Cat 308 CR Fixed Boom Mini Excavator Brings Muscle to the 8-Ton Class

Caterpillar keeps refining its mini excavator lineup. Enter the new Cat 308 CR Fixed Boom unit. This model replaces the 307.5 and lands squarely in Cat’s 8-ton class with more power, more lift, and far better control in tight spaces. The biggest shift is right in the name. This is a compact radius (CR) machine, cutting tail swing dramatically. With the 250-kilogram counterweight, overhang drops 67 percent versus the outgoing 307.5. Even with the optional 500-kilogram counterweight, the reduction still sits at 61 percent. That matters on urban sites, utility work, and anywhere swing clearance is tight. The fixed boom design adds stability and lifting confidence, especially when paired with the wider undercarriage. This machine feels planted. Cat also ups gross horsepower by 25 percent, which shows up quickly when running hydromechanical attachments. Let’s dig in.

Engine, pin sizes, and track options   

The 308 CR uses the Cat C2.8 turbo engine, delivering 69 net horsepower while meeting Tier 4 Final and Stage V standards. Remember that’s a 25 percent gross horsepower increase over the 307.5, which is significant. Cat pairs that engine with a smart hydraulic system using a variable displacement pump. Stability also gets attention. Cat increases track width, undercarriage length and operating weight compared to the 307.5. Dig depth stretches to 185 inches and maximum reach hits 272 inches with the long stick. Lift capacity also improves over the front and over the side with the blade down. Importantly for fleet owners — a big part of our readership — pin sizing stays the same. If you already run a 307.5, your work tools carry over. It’s the small things, folks. 

This machine is also built for series attachments. Hydraulic flow reaches 44 gallons per minute. That opens the door for demanding implements. Track options include rubber, steel, and steel with rubber pads. That flexibility helps contractors match the machine to pavement work, landscaping, or wonky utility sites. Before I forget, there’s also auto idle and auto shutdown to help control operating costs.

Price point tech: Ease-of-Use on the 308 CR 

Economy grade control is cool. The 308 CR supports Cat Indicate and E-Fence, available from the factory or as upgrades. Indicate gives visual and audible cues for grade and slope. E-Fence limits machine movement within operator-defined boundaries. Ceiling, floor and wall constraints help avoid powerlines, buried utilities and nearby structures. New laser catcher support (added late last year) adds a site-wide grade reference. For crews chasing accuracy without a full grade control system, this hits the middle ground nicely. I’m a big fan of entry grade control, and this is a cool setup I’ve worked before. For contractors who want more, Cat Grade Advanced systems remain available aftermarket. 

Next Gen cab and control features

Cat continues to refine its Next Generation mini excavator platform, and the 308 CR benefits fully.

Key features include:

• Sealed and pressurized cab with strong HVAC
• Adjustable wrist rests and suspension seat
• Next Gen monitor with customizable settings
• Standard Stick Steer for joystick travel control
• Cruise control for long site moves
• Rearview camera standard with optional side camera
• Ground-level service access

Watching Cat’s mini excavator line grow

I was there in 2021, standing in the dirt when Caterpillar completed its Next Generation mini excavator lineup. But it’s not complete, right? Cat just keeps refining it. The 308 CR Fixed Boom is proof. These are some big upgrades from the 307.5. For crews who live in the 8-ton class, this one deserves a hard look.