Strap In: How to Properly Install a Racing Harness

By Staff Writer
Nov 12, 2022 | Safety Gear, Safety, Racing Harness | Posted in Safety | From the April 2014 issue | Never miss an article

On the surface, a driver harness seems so simple: Some webbing is strapped across the driver’s hips and chest and secured to the car. Once you start considering the forces at work, though, it gets complicated. HMSMotorsport, the U.S. distributor for Schroth harnesses, publishes a harness safety checklist and allowed us to share it with our readers. If every item on these lists is true of your harness, congratulations. Otherwise, you may not be as safe as you thought.

Shoulder Belts


Shoulder belts are correctly wrapped to the harness bar or cage. 

Only one bar of the three-bar adjuster is showing, and it is adjacent to the harness bar.

Three-bar adjuster is wrapped and positioned directly against the harness bar/cage or mounting hardware.

Shoulder belt three-bar adjusters are not obstructing the belt flow through the shoulder belt opening and are positioned behind the seat back–as close as possible to the bar.

The belt is not twisted or constricted through the shoulder belt opening in the seat. Shoulder openings allow direct passage from the top of the HANS or shoulders–directly to the attachment points.

Shoulder belts are securely fixed in position so that they cannot slide horizontally on the harness bar or roll cage. 

Shoulder belts run down from HANS or shoulder to the harness bar at an angle from zero degrees to a max of negative 30 degrees. In no case should the shoulder belt run at an upward angle from the shoulder or HANS to the attachment points.

Shoulder belts are secured with the proper spacing between the anchor points and cross over each other as needed.

Lap Belts


The angle of the lap belt is between 60 degrees (touring cars) and 80 degrees (formula cars) measured from the horizontal, allowing the lap belt to ride properly over the pelvis. An angle less than 50 degrees may allow submarining and cause the lap belt to ride up into the abdomen, causing injury to the soft-tissue region.

When wearing the lap belt, the webbing is not bunched or folded around the seat opening. It must lay flat. The adjusters are not caught or positioned in the opening, which may cause accidental release or failure when loaded.

Check beneath the webbing path to ensure it is not rubbing on any edges of bolts, seat brackets or seat openings that may cut or abrade the webbing.

The lap belt is positioned close to the seat at an angle–not more than 25 to 30 degrees off the seat.

The snap hooks are correctly clipped to the eye bolts, with the latch toward the bottom and secured with wire or a cotter pin.

The snap-on bracket does not bind on the eye bolt when pulled in the direction the belt is worn. Adjust alignment of eye bolt using additional wavy washers.

The wrap-in end of a bolt-in or snap-on bracket has the three-bar adjuster as close to the bracket as possible, and the final loop of the wrap is complete.

The bolt-in lap belt bracket pivots at the bolt, allowing the webbing to align with the flow of the webbing across the lap with an even load across the bracket. Use a pivot sleeve or a lock nut and red Locktite to back it off just enough to pivot.

The webbing load of any bolt-in or snap-on bracket must be in plane with the flat side of the bracket. Pulling at a 90-degree angle will reduce the maximum load of a bracket 60 percent.

Anti-Sub Straps


The sub-strap opening in the seat bottom is positioned properly.

Sub-strap must not be routed around the front of the seat.

A five-point (single) sub-strap is center-mounted 10 to 20 degrees forward of the tangential plane of the shoulder belts through the sub-strap hole.

A six-point (dual) sub-strap is mounted a minimum of 20 degrees rearward from perpendicular (drawn to the floor through the sub-strap hole in the seat, immediately in front of the groin.) Two points of attachment should be approximately 4 to 6 inches apart–2 to 3 inches to the right and left of centerline.

Note for formula cars where the driver is sitting on the sub-straps: Attach sub-straps rearward in approximately the same location as the lap belts. This type of setup is typically used with a formula-style or hybrid-style looped sub-strap.

Adjusters on the sub-straps are not positioned or caught in the sub-strap opening in the seat.

Snap-on or bolt-in brackets are attached properly with approved backing plates using the hardware provided by the harness belt manufacturer. 

Never mix hardware from different manufacturers. 

If using double brackets for bolt-in sub-strap applications, wrap is as pictured with 2 inches of extra webbing.

