MARIN SAN QUENTIN 20 KID'S MTB BIKE 2025 WHITE/BLACK

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Product Details - Marin San Quentin 20 Kid's Mtb Bike 2025 White/black

We took our Matt Jones-inspired Marin San Quentin and shrunk it down to fit 20” wheels. It's the perfect bike for kids who are ready for their first proper, hardcore hardtail mountain bike.

The Marin San Quentin 20”, just like the big kid’s version, shreds the boundaries of the mountain bike genres - doing it all with a huge splash of big air, speed and style.

Designed with the input of freeride legend Matt Jones, the San Quentin takes the DNA of our dirt-jumping Alcatraz and mutates it into a go-further and faster all-round, hardcore hardtail. The San Quentin 20” will feel just like a ‘grown up’ mountain bike to your little ripper, built with a stout Series 2 aluminum frame, 20” wheels, an SR Suntour XCM suspension fork, 8-speed Shimano drivetrain and kid’s specific hydraulic disc brakes.

Key Features 

  • Lightweight frame: Coast Trail models are all built upon lightweight Series 1 aluminium frames and aluminium forks.
  • Modern Trail Geometry: A slack headtube angle paired with a steep seat tube angle creates a ride that will fly uphill, yet descend like it’s on rails.
  • 1X Wide-Range Drivetrain: Modern 1x drivetrains, just like the larger San Quentins, give the rider the benefits of shifting simplicity and chain retention.

Full Specification

  • Frame: Series 2 6061 Aluminum, 20” Wheels, Disc Specific, 135mm Dropouts
  • Fork: SR Suntour XCM 24 BOOST, 80mm Travel, 110mm Axle Spacing
  • Shifters: Shimano Altus SL-M315, 8-Speed
  • Crankset: Forged Alloy, Narrow Wide 30T, 140mm
  • Cassette: Shimano 8-speed, 11-32T
  • Chain: KMC Z8
  • Rear Derailleur: Shimano Altus
  • Bottom Bracket: Sealed Cartridge Bearings, Square Taper
  • Pedals: Kids Specific Nylon Pedal
  • Rims: Marin, Double Wall Alloy, 25mm Internal
  • Front Hub: Forged Aluminium, 32H, Disc Specific
  • Rear Hub: Forged Aluminium, 32H, Disc Specific
  • Tyres: Vee Tire Crown Gem, 20x2.6”, Wire Bead
  • Brakes: Tektro HD-J285 Kid's Specific Hydraulic Disc
  • Handlebar Grips: Marin MTB
  • Handlebar: Marin Riser, 31.8 clamp, 30mm Rise, 590mm Width
  • Stem: Marin Alloy, 35mm
  • Saddle: Marin Kids MTB
  • Seatpost: Marin Alloy, 30.9mm
  • Accessories: N/A
  • Age Range: 8-10 years

    We reserve the right to make changes to the product information contained on this site at any time without notice, including with respect to equipment, specifications, models, colours, materials and pricing. Due to supply chain issues, compatible parts may be substituted at any time without notice.

    Bike and frame weights are based on pre-production painted frames at time of publication. Weights may vary in final production.

    Size Guide

    Marin Bike Sizing Guide Size Guide

    How we Build & Pack Your Bike

    Aftercare

    At All Terrain Cycles, we want you to ride with confidence every time. To ensure your bike or e-bike stays in peak condition, here are some essential safety and maintenance tips.

    Bicycle Safety 

    Always wear a helmet – Safeguard against head injuries by using a properly fitted, safety-certified helmet.

    Perform pre-ride checks – Before each ride, verify that brakes, tyres, and gears are in good working order.

    Stay visible – Utilise lights and reflective gear when cycling in low-light conditions.

    Follow road rules – Ride responsibly and remain aware of your surroundings.

    Aftercare for Your New Bike Initial Check-Up (First 50-100 miles)

    Gear Adjustment – New cables may stretch slightly; have a qualified mechanic check and adjust them.

    Brake & Wheel Check – Inspect brakes for wear and ensure wheels are aligned properly.

    Lubrication – Apply chain oil and check bolt tightness to maintain smooth performance.

