1951-15 adapter stud
The #1951-15 is a threaded stud that will allow the 100-25D to fit the PRS-15 repair stand. NOTE: The clamp will not fold downward as the original 100-15X clamp design.
The #1951-15 adapter stud works only is the PRS-15 has the three-pointed knob behind the clamp, as seen on the top tube in image #1. See note at end of article for models with a different top tube handle.
To install the 1951-15, begin by removing the 100-15X clamp and handle assembly (figure 1).
Figure 1. Remove clamp and handle assembly
1. Loosen and remove the top tube knob screw and washer (figure 2). NOTE: This is a left-hand threaded screw and is installed with a thread locker. Use mild heat as from a hair dryer or air gun. Remove by turning clockwise.
Figure 2. Loose left-hand threaded screw by turning CLOCKWISE.
2. Unthread knob completely from main clamp screw.
3. Remove clamp and parts from top tube (figure 3).
Figure 3. Parts of the 100-15 and top tube of PRS-15
4. Use from the previous parts the knob, two thrust washers and the one thrust washer bearing. Clamp thread and top tube tapered sleeves from the 100-15X will not be used with the 100-25D.
5. The 1951-15 has two threads, one side in 1/2" and the other a smaller 7/16" thread (figure 4). Install the 1/2" jam nut onto the 1951-15. Thread the larger 1/2" thread into the back of the 100-25D clamp (figure 4).
Figure 4. The 1951-15 threaded stud with two threaded ends
6. Tighten the jam nut against the 100-25D (figure 5).
Figure 5. Secure jam nut to hold 1951-15 in place
6. Place the 100-25D through the top tube. The 7/16" thread will protrude through the back of the top tube. Install one thrust washer, the thrust bearing, and then the other thrust wash on the thread (figure 6).
Figure 6. Assemble the 100-25D into the top tube
7. Thread the knob onto the thread and secure. To rotate, loosen knob to free clamp in top tube. Clamp is installed and ready for use (figure 7).
NOTE: There is no stop built into the knob assembly. Use care not to unthread the knob too far. Unthreading the knob completely will allow the clamp and any bike to fall out of the stand.
Figure 7. PRS-15 top tube with 100-25D ready for use
First generation PRS-15 models use a single long handle to secure the clamp from rotation (figure 8). The three pointed handle, part #1233, must also be added for the 1951-15 adapter stud to work with the 100-25D (figure 9).
Figure 8. The first generation top tube levers will not work with 1951-15 adapter studs
Figure 9. The 1233 top tube knob is necessary for the 1951-15