Mountain Bike Action Bike Test: Marin San Quentin 3 Trail Bike

Marin San Quentin 3
Trail Bike

Action photos by Travis Fant

Named after the rough-and-tumble prison where Johnny Cash once performed, the all-new Marin San Quentin 3 is a bike that’s tough as nails. Blurring the lines between a dirt jumper and an aggressive hardtail, Marin found the right balance by incorporating the design of its Alcatraz dirt-jump frame with the trail readiness of its Nail Trail hardtail. The San Quentin 3 runs free and embodies the rebellious attitude of legendary singer and songwriter Johnny Cash. This month the MBA wrecking crew tunneled its way out of prison using nothing but cranksets and chainrings to experience the freedom that comes with Marin’s new-age hardtail.  


A hardtail is arguably the purest form of mountain biking, offering trail feedback that’s normally absorbed when riding a full-suspension bike. The San Quentin falls into a different category than most other hardtails by removing itself from the spandex-wearing crowd and replacing that attire with jeans, a T-shirt and a BMX helmet. This bike is more at home riding jump trails than it is racing around a cross-country track. That said, the San Quentin is still considered a trail bike thanks to its dropper post, slack head angle and long reach accompanied by a short rear end. The San Quentin can be pedaled around the trails or be used to hunt down urban riding zones. 


Marin’s goal was to make the San Quentin affordable and fun, which we believe they absolutely nailed. Starting price for these bikes is as low as $850, while the model we tested sells for $1900. Our test rig came complete with an aluminum frame, semi-internal cable routing and a threaded bottom bracket. The bike also features Boost hub spacing, wide 27.5-inch wheels and snappy 425mm chainstays. Marin designed this bike for trail riding with an aggressive 65-degree head tube angle for conquering steep terrain and a 75-degree seat tube angle for a balanced, seated climbing position. A low standover height (inspired by Marin’s Alcatraz dirt jumper) was incorporated into the San Quentin to boost confidence for when the trails get rowdy. 


With a price of $1900, you can’t expect pro-level components; however, Marin managed to offer a good bang for the buck that won’t leave you looking to upgrade soon after your purchase. Featuring a 130mm-travel RockShox Revelation fork and a Shimano SLX 11-speed drivetrain, the San Quentin is ready to take on serious trails right out of the box. Our test bike came with an X-Fusion Manic dropper post providing ample travel, and the Marin cockpit offered a great feel with a short 45mm stem and wide 780mm bars. Where the components fall short are the lower-end Shimano brakes and Marin’s house-brand wheels. That said, the San Quentin 3 offers value and a great platform to build from.  


Setting sag: What makes a hardtail mountain bike so timeless and enjoyable is its ease of setup. Our testers placed 20-percent sag in the fork, dialed in their rebound and left the compression knob wide open. After just a few minutes of adjusting air pressure and a quick neighborhood jaunt to test out the rebound setting, our bike was ready to hit the trails. 

Moving out: The San Quentin offers a unique feel that relates more to a trail bike than a traditional hardtail. Its long reach and slack head angle hint at this bike’s capability long before you head off-road. In a seated position, the bike has a neutral fit, thanks to its steep seat tube angle that’s on par with most modern trail machines. Dropping the seatpost and standing over the bike quickly change its attitude. With the saddle slammed, the San Quentin feels like a dirt jumper but with bigger wheels, additional travel and a slacker front end. Holding manuals down the street or ripping around a local pump track is right up this bike’s alley. 

Climbing: Hardtails are often known for their climbing prowess, and while the San Quentin is no slouch on the climbs, it doesn’t fly up the trails quite like an XC hardtail does. That said, the San Quentin is an efficient machine with a nice wide range of gears. Due to its aluminum frame and robust parts, the San Quentin is not a lightweight racer, but its eagerness to get to the top of the trail is second to none. Furthermore, its balanced, seated position and long reach plant the front end to the ground even during steep climbs. 

Cornering: Marin paired wide 2.6-inch tires with short chainstays to ensure the San Quentin could be tossed around the trails with ease and control. Boost hub spacing helps provide stiffness to the wheels, allowing riders to slash up corners and drive the rear wheel around turns. Up front, the slack head angle provides stability at speed, and the 150mm-travel dropper, along with a low standover, contributes to rider confidence out on the trails. 

Descending: Hardtail mountain bikes require riders to choose their lines more carefully, since bikes that lack rear suspension are almost always less forgiving of bad line choices. This Marin, however, tackles rough terrain well. In fact, our testers were quite surprised at just how smoothly the San Quentin descends. The 130mm-travel fork does a nice job of soaking up the initial hits, while the rear end uses its wide tire with low pressure to reduce chatter while ripping down the trails. Of course, a rocky trail will challenge a rider’s skills, but fast singletrack is met with speed and precision. The San Quentin is a bike that enjoys flowy jump trails; however, it’s not limited to that setting. A rider skilled and fit enough to handle the added abuse of a hardtail will thoroughly enjoy ripping up the trails aboard this steed. 


The San Quentin, even in its top-level trim, would be considered an entry-level bike due to its component package. That said, with just a few upgrades, this bike could be a true trail shredder. The first upgrade we would recommend is trading the brakes for something with a touch more power. Shimano XTs would be a welcome upgrade and would offer a familiar feel. Next, we would suggest setting the bike up tubeless in order to run lower tire pressures and to help reduce trail chatter.  

If a rider wanted to go all in, we would recommend a new set of wheels to reduce rolling weight, along with upgraded drivetrain components for smoother shifting. Overall, the San Quentin 3 offers a solid build for its price that will appeal to many riders.

The San Quentin 3’s new color for 2021.


The ideal candidate for the San Quentin is actually a few different types of riders. Due to its dirt-jumper inspiration, we imagine younger riders being drawn to this bike, as it can handle a day hitting jumps but can still go out on trail rides with full-suspension bikes. Other riders who might be drawn to the San Quentin are those looking to add an inexpensive bike to their stable for muddy trail days, which would wreak havoc on pivot bearings and suspension components. All in all, the San Quentin is a versatile hardtail made to shred as hard as any trail bike. With a competitive price, a fun-to-ride geometry and the ability to ride all over the mountain, the San Quentin is a bike worth breaking out of prison for.




Check Out Mountain Bike Action’s First Ride On The Marin San Quentin 3 Trail Bike Here

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