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

XTR CS-M9101 Cassette

SKU: ICSM9101051

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 depending on your location. 


Effective Nov 19, 2021, for all online orders placed on or after Nov 19, 2021.

Note: For all orders placed before November 19th.  Please see the old Policy here.

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 delivery date. 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.  If you are unsure if your item qualifies for a return.  Please email us first:

Return shipping charges will be paid for by the customer. 

As a convenience, we can send you a pre-paid return label. The return shipping charge will be deducted from your refund when using our pre-paid label. Return shipping rates are as follows:  

  • Bicycles: Customer pays the quoted amount. Please contact us.
  • Oversized (Kuat racks etc.): $40 per box
  • Wheels: $20 per box
  • Medium packages: $10 per box/envelope
  • Small packages (Grips, brake pads, etc.): $5 box/envelope

*Paid shipping charges will not be refunded.

Return Process

To return an item, please follow these steps:

  1. Email us at Please note the order number, the items that needed to be returned, and why.
  2. Once approved, we will notify you of the return label charge and email a pre-paid shipping label.
  3. Place the item in its original packaging, including all tags
  4. Pack the item securely to prevent any damage on its return trip.
  5. Drop the item off at your local post office.


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. Paid shipping charges will not be refunded. 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.


We do not accept Exchanges. Instead, return the item as outlined above and place a new order for the item you would like to purchase. This will get the item into your hands weeks faster than an exchange would.


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 4 reviews
Tony Bautista
XTR CS-M9101 Cassette

Excellent product! The cassette was unbelievable light and performed better than my XT cassette. I live how it made my bike come together with my XTR derailleur.

Shane Ozment
Hard to find part

Thunder Mtn Bikes was the only sites I could find the shimano cassette I was looking for. Fast, easy and arrived a couple of days after order. Will certainly use again.

Lloyd Davies

Great product, great seller

Michael Mcguire
Granny gear

The 12s 51t cassette in lowest gear felt like no drive up hill
The 45t cassette seems better at climbing

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