Marin Alcatraz 2 Dirt Jump Frameset (Purple Fade)
74154402-L
A 26-inch single-speed frameset for the rider who wants to build a dedicated dirt jump or pump-track bike, light and simple enough to throw around on poppy manuals and big sends without a drivetrain to worry about.
Overview
The Alcatraz 2 frameset is built around a Series 3 6061 aluminium frame designed specifically for dirt jump and park riding - short chainstays, a low stack, and horizontal rear dropouts that let you tension a single-speed chain by sliding the rear wheel rather than relying on a derailleur or tensioner cage alone. It's sold as a frame plus the small parts that are frame-specific rather than swappable build choices: the FSA No 57E headset and the Marin MTB bolt-type seat clamp both come included.
The frame takes a 73mm threaded bottom bracket with ISCG 05 tabs for a chain guide, and its 135x10mm horizontal rear dropout is built around single-speed use, with a Marin chain tension device keeping things snug without a derailleur. Internal cable routing is ambidextrous, so the rear brake line can be run on either side of the bars depending on how you set up your cockpit. Marin's own complete-build equivalent pairs this frame with a 100mm-travel coil fork and a single 32T chainring on a 104mm BCD, giving a sense of the build this frame is designed around.
This is the frameset for a rider who already knows they want a dedicated 26-inch dirt jump or pump-track bike and would rather choose their own fork, wheels and cockpit than buy a complete build.
Why You'll Like It
Built around single-speed simplicity
The horizontal rear dropout and included chain tension device mean you can run a true single-speed drivetrain with simple chain-line tensioning, with no derailleur hanger to protect or bend.
Headset and seat clamp already sorted
The FSA No 57E headset and Marin MTB bolt-type seat clamp both come with the frame, so you're not sourcing frame-specific small parts separately before you can even start the build.
Routing that adapts to your cockpit
Ambidextrous internal cable routing lets the rear brake line run on either side of the bars, so you can set the bike up moto-style or regular without being locked into one routing direction.
A chain guide ready to go
ISCG 05 tabs mean a chain guide can be bolted straight on, which matters more on a dirt jump or park bike than almost any other riding style.
Two sizes for different-height riders
Short and Long options keep the geometry proportionate across a real range of rider heights, rather than forcing everyone onto one compromise frame size.
Who Is It For?
The Alcatraz 2 frameset is for a rider who's set on building a dedicated dirt jump or pump-track bike and wants to choose their own fork, wheels, bar and cockpit rather than take a complete build's spec as given. It suits someone upgrading from a complete dirt jump bike who wants to keep a favourite fork or wheelset while refreshing the frame.
In India, that fits riders at the handful of dedicated pump tracks and dirt jump spots now appearing around the bigger cities, as well as BMX and freestyle riders looking for a 26-inch platform with modern mountain-bike sizing rather than a true BMX frame.
Good to Know
Because the headset and seat clamp are already included, the remaining build list is mostly fork, wheels, bars, stem, cranks, chainring and brake - plan your parts list around those. The ISCG 05 tabs mean a chain guide is a simple bolt-on addition whenever you want one, rather than a frame-dependent upgrade.
Technical Specifications
- Model Year: 2026
- Frame Material: Series 3 6061 aluminium
- Fork Material: N/A - sold as frame-only; fork not included
- Fork Construction: N/A - fork not included
- Dropout Style: 135x10mm horizontal rear dropout (single-speed chain tensioning)
- Brake Type: Disc (complete-build equivalent uses Shimano MT201 hydraulic disc, 160mm rotors front and rear)
- Headset Included: Yes - FSA No 57E, semi-sealed cartridge bearings, 1 1/8" x 1 1/2"
- Headtube Diameter: Tapered 1 1/8" x 1 1/2" (matches included headset)
- Seatpost Included: No
- Seatpost Diameter: 30.9mm
- Seatpost Clamp Included: Yes - Marin MTB Seat Clamp, bolt type
- Front Derailleur Mount: N/A - single-speed frame
- Front Derailleur Type: N/A - single-speed frame
- Bottom Bracket Type: Threaded, 73mm shell, external sealed cartridge bearings
- BB Shell Width: 73mm
- Cable Routing: Internal, ambidextrous (rear brake can run either side)
- Di2 Compatible: No - single-speed frame
- Hub Spacing: Rear 135x10mm; front 110x20mm (per complete-build fork)
- Max Chainring: 32T (104mm BCD, per complete-build spec)
- Chain Guide Mounts: ISCG 05 tabs
- Wheel Size: 26"
Additional Information
- Country of Origin: China
- Imported By: Ciclo Essentials Private Limited, B-55A, Sahakar Marg, Jaipur - 302005, India.
- Net Quantity: 1N
- Customer Care Address: 291, 10 Main, 5 Block, Jayanagar, Bangalore - 560041. Ph: (080)47183232, Email: support@bumsonthesaddle.com
- Commodity: Framesets
