Marin San Quentin 3 29" Mountain Bike 2026 - Hardtail MTB



The San Quentin 3 29 is built for riders who want dirt-jump attitude with real trail capability. A tough alloy frame, 140mm travel and a 12-speed drivetrain combine to deliver control, confidence and pure fun on technical singletrack and bike-park style trails.
Key Features:
- Series 3 double-butted aluminium frame with aggressive trail geometry
- Marzocchi Bomber Z2 fork, 140mm travel
- Shimano Deore 12-speed wide-range drivetrain
- TRP Slate EVO 4-piston hydraulic brakes
- 29" tubeless-ready Marin wheels with Maxxis Assegai tyres
- TranzX dropper post for on-the-fly saddle height adjustment
- Built with tough Marin kit, inspired by Matt Jones
- Available with 0% APR finance
The Marin San Quentin 3 29 has been shaped by freeride legend Matt Jones and built for riders who want a hardtail that thrives when the trails get loose, fast and technical. Its Series 3 double-butted aluminium frame blends the strength and style of Marin’s Alcatraz dirt-jump platform with the poised control of their trail bikes. The result is a hardtail that encourages playful riding—manuals, jumps, steep corners—but still offers stability and comfort for longer days on rough terrain.
Up front, the Marzocchi Bomber Z2 delivers 140mm of plush, supportive suspension. Its Kabolt axle and Boost spacing improve stiffness, helping the fork track precisely through rock gardens and compressions. Paired with the frame’s long front end and short stem, it creates confidence-inspiring handling on technical terrain.
A Shimano Deore 12-speed drivetrain supplies crisp, reliable shifting and a huge 10–51T cassette range, making steep climbs achievable and letting you carry speed on rolling terrain. Stopping power is handled by TRP Slate EVO 4-piston hydraulic brakes with large 203/180mm rotors—giving powerful, controllable braking for steep descents and wet conditions.
The 29" wheelset uses wide, tubeless-compatible rims matched with Maxxis Assegai 2.5" tyres in EXO casing. This combination offers impressive cornering bite and predictable grip on loose, rooty and rocky surfaces. A TranzX dropper post—up to 200mm travel on larger sizes—lets you shift between climbing and descending positions effortlessly.
From aggressive trail riding to bike-park laps, the San Quentin 3 29 is built to handle modern riding styles with durability, precision and energy. It’s a hardtail that encourages progression and turns every trail into an opportunity for fun.
Occasionally, without notice, manufacturers change product design and/or specifications.
| Frame | Series 3 6061 Aluminum, Double Butted Frame, Internal Cable Routing, 12x148mm Thru-Axle, 73mm Threaded BB |
| Fork | Marzocchi Bomber Z2, 110x15mm Boost Spacing, 140mm Travel, Kabolt Axle |
| Headset | FSA No 57E, Semi-Sealed Cartridge Bearings, 1 1/8" x 1 1/2” |
| Stem | Marin 3D Forged Alloy, 35mm |
| Bars | Marin Mini-Riser, 6061 Double Butted Aluminum, 780mm Width, 28mm Rise, 5º Up, 9º Back |
| Front Brake | TRP Slate EVO, 4-Piston Hydraulic, Resin Pads, 203mm Rotor |
| Rear Brake | TRP Slate EVO, 4-Piston Hydraulic, Resin Pads, 180mm Rotor |
| Brake Lever | TRP Slate EVO, I-Spec EV Compatible |
| Rear Mech | Shimano Deore, 12-Speed, SGS |
| Shifters | Shimano Deore, 12-Speed, SL-6100IR |
| Speed | 12 |
| Rims | Marin Aluminum Double Wall, Specific, 29mm Inner, Pinned Joint, 32H, Tubeless Compatible |
| Front Hub | Shimano HF-MT410B, 32H, 110x15mm |
| Rear Hub | Shimano FH-TC500, 148x12, 32H, Standard Freehub Body |
| Spokes | 14g Black Stainless Steel |
| Front Tyre | Maxxis Assegai, 29x2.5 MAXX TERRA, EXO Casing, Tubeless Compatible |
| Rear Tyre | Maxxis Assegai, 29x2.5 MAXX TERRA, EXO Casing, Tubeless Compatible |
| Seat Post | TranzX, YSP23JL, 1x Remote, Size S 125mm Travel, Size M 150mm, L 170mm Travel, and Size XL 200mm Travel, 30.9mm |
| Saddle | Marin Speed Concept |
| Chainset | FSA Comet, Modular 1x, 32T Direct Mount Chainring, MegaTooth Technology, Boost Spacing |
| Bottom Bracket | MegaExo 73mm BSA |
| Chain | KMC X-12 Silver and Black |
| Cassette | SunRace, 12-Speed, MicroSpline, 10-51T |
| Pedals | Marin MTB Plastic |
San Quentin Sizing
See the table below to find the right size Marin San Quentin.
