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 Sale price$349.99
Shipping calculated at checkout.
  • In stock, ready to ship
  • Backordered, shipping soon
  • Free shipping on all orders $59+

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 items 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 $59 are eligible to ship for free via an economy ground option of our choice.

Most bikes ship free within the continental US. Bike shipping to AK, HI, or PR is $250.

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.

Component & Gear Returns

Returns may be requested within sixty (60) days of the delivery date. All returned items must be received in new, unused, and uninstalled condition, with the original tags and labels attached and in the original packaging. We cannot accept returns on any items installed or show wear of any kind.

Bike Returns

Returns or exchange requests for bikes must be requested by emailing us at within fifteen (15) days from the date of delivery. Bikes must be in un-ridden condition. Custom-built bikes may not be returned. Returned bikes have a $200 restocking fee and the customer pays for return shipping.

Return Shipping

Customers may choose to use our provided flat-rate return shipping label at $9, or choose a carrier of their choice to handle their product return.

The $9 flat rate label will be deducted from the refund issued for the return. You can either print this label after requesting a return from the Order History in your Account profile, or you can request that we email you the label.

For all other return shipping methods, please email us at after submitting your return request so that we can confirm the shipping information you should use to return your item(s).


We will process your return after we receive your returned item(s) and inspect the condition. Please allow at least seven (7) days from the receipt of your item to process your refund. We will notify you by email when your return has been processed.


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


To request a return, please log in to your customer account by clicking the customer account icon Profile icon in the top right of any page or visit

1. In the Email field, enter your email address and click Continue.

2. In your email account, open the email sent from our store and copy the six-digit verification code included in the email.

3. Go back to the online store and enter a six-digit verification code to log in.

4. Find and click on the order that you want to submit a return for.

5. If your order has more than one item, select only the items you want to return.

6. Select a return reason and add a note for the store if needed.

7. Click Request Return.

Once your return request is approved, you will receive an email with shipping instructions and a return shipping label.


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

(928) 282-1106   |

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Customer Reviews

Based on 10 reviews
Jmz (Monroe, US)

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 K. (Fremont, US)
Awesome customer service

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

Mr. C. (Rock Hill, US)
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.

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