    Tyre Pressure – Regularly monitor to prevent flats and enhance efficiency.

    Pedals - Ensure pedals are still tight and correctly fitted.

    Routine Maintenance (Every Few Weeks)

    Chain Care – Clean and lubricate your chain to minimise wear and prolong its life.

    Brake Safety – Check brake pads and responsiveness before each ride.

    Tyre Inspection – Look for punctures and ensure correct air pressure.

    Handlebar & Stem Alignment – Confirm they are tight and secure to prevent instability.

    Frame Safety Check – Look for any signs of damage or cracks.

    Pedals - Ensure pedals are still tight and correctly fitted.

    Professional Check-Ups

    Have your bike serviced at least once a year, or more frequently if you ride often.

    Aftercare for Your New Electric Bicycle (e-Bike) Initial Check-Up (First 50-100 miles)

    Battery Care – Fully charge your battery (if required) before the first ride and store it in a dry, moderate-temperature environment.

    Avoid Overcharging – Unplug the charger once fully charged to extend battery life.

    Pedals - Ensure pedals are still tight and correctly fitted.

    Routine e-Bike Maintenance (Every Few Weeks)

    Motor Inspection – Listen for unusual noises and ensure smooth operation.

    Battery & Connection Checks – Inspect cables and connectors for dirt, moisture, or damage.

    Pedals - Ensure pedals are still tight and correctly fitted.

    Seasonal e-Bike Maintenance

    Check Electrical Components – Ensure wires and connections are clean and secure.

    Professional Servicing – Have your e-bike inspected at least once a year or every 500-1000 miles for optimal performance.

    By following these aftercare guidelines, you’ll help ensure that your bicycle runs smoothly, lasts longer, and remains a joy to ride. Stay safe and enjoy the ride!

    Read our full advice

    If you have any problems or concerns: Contact All Terrain Customer Services on 01274 588488 or email sales@allterraincycles.co.uk

    MARIN SAN QUENTIN 20 KID'S MTB BIKE 2025 WHITE/BLACK
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    Regular price £649.00
    Regular price £649.00 Sale price £649.00
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    More information

    • SKU: 737618001
    • EPOS Code:
    Est. Dispatch
    Delivery Available
    Finance Available
    Family Owned Independent
    Built by Cytech Mechanics
    10% Off Accessories
    We Accept Cyclescheme
    View full details

    Product Description

    We took our Matt Jones-inspired Marin San Quentin and shrunk it down to fit 20” wheels. It's the perfect bike for kids who are ready for their first proper, hardcore hardtail mountain bike.

    The Marin San Quentin 20”, just like the big kid’s version, shreds the boundaries of the mountain bike genres - doing it all with a huge splash of big air, speed and style.

    Designed with the input of freeride legend Matt Jones, the San Quentin takes the DNA of our dirt-jumping Alcatraz and mutates it into a go-further and faster all-round, hardcore hardtail. The San Quentin 20” will feel just like a ‘grown up’ mountain bike to your little ripper, built with a stout Series 2 aluminum frame, 20” wheels, an SR Suntour XCM suspension fork, 8-speed Shimano drivetrain and kid’s specific hydraulic disc brakes.

    Key Features 

    • Lightweight frame: Coast Trail models are all built upon lightweight Series 1 aluminium frames and aluminium forks.
    • Modern Trail Geometry: A slack headtube angle paired with a steep seat tube angle creates a ride that will fly uphill, yet descend like it’s on rails.
    • 1X Wide-Range Drivetrain: Modern 1x drivetrains, just like the larger San Quentins, give the rider the benefits of shifting simplicity and chain retention.

