As with all racing safety equipment, Frontal Head and Neck Restraint (FHR) fitment is critically important, and the Head and Neck Restraint user can increase the risk of injury if they are not fitted properly.  A Frontal Head and Neck Restraint (HNR) restrains the driver’s head relative to the torso during a frontal impact, thereby reducing the loads to the head and neck.

There are different types of FHR systems approved, one of them being the Schroth® Racing SHR Flex™ system. Please refer to the general Head and Neck Restraint sizing chart below for proper fitment of the Schroth® Racing SHR Flex™ system.    

This system sizing chart is for the ADULT Schroth® Racing SHR Flex Head and Neck System.  Youth Head and Neck Restraint systems are NOT available at this time.    

If you need a Youth Head and Neck Restraint system or an Adult system outside of this chart range, please contact our Technical Sales staff for other brand options that may be available for you.  

Properly Measuring Fitment for a Schroth® SHR Flex™ Head and Neck Restraint System


Locate a cloth tape measure and record the following body measurement:

  • A - Neck Circumference - Measure CIRCUMFERENCE around the fullest part of the neck line, keeping the tape semi-taunt.

The Schroth® SHR Flex™ Head and Neck Restraint System comes in two (2) sizes as shown in the fitment chart below.    

Remember, if you DO NOT find a Head and Neck Restraint System that suits you or fits you properly, please contact one of our Technical Sales Specialist and they will work with you to find a solution for you.

Schroth® SHR Flex™ System - Head & Neck Restraint Sizing and Fitment Chart***
Factory Device Size
- Neck Circumference (in.)
13.5" to 16" 
16" to 20"

A NOTE ABOUT SEAT ANGLE -  The Schroth® SHR Flex™ Head and Neck System is 'Angle Independent'.  This means that the unit's small, low collar works perfectly with any seating angle and does not interfere with the seatback.  The articulating collar rises in an impact to create the optimum tether angle.  Many other HNR devices on the market require a special HNR unit depending on racing seat angle.  The Schroth® SHR Flex™ is designed to work with ANY TYPE of seat angle.  It's perfect for drivers with multiple cars and seat angles as shown and described in the illustration and chart shown below.

 Schroth® SHR Flex™ System - Model Application for Head & Neck Restraint Systems***
Seat Angle
Typical Racing Application
Applicable Schroth® Model


Adult Size Schroth® SHR Flex™  System Works with All Types of Race Cars and Various Seat Configurations including Sprint Cars - East Coast Modifieds - Asphalt Late-Models - Dirt Late-Models - Street Stocks - Legends - IMCA/UMP/Wissota Modifieds - Full-Bodied Drag Cars and Dragsters - Sedan Sportscars - Drag Boats - Open Wheel/Road Race Cars including Formula Ford®, Formula Mazda®, Barber Dodge® and Infiniti® Pro
Schroth® SHR Flex™

TECHNICAL CREDIT AND ACKNOWLEDGEMENT: The above HNR, seat and helmet technical information and illustrations were compiled using excerpts from the Federal Internationale De L'Automobile (FIA) 'Guide and Installation Specifications for FHR Devices in Racing Competition' document published in June 2017.  To review this full PDF document click here or visit the FIA website Safety Section at (both links open new browser window).

Racecar Engineering™ Has All of Your Racing Safety Gear Needs Covered

Please remember that Racecar Engineering™ carries a full assortment sizes and replacement parts for the Schroth® SHR Flex™ System.  On top of that, we also have in stock and ready to ship,  Schroth® Racing seat belt restraints, harness pads, window nets, related hardware and much more.

Browse our wide selection of safety products and buy online today.  If you have questions about choosing the right safety equipment for your motorsports segment, please contact one of our Technical Sales Associates for assistance.

At Racecar Engineering™ we make every attempt to be every racer's 'One-Stop Safety Shop'.

Return To:  Main Technical Center Page  |  Head and Neck Restraint Info/Sizing Chart Page - All Brands

Related Tech Safety Topics:  Racing Helmets | Racing Suits | Driving Gloves | Driving Shoes | Racing Seats

*** HEAD & NECK RESTRAINT SYSTEM SIZING/FITMENT CHART DISCLAIMER: This head and neck restraint system sizing/fitment chart has been created by Racecar Engineering™ for our customer's reference and ease-of-use using the latest fitment information available from the factory.  Please always refer to the factory website, factory printed materials and factory personnel advice for the latest head and neck restraint system information about their brand of safety product.  The Schroth® factory website can be accessed directly at (link opens new page) - Racecar Engineering™ is not responsible for any typographical errors contained in this head and neck restraint system sizing chart/fitment material or the end-user's failure to verify & follow factory fitment specifications.