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Tune With Anti-squat

If you’re having a hard time getting your truck to “stick” to the track and you feel you have the right tires, it may be time to adjust anti-squat. Or, maybe need a little help getting your truck to slide its rear tires around a tight corner. Once again, it may be time to adjust anti-squat.

WHAT IS ANTI-SQUAT
Anti-squat is a suspension adjustment that, as the name implies, limits how much the rear suspension squats under acceleration. Physically, anti-squat is the angle of the lower, inner suspension arm hinge pin. When viewing the lower inner arm mount from the side, the angle of the hinge pin dictates the amount of anti-squat–measured in degrees–that a RC vehicle has. In the full-size world, anti-squat is often referred to as a percentage, so trying to apply full-size tech articles on this subject may cause some confusion. In an RC race truck with the typical lower H-arm and upper control arm or camber link, if the front of the inner hinge pin is higher than the rear, the truck has anti-squat. If the hinge pin is level, it has zero anti-squat.

WHAT ANTI-SQUAT DOES?
As you’ve probably noticed, when a vehicle accelerates, the rear end squats down. Anti-squat controls control this. When the rear squats, weight is being transferred to the rear. It is important to note that anti-squat really only has an impact on handling while accelerating or braking.

When a vehicle has anti-squat dialed in, it will want to track straight under acceleration. That’s on power. When off power, the truck will rotate better. For tight indoor tracks that have a high level of traction, running anti-squat will help your truck carve around the track without losing a lot of speed. Be warned that while on tight tracks anti-squat can be a good thing, too much of this good thing will cause your truck to want to spin out regardless of how high the traction is.

If your truck is loose entering corners, try reducing anti-squat. Trucks with less anti-squat or no anti-squat are generally easier to drive (if the rest of the setup is working). If you’re running on a slick track, it is unlikely dialing in anti-squat will help handling. A loose truck will benefit from less anti-squat.

Anti-squat can also have an impact on how a truck jumps. Adding anti-squat may help the rear of the truck pop off the jump better.

ADJUSTING ANTI-SQUAT
Most often, anti-squat is adjusted by either adding or removing thin shims under the front suspension arm mount or by replacing the front suspension arm mount. You can add washers under your front arm mounts if shims aren’t specifically made for your truck.

These Team Associated anti-squat shim have tabs to indicate anti-squat amounts.
These Traxxas Jato blocks are a good example of front suspension arm mounts that adjust anti-squat.

You should only deviate from the factory recommended anti-squat setting after you are 100% positive you have the right tires. If you have the wrong tires and try to use setting such as anti-squat to cure some handling ills, you are guaranteed to get into what is called chasing a setup.

 

You learn about tuning with bump steer here.

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12 Comments

  1. Great write up!!!! I have a Kyosho ST-RR evo; all the pro guys switched to 3 degrees of antisquat. I didn’t understand why at first but now after reading your article it sums it up perfectly. Thanks Matt

  2. I thought the more you squat under acceleration the better weight transfer, so more traction. Now I’m confused!

  3. I’m sorry, but I’m confused. In the beginning of the article you said that anti squat limits the rear squat and is measured by the angle of the lower inner suspension arm hinge pin. I’m with you so far I think. Then when you explain adjusting the anti squat you say to place shims under the “front suspension arm mount.” Are we still talking about the rear of the truck, or the front suspension arm mounts? Sorry this is probably a dumb question but I lost you somewhere. Thanks,
    Mike

    1. Hi, Michael. Even when I refer to front, I am still talking about the rear of the truck–just the front of the rear arms. We are completely ignoring the front suspension. So, when we refer to “front,” we mean the front part of the rear suspension. With that said, I can see where the confusion is coming in. This is a great question and I’ll do my best to explain. The rear suspension has upper (usually a camber link) and lower arms. We are ignoring the upper camber link for anti-squat. Sometimes the rear arms have separate front and rear mounts and shims can be placed under the front mount and that will adjust anti-squat (see the top detail photo above). Sometimes the entire mounts are swapped out (see bottom detail photo). Another option is when a one piece mount is used and the whole thing gets swapped out. Pro-Line’s Pro-2 transmission for the Traxxas Slash works this way (see below). I hope this helps.

      Pro-Line Anti-squat mounts

  4. O.k. now I get it. Thank you so much for your rapid response, and making me feel better about the question :)I run mainly on an indoor carpeted track that has so much grip I might be able to make my Super Stock car hook. So this may be a great adjustment for me to try. Love your articles, keep up the good work. Thanks again,
    Mike

    1. My pleasure, Mike. Have you seen Pro-Line’s new Pin point tires? They are made for carpet off-road. Right now, they offer them for 1/10-scale buggies, but hopefully they will expand the sizes.

      1. No, I haven’t Matt thanks for the heads up. I was actually looking into a street tire by Pro-Line yesterday. Hey since were talking, I had a request. I was wondering if you have or could do a right up on caster? What it is exactly, how to adjust it, and the affects the changes would have on a Short Course truck. I’m new to this as you can probably tell, and I’m just not quite getting caster. As we speak my new Losi XXX Tuff Country is apart to add some anti squat, and bump steer I’ve learned more from reading your articles in the past couple of days than I have playing with the truck for a month. Thanks for everything,
        Mike

        1. We’ll do caster soon for you really. Caster is a great adjustment because you can really see/feel the difference unlike some other adjustments that the improvement is more in our heads than on the track.

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