Intro            

In all modesty, this project is awesome! Might be my new favorite of all time. A lot of thought went into it, and a lot of trial and error. The end result definitely surpassed my expectations.

If you are unaware, flywheels provide variable resistance – in that the harder your pull – the harder it pulls. By applying the inertia of a flywheel to your training (instead of just gravity like you get with traditional methods such as free weights or pulley systems) you will experience a different resistance curve and gain the benefits of eccentric overload.

The Design

The unit mounts to the rack using hitch pins, and it can slide up and down your any one of your rack’s  uprights – but can also be mounted to your rack’s lower cross members.

FULL DISCLOSURE: I don’t think it safe to mount it upside down to your upper crossmembers – after all the MOUNT is made of wood, screws, and glue – NOT STEEL….so don’t do that.

The design incorporates Adjustable length rope for different exercises. If you need it to be short – you keep the rope wrapped on the rope cleat on the rear of the unit…and to extend the length of the rope – you unwrap the rope from the rope cleat.

With this DIY Project  you can perform:

• Deadlifts

• Curls

• Triceps Push Downs

• Belt Squats

• REALLY ANY EXECERISE YOU can think of that you could also do with a cable pulley system!

Resistance Levels

I added two 10 LBS weights to mine. The more weight you add, the more inertia will be produced.

Having said that, even though I have 20LBS on mine – my advice is to leave enough room on the threaded rod to add as many plates as you want. I left enough room on my version’s threaded rod to add up to three 10LBS Plates, but perhaps just start with just 10LBS. You can always add more plates later. 20 LBS of plates actually provides a LOT of resistance.

Now I know the number one question you are going to ask – how many pounds of resistance does 20 LBS of plates offer? How many pounds of resistance does 10 LBS of plates offer? Unfortunately,  it’s difficult to measure the amount of resistance

On gravity-based systems, such as cable-pulley systems, I can use a luggage scale to determine the resistance level. This works because I can hold the luggage scale steady, in a static position.

However, with a flywheel, it’s always in motion, so using a luggage scale does not really work.

Resistance Quick Change Options

My current design does not allow for any kind of quick change of the plates “organically.” Using 1” hole plates on 3/4” threaded rod, meant that I had to use lock nuts/washers/grippy shelf liner to press the plates together to keep them rotating at the same rate  as the threaded rod.

Having said that ONE hack that can be used to rapidly add/remove weights is to use one of my earlier DIY projects from back in 2021: Magnetic Plate Blocks.

If I add 6 Magnetic Plates Blocks, I can easily add/remove plates - as long as all plates have a flat surface. The weight plates must have a flat surface so that the magnets have a maximum amount of surface area to adhere to. In the YouTube video - I tested it by adding one more 5 LBS plate. I have subsequently successfully tested using a 10 LBS plate as well. Picture here:

DIY Tutorial

Step1: Cut a piece of 2x6 Lumber that is 16” long

• Using a pencil, Draw a line down the center (i.e., at the 8” mark).

Step 2: Cut a Piece of 2x6 Lumber that is as long as your rack is wide (probably approximately 2” or 3”).

• Do not assume that your 3” rack is exactly 3” – and don’t assume your 2” rack is exactly 2” wide. Get out a piece of 2x6 Lumber – clamp it to your rack, and mark the edge of your rack with a pencil . THEN cut it. We need this piece to be EXACTLY as long as your rack is wide. If it’s too short – the unit will not fit on your rack. If it’s too long – the unit will wiggle on your rack.

• Using a pencil, Draw a line down the center. This line will help you center this piece later on the board from step 1.

Step 3: Create a PVC Roller

• To do so, Cut a length of Schedule 40 PVC Pipe that is as long as your rack is wide LESS about 0.25” . My rack is approximately 3” wide – so I cut mine to be 2.75” long. If you are using 1” Hitch Pins – use 1” Schedule 40 PVC. In the video I used 1.25” Schedule 40 PVC. However, in retrospect 1” will work better and won’t wiggle as much on the 1” Hitch pin.

• Now, full disclosure  - this roller (and the accompanying SECOND hitch pin) are completely optional. You do not HAVE TO have this roller/second hitch pin to use the device. I just thought it would make the unit easier to move up and down your uprights because it prevents the unit from moving forward (away from the rack) when sliding up and down your uprights, and will keep the device’s PRIMARY hole more centered on your rack’s holes – making it easier to reinsert the PRIMARY hitch pin.

Step 4: Cut a Cut a piece of 2x6 Lumber that is X” long.

• X = 1.5” + Your rack’s thickness+ Outer diameter of the of the PVC roller+ 1.5” Buffer. For me this resulted in length of 2x6 Lumber that were 7.5” long.

• To aid in measuring, in the video I  Clamped the pieces of wood from Step 1 and 2 onto my rack.

• Using a pencil, Draw a LENGTHWISE line down the center of one of these Step 4 pieces.

Step 5: Mark Hole Positions

• With the Pieces of wood from Step 1 and 2 clamped to your rack, take one of the pieces from Step 4 and hold it against the piece from Step 1. Position the LENGTHWISE line you drew so that it bisects one of the holes on your rack. Now, using a pencil, TRACE your rack’s hole pole position on top of the LENGTHWISE line. Then hold up your PVC roller against your upright, and trace its position on top of the same LENGTHWISE line.

Step 6: Drill holes for Hitch Pins

• If you use 1” hitch pins, use a 1 1/8” Spade Bit or Forstner bit. If you are using 5/8” hitch pins, you will likely want to use 11/16” Spade bit or Forstner bit.

• The trick here is we want the holes in BOTH pieces from Step 4 to be perfectly lined up with one another. Therefore. I clamped both Step 4 pieces together and drilