33mm. Every major Class 8 tractor sold in North America — Freightliner Cascadia, Kenworth T680/T880, Peterbilt 389/579, Volvo VNL/VNR, Mack Anthem, International LT, and Western Star — uses an M22x1.5 wheel stud with a 33mm hex lug nut on standard hub-piloted 22.5" and 24.5" wheels. The IND33MM is the correct indicator for all of these.

Note: M22x1.5 is the stud thread size, not the nut hex. A common mistake is ordering a 22mm indicator because the stud is “22mm.” The nut that threads onto an M22x1.5 stud has a 33mm hex head.

33mm for most North American transit and school bus applications. New Flyer Xcelsior, Gillig Advantage/BRT, NovaBus LFS, Blue Bird Vision/All American, IC Bus CE/RE, and Thomas Built C2/Saf-T-Liner all run hub-piloted 22.5" wheels with M22x1.5 studs and 33mm hex lug nuts. Torque-Tight 32mm & 33mm indicators are in active service with transit agencies including Sawannee Valley, RIPTA, MTA New York City Transit, LA Metro, King County Metro and others.

European coach platforms (Setra, MAN, Mercedes Citaro) typically use a 32mm hex — use IND32MM for those applications.

22mm for most half-ton through one-ton GM and Ram trucks with aluminum or alloy wheels. This covers GMC Sierra/Chevy Silverado 2500–3500, Chevy Express/GMC Savana 2500–4500, and Ram 2500–3500. These trucks use M14x1.5 studs with a 22mm hex lug nut on alloy wheels (dependent on wheel style).

Steel wheels on some older models may use a 19mm or 21mm hex. If you’re unsure, pull the socket that fits and match it to the chart above.

It depends on the wheel type and model year. Ford F-250/F-350 with alloy wheels typically run a 22mm hex (M14x1.5 stud) — use IND22MM. Ford F-450/F-550 commonly run a 21mm hex — use IND21MM. Steel wheels on older F-250/350 may use 21mm. Always confirm with a socket before ordering.

Hub-piloted wheels (introduced industry-wide after 1997) are centered on the hub with a single two-piece flange nut. Stud-piloted (Budd) wheels are centered on the studs with inner and outer cap nuts. Both wheel types have been available with 33mm hex nuts, so wheel type alone does not determine indicator size — the nut hex does.

Older Budd-wheel vocational equipment (concrete mixers, older dump trucks, legacy trailer axles) sometimes used a larger outer cap nut, which can run 38mm hex. If you’re working with pre-1997 stud-piloted equipment, measure the outer nut hex before ordering.

Standard orange and green lug nut indicators (all sizes) are injection-molded right here in the USA. These meet Buy America requirements applicable to FTA-funded transit procurements.

Chrome Protect indicators (CAP33MM-CHR) are sourced globally

Count the total number of lug nuts across all wheels. Common configurations:

• Class 8 6x4 tractor (3 axles, 6 wheels, 10 studs/wheel each): 60 indicators
• 53’ trailer (2 axles, 4 wheels, 10 studs/wheel each): 40 indicators
• Tractor + trailer combination: 100 indicators
• Transit bus (3 axles, 6 wheels, 10 studs/wheel each): 60 indicators
• School bus (2 axles, 4 wheels, 10 studs/wheel each): 40 indicators

Torque-Tight is available standard in 10-piece, 100-piece, 1,000-piece, and 4,000-piece pack sizes (packaged 100/bag). View all pack sizes. Contact us for larger bulk orders.

Yes. Torque-Tight standard indicators are made from LDPE (low-density polyethylene), which remains flexible and maintains interference fit from −40°F to over 250°F. They are in active use by transit agencies and fleets operating in Alaska, Canada, and northern US states year-round.

UV color stability is independently verified by Element Materials Technology (ISO 17025, ASTM G154-23 Cycle 1, 500-hour test), confirming Torque-Tight maintains color while competitive products showed significant degradation.