1. Product Overview
This manual provides instructions for the proper installation, use, maintenance, and troubleshooting of your KENDA bicycle inner tubes. Please read this guide thoroughly before installation and use to ensure safety and optimal performance.
Image: KENDA bicycle inner tube and packaging.
2. Setup and Installation
2.1 Core Adaptation Principles
- Specification Matching: The inner tube size (e.g., 650x23-25C) must exactly match the outer tire/rim. Cross-specification use is prohibited.
- Tire Bead Fitting: Ensure the tire bead hole dimensions match your valve type. French (Presta) valves are common for road bikes and high-end mountain bike rims.
- New Tire Inspection: Before installation, inspect the inner tube for any folds, damage, or delamination. Ensure valve stems are secure and free of air leaks.
2.2 Key Installation Steps
- Preparations: Ensure the inner side of the outer tire and the rim are free of sharp foreign objects. Securely seat one side of the tire bead in the rim. Inflate the inner tube slightly (3-5cm bulge) to prevent folding during installation.
- Insertion: Align and adhere the inner tube to the inner side of the outer tire without twisting. Align the valve to pass through the valve hole in the rim. Manually press the inner tube into the other side of the outer tire. Avoid using hard tools like crowbars or screwdrivers to pry it in, as this can damage the tube.
- Fastening: For Presta valves, secure the French-style locking ring (do not overtighten). Initially inflate the tube to approximately 1/3 of the recommended pressure. After confirming there are no bulges or pinched areas, proceed to full inflation.
3. Operating and Inflation
3.1 Key Points for Standardized Inflation
- Pressure Standard: Inflate the inner tube according to the specified pressure range on the outer tire (e.g., 35-65 PSI, 2.5-4.5 bar). Do not exceed the maximum or fall below the minimum pressure.
- Operation: Clean the valve core and ensure the air cylinder connector is tightly attached to the valve. Inflate in multiple stages while monitoring the pressure with a gauge. In high-temperature environments, reduce the pressure by 5-10 PSI to account for expansion.
- Pressure Check: Inspect tire pressure before each ride and after parking for more than 3 days. Promptly inflate if natural air leakage occurs.
4. Maintenance
4.1 Daily Protection Taboos
- Avoid sharp road surfaces and pothole impacts.
- Do not overload the bicycle (e.g., riding with two people on a single-person bike) to prevent inner tube damage.
- Storage (Long-term): If the bike will not be ridden for over a month, lift the bike off the ground and reduce the inner tube pressure to 50% of the recommended level. Avoid exposure to direct sunlight and corrosive substances such as gasoline or alcohol.
- Spare Inner Tube Storage: Store spare inner tubes sealed in a cool, dry place. Avoid folding and keep them away from sharp objects.
5. Troubleshooting and Replacement
5.1 Emergency Tire Patching Procedure (For Small Tread Damage ≤3mm)
- Remove the tire and inner tube. Immerse the tube in water or apply soapy water to locate the leak. Mark the leak point and dry the area thoroughly.
- Grind the air leakage point (making it slightly larger than the patch) to a matte finish using a sanding disc. Apply adhesive and let it dry for 1-2 minutes until semi-dry.
- Press the patch firmly onto the prepared area for more than 30 seconds. Allow it to cure for 5-10 minutes. Reinstall the tube after slight inflation.
- Prohibited: Do not perform more than 2 patch repairs at the same location. Repairs are prohibited for punctures at the valve stem base or sidewall.
5.2 Mandatory Replacement Standards
Replace your inner tube if any of the following conditions are met:
- Damaged or detached valve stem, or if the air valve core cannot be secured, causing air leakage.
- Damage, openings greater than 3mm, or tear-like conditions near the sidewall/valve stem.
- The inner tube surface becomes hard and brittle, with a network of cracks and delamination.
- A single inner tube has been patched 3 or more times, or if there are irreparable bulges and folds.
6. Specifications
| Feature | Detail |
|---|---|
| Brand | Kenda |
| Model Number | 650x23-25C |
| Type | Bicycle Inner Tube |
| Valve Type | Presta (FV) |
| Valve Lengths | 48L, 60L (Length in millimeters) |
| Approximate Weight | 130g |
| Recommended Use | Road Bikes, Mountain Bikes |
| Origin | Mainland China |
| High-Concerned Chemical | None |
7. User Tips
- Valve Length Selection: The 'L' in 48L or 60L refers to the length of the Presta valve stem in millimeters. Choose the appropriate valve length based on your rim's depth. Deeper rims require longer valve stems to allow for proper inflation and valve cap attachment.
- Always carry a spare inner tube and a portable pump or CO2 inflator when riding, especially on longer trips.
8. Safety Warnings
- Secure the bicycle properly during installation and inflation to prevent tipping and potential injury.
- If using with a children's bike trailer, adult supervision is required. Always check tire pressure and fixation status before riding.
- Improper installation or inflation can lead to tire blowouts or accidents. Always follow the instructions carefully.
9. Warranty and Support
For any questions, concerns, or support regarding your KENDA bicycle inner tubes, please contact the seller or authorized distributor. Keep your purchase records for any warranty claims.
A PDF version of this user manual may be available for download from the product page or seller's website.