Shimano XTR CS-M9101 Cassette - Thunder Mountain Bikes
Shimano XTR CS-M9101 Cassette - Thunder Mountain Bikes

XTR CS-M9101 Cassette

SKU: ICSM9101045

Regular price$409.99
  • In stock, ready to ship
  • Inventory on the way
  • Free shipping on all orders $49+

Shimano XTR CS-M9101 Cassette - 12-Speed

With its Beam Spider construction, the updated XTR M9101 12-speed cassette shaves weight while increasing Shimano's MTB gearing range another gear. Using Shimano's new Micro Spline freehub body and Hyperglide+ tooth profile, these 10-45t and 10-51t cassettes deliver the best MTB shift experience available.

New for Spring 2021! This is the updated version of the CS-M9100 XTR cassette.


  • Model No: CS-M9101-12
  • Series: XTR M9100
  • Cog sizes: 10-45t:10-12-14-16-18-21-24-28-32-36-40-45t
  • Cog sizes: 10-51t: 10-12-14-16-18-21-24-28-33-39-45-51t
  • Compatible chain: HG 12-speed
  • Number of speeds: 12
  • Finish: Anodized


  • All Micro Spline freehub body's
  • Rear Derailleur: 10-45t: XTR RD-M9100-GS, Medium cage
  • Rear Derailleur: 10-51t: XTR RD-M9100-SGS, Long Cage


Please reach out to us with any questions you may have on anything we sell. We want to make sure you get the right part the first time. Our lifelong riders at Thunder Mountain Bikes are knowledgeable and would love to talk to you!


We currently offer both economy and expedited shipping options though FedEX and USPS. 

Orders totaling over $49 are eligible to ship for free via an economy ground option of our choice. 

If you're in need of something super-quick, please contact us directly. We may be able to overnight your order with an additional fee and depending on your location. 


Should there be an issue with the item you bought, or you no longer need your purchase, we will be happy to set up a return.

All returns must be requested within sixty (60) days of the fulfillment date (i.e. the date we printed the shipping label and boxed up your order.) All returned items must be received in new and unused condition, with the original tags and labels attached, and in the original packaging.  We cannot accept returns on any items that have been installed or show wear of any kind. 

Return Process

To request a return, please visit: and follow the steps to return eligible items from your order. 


After receiving your return and inspecting the condition of your item, we will process your return. Please allow at least seven (7) days from the receipt of your item to process your return or exchange. We will notify you by email when your return has been processed.

For all Special Order items, there is a 25% restocking fee. Special Order items are those that we do not currently stock.


For defective, damaged, or if we sent you the wrong products, please contact us using the phone number or email below.

Other questions?

If you have any questions concerning our return policy, please contact us at:

(928) 282-1106   |

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Customer Reviews

Based on 9 reviews

I ended having to upgrade to this cassette in 2020-21 when I couldn't find anything else in stock. It was the only one left so I coughed up the $$$ and mounted it up with a full XTR groupset (figure I'd go all in the get the full XTR 12 experience) We'll I have to say it is undoubtedly the best I've ever ridden. I shift whenever I want, under any level of power, and never have to stop pedaling! Unbelievably smooth, quick, and immediate shifts. I have been upgrading all my drivetrain to XTR since.

Thanks to Thunder mountain bikes too for getting them in stock and not jacking the price up!

Roger Katz
Awesome customer service

I had an issue with a Shimano part and Thunder Mountain addressed immediately. Excellent customer service!!!

Mr. Cornish
Great Shimano Reliability

Thunder Mountain Bikes actually had an XTR cassette in stock!
Fast shipping and great service. Not much to say about the cassette, as it is a light weight Shimano XTR 12s Cassette.

nicole spaulding

XTR CS-M9101 Cassette

Erin J
Shipped quickly

Great experience, no complaints. Shipped quickly and product exactly what I needed

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