JBob Design and Installation Guide
This guide walks you through the design considerations and installation of GroupJ's JBob Bicycle Frame Couplings to convert your steel frame into a world travel bike. We recommend that you read this guide thoroughly before starting your conversion and Contact Us with any questions before you begin.
Design
The primary consideration for frame conversion is the location of the couplings and the routing of control cables around the couplings. If your frame has internal routed cables it is recommended that you convert to externally routed cables. Use of the Ritchie shift cable connectors is a straightforward method of breaking the shift cables. We recommend that the brake cables remain continuous and just remove the brake caliper assemblies to break apart the frame. (We have not yet converted a disk brake bike but the concept is the same). |
JBobs are generally located on the upper and down tubes as close to the seat tube as practical. Before you cut your frame apart, it is recommended that you select your travel case (see SandS.com) and make sure your break-apart frame will pack into the case. Larger frames are a challenge to pack and sometimes require more than 2 couplings. Scale drawings of the case and frame are recommended.

Considerations for coupling placement:
Packing in the travel case
Control cable routing
JBob Placement
Packing in the travel case
- Small movements in coupling location can make a big difference in the ability to fit the frame in the case – plan carefully
Control cable routing
- The rear brake cable usually routes outside of the top tube coupling. If the coupling is close to a cable bracket, make sure there is room for a smooth cable path with large bend radii
- Think about how to route the rear brake cable so as not to foul the rider
- The front and rear derailleur cables generally route outside the down tube coupling. Place the Ritchie shift cable couplings well clear of JBob
- The outer shift cable usually terminates at the down tube shift bosses on vintage frames. If you are shopping for a frame to convert look for these bosses. If your frame does not have them, use a clamp-on cable stop available at bike shops or search for frame builders supply.
JBob Placement
- Ensure the JBobs are not too close to adjoining tubes, brackets or lugs. JBobs require a length of 60mm of constant tube outside diameter (OD), without obstructions, for installation
- The JBob selection table lists the length of tube to be removed for each coupling size. Use these lengths to identify two cut lines for each tube. The centerline of the coupling will be equal distance from these two lines.
Frame Preparation (video coming soon)
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Coupling Installation (video coming soon)
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