The sub-strap webbing is pulling in the proper plane on the hardware.

Shoulder Spacing


The following formula is used to determine the spacing of the shoulder belts at their attachment to the harness bar or cage.

Y = Z - (X * 0.50)

X = Distance from shoulder points to attachment. Measure from the highest shoulder point (on top of the HANS, if worn). Z = Distance between the middle points of both shoulder harnesses. Y = Approximate distance between anchor points (measured middle to middle of webbing at anchor point).

The shoulder belts will cross over when anchor points are located more than 18 inches behind the seat backrest.

We recommend a distance of 8 inches or less from the back of the HANS to the harness bar when possible.

Belt Wrapping


  1. Webbing should wrap from the body-facing side of the bracket up into Slot 1. 
  2. Pull through approximately 11 inches of belt and then fold down through Slot 3, temporarily leaving 2 inches of slack.
  3. Fold back up from the body side through Slot 1 and back down through Slot 2.
  4. Fold back through Slot 3 and finally through Slot 1, with the webbing exiting to the underside of the belt.
  5. Pull the lap belt firmly to ensure the wrap is tight. Leave a tail of approximately 4 inches. Excess webbing can be cut off, providing that the remaining edge is heat-sealed to prevent fraying.

Other Information

High-density padding is used around the cage where the driver’s head could potentially come in contact with it. Padding should be either SFI 45.1 or FIA Type A. Flat surfaces should use SFI 45.2 sheet padding.

Zip-ties are used around all roll-bar padding to keep it in place.

Headrest padding–if used–should meet SFI 45.2 standards. (Soft padding will allow the head to bounce off the headrest, increasing head and neck tensions.)

All webbing and hardware is in good condition. No signs of damage, cuts, fading, elongation, etc. Must be within date spec for competition use: SFI says two years from manufacturing; FIA says within five years. Schroth Rallye-series belts do not have an expiration date, but HMS recommends changing them every seven to 10 years or sooner, depending on the condition of the webbing.

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View comments on the GRM forums
RadBarchetta New Reader
2/7/20 3:17 p.m.

Don't do this. If you're gonna use a six-point harness, use it correctly. This guy even has holes in the seat to properly use his harness and save his testicles, but he choose not to. He bought a six point harness and turned it into a five point.

kb58 SuperDork
2/8/20 6:23 p.m.

I went through this with Midlana. I received contradictory advice from belt manufacturer websites regarding recommended belt routing and angles, which was surprising since the physics is the same. Had to just go with the set of instructions that seemed to make the most sense.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) HalfDork
7/12/21 2:13 p.m.

As an SRF racer, that cover photo gave me a cold shiver.

w123mb None
10/25/21 4:51 p.m.

Whats the deal with harness bars? Everyone I've heard says just get a rear hoop, as it comes with roll-over protection. Is there a use case for harness bars in autox or hpdes?

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
10/25/21 5:52 p.m.

In reply to w123mb :

There is no use case for harness bars. So close to a proper roll bar in cost, installation and making the back seat unusable, but more dangerous than stock safety gear. 

Tom1200 UltraDork
10/25/21 7:57 p.m.

In reply to w123mb :

Its a case of all or nothing. If you are using a harness it should be part of a roll hoop (at a minimum) and you should also be wearing some kind of head and neck device.

If you're not doing that then as Tom mentioned the standard factory 3 point is the way to go.

Poor_sh GRM+ Member
7/29/22 11:24 p.m.

In reply to RadBarchetta :

Could you elaborate please? Should the camlock be just closer to the hole or is there something I'm missing that shows a way to split the two crotch straps before they go through the seat?

DaleCarter GRM+ Memberand New Reader
7/30/22 12:26 a.m.

     If your track car is your daily driver, I'd like to offer a different view of a harness bar vs roll hoop. Most of the cars we tend to use are small and fitting a proper roll bar with enough clearance to drive the car without a helmet is a challenge. For instance, I put a Hard Dog roll hoop in my Miata and anything but the most minor collision would put me in danger of banging my melon on the padded rollbar. Even wioth the padding, that would be bad. I just got a Cayman, so I will only be driving the Miata to the local autocross and for local track days. I daily the Cayman and, although really nice harness bars are available,  the seats don't have shoulder harness ports, so I wear a Simpson Hybrid S in that car.

