Altaline 20 X 2.125 Bicycle

AltaLine 20x2.125 Retro Schwinn-Style Tire – Wide Slick for Krate, Stingray & Lowrider Bikes!

• Brand: AltaLine

• Model / Tread Code: AL-1521 (Slick)

• Tire Name: Slick (Wide Slik – Schwinn Style)

• Size (Inches): 20 x 2.125

• ISO / ETRTO Size: 54-406 (Bead Seat Diameter 406 mm)

• Type: Clincher Tire (uses inner tube)

• Bead Type: Wire Bead (non-folding)

• Material: High-durability rubber compound with reinforced sidewalls

• Tread Pattern: Smooth Slick Center 

• Recommended Pressure: 60 – 65 PSI (4.1 – 4.5 BAR)

• Rim Compatibility:

• • Designed for Schwinn S2 rims (20" / 406 mm BSD)

  • Compatible with most 20" rims 25–32 mm inner width

• Tube Compatibility:

  • Fits standard 20 x 1.75 – 2.125 tubes

  • Schrader valve 

• Color / Sidewall Options:

  • Black / Black Sidewall

  • Black / White Sidewall

  • Black with Colored Pinstripe (Red, Blue, Green, Yellow, Orange, or White Line)

• Classic Schwinn Replica Design:
  The AltaLine AL-1521 is a reproduction-style tire designed specifically to mimic the look and ride of the original Schwinn Stingray and Krate slicks used on vintage muscle bikes of the 1960s–70s.
  Its rounded profile, smooth tread, and correct 20 x 2.125 size make it a near-perfect fit for authentic restorations.

• Rim Fitment:
  Engineered for Schwinn S2 rims (406 mm BSD) — the same rim type used on original Stingray, Krate, and early 20" muscle bike models.
  The tire bead seats precisely on S2-style rims without excessive stretch or gap, maintaining correct sidewall shape and clearance.

• Tread & Ride Characteristics:

  • Smooth center tread provides low rolling resistance for pavement and boardwalk riding.

  • Rounded shoulders maintain a classic silhouette and predictable handling at cruiser speeds.

  • Ideal for show bikes, daily cruisers, and collectors restoring original Schwinn models.

• Rubber Compound:
  Standard dual-density rubber designed for urban and light recreational use.
  Optimized for durability, UV resistance, and smooth ride quality rather than high-performance grip.

Direct replacement tire for classic 20" S2 Schwinn bicycles including:

• Schwinn Stingray (all variants)

• Schwinn Krate series: Orange Krate, Apple Krate, Lemon Peeler, Cotton Picker, Pea Picker

• Schwinn Fastback, Fair Lady, and similar muscle bike models

• Custom lowriders, cruisers, choppers, and retro rebuilds

• Compatible with many 20" BMX-style or cruiser frames using 406 mm rims and 2.125" tire clearance

Frame Clearance:

• Tire width is approximately 2.125" (54 mm) when mounted and inflated.

• Ensure at least 3–4 mm side clearance at frame and fork.

• Most Schwinn Krate/Stingray frames and forks clear this tire with fenders installed.

• Surface Type: Smooth pavement, concrete, or asphalt

• Recommended Usage: Cruiser riding, show/display bikes, restorations, and casual recreational use

• Not Intended For: Off-road, trail, or aggressive riding

• Ride Feel: Smooth, stable, classic muscle-bike ride quality

• Tube Selection: Always match with a 20 x 1.75–2.125 inner tube (Schrader valve recommended).

• Mounting: Use proper tire levers to avoid damaging bead or rim; seat bead evenly before inflation.

• Inflation: Inflate gradually, checking bead alignment on both sides. Do not exceed printed PSI.

• Pressure Check: Maintain 55–65 PSI for optimal ride and tire longevity.

• Storage: Store in a cool, dry environment away from sunlight and ozone sources to preserve rubber quality.