Rock Bottom

The ultimate modular frame protection and chain retention

Recommended setup

Get started with the Rock Bottom Standard chain path kit or High Pivot chain path kit


  • ISCG05 Frame
  • Guard
  • Standard Chain Path Guide Kit
  • Chain Catch Kit
  • Custom Engineered hardware


  • ISCG05 Frame
  • Guard
  • High Pivot Chain Path Guide Kit
  • Chain Catch Kit
  • Custom Engineered hardware


Choose the parts you want for your Rock Bottom setup. 

STEP 1: Select A frame mount style

ISCG05 M6 lugs mount style. The frame features our beautiful black anodized machined finish to add some brutality to your rig.

bottom bracket frame front

Bottom Bracket threaded cup mount style. The frame features our beautiful black anodized machined finish to add some brutality to your rig.

STEP 2: Select a guard

Designed to protect chainrings with 38 teeth or fewer.

STEP 3: Pick the right Chain Guide for Your Bike's Chain Path.

Add the Rock Bottom Standard Chain Path Guide Kit if your chain goes straight from the cassette to the chainring.

Add the Rock Bottom High Pivot guide if your chain goes from the cassette to a high pivot idler pulley and then the chainring.


The Chain Catch provides a friction free way to keep your chain from whipping off the bottom of the chainring. It is easily replaceable if it rips off in the gnar.


Get adjustable tension without having to adjust the angle of the bash guard frame. Premium ABEC7 bearing, custom engineered labyrinth caps, durable natural rubber roller, and one screw roller access ensures you can keep it functioning in tip top shape. This is not required for chain retention.

Fitment Commitment

We are building a database of frame and component compatibilities. If you can't make the Rock Bottom work with your setup please take pictures and contact us for free U.S. return shipping if you return all parts and packaging.


There are endless combinations of frame geometries and components. We designed to correct chain alignments but there are certainly products that don't fall within that range. Rubbing or part interference are possible.

Future Proof

We will keep up with the trends and develop new frames, guides, arms, and attachments as they become available.

Technical Specs

The Rock Bottom Frame is manufactured in Maryland, USA by Brutal Engineering. Material is 6061 T6 Aluminum milled on our HAAS VMC. The Rock Bottom Guard is manufactured in Maryland, USA by Brutal Engineering. Material is our secret ballistic polymer which is notoriously hard to machine due to slickness, softness, and propensity to melt. Milled on our HAAS VMC. Hardware sourced internationally.


The Rock Bottom has had 2 2nd place UCI World Cup Elite DH victories, more than 7 USA cycling national points championships, and over 50 1st place UCI sanctioned finishes.

We began product development in 2013. 100’s of prototypes later we reached Rock Bottom. Through 1000’s of miles of testing and racing riders have experienced: 0 dropped chains running only the upper guide and catch, 0 damaged chainrings from impacts, 0 broken guards. Our riders have had impacts which have broken off pedals, broken cranks, and sprained ankles, but to date no guard has failed when correctly installed. 

We recommend using your local bike shop or a professional race mechanic for installation as these instructions do not cover unique removal procedures for critical drivetrain components.

Read through the entire instructions before installing! Due to the modular nature of the Rock Bottom certain steps may require the removal of your cranks. Understanding the instructions will avoid needing to remove the cranks multiple times.

We recommend installing the Rock Bottom frame using a bike stand.

What's in a name?

The Rock Bottom name started as a simple clever pun. We wanted to start Brutal Engineering without investors pushing for deadlines and profit. To do that we needed to start at Rock Bottom. Coincidentally the first prototype bash guards were designed to mount on threaded bottom brackets and protect against rocks. Rock Bottom protection.

The name soon grew to hold a deeper meaning. In 2013 Brutal Engineering owner, Joe, started to lose his limitless energy. He began feeling dizzy all the time and passing out when lifting weights. Gradually his condition got so bad that he could no longer ride his bike. That didn’t stop him from trying to push himself though. One day he blacked out in the transition of a jump and ran chest first into a tree at over 20 mph. He separated his sternum entirely and suffered a severe concussion. Thankfully doctors began to listen after that event and he received an external heart monitor. One night Joe felt what seemed like some sort of heart event while wearing the monitor. Shortly after his Cardiologist called and said he had to be driven to the ER or he would send an ambulance. At the ER Joe learned he had 30 seconds of Ventricular Tachycardia. His heart had convulsed at over 300 beats a minute, but blood wasn’t’ flowing. Joe learned normally people don’t recover after just 6 seconds, but because he kept forcing himself to exercise he survived.

Joe was scheduled for surgery and now has an implanted heart monitor. VTAC was the key to seeing the top doctors at John’s Hopkins. He was scheduled for a tilt table test. They strap you to a table, let you rest, tilt you up and monitory your body’s response. When they repeated the test on Joe with adrenaline he went into VTAC again and blacked out. When he came to the doctor told him that VTAC meant he was clinically dead for the second time. He was diagnosed with Postural Orthostatic Tachycardia Syndrome (POTS) and Neurally Mediated Hypotension (NMH). Both of those conditions are really just symptoms of a deeper problem so he got more tests.

Soon Joe’s condition worsened. He was losing his balance walking, passing out from simple body movements, and couldn’t think straight enough to work on CAD. He couldn’t ride his bike on flat ground. That was the real rock bottom.

Bloodwork revealed an extremely high concentration of antibodies that are known for attacking nerves and muscle. A nerve biopsy revealed he has severe neuropathy. Joe was diagnosed with undifferentiated connective tissue disease and is working through different treatments which have been helping. He has regained his energy, he is nearing previous strength, and best of all the team riders have  taken the Rock Bottom to the top of the podium.