🏷️ Not eligible for coupons or discounts.
Shimano Deore XT FC-M8100 Crank Arms
Shimano Deore XT FC-M8120 Crank Arms
Shimano Deore XT FC-M8130 Crank Arms
The Shimano Deore XT Crank Arms are compatible with the following:
Please reach out to us with any questions you may have about 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 through FedEx and USPS.
Most orders totaling over $69 before tax are eligible to ship for free via an economy ground option of our choice.
Due to larger box sizes, handlebars, wheels, and other oversized items, an additional shipping fee will be applied.
Most bikes ship for only $200 within the continental US. Bike shipping to AK, HI, or PR is usually $350, but may incur additional fees depending on the exact delivery location.
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, depending on your location.
Should there be an issue with the item you bought, or if you no longer need your purchase, we will be happy to set up a return.
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 that have been installed or show wear of any kind.
Returns or exchange requests for bikes must be requested by emailing us at sedona@thundermountainbikes.com 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 incur a $200 restocking fee, and the customer is responsible for the return shipping costs.
Customers are responsible for return shipping fees and may choose the carrier of their choice to handle their product return. We no longer provide shipping labels directly.
For any return shipping questions, please email us at sedona@thundermountainbikes.com 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 receiving your returned item(s) and inspecting their 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. All refunds will be returned to the original payment method. No store credit or other refund methods are available.
If you receive defective or damaged products or if we sent you the wrong item(s), please contact us using the phone number or email below.
To request a return, please log in to your customer account by clicking the 
Profile icon in the top right of any page or visit account.thundermountainbikes.com.
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 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 a confirmation by email.
If you have any questions concerning our return policy, please contact us at:
Bought these to replace the heavy M511 cranks so I could run a power meter. It was great that Thunder Mountain had these at a great price and I was able to get 170mm cranks
Every time I need a part of an accessory, and everyone online is backordered, Thunder Mountain ALWAYS has what I need and ships it to me super quick….Thunder Mountain is my Go To shop…..You all ROCK….My Rocky Mountain Growler Hardtail with this Shimano XT 165mm crankset and all my other upgrades is a beast.....THANK YOU....
Perfect site description of the product install was a breeze. Thanks again!
Best value in cranks as far as I’m concerned. Great rigidity and quality.
First rate in sales and problem solving service !!
Helmets off to these folks !!
I've read about using shorter crank arms and decided I'd try it. These are the same Shimano crank arms that were on my bike, so I already knew their quality. I went from 170mm to 165mm on a steel suspensionless mountain bike. Like the greater clearance and so far the pedal motion feels great. Very easy transition to make.
Best crank set I’ve used, solid, light, Shimano quality
Of online orders. Also great service in store! This place rocks!
Great product and great service.
They always have what i need when im building a bike makes it easy and they have fast shipping.
I replaced the 170mm XTs with 165mm and it is interesting how lightweight the spindle/crank arms are and how well designed these are.
Updated the drivetrain on my 22 Ripley from SLX to XT, bought the 165mm cranks to match my bike fit. Standard Shimano quality, fit & finish. Thunder Mtn Bikes had them in stock, priced competitively, shipped them quickly!
Great customer support and fast shipping
My bike came with Deore 175mm cranks. Wanted to drop to 165. Definitely didn’t need XT-level cranks. It was just literally impossible to find Deore or SLX cranks in 165. Thunder Mountain happened to have XT cranks in 165 and I caught them during Black Friday for 20% off. Why not! They’re smooth and work with the entry-level Shimano BB already in my frame. Thunder Mountaun shipped quickly!
Only complaint is they don’t come with the VERY specific tool needed to tighten the center lock chain ring in place. Caught me off guard and needed to run to a LBS just to get them to tighten the chain ring in place. Make sure you have this tool handy if you’re installing on your own!
Ordered Deore XT 165 cranks. Order was processed and shipped by Thunder Mountain in 2 hours. Unbelievable service and the order was perfect! These guys are awesome!
Love the shorter cranks, you wouldn’t think 5mm would make that much difference but I really like how they perform.
As described. Solid cranks. Wanted to try 165mm.
Superior product
Purchased 165 mm cranks to replace my stock SLX 175mm cranks. 30 miles so far with no pedal strikes, so I'm very pleased. XT is a little nicer than SLX. Worth the extra money, IMO.
they were the only store that had the crank I needed
Very happy with quick shipping and great customer service! Looked for weeks to find these 12sp XT 165mm cranks!
