight increase going from Deore XT to XTR, for both the 11 speed and 12 speed versions.