|
Height |
Size |
||||||
|
4’8” / 143cm |
XXS |
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|
|
|
|
|
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4’9” / 145cm |
XXS |
|
|
|
|
|
|
|
4’10” / 148cm |
|
XS |
|
|
|
|
|
|
4’11” / 150cm |
|
XS |
|
|
|
|
|
|
5’0” / 152cm |
|
XS |
|
|
|
|
|
|
5’1” / 155cm |
|
XS |
S |
|
|
|
|
|
5’2” / 158cm |
|
|
S |
|
|
|
|
|
5’3” / 160cm |
|
|
S |
|
|
|
|
|
5’4” / 163cm |
|
|
S |
|
|
|
|
|
5’5” / 165cm |
|
|
S |
M |
|
|
|
|
5’6” / 168cm |
|
|
|
M |
|
|
|
|
5’7” / 170cm |
|
|
|
M |
|
|
|
|
5’8” / 173cm |
|
|
|
M |
|
|
|
|
5’9” / 175cm |
|
|
|
M |
L |
|
|
|
5’10” / 178cm |
|
|
|
M |
L |
|
|
|
5’11” / 180cm |
|
|
|
|
L |
|
|
|
6’0” / 183cm |
|
|
|
|
L |
XL |
|
|
6’1” / 185cm |
|
|
|
|
L |
XL |
|
|
6’2” / 188cm |
|
|
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|
|
XL |
|
|
6’3” / 191cm |
|
|
|
|
|
XL |
XXL |
|
6’4” / 193cm |
|
|
|
|
|
|
XXL |
|
6’5” / 196cm |
|
|
|
|
|
|
XXL |
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6’6” / 198cm |
|
|
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|
|
|
XXL |
Read our bike size guide for more information on sizing.
San Quentin Geometry
|
Size |
S |
M |
L |
XL |
|
Stack |
586.1 |
590.7 |
599.7 |
604.3 |
|
Reach
|
422 |
444 |
464 |
484 |
|
Head Tube Angle |
65 |
65 |
65 |
65 |
|
Head Tube Length |
105 |
110 |
120 |
125 |
|
Seat Tube Angle (Virtual) |
75 |
75 |
75 |
75 |
|
Seat Tube Angle (Actual) |
75 |
75 |
75 |
75 |
|
Seat Tube Length |
385 |
420 |
475 |
515 |
|
Top Tube (Actual) |
564 |
582 |
604 |
626 |
|
Top Tube (Effective) |
579.1 |
602.3 |
624.7 |
645.9 |
|
Bottom Bracket Height |
310 |
310 |
310 |
310 |
|
Bottom Bracket Drop |
50 |
50 |
50 |
50 |
|
Chain Stay |
425 |
425 |
425 |
425 |
|
Wheelbase |
1144.8 |
1168.9 |
1193.1 |
1215.3 |
|
Standover Height |
664 |
677 |
714 |
745 |
|
Fork Offset |
46 |
46 |
46 |
46 |
|
Seatpost Diameter |
30.9 |
30.9 |
30.9 |
30.9 |
|
Handlebar Width |
780 |
780 |
780 |
780 |
|
Stem Length |
45 |
45 |
45 |
45 |
|
Crank Length |
170 |
175 |
175 |
175 |
Read our Mountain Bike Geometry Explained guide for more information on MTB geometry.
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Get this on cycle to work
Save up to £713.58
Cycle to work is a government funded salary sacrifice scheme which allows you to spread the cost of purchasing a bike and equipment and save on Income Tax and National Insurance.
Lower Tax Rate | Higher Tax Rate | |
|---|---|---|
Monthly pre-tax cost | £141.58 | £141.58 |
Monthly cost to you | £101.94 | £82.12 |
Total cost over 12 mths | £1,223.28 | £985.42 |
Total savings | £475.72 | £713.58 |
The calculations provided here are based on a monthly pay frequency and will vary depending on your personal taxation and your employers scheme.
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