A proper harness bar, like a four-point hoop, allows the use of racing harnesses and HANS with a good racing seat, which is much more safe than a factory seat and 3-point belt. The better seat and harness will cut time off your laps right away, too. If the car has good rollover protection as built, a harness bar may be your answer. Most convertibles are another story, though.

My other cars all have proper roll cages, door bars, etc which are far superior to a harness bar or roll hoop, but just wanted to make the case for a harness bar in some situations.


DaleCarter GRM+ Memberand New Reader
7/30/22 12:28 a.m.

In reply to Tom Suddard :

I'm curious how a harness bar, with a proper seat, 5-6 pt harness and HANS is more dangerous than the factory seat and 3 point.

amg_rx7 (Forum Supporter)
amg_rx7 (Forum Supporter) SuperDork
7/31/22 12:37 p.m.
RadBarchetta said:

Don't do this. If you're gonna use a six-point harness, use it correctly. This guy even has holes in the seat to properly use his harness and save his testicles, but he choose not to. He bought a six point harness and turned it into a five point.

I have not seen any race seats with 2 holes for a 6 point with 2 crotch straps. 

RadBarchetta New Reader
11/12/22 8:40 a.m.
amg_rx7 (Forum Supporter) said:
RadBarchetta said:

Don't do this. If you're gonna use a six-point harness, use it correctly. This guy even has holes in the seat to properly use his harness and save his testicles, but he choose not to. He bought a six point harness and turned it into a five point.

I have not seen any race seats with 2 holes for a 6 point with 2 crotch straps. 

They exist. Admittedly it's hard to find in seat advertisements since they rarely show a good view of the hole patterns. Some seats combine the three holes into one triangular hole. Kirkey does this a lot. You usually have to ask the manufacturer or the vendor for such details. Look very closely at the one in the picture. That one has such holes. If you start at the cam lock and move your eyes straight down from there, you can see one of them.


I should clarify that I'm not saying that doing this is unsafe. Just that it it isn't any safer than just using a 5-point. You're just spending extra money for that sixth belt and not getting any benefit out of it.

APEowner GRM+ Memberand UltraDork
11/12/22 12:21 p.m.
DaleCarter said:

In reply to Tom Suddard :

I'm curious how a harness bar, with a proper seat, 5-6 pt harness and HANS is more dangerous than the factory seat and 3 point.

The problem is that if the roof structure gives way in a rollover the factory 3 point moves with it allowing your body to be shoved along with it.  A race seat, harnesses and HANS holds your body in place so your head and neck end up supporting the car.

Whether or not that possibility is outweighed by the improved control from the harness and, the theoretical, resulting reduced chance for crashing in the first place could be debated.

jfryjfry SuperDork
11/12/22 3:23 p.m.

In reply to APEowner :

The chances of a newer car landing on their roof hard enough and in such a way to exceed the built-in rollover protection are far slimmer than getting into any number of other crashes where having a proper harness and seat would provide superior protection to a stock seat and belts. 

There are some really interesting videos about vehicle race safety and they talk about this topic a bit. 
i can't find the ones I've really liked but will keep looking and post when I find them 


adam525i GRM+ Memberand Dork
11/12/22 3:29 p.m.

In reply to jfryjfry :

This is one of the better ones I've watched/listened to from HMS motorsports (GRM sponsor).


APEowner GRM+ Memberand UltraDork
11/12/22 3:34 p.m.

In reply to jfryjfry :

I agree.  Combining the safety systems (street and race) produces compromises and I think it's important to understand what the compromises are.  For me, I drive street cars on the track with enough margin that the chances of wrecking are pretty low.  Probably lower than on the street where there are many more factors that are out of my control.  If I'm really going to push a car on track it's going to have all the gear.

Modular GRM+ Memberand New Reader
12/3/22 11:35 a.m.

In reply to adam525i :

Great video. Thanks for posting it. I'm going to be installing a center net this winter after watching the halo seat fail entirely at 1:05 mins. They also make a great point about the halo seat protection failing in an offset front impact. 

Also thanks to GRM for this article. This type of content can (will) save someone's life.


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