Available in up to four sizes for a tailored fit, Quantum features great ventilation, excellent coverage, and of course Bontrager's signature out-of-the-box comfort and incredible ease-of-use.


  • In-mold composite skeleton allows a greater variation of vent shape and size
  • Micro-Manager - Fully-adjustable fit system fits a wide range of head sizes
  • Soft, comfortable, moisture-wicking and washable helmet pads
  • LockDown strap dividers - Helmet strap management made simple
  • Internal, recessed channels manage airflow through the helmet and over the head
  • Removable snap-on visor with visor port plugs
  • Crash Replacement Guarantee - Free replacement if your helmet is involved in a crash during the first year of ownership
Part No. Size Certification Color Weight
433032 Small (52-56cm) CE, CPSC Adult Red / White 310g
433033 Medium (54-60cm) CE, CPSC Adult Red / White 340g
433034 Large (58-64cm) CE, CPSC Adult Red / White 350g
501173 Small (52-56cm) CE, CPSC Adult Black 310g
501174 Medium (54-60cm) CE, CPSC Adult Black 340g
501175 Large (58-64cm) CE, CPSC Adult Black 350g
501176 X-Large (60-66cm) CE, CPSC Adult Black 360g
501165 Small (52-56cm) CE, CPSC Adult White 310g
501166 Medium (54-60cm) CE, CPSC Adult White 340g
501167 Large (58-64cm) CE, CPSC Adult White 350g
501168 X-Large (60-66cm) CE, CPSC Adult White 360g
434467 Small (52-56cm) CE, CPSC Adult Visibility Yellow 310g
434468 Medium (54-60cm) CE, CPSC Adult Visibility Yellow 340g
434469 Large (58-64cm) CE, CPSC Adult Visibility Yellow 350g

Pro Sizing

Measure the circumference of your head using a cloth tape measure or a piece of string and a ruler. Use the chart below to find the proper helmet size based on your measurement.

cm 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

1 Head

Take your measurement horizontally across your brow and over your ears.

Ride it and love it. If not, we’ll take it back.

Ride it and love it. If not, we’ll take it back.

It’s that simple.

If for any reason you’re not satisfied with your Bontrager products, return the item - along with the original sales receipt - to the place of purchase within 30 days of purchase date for exchange or store credit.