The FOX 40 Factory is the ultimate downhill race fork—engineered for the world’s fastest riders and the toughest tracks on the planet. With 203mm of buttery-smooth travel and a chassis honed through World Cup competition, the 40 is built to dominate the steepest, roughest terrain out there.
At its core is the GRIP X2 damper, delivering unmatched control, adjustability, and grip. Whether you're charging rock gardens or launching gaps at race speed, the 40 stays composed, planted, and ready for anything.
Designed for elite performance and backed by a legacy of podiums, the 40 Factory is the gold standard for gravity racing. If you're aiming for the top step, this is your edge.
Fox 40 Factory Suspension Fork Features
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GRIP X2 Damper - FOX’s most advanced damper offers independent high- and low-speed compression and rebound adjustments, giving you unmatched control and traction. Whether you're smashing through rock gardens or floating over jumps, GRIP X2 keeps your front end planted and predictable.
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203mm of Travel with FLOAT EVOL Air Spring - Designed for the roughest tracks on the planet, the 40’s massive travel paired with FOX’s EVOL air spring delivers a plush, supportive ride with excellent small-bump sensitivity and mid-stroke control.
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Factory Series Performance with Kashima Coat - The signature gold Kashima-coated stanchions reduce friction, improve durability, and deliver the buttery-smooth performance top racers demand. Factory Series also means pro-level tuning and build quality straight from FOX’s elite lineup.
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Downhill-Race Ready Chassis - Built around 29" wheels and a stiff 20x110mm Boost chassis, the 40 offers precise handling and incredible front-end confidence. With bleed ports for pressure equalization and an updated arch design for maximum clearance and rigidity, this fork is built to dominate the podium.
Fox 40 Factory Suspension Fork Specs
| Model Year: | 2026 |
| Wheel Size: | 29" |
| Travel: | 203mm |
| Damper: | Grip X2 |
| Damper Controls: | HSC - LSC - HSR - LSR |
| Offset (Rake): | 29" - 52mm, 27.5" - 48mm |
| Axle: | 20TAX110 |
| Upper Tube Finish: | Kashima Coat |
| Rotor Size: | 203 Direct Post Mount, up to 230 compatible |
| Air Spring: | Float Evol |
| Steerer: | 1.125 Straight |
| Starting Weight: | 2745g (40, 29, F-S, 200, Grip X2, Kabolt) |
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!
Shipping
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.
RETURNS
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 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.
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).
REFUNDS
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.
EXCEPTIONS
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.
RETURN PROCESS
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.
QUESTIONS ABOUT RETURNS?
If you have any questions concerning our return policy, please contact us at:
