How to Fit Driving Harness

A Guide on Fitting Your Harness

Fitting harness can be tricky. Especially if one is new to driving and harness! If you are new to driving harness, we suggest you first take a look at this blog: Harness Part Names, to brush up on the terminology and different parts of the harness discussed here.

Sometimes it’s easy to see when a harness is not fitting quite right. Sometimes it’s not so obvious! We are here to help with harness fit once you receive your new harness. You can take photos of your equine in harness, fully showing the animal from the side and then photos from the front and back, if you desire. I need to be able to see the entire animal with the harness to help you trouble shoot the fit.

Let’s Get on to a Few Rules of Thumb!

In the photo above the harness is quite clearly too small for this pony. The saddle doesn’t come down far enough on her sides, the breeching rings don’t reach the flank swirl and the breast collar is too short and too narrow.

The same pony in a harness that is correctly sized for her. The saddle comes down lower on her sides, the breeching rings are at her flank swirl and the breast collar is much better matched. This was a pretty obvious harness fit issue. There are times the fit is a little more obscure. I’ll try to share that below!

Fitting Each Part of the Harness

The Bridle

A properly fitted bridle with blinders will allow you to adjust the blinder so the equine’s eye is sitting in the center of the blinder.

The brow band can interfere with the blinder fit. If the brow band is too short it will pull the cheeks and the blinders, forward into the equine’s eyes. When the brow band is too short it will also make it so you can’t adjust the wire in the winker stays. To find out more about doing that you can read the blog “How to Adjust the Winker Stay Wire on a Driving Bridle.”





The cheeks of the bridle come in different lengths and the blinders are sized differently for the different sized equines. The chart below shows the sizes for the ComfyFit Bridle. The Pleasure bridle has square blinders that are a little smaller but the cheek measurements are the same!


A well fitting bridle will allow you to adjust the bit just right in your equine’s mouth. Sometimes you will have a little extra material and that’s perfectly alright as long as your bit is sitting right! If you don’t have enough holes then it’s time to size up. Or if you can’t get the bit up high enough in your equine’s mouth, then you will need shorter cheeks.


Both of the photos above show a properly fitting bridle.

The bridle is a part that is pretty easy to tell when it’s not quite right. Aside from the brow band issue that is! Most of the bridle fit issues I run into are the result of the brow band being a little too short. Fix that and everything seems to fall into place!

The Breast Collar

The Deluxe Style (deep v) breast collar is one of the hardest to fit, in my experience. Sometimes it just doesn’t work for some horses and ponies and usually doesn’t work well on donkeys. The fit is tricky in that it needs to come back some on the shoulder but not too far. If it comes back too far it will want to wrap around the back of the shoulder and interfere with the stride.

Below is a photo of the Deluxe breast collar on a Quarter Horse mare. This breast collar is too short for this mare;

We do like to see the neck straps hanging straight down from the top of the neck, so that looks great in this photo. But the sides of the collar don’t come back quite far enough.

This one was a little tricky however. Often the way the breast collar is laying on them changes once they are hitched to something. So, for example, this breast collar can look too short just sitting on the horse but once hitched it will contour to the horse and lay back along the shoulder a bit more. I asked for a video of this mare pulling something so I could see if the breast collar was going to work:

Though she was doing just fine with this one I felt it should come back a little further on her shoulder for longevity.

We sent her the next size up and this is how it looks!

The Standard Curve Breast Collar will come back along the shoulder a bit more. Because it’s narrower and less shaped it doesn’t seem to interfere with the animals shoulder at all. This style is easier to fit!

Again, you want the neck straps to hang fairly straight down and not be pulled forward. If they are being pulled forward then the breast collar is too small/short.

I have written a blog about fitting the SuperFlex and the Comfy Collar. You can go her to read that: Fitting a SuperFlex or Comfy Collar

The Saddle

Sometimes the saddle fit can be quite tricky. There are times we don’t know it’s not fitting well until we drive in it a few times. Most of the time this is when using a treed saddle versus a treeless. The treed saddles can be a bit too narrow for some minis, ponies, and horses. I have written a few blogs on that! You can find them here: Harness Saddle¬†

Quickly, we can discuss the sliding back band saddle as well…

You can see the strap is not sewn at the bottom, so it can slide up and down.

The idea behind the sliding back band is when you are driving an equine with a two wheeled vehicle down rough, pot hole filled roads, the saddle will allow the shafts to drop down when a wheel hits a hole. This sounds like it would be lovely for the animal pulling the vehicle. But in reality what happens is the wheel hits a hole, or a rock or a bump, then the shaft jerks the shaft loop to the side as it drops down and you end up with the shaft loop dropping and the other shaft smacking them in the side. To mitigate this you have to have a very snug over girth.

Also, all the movement in the saddle with the shaft loops sliding back and forth can make the animal quite sore over time. In reality, the less movement you have in your harness, the better. Stability is the name of the game!

I have also heard of people tipping their vehicle over using the sliding back band. For people just starting out in driving I can not recommend this style of saddle.

As for saddle fit, we are looking that the saddle comes down along the animal’s side and wraps around them. You can have this with both the ComfyFit saddle and the Pleasure/MaraFUN style saddle.

The ComfyFit Saddle
The Pleasure Style Saddle

Both saddles above are shown with padding. I wrote a blog about that as well! You can find it here: Which Harness Pad is Best?

We often are asked how tight the girth should be. I also wrote a blog about that! You can find that here: How Tight Should Your Girth Be?

The Breeching

When we ask for measurements for a harness we suggest you measure from the middle of the flank swirl around the widest part of the rear to the middle of the flank swirl. Therefor, we prefer the breeching rings to end in the middle of the flank swirl!

As for how high the breeching should be… The rule of thumb is to have it be at the widest part of the rear.

For donkeys this is trickier as they don’t really have a widest part of the rear, so in that case we suggest the breeching be about a hands width (6 or so inches) above the bottom curve of the rear end.

It’s suggested the breeching be snug enough for you to put your hand in sideways on horses. But on minis and small ponies I feel this is too sloppy. I suggest you be able to put about three fingers in sideways between the butt and the breeching on the minis and small ponies. The key is that the hold backs and breeching engage in holding the cart off the pony BEFORE the shaft loops have to take up the slack and the saddle begins to hold the cart back. If you have this happen when you are going downhill you need to tighten up your breeching a little bit.

The hip straps “should” hang over the top of the hip. Sometimes it’s a little difficult to get that turn back strap short enough to bring the hip straps forward and then still be able to buckle the crupper. In most cases it will work but sometimes you may need a little longer crupper. The Pleasure harness has two slots in the turn back strap so you can move your hip straps forward if you need to! Making it a little easier to adjust this.

The turn back strap (the strap that connects the saddle to the crupper) should be snug enough that it doesn’t slide off to one side or the other, like the photo below. This can cause rubbing and soreness under the equines tail.

The turn back strap and crupper should look like this photo:

This brings me back to everything being equal. When harnessing your girth should be buckled on the same hole on each side, the crupper should be buckled on the same hole on each side, same for the breeching hip straps and the neck straps on the breast collar. Everything should be the same on both sides! I wrote a blog about this as well! You can find that here: All Things Equal


Trace length can change with the vehicle you are hitching to. For instance, an easy entry cart with a horizontal line of draft will need shorter traces than a vehicle with a low line of draft such as a wagon, a harrow or a sled. It is helpful for us to know what kind of vehicle you will be driving.

Vehicle on the left has a low line of draft; vehicle on the right has a horizontal line of draft.

Surprisingly, the Hyperbike and other bike kind of vehicles usually need longer traces than the easy entry carts do because the single tree is under the seat.

Typically, the harness makers will look at the height of your equine and send you traces that usually fit that size animal. If you have a set of traces that are the correct length it is very helpful if you measure those and let us know exactly how long you need them to be. Especially for the farm/work style harness.

A good rule of thumb when hitching to a horizontal line of draft vehicle is to have 12-17″ between the equine’s tail and the single tree/front of the vehicle. For a low line of draft you’ll need a few more inches to account for their stride when trotting out and cantering.

You can see on our breast collars that the traces buckle in at the shoulder. So sometimes when you measure from the horse’s chest to the front of your vehicle you will end up with traces that are too long. OR you need to tell us that you measured from the chest and not from the shoulder where our traces buckle in. Simply adding 12-15″ to the length of horse measurement won’t necessarily get you the correct trace measurement. Our traces are measured from end to end, including the ring and slot, if you have the combo end traces.

Traces should be adjusted so there isn’t any slack when you are standing still, but not so tight that there is constant pushing pressure on the equine. There is a fine balance between the snugness of the traces and the snugness of the breeching. This push/pull of the two parts of harness are what help make your cart ride smooth. If you have a lot of lurching at the trot and canter then chances are your traces are a little too long. If your shafts are falling out of the shaft loops, then your traces are adjusted too long. If your shaft ends are up by your equine’s nose, then your traces are too tight. If you have to struggle to get the traces onto the single tree, then your traces are too tight.

I am always happy to trouble shoot harness fit! Pictures help tremendously. I wrote a blog about the type of photos I need to be able to assess harness fit and you can find that here: Harness Fit 

You can email me at mindy@chimacumtack.com if you need some help with your harness.

3 thoughts on “How to Fit Driving Harness

  1. Terry Sims says:

    I will be looking for harness like I used as kid growing up . Our mules stood 16.5 to 17 hands .. with 4 inch adjustable band going around hame string at top of hames that when needed it can be adjusted . This band runs thru back band strap thru and that loop then to padded ring residing on top of hip ring . With that strap attached to detachable crupper ring that as mules hold back going down creek banks or to stop wagon from overrunning mules . Trace chains or trace straps ends hold traces when unhooked by snap attached to rump ring pad . Mules were protected by traces guards at shoulder belly breeching belly straps had big oval
    strap carried on each mules collars . Belly straps snapped into belly ring under and between front leg of each mule and was adjustable to need this prevents mule from stepping into breeching belly strap from each side those straps attached to butt strap . Belly bands were attached and adjustable and centered slightly in behind each mule’s front leg.. back bands saddles were long enough that the pull or draft of each trace beared the load pull making the mule comfortable pulling his or her fair share of the load .. heavy spots or diamond spots covered each piece as to look great in parade down the road or comfortable as the mule sweats in long hours at labor . Bridles were pigeon faced blinders centered over each eye of the mule and had matching ornaments on face of each mule and stainless steel bits rolled in smooth twist in event mule becomes shy and in need of correction just below the ears is a stainless big stamp with BIG letters engraved on each side showing this US brand indicating on each bridle brand being an American label Blinders were always centered so as to prevent shying in traffic and at bridge edges creek banks dogs and etc .
    Driving lines were linked with detachable snaps as to prevent unnecessary tangles when unhitching and also to give muleskinner ability to unhook swiftly and to give ease in extending various hitches and to go from working labor to resting at the of each row so mule can rest under the shade tree . Or driving lines can be used as single mule plowing or switch back to team plowing or work to a wagon or parades mowing . Ps bridles also had strap attached to each side of bits for use in hold back driving or can be made longer to make mule hold their head up also driving lines may be used as single mule work or team work for all needs and length of each set of lines can be used to ground tie mule . Butt straps should be double or triple layered that teamster also may use harness for multiple ways that one the mule will work or drive in as much comfort as feasibly possible
    can be had signed Terry Sims 270-970-2103: Mayfield KY 42066v

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