Focus BlackSTer: Going Wide

Published On May 23, 2017 | By Jeff Hall | Articles, Interviews, Readers Rides, Tech

It’s no surprise to know that many people modify their cars. And whether it be simple stuff such as new wheels or an intake, or even a more extreme turbo upgrade or engine swap, it takes a true enthusiast to look at a car and think, “yeah, let’s go ahead and cut these fenders.” Brad Patterson, it turns out, is one of those people.

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The idea seems not that hard of a task to take on; tape the flares on, draw a line, take the flares off, cut, drill, paint, attach, and it’s all going to look awesome. There is actually so much more to it than that, but don’t let that scare you away! Before we even start down this road lets get this out in the open – yes, you have to cut your fenders if you plan to use this TrackSTer flare kit to fit oversize wheels and tires.


Brad has been the owner of this Focus ST for about three years. He went with the ST1 package because he knew it wouldn’t be stock for long and didn’t really need anything from the ST2 or ST3 packages, which really makes a lot of sense. Being from a Ford family the love for the brand truly ran deep. Sticking with the Ford theme, he went and bought his wife a car – a Focus SE. It provided great gas mileage and handling but lacked in power and styling. That is where the Focus ST stepped in – power, styling, handling, and gas mileage with a manual transmission. Brad’s F-150 was soon traded in for a hot hatch and that is when the modding began.


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The idea for the car was to have something that looked cool and had a classic track-car kind of feel. Several parts of the car have been modified including fifteen52 cup spoilers and Turbomac wheels, but also some highlights including exhaust, intake, coilovers, and rear wing extension.


Now to the main event, those fender flares. As we’ve already referenced, these flares are modeled after the custom flares we created for our project Focus TrackSTer, and they are now available for purchase. Before the build even started a small list was put together to help plan out the build. Fit the flares, sand and prime, mount hardware, cut body, wet sand, paint, and then final install. Sounds easy enough, right?

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The first step is test fitting the flares by taping them onto the body to get an idea regarding what imperfections there may be in the flares (fiberglass parts often need some minor tweaking to have them fit perfectly) and where adjustments need to be made using filler and/or sanding. Make sure to tape up the body panels so you don’t scratch the paint above where you are not cutting while doing the mock up. Then sand the areas needing adjustment. 180 grit sandpaper was used in this instance.


Once you are done sanding you then need to prime the flares to fill in the imperfections or sanding marks to help set yourself up for smooth body work. Apply a heavy coat of vinyl filler primer (not paintable) to the flares.

sanded primed fender

Next up is to start mounting the hardware included in the kit. Mock up the flares again to get an idea on where the holes go, leaving the tape on to protect the paint, and mark the holes on the tape. Begin drilling with a small bit to start and progressively going up in size till you reach the desired sized opening. Next part will require you to have a nutsert tool to install the hardware onto the body. Make sure to put some silicone on the nutsert to protect the body metal from rusting. Once all the nutserts are fitted you can reinstall the body kit using the included allen bolts. Make sure not to cross thread these or else you will have to drill out the nutsert and do it again. Also, be careful not to over-torque the fasteners.

drilling riv nut

riv nut tool

Next up is the exciting part – cutting the body. The goal is to cut enough to give you proper tire clearance, so working around the actual wheels and tires you plan to use is very important. With the flare on measure from the lip to the flare to give you an idea of how high you need to cut. Then you need to create a radius similar to factory, our example being make a cardboard template. Once you have that and everything is drawn onto the body its time to start cutting. The front is pretty simple; follow the line you created and cut through the metal. After you’re done cutting, sand down any hard edges and burs with an 80 grit sanding wheel. Then prime/paint to prevent it from rusting.

chopping front fender

sanding front fender

The rear is a little bit more involved. The rear quarter panel is made up of two panels that come together and are welded to form the complete panel. What you need to do is first cut the top layer by following your guide. Once the top layer is removed you then cut the bottom layer 3/4″ below the top layer. Then with an 80 grit sanding wheel repeat what you did on the front to smooth out the edges and remove the burs. Once that is done cut a few vertical lines into bottom layer to then be folded up into the top layer at a 90 degree angle, with the idea being to create a new seam. Make sure to epoxy prime the edges before sealing. In Brad’s case the seam was close enough where he could just use seam sealer to connect back the two panel, but typically (especially if you live in a northern climate that uses sand and salt in the winter) you would want to first tack-weld the two panels back together and then use seam sealer to finish it.

line drawn rear

cutting rear

rear gap openpainting fender cut

Once this is done make sure to put on the kit and wheels with tires to then test for full suspension travel in order to verify you have the proper clearance. Some more trimming may be required of the fender, inner fender liner, or bumper to allow enough room for the new setup.

installing riv nut

Next up is everyone’s favorite part, more sanding. You will want to have the kit installed on the car and then begin to sand down any high spots caused by bolting on the fender flares. You will want to use 220 grit sand paper and foam blocks for this part. Once that is done remove the flares and spray on a 2k high build primer. Once the primer has dried wet sand it with 400 grit sandpaper and by that point the surface will be ready for paint. We recommend a professional to paint the flares and blend the body for best results.

prime front fender

gloss painting flares

Now its time for hopefully the final installation of the flares. Exercise extreme care while doing this because you are working with fresh paint and wouldn’t want to damage it before the car even gets to be driven. A few tips here is that after painting, the holes may be a bit smaller than the hardware provided due to build up of material. So you may need to slightly re drill the hole. Also, as mentioned earlier, do not torque down too hard on the flares because it may cause cracking in the fiberglass. After a few days re-check all the hardware because the fiberglass may move once it has been sitting in the sun. More trimming may be required if there are any rubbing issues.

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A huge thanks goes out to Brad for going all out and and installing and documenting the flare install on his car. Becoming officially the first (non-TrackSTer) Focus ST running the TrackSTer kit. Thanks also for the photos featured. Of course we can’t forget to shout out Jarret Black (also known as @built_boosted) who helped out with the project and did the cutting/painting. As you can see it came out killer and insanely aggressive! It definitely gives off that feel of a track car. Project BlackSTer will continue to change and develop and we’ll definitely cover it here on

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You can check out more photos of the car on Instagram @forcedinduction

*Disclaimer: Though we offer this behind-the-scenes look into installing the fifteen52 Focus TrackSTer flare kit, we recommend only the most confident of do-it-yourselfer attempt to tackle this install. And as with any mods that involve body and paint work, when in doubt, hire a professional!

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