    Full Specification

    • Frame: Series 2 6061 Aluminum, 20” Wheels, Disc Specific, 135mm Dropouts
    • Fork: SR Suntour XCM 24 BOOST, 80mm Travel, 110mm Axle Spacing
    • Shifters: Shimano Altus SL-M315, 8-Speed
    • Crankset: Forged Alloy, Narrow Wide 30T, 140mm
    • Cassette: Shimano 8-speed, 11-32T
    • Chain: KMC Z8
    • Rear Derailleur: Shimano Altus
    • Bottom Bracket: Sealed Cartridge Bearings, Square Taper
    • Pedals: Kids Specific Nylon Pedal
    • Rims: Marin, Double Wall Alloy, 25mm Internal
    • Front Hub: Forged Aluminium, 32H, Disc Specific
    • Rear Hub: Forged Aluminium, 32H, Disc Specific
    • Tyres: Vee Tire Crown Gem, 20x2.6”, Wire Bead
    • Brakes: Tektro HD-J285 Kid's Specific Hydraulic Disc
    • Handlebar Grips: Marin MTB
    • Handlebar: Marin Riser, 31.8 clamp, 30mm Rise, 590mm Width
    • Stem: Marin Alloy, 35mm
    • Saddle: Marin Kids MTB
    • Seatpost: Marin Alloy, 30.9mm
    • Accessories: N/A
    • Age Range: 8-10 years

      We reserve the right to make changes to the product information contained on this site at any time without notice, including with respect to equipment, specifications, models, colours, materials and pricing. Due to supply chain issues, compatible parts may be substituted at any time without notice.

      Bike and frame weights are based on pre-production painted frames at time of publication. Weights may vary in final production.

      Size Guide

      Marin Bike Sizing Guide Size Guide

      How to Build Your Bike

      Aftercare

      At All Terrain Cycles, we want you to ride with confidence every time. To ensure your bike or e-bike stays in peak condition, here are some essential safety and maintenance tips.

      Bicycle Safety 

      Always wear a helmet – Safeguard against head injuries by using a properly fitted, safety-certified helmet.

      Perform pre-ride checks – Before each ride, verify that brakes, tyres, and gears are in good working order.

      Stay visible – Utilise lights and reflective gear when cycling in low-light conditions.

      Follow road rules – Ride responsibly and remain aware of your surroundings.

      Aftercare for Your New Bike Initial Check-Up (First 50-100 miles)

      Gear Adjustment – New cables may stretch slightly; have a qualified mechanic check and adjust them.

      Brake & Wheel Check – Inspect brakes for wear and ensure wheels are aligned properly.

      Lubrication – Apply chain oil and check bolt tightness to maintain smooth performance.

      Tyre Pressure – Regularly monitor to prevent flats and enhance efficiency.

      Pedals - Ensure pedals are still tight and correctly fitted.

      Routine Maintenance (Every Few Weeks)

      Chain Care – Clean and lubricate your chain to minimise wear and prolong its life.

      Brake Safety – Check brake pads and responsiveness before each ride.

      Tyre Inspection – Look for punctures and ensure correct air pressure.

      Handlebar & Stem Alignment – Confirm they are tight and secure to prevent instability.

      Frame Safety Check – Look for any signs of damage or cracks.

      Pedals - Ensure pedals are still tight and correctly fitted.

      Professional Check-Ups

      Have your bike serviced at least once a year, or more frequently if you ride often.

      Aftercare for Your New Electric Bicycle (e-Bike) Initial Check-Up (First 50-100 miles)

      Battery Care – Fully charge your battery (if required) before the first ride and store it in a dry, moderate-temperature environment.

      Avoid Overcharging – Unplug the charger once fully charged to extend battery life.

      Pedals - Ensure pedals are still tight and correctly fitted.

      Routine e-Bike Maintenance (Every Few Weeks)

      Motor Inspection – Listen for unusual noises and ensure smooth operation.

      Battery & Connection Checks – Inspect cables and connectors for dirt, moisture, or damage.

      Pedals - Ensure pedals are still tight and correctly fitted.

      Seasonal e-Bike Maintenance

      Check Electrical Components – Ensure wires and connections are clean and secure.

      Professional Servicing – Have your e-bike inspected at least once a year or every 500-1000 miles for optimal performance.

      By following these aftercare guidelines, you’ll help ensure that your bicycle runs smoothly, lasts longer, and remains a joy to ride. Stay safe and enjoy the ride!

      Read our full advice

      If you have any problems or concerns: Contact All Terrain Customer Services on 01274 588488 or email sales@allterraincycles.co.uk