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28 Finley Drive
#1
Sedona AZ 86336
United States
+19282821106
Meet the world’s first mechanical drivetrain with Full-Mount durability, rebuildable toughness, and rock-solid shifting under max power. With an easy, foolproof setup and unmatched reliability, Eagle 90 Transmission redefines mechanical shifting for the modern MTB rider.
Power through every shift, no matter the terrain. With X-Sync tooth profiles and 44 optimized shifting points, Eagle 90 delivers precise, smooth gear changes under full load, whether on an E-MTB or a hard-charging trail bike.
Forget bent derailleur hangers! Eagle 90’s Full Mount interface anchors directly to the frame at the axle for unmatched strength and precision. It’s so strong you could stand on it, yet smart enough to rotate away on impact, allowing for a quick trailside reset so you can keep riding.
With industry-leading durability, you may never need to rebuild your Eagle 90 derailleur. But if you do, it’s the easiest to service ever. With just three tools and a few minutes, you can swap all parts and get back on the trail fast. Plus, rebuild kits and skid plates are readily available to keep your drivetrain running for a lifetime.
The Eagle 90 crankset is crafted from forged aluminum for ultimate strength and comes in 5mm increments from 155mm to 175mm. Prefer more torque? Go 175mm. Want fewer pedal strikes? Opt for 155mm. It’s all about what fits your riding style.
With Eagle 90’s "prepare, hang, tighten" process, installation is shockingly simple. Just route and tension the shift cable, and you’re ready to rip. Plus, the redesigned Eagle 90 shifter delivers the most satisfying mechanical click yet - sleekly mounted parallel to the bar for a clean, modern cockpit.
Eagle 90 isn’t just mechanical shifting, it’s the next evolution of it.
| Crank Arm Length: | 150mm, 155mm, 160mm, 165mm, 170mm |
| Motor Interface: | Brose, Bosch, Bosch BDU38 |
| BB Spindle Interface: | ISIS |
| Weight: | 490 grams (160mm) |
| Model ID: | FC-90-PA-A1 |
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 through FedEX and USPS.
Most orders totaling over $59 are eligible to ship for free via an economy ground option of our choice.
Due to larger box sizes, handlebars and other oversized items will have an additional shipping fee.
Most bikes ship free within the continental US. Bike shipping to AK, HI, or PR is available at an additional charge 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 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 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 have a $200 restocking fee and the customer pays for 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 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 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 
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 an email with shipping instructions and a return shipping label.
If you have any questions concerning our return policy, please contact us at:
