
Gravity
Gravity Bullseye Monster Fat Bike Frame Kit
★★★★★
Fat bike frame kit with aluminum frame, steel fork, and pre-installed headset ready for your custom 26-inch build.
$199.00*
Check availability
*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.
Affiliate Disclosure: Studio Supplies may earn a commission from qualifying purchases made through links on this page, at no additional cost to you. This helps support our editorial team.
Notice a mistake? Let Us Know
Overview
Key Features
Aluminum Frame with Steel Rigid Fork
170mm rear spacing 135mm front spacing
Will Accept 26 x4.0 Tires
Seatpost and Seatpost Clamp Are Included
Headset and Stem are Included and Installed!
Specifications
Brand
Gravity
Model
Bullseye Monster
Frame Material
6061 Aluminum Alloy
Fork Material
CrMo Steel (Rigid)
Wheel Size
26 inch
Max Tire Size
26 x 4.0
Rear Spacing
170mm
Front Spacing
135mm
Included
Frame, Fork, Headset (installed), Stem (installed), Seatpost, Seatpost Clamp
Color
Matt Nautical Blue
Pros & Cons
👍 Pros
- Headset and stem come pre-installed, saving time and the need for specialized press tools
- 6061 aluminum frame offers a lightweight yet strong foundation for a fat bike build
- 170mm rear and 135mm front spacing are standard fat bike dimensions compatible with widely available wheelsets
- CrMo steel fork provides durability and natural vibration absorption on rough terrain
- Includes seatpost and clamp so you can focus your remaining budget on wheels and drivetrain
👎 Cons
- Rigid steel fork offers no suspension travel, which limits comfort on very rough or rocky trails
- Does not include wheels, tires, drivetrain, brakes, or handlebars — significant additional investment required to complete the bike
- Limited publicly available geometry data makes it difficult to assess fit before purchasing
- Only available in one color option (Matt Nautical Blue)
- Frame-only kits appeal mainly to experienced builders who already own or can source compatible parts
Frequently Asked Questions
What components are included in this frame kit?
The kit includes the aluminum frame, CrMo steel rigid fork, headset (installed), stem (installed), seatpost, and seatpost clamp. Wheels, tires, drivetrain, brakes, handlebars, and pedals are not included.
What is the maximum tire size this frame accepts?
The Gravity Bullseye Monster frame accommodates up to 26 x 4.0-inch fat bike tires, which is standard for most fat bike builds.
What are the hub spacing measurements for this frame?
The rear dropout spacing is 170mm and the front fork spacing is 135mm. Make sure your wheelset hubs match these dimensions before purchasing.
Is the fork a suspension fork or rigid?
The included fork is a rigid CrMo steel fork. There is no suspension. If you want front suspension, you would need to source a compatible suspension fork separately with 135mm spacing.
What frame material is used?
The frame is made from 6061 aluminum alloy, which provides a good balance of light weight and durability. The fork is CrMo steel for added strength and vibration dampening.