So you bought a Ford ST vehicle – congratulations. Maybe you’ve owned it for a year, maybe you just bought it. But you sure noticed that your Focus ST struggles with wheel hop and harsh shifts, and the bounciness between gears. Ever shifted quickly only to be rewarded with a sharp jolt? These problems are all caused by the same part – and it’s on both the Focus ST and the Fiesta ST.

What am I talking about? The “Rear Motor Mount”, which truth be told, ought to be called a “roll resistor”, as the engine is not going anywhere if you remove that mount – this part’s purpose is to keep the motor from twisting forward and back as you drive. The trick is, Ford engineered the car with NVH – Noise, Vibration and Harshness concerns in mind. If you drive it like a baby, sure it’s possible to drive without that wheel hop and harshness whilst shifting, but because of those NVH concerns, as well as cost savings, Ford opted to use more-or-less the same part as is used on Non-turbo Focii and Fiestas.

This upgrade isn’t so much an outright mod for the sake of modding – installing more firmly calibrated durometer bushings into the OEM Rear Motor Mount for Focus ST or Fiesta ST or replacing the RMM altogether with a bolt-in unit is almost a necessity, addressing and FIXING the car’s natural shortcomings. The Recall motor Mount fix for the Focus ST did improve the problem but does not fix it completely, which is why a Rear Motor Mount Upgrade should be high priority for your mod list.


Because the durometer of the bushings is too soft, the torquey EcoBoost engines easily overwhelm the stock roll resistor and bottom out, giving you that jarring harshness when shifting, and the soft bushings also create that “bouncy” feeling right after shifting. All that engine movement under load creates less-than-predictable mid-corner partial-throttle handling and contributes to problematic wheelhop and reduced traction.

By installing a Fiesta ST Cobb Rear Motor Mount or Focus ST Cobb Rear Motor Mount, the OEM Rear Motor Mount is replaced with a new heavy duty component that features bushings calibrated to the proper durometer stiffness to make every shift more positive and enhance traction. By fitting a stiffer mount, your engine is no longer moving all over the engine bay, making for more consistent handling and the reduced bounce helps alleviate wheelhop issues, improving traction and take-off grip. In terms of ease of use, it doesn’t get simpler than the Cobb Tuning Rear Motor Mounts – engineered with heavier duty bushings and a sturdier design, these mounts improve stiffness but are engineered for an ideal compromise of vibration and comfort, leaving your car still pleasant to drive. Other options, including Powerflex Rear Motor Mount Bushing Inserts for Fiesta ST are available as well but are a little tougher and more time consuming to install as you must press out the old bushing before you can fit the new one.

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Actually installing a complete bolt-in replacement Rear Motor Mount is easy – on the Fiesta ST you can do it yourself in about 15 minutes, and the Focus ST can be done in about an hour. With the Cobb complete replacements available at well under $175, you owe it to yourself and your ST to make this upgrade.

To get yours, visit, call 714-582-3330 to speak with the Mod Experts if you have questions or need advice. Need installation? Visit our shop in La Habra on Lambert Rd at Harbor to have our experienced, professional techs fit your upgraded Rear Motor Mount for you. Thanks for reading and please comment!

Story & Photos by Nicholas Gregson