Product Description
Rubber Press-On
Specifications: 21.000 inch diameter x 7.000 inch width (21.000" x 7.000" | 21 x 7 wheel | 21 x 7-0 | 533.40mm x 177.80mm)
Specifications
Wheel Specifications
| Outside Diameter (in) | 21.000 |
| Width (in) | 7.000 |
| Outside Diameter (mm) | 533.40 |
| Width (mm) | 177.80 |
| Drive Tire Profile | Smooth Flat |
| Material | Rubber |
Frequently Asked Questions
Q: What is a press-on tire and how does SU 21 X 7 X 15-SF-R differ from a molded wheel?
A: Press-on tires are rubber or polyurethane sleeves that are pressed onto a metal rim or hub core. SU 21 X 7 X 15-SF-R is a rubber press-on tire with a 21 inch OD, 7 inch width, and 15mm bore. The advantages are lower cost than molded wheels, easy swapping of tires, and simplified repair (tire can be removed without destroying the core). Disadvantages are potential tire slippage under extreme load and longer installation time compared to molded wheels. Press-on tires are standard for lift trucks and pallet jacks.
Q: Can I use the 21 inch tire on a jack that currently has 18 inch tires?
A: No. Do not install a 21 inch tire on a jack designed for 18 inch wheels. Upgrading wheel diameter changes the jack geometry: load center distance increases, hydraulic lift height changes, and steering response is affected. The jack frame and axle assembly must be rated for 21 inch wheels, and the mounting bore (15mm in this case) must match your jack hub. If your jack currently has 18 inch tires, consult the manufacturer or a service technician before attempting a wheel size upgrade.
Q: What load capacity does the 21 X 7 X 15-SF-R tire support and does size increase the rating?
A: SU 21 X 7 X 15-SF-R supports up to 2000 lbs per wheel. The larger diameter (21 inches versus 18 inches) does not increase load capacity per tire, but it does reduce rolling resistance and improve ground clearance. The wider 7 inch width improves load distribution. Your jack capacity is determined by the hydraulic pump and frame, not the wheel. If your jack is rated 4000 lbs total, two 21 inch wheels can carry that load; the wheels do not increase jack capacity beyond the manufacturer rating.
Q: How do I properly install and secure a press-on tire to prevent slipping?
A: Press-on tires require a tire press set to 8-12 tons of force for 21 inch wheels (higher than smaller tires due to weight and stiffness). Lubricate the core hub bore lightly with soap solution or press-on oil to reduce friction during installation. Press the tire straight and evenly; do not tilt or force by hand. After pressing, allow the tire to settle for 30 minutes before operating under load. To prevent future slipping, perform a 50-hour operation check and re-press if the tire has shifted. Some facilities use set screws or clamps on the rim flange to lock the tire in place.
Q: What is the lifespan and maintenance requirement for SU 21 X 7 X 15-SF-R rubber tires?
A: SU 21 X 7 X 15-SF-R rubber tires typically last 24-48 months or 3000-6000 operating hours depending on load and floor conditions. Rubber tires are more forgiving than polyurethane and maintain grip in cold environments. Inspect monthly for tread wear, sidewall cracking, and tire creep on the hub. If the smooth flat profile becomes glazed or shiny (reduced traction), the tire is nearing end of life. Replacement cost is lower than molded wheels because you only replace the rubber sleeve, not the entire core assembly.
Q: Is SU 21 X 7 X 15-SF-R equivalent to any competitor press-on tire models?
A: SU 21 X 7 X 15-SF-R is equivalent to Crown WH-TR21070000, Yale YL-580072001, and Hyster 1302304 when all share the same 21x7 size, smooth flat profile, rubber material, and 15mm bore. Cross-referencing is safe if these four specs match the manufacturer data sheet. Some OEM jacks may use clipped or keyed bores (15mm with a flat spot or key groove); verify bore type before ordering. Standard press-on tires fit standard bores; do not force a tire onto a keyed bore.