Keeping your mountain bike suspension in top shape requires periodic rebuilds. Whether you're servicing a Fox fork, a RockShox shock, or an Öhlins damper, choosing the right rebuild parts is critical for restoring performance and extending the life of your components. This guide covers the essential parts you need and the best options available so you can make an informed purchase without overpaying.
Shop on Amazon
Browse the latest options and prices.
Fox 2.0 Bump-Stop/Air-Shock Rebuild Seal Kit (1-1/4 Shaft)
Understanding MTB Suspension Rebuild Kits
A suspension rebuild typically involves replacing seals, wipers, o-rings, and sometimes bushings and oil. Most brands offer official rebuild kits that include everything needed for a specific model. These kits simplify the process and ensure compatibility.
What's in a Rebuild Kit?
Most fork and shock rebuild kits contain:
- Dust wipers and foam rings
- Main seals (often quad-lip or X-ring)
- O-rings for the air spring and damper
- Oil (quantity may vary; check your service manual)
- Crush washers or copper washers for the damper
Some kits also include new air piston seals, rebound piston seals, and even replacement hardware like bolts or schrader valves. Always verify which parts are included before purchasing.
OEM vs. Aftermarket Rebuild Parts
OEM (Original Equipment Manufacturer) rebuild kits are made by the same company that built your fork or shock. They guarantee exact fitment and often come with detailed instructions. Aftermarket parts, like those from Enduro, SKF, or WTB, may offer improved durability or lower cost. Many riders find aftermarket seals last longer than stock, but compatibility can vary. For critical components like damper seals, OEM is usually safer, while air spring seals are often fine with quality aftermarket replacements.
Key Components to Consider
When buying rebuild parts, you'll likely need some or all of the following:
Seal Kits
Seals are the most common reason for rebuilding. Worn seals cause oil leaks, reduced sensitivity, and poor performance. Look for a kit that matches your fork or shock's stanchion diameter and travel. Brands like SRAM (RockShox), Fox, and Öhlins sell dedicated seal kits. Aftermarket options from SKF and Enduro are known for low-friction seals that can improve small bump compliance.
Damper Oil
Damper oil viscosity affects damping performance. Most modern forks use 5wt or 7.5wt oil, but always check your service manual. Popular brands include Maxima, Motorex, and Bel-Ray. For suspension, look for a high-quality synthetic oil that resists foaming and viscosity breakdown. Avoid using automotive shock oil, as it may not have the right anti-foam additives.
Air Can Seals
For rear shocks with an air can, the air can seals must be replaced during a rebuild. These large seals prevent air leaks and maintain proper sag. OEM kits usually include these, but you can also purchase them separately if you only need the air can serviced.
Bushings and Hardware
Some forks and shocks use bushings that wear over time. For example, Fox 36 and 38 forks have lower leg bushings that can be replaced. Worn bushings cause play and reduce stability. Bushing kits often include the upper and lower bushings plus the necessary tools for installation. If your fork feels loose, replacing bushings can restore rigidity.
Top Brands for Rebuild Parts
Several brands dominate the mountain bike suspension parts market. Here's a breakdown of the most reliable:
SRAM / RockShox
RockShox offers comprehensive rebuild kits for all their forks and shocks. The kits are well-organized and include all necessary seals and o-rings. For older models, you may need to check compatibility with the service manual. Aftermarket seals from SKF are a popular upgrade for RockShox forks, as they reduce stiction.
Fox
Fox rebuild kits are model-specific and cover everything from the 32 to 40 series. They also sell separate dust wiper and foam ring kits. Fox's official oil (Fox Suspension Fluid) is recommended for optimal damping performance. Many riders use 10wt for trail forks and 5wt for cross-country.
Öhlins
Öhlins provides detailed rebuild kits for their DH and enduro forks. The kits are pricey but include high-quality seals and shims. If you own an Öhlins shock, buying the official kit is essential for proper function, as aftermarket parts may not match the specific tolerances.
Enduro Bearings
Enduro is known for low-friction seals that many riders prefer over OEM. Their seal kits are compatible with many Fox and RockShox models. They also offer silicone-free lubricants that can improve sensitivity. If you're looking to upgrade performance, Enduro seals are worth considering.
SKF
SKF makes seals for several OEMs and sells aftermarket upgrade kits. Their seals are praised for durability and low friction. SKF seal kits are available for many popular forks and shocks, often at a lower price than OEM.
How to Select the Right Parts for Your Fork or Shock
Choosing the correct parts starts with knowing your suspension model. Check the manufacturer's sticker or engraving on the lower leg or shock body. Write down the exact model and year. Then:
- Look up a service manual online (most brands provide PDFs).
- Identify the specific rebuild kit part number recommended.
- If going aftermarket, cross-reference compatibility by stanchion diameter, travel, and damper type (e.g., Charger 2.1 vs. FIT4).
Matching Model Year
Suspension manufacturers revise designs frequently. A 2020 Fox 36 uses different seals and wipers than a 2023 model. Always buy parts meant for your specific year. OEM kits are the safest choice, while aftermarket brands often include notes on which years they fit.
Riding Style Considerations
Your riding style affects which rebuild parts to prioritize:
- Aggressive trail/enduro riders need durable seals that withstand mud and grit. Consider upgraded SKF or Enduro seals.
- Cross-country riders may prefer low-friction seals for better small bump compliance.
- Downhill racers should stick with OEM for reliability under extreme loads.
Practical Recommendations
If you are new to suspension servicing, start with an OEM rebuild kit for your fork or shock. It includes everything you need and reduces mistakes. For example, a RockShox Lyrik rebuild kit costs around $40–$60 and includes seals, foam rings, o-rings, and oil. Pair it with fresh damper oil (approx. $10 per bottle) and a set of crush washers.
When replacing seals only, consider an aftermarket upgrade like SKF or Enduro. Many riders report longer service intervals and improved feel. Just make sure the kit explicitly lists your fork or shock model.
For bushings, purchase a dedicated bushing kit from the brand. Fox offers a bushing and seal kit for their 36/38 forks that also includes the tool. This is cost-effective compared to buying parts separately.
Finally, always replace the required oil amount as specified in the manual. Overfilling can cause lockout issues, while underfilling reduces damping. Use a syringe or graduated cup for accuracy.
Final Recommendation
For most riders, the best value is the OEM rebuild kit from your suspension brand combined with high-quality aftermarket oil like Motorex or Maxima. This combination ensures fitment and performance without breaking the bank. If you want to reduce friction, swap the OEM wipers for SKF or Enduro versions. For those on a tight budget, complete aftermarket kits from Enduro or WTB can save money while still restoring function. However, for critical dampers, stick with OEM to avoid compatibility headaches.
Investing in the right rebuild parts keeps your suspension performing like new, saves money on full service fees, and lets you dial in your setup. Always double-check compatibility, and don't hesitate to consult your suspension brand's online resources if you're unsure.