Top of their line in MTB helmets is the Treelium MTB Helmet. While there are 26 vents, they are somewhat constricted. This may actually be an advantage if you are riding in the winter months though. Also, there a not a lot of sizes. This is only a problem if you have a larger head.

Louis Garneau Trellium MTB Helmet Specifications:

• Weight: 10.9 oz/310 g
• Certifications: CPSC-ASTM-CEN
• Vents: 26
• Ringlock: Frame ring that ensures helmet’s integrity on impact.
• In-Mold Construction: Industrial process binding the microplastic and polystyrene together to add superior mechanical properties to these materials
• Spiderlock Elite: Adjustable and detachable rack-and-pinion mechanism using only one hand to stabilize the helmet on the head. It is provided with ergonomic padding
• Composite Reinforcement: Inner composite-made frame which spreads the shock of impacts. It provides support and protection while being lightweight
• Steplock Side Adjustment: Cam locking device to quickly adjust strap position
• Sealed Airdry Padding: Sealed adjustment padding for enhanced durability, ergonomic design for optimum comfort, and is washable
• V-Pro System: Receptacle molded into the helmet in order to put on and off the visor as often as you wish. Plastic plugs are included to fill the holes when not used.
• Sizes:
  • Small/Medium (SM): 6 1/2-7 1/8, 20″ 1/2-22″ 3/8, 52-57 cm
  • Medium/Large (ML): 6 3/4-7 5/8, 21″ 1/4-24″, 54-61 cm
• Colors: White/Grey, Brown/Tan, Black/Red

Louis Garneau’s middle of the line model is the Robota MTB Helmet. I actually prefer the aesthetics of this model over the others, but your taste may be different. This is also the lightest mountain bike helmet in the Louis Garneau line. Venting is minimal with only 16, but they are larger than in the Trellium. Also, this model comes in a full range of sizes for those outside the normal range.

Louis Garneau Robota MTB Helmet Specifications:

• Weight: 9.7 oz/275 g
• Certifications: CPSC-ASTM-CEN
• Vents: 16
• Ergobuckle: Ergonomically-shape quick-release helmet fastener
• Keylock: Easy strap position adjustment
• In-Mold Technology: Technology for better durability
• Inner-Nerves: Internal support system reinforcing the helmet structure
• Spiderlock Elite: stabilizing device    One-hand quick and accurate fit
• Airdry Fusion: Better comfort and optimum ventilation
• V-Pro Visor: Sun protection, easy to adjust
• Visor in the box
• Sizes:
  • Small: 20 1/2-22″/52-56 cm
  • Medium: 22-23 1/4″/56-59 cm
  • Large: 23 1/4-24 3/8″/59-62 cm
  • X-Large: 24 3/8-25 1/4″/62-64 cm
• Colors: Red/Grey, Brown/Yellow, Black/Grey

Finally, their lowest model is the Louis Garneau Global. This is the most popular of the Louis Garneau Helmets. Somewhat strange looking for my tastes, but a lot of people think the Honda Element is ugly and I love it. You’ll have to make that call for yourself. Again, sizing can be a problem in this model for people with larger domes.

Louis Garneau Global MTB Helmet Specifications:

• Weight: 10.8 oz/305 g
• Certifications: CPSC-ASTM-CEN
• Vents: 21
• Evacuation Channels: Moisture channels providing better airflow and moisture wicking.
• In-Mold Construction: Industrial process binding the microplastic and polystyrene together to add superior mechanical properties to these materials
• Spiderlock Quad: The rack-and-pinion mechanism helps the helmet to keep a steady position on the head. It keeps the webbing system in the proper position to make the helmet adjustment easier.
• Inner Nerves: Inner frame which spreads the shock of impacts. It provides support and protection while being lightweight.
• Steplock Side Adjustment: Cam locking device to quickly adjust strap position.
• Airdry Fusion Padding: Fusion adjustment padding for better comfort. Antibacterial. Washable.
• V-Pro System: Receptacle molded into the helmet in order to put on and off the visor as often as you wish. Plastic plugs are included to fill the holes when not used
• Sizes:
  • Small/Medium (SM): 6 1/2-7 1/8, 20″ 1/2- 22″ 3/8, 52-57 cm
  • Medium/Large (ML): 6 3/4-7 5/8, 21″ 1/4-24″, 54-61 cm
• Colors: Blue/Black, Brown/Grey, Grey/White

If you like the aesthetics of one of the models then go for it. Otherwise, you can get a nicer helmet elsewhere. The only exception being that you can often find Louis Garneau Helmets at deep discounts online.

It is quite expensive, but it’s one sexy lid that will keep your head safe without you hardly knowing it is there. With 26 vents and Giro’s Wind Tunnel Ventilation, it will keep your head cooler than if you were not wearing a helmet at all. Giro does this with active vents and internal exhaust channels. The small weighs in at just 240g in the small so you will hardly know it is there.

The Giro Atmos Helmets Product Specifications:

• Vents : 26
• Sizes :
  • S (20”-21.75” / 51-55 cm)
  • M (21.75”-23.25” / 55-59 cm)
  • L (23.25”-24.75” / 59-63 cm)
• Certification : CPSC
• MSRP /Street: $175/$150
• In-Mold Construction
• ROC LOC 4 Adjustment System
• Super Fit Engineering
• Wind Tunnel Ventilation
• Weight : 275g

Theoretically, you can buy any helmet and keep your noggin just as safe due to the fact that all helmets must meet CPSC specifications. What you are paying for in higher priced models such as the Giro Atmos helmet is the increased number of vents, which reduces weight and increses comfort. You also get a much nicer looking product without the exposed foam at the back as found on lower priced models.