custom carbon fiber bicycles & components

I used the Predator Cycling DIY carbon frame repair kit to fix cracked seat tube on a Stumpjumper 6Fattie. The kit was affordable, had plenty of materials (I have about 50% of the carbon left. I'd mixed all of the resin to be sure of the ratio but half was wasted), and the materials were high quality. Even after lots of wet sanding before and after the repair, the 3M sandpaper is still quite usable. The excess resin dried in the cup, making a clear and very hard puck that was difficult to scratch with a metal pick. That really encouraged me on the strength of the repair. I've attached some photos of my process. The repair ended up being more substantial than I'd planned. When I first bought the frameset last spring 2022, I noticed what felt was a flaw in the layup at the rear seat tube. This area retained the "Raw Carbon" look and has just a clear coat. Although there was no discernable texture in the area, because of no paint other than clear coat, I could see that the CF layup looked creased. I built the bike and kept my eye on it. My seat posts (I used a regular first, then moved to a dropper) both extended 10mm or more past the area of the flaw. After about a month of riding fairly tame single track, the clear coat started to crack and flake away at the spot. Coin test revealed probable delamination. Wanting to keep riding, I drug my feet contacting Specialized, and researched carbon fiber repair and slapped a double layer of gorilla tape around the seat tube and ride for about 2 months. I pulled the tape to find a notable crack involving 2/3 the circumference of the seat tube. The upside is Specialized not only replaced my frame with an S-Works 6Fattie of the same model year, but also let me keep the cracked frame. That's when I reached out to Predator Cycling.
Aram, himself, responded to questions I had regarding the specific repair prior to my purchase. I chose the PredatorCycling DIY kit because of the YouTube videos and the guidance I'd gotten when in contact with Predator. They appear to be a quality operation and I can confirm that's the case from the product to the support.
The more extensive repair than expected came about as I prepped the area for repair. As my sanding revealed the cracked CF, it also revealed the frame factory had used some sort of "Bondo" or filler material on the drive side portion of the seat tube. There must have been a notable flaw in the layup or damage down the line. The area that was a crack in most of the seat tube, here became a thin single layer of CF which was cracked and ready to flake off. It did leaving a 30mm horizontal stretch of void between 5 to 13mm in the vertical. The perimeter of this was a white body filler (Bondo).
I had in place a seat post, 3/10ths of a mm narrow (30.6 vs. the 30.9 required by the frame), wrapped in a few layers of waxed paper to make up the diameter as well as a release material. The whole thing acting as internal support or mold, if you will. My first step (not likely endorsed by Predator) was to fill the void with a two part urethane epoxy marketed as a "body filler" and compatible with carbon fiber. While likely this can contribute to the strength of the repair, the goal here was to provide a solid backing for the carbon fiber repair layers. If it was in another frame tube where internal diameter tolerance wasn't so crucial, the proper way to begin the repair is by making an internal layer of resin-CF which fills the void, provides backing for the external repair and provides additional structural integrity.
The rest of the repair I completed as directed in the kit and videos. I used thin cardboard templates of my successive repair layers. Each layer wrapped 360° around the seattube, and were cut in such a way that the weave of the successive layer was 45 degrees to next. One thing I need to change next time is the amount of resin I used. It was excessive not only the total prepared but the amount on the CF layers. Too much is counter productive by the mess, it can keep the CF layers apart, interferes with the compression tape application, and can allow wrinkles and irregularities to form in the layup. All these factors create more finish work later on (a lot more!)and may compromise the integrity of the repair (and for sure the repairer). Aram emphasizes and demonstrates well the amount of resin needed.
My repair is complete, I'm satisfied with my first time results, and the Predator Cycling carbon fiber repair system and support thereof is high quality. I'm very pleased with the results and the experience.

These guys are so ahead of the curve, like light years. It’s insanity to have this type of cutting edge bike performance with such stylish aesthetics AND with a first class hands on service approach. Got to speak with and eventually meet Aram in person and check out where he built my killer bike!!! He was so humble, knowledgeable and true to the roots of racing while pushing the technological possibilities to the max without all the bureaucracy in everything today. So excited to now be part of the Predator Cycling family!

I received my kit and it has worked beautifully. The instructions are concise and most of all I saved a bunch of money by doing it myself. Thank you!

I do a few centuries a year and wanted a bike that would be comfortable and yet still aero. This bike fit that well. I got a century under my belt on this new bike and it did excellent. Looking forward to many more miles.

I have had a few Predators over the the years and this new Road bike is great. Its good balance of stiffness and Aero with a great ride. All the details are next level. Love my Bike!