2
OMA33C
Table 2
Product Minimum Axle Length
Inches (mm)
Maximum Axle Length
Inches (mm)
BOB Nutz 3/8 x 24 tpi 3/8” (9.5 mm) 7/8” (22.2 mm)
BOB Nutz 3/8 x 26 tpi 3/8” (9.5 mm) 9/16” (14.3 mm)
BOB Nutz IGH 9/32” (7.1 mm) 15/32” (11.9 mm)
BOB Nutz 10 x 1 3/8” (9.5 mm) 9/16” (14.3 mm)
If you find that the axle length
on either side does not fall between the minimum and
maximum values, do not continue the installation and see
your local bike shop or contact BOB.
Table 3
Axle Thread
Specification
Overdrop Dimension Range
Inches Millimeters
3/8 x 24 4-1/2” to 5-3/32” (114 mm - 129 mm)
3/8 x 26 5-5/16” to 5-7/8” (135 mm - 149 mm)
10 mm x 1 5-5/16” to 5-7/8” (135 mm - 149 mm)
13/32 x 26 or
10.5 x 1 mm 4-7/16” to 5” (113 mm - 127 mm)
2) Wheel Overdrop
BOB Nutz are designed to work with bicycles having rear wheel
Overdrop Dimension Ranges listed in Table 3.
a. To determine your frame’s Overdrop Dimention, measure
the outside dimension of the rear wheel dropouts using a tape
measure, ruler or a pair of calipers as shown in FIG. 3.
FIG. 3 - Measuring Overdrop
The Overdrop Dimension must fall in the range listed in Table 3.
3) Threading Instructions
a. For IGH models skip to step C.
b. Place the Serrated Washers provided with BOB Nutz over the
axle.
c. Thread on both BOB Nutz in a clockwise direction and tighten
simultaneously to 20-25 ft-lbs (27-34 N-m) of torque. If there is
difficulty, double check to ensure the axle is clean, that you have
the proper size BOB Nutz, and you have not crossed threaded
them.
Now that the BOB Nutz are installed, you are ready to attach the
trailer to the bike.
Attach and detach the trailer
ONLY when it is in a straight line with the bike or you may
bend the fork. It is easiest to attach and detach the trailer
when it is unloaded.
CHECK BOBBIN SPACING
1) With the bike stabilized and the trailer unloaded, check the
fit between the Fork Hooks and the slots of the Bobbins. It is
easiest to do this with the bike in the upright-position and trailer
straight behind the bike. Stand on the non-drive side of the bike
facing towards the trailer. Allow the bike seat to rest against
you. Bend at the hips and lift trailer with both hands, FIG. 4, and
place the Fork Hooks on the BOB Nutz Bobbins.
Pin Correctly Installed
FIG. 4 - Correct Position for Trailer Attachment
a. If the Fork Hooks fit into the Bobbin slots by
expanding or compressing of the fork slightly, skip to
the ATTACH TRAILER section of this manual.
b. If the Fork Hooks do not fit into the Bobbin slots by slightly
expanding or compressing the fork, it will be necessary to
adjust the Bobbin spacing as described in the ADJUST BOBBIN
SPACING section of this manual. FIG. 5 shows a situation where
the Fork Hooks do not fit easily and the Bobbin spacing needs
to be adjusted.
FIG. 5 - Bobbin Spacing NOT Aligned with Fork Hook
Fork Hook
ADJUST BOBBIN SPACING
1) The stainless steel pivoting Bobbins on the BOB Nutz are
asymmetrical as shown in FIG. 1a and 1b. This asymmetrical
design allows the Bobbins to be reversed, allowing for a variance
of approximately 1/2” (12.7 mm) in outside dimensional span of
the bike’s dropouts.
For IGH Models do the following in lieu of steps 1) and 2)
below:
Use a pair of external snap ring pliers to remove the Circlip on
both the right and left sides. Remove the Bobbins and reverse
them noting the positions of the Flat Washer. Then re-install the
Flat Washer and Circlip so it completely engages the slot in the
Bobbin. (Go to step 4)
For Non IGH Models Only:
2) With the BOB Nutz installed, and using a 4mm Allen Wrench,
remove the M5 Bobbin Retaining Socket Screws, FIG. 1a, on
both the left and right sides. Remove the Bobbins and reverse
them noting the position of the Lock Washer and Flat Washer.
3) With the Bobbins reversed, reinstall the Flat Washer, Lock
Washer, and M5 Bobbin Retaining Socket Screw. Tighten the M5
Bobbin Retaining Socket Screws to 35-45 in-lbs (4-4.5 N-m).
