My pops recently hooked me up with a set of PowerBlocks (Sport 24 series) to use for high-volume rehab exercises. They're solidly built & super quick to adjust, but I found the stock handle to be a bit thin for my liking. After using Fat Gripz on everything for a while, it's pretty hard to go back to anything with less than a 1.5" diameter. I decided to make my own thick grips since the inner handle of the PowerBlocks is shorter than Fat Gripz, and Fat Gripz are also too wide for the amount of space between the handle & the outer wall of the PowerBlocks (your knuckles would get pushed against the metal rungs from lack of space).

Size Comparison:

____________________Diameter____Circumference
PowerBlock Handle:  1.25"       4"
This Modification:  2"          6.25"
Fat Gripz:          2.25"       7"

Tools Needed:

any one of the following:

utility knife / box cutter
hacksaw
jigsaw

(I used a jigsaw and cleaned up the edges with a utility knife, but the edges might have come out a bit cleaner if I had used a hacksaw instead.)

Parts (Required):

2' Braided Vinyl Tubing (1.75" OD, 1.25" ID)

Tennis Racket Grip Tape (I used Gamma Supreme Power Overgrip)

(You might want to go with a smaller size of vinyl tubing or thin-wall PVC if you have larger hands. My hands are about 7.5" from the edge of my palm to the tip of my middle finger, and my index finger's knuckle has about 1" of depth. The 2" final diameter using the listed materials is perfect for my hand when my grip is fully engaged and my wrist is completely neutral, but if I slack on form, my knuckles will bump into the metal rungs of the PowerBlock wall. For me this isn't a problem, as the contact is minimal and it also encourages a strong grip with proper form.)

Parts (Substitutable):

something to fill in the concave areas of the PowerBlock handle (I used shelf liner held in place with painter's tape, some kind of cloth or tape would also work)

something to fill in the gap of the split in the vinyl tubing (I cut out strips from some foam pipe insulation, but in retrospect I maybe could have used some of the excess vinyl tubing)

Step 1: Fill in the Concave Areas of the Handle

The PowerBlock handles have concave sections around where your index and pinky fingers rest. Fill those sections in so the entire handle is about the same diameter. This will ensure that the vinyl tubing rests evenly in the center of the PowerBlocks.

I cut some strips of shelf liner, wrapped them tightly around the handles a few times, and then secured them in place with painter's tape. Any kind of liner/cloth/tape should work for this step.

(In the pictures, you can see that the shelf liner protrudes a bit, but since the material is not very dense it will compress once the vinyl tubing is placed over it. Make sure that your wrapping does not increase the overall diameter of the handle, as excess width will result in less space for your hands inside of the PowerBlock.)

Step 2: Cut the Vinyl Tubing to Size

Measure the inside of a PowerBlock, and cut 2 sections of appropriate length from the vinyl tubing.

Next, make a cut down the length of each piece so that you can split them open to place them over the PowerBlock handles.

Fill in the gap with something relatively dense, so that your fingers don't sink in to the gap & stretch the grip tape that we'll be wrapping these with. I used some foam pipe insulation, but you could possibly cut some strips out of your left-over vinyl tubing instead.

Step 3: Wrap the Vinyl Tubing With Grip Tape

Wrap the vinyl tubing with grip tape, making sure to keep a good amount of tension all the way around.

(The tension is especially important if you used foam to fill in the gap, since it will compress the foam so that it doesn't protrude from the handle)

The Gamma overgrip linked in the first section is nice because it doesn't use very much adhesive, so there's no glue that would seep out if using these out in the sun or if the tape happens to curl back a bit after extended use. They have a 1/2" section of adhesive on one end that anchors to the starting point, and a small piece of tape to wrap around the ending point to keep it in place.