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MTB 4.0 AllMtn Helmet

2.75 out of 5 stars
4 Reviews
Current price: $139.99 Original price: $199.99
30% off


Size Chart


Why We Like The MTB 4.0 AllMtn Helmet

Brush up on your history of Leatt, and you'll discover a rich past based upon the creation of safer, smarter equipment for those that ride off-road. The California-based brand's two decades of experience has provided us with reliable gear from body armor to neck braces, and the MTB 4.0 AllMtn Helmet is their latest launch to offer superior protection at an affordable price. Its rugged frame is built from a lightweight polymer compound to reduce neck fatigue as you grind up the mountain, and EPS foam handles higher speed impacts no matter where the trail takes you. We especially like Leatt's 360-degree Turbine Technology, which dramatically reduces harmful rotational and low-G impact forces.


  • Rugged helmet tackles trail rides and enduro
  • 360° Turbines guard against low-speed and rotational impacts
  • Polymer shell pairs with EPS foam to absorb greater impacts
  • Dri-Lex liner wicks moisture to promote breathability
  • Fidlock magnetic buckle for easy entry and exit
  • Item #LBRI063
Shell Material
polymer compound
Impact Management
360° Turbine Technology
22 vents
Fit Adjustment
retention dial
AS/NZS 2063:2008, ASTM F1952¢€“10, EN1078, Complies with U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 5 and Older
Claimed Weight
Manufacturer Warranty

Overall Rating

3 based on 4 ratings

Review Summary

1 Stars - 1 reviews
2 Stars - 1 reviews
3 Stars - 0 reviews
4 Stars - 2 reviews
5 Stars - 0 reviews

Fits Large

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?


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4 out of 5 stars

April 28, 2023

3.5 star, go down if size is close

I've used it several times

Originally bought size L, as it starts at 23.3 in and I have a 24in headband... thing was massive, even tightened all the way it wouldnt fit. Since exchanging for a medium, fits much better. It is still a pretty thick helmet, better for more aggressive riders as its probably a bit much for most riders. Airflow is decent considering how large it is. Not crashed in it but seems to provide a lot of protection, and the bigger lining is comfortable.

liam U

Originally reviewed on

1 out of 5 stars

June 4, 2021

Extremely Disappointing

I've used it several times
Size Bought:
6' 5"

Upgraded from a 3.0 to this and couldn't be more disappointed. The retention dial broke and fell apart after just a handful of rides rendering the helmet completely useless. I purchased the helmet early in the year and didn't get to ride much due to the very wet spring in Colorado this year. Unfortunately, that means that the helmet was past the 30 day return window for Backcountry when it failed. Hopefully Backcountry will do the right thing and resolve this equipment failure.

Jeremy R
4 out of 5 stars

March 29, 2021

Serious Helmet

I returned this product before using it

Bought the 3.0 and this one (4.0). The quality and fit seemed very good for this range of MTB helmets. Adjustment was easy and fit was very good. Returning because it is a bit heavier than the 3.0 and was more protection than I probably need doing slower, technical riding. These helmets (Leatt) appear to fit more oval-shaped domes. Wasn't overly impressed by the eyeware on-board storage but I also didn't try very hard to make my Smith Longfins attach easily.

Ian B

Originally reviewed on

2 out of 5 stars

March 13, 2021

Look out Dark Helmet!

I returned this product before using it
Size Bought:
6' 1"

This thing is massive! Very nice looking, but way too huge! Sticks off the head more than any helmet I have owned. I was super disappointed in how grande this helmet fit because of how awesome it looks. I wanted to keep it, but I knew my riding buddies would ridicule me with endless Space Balls jokes... It's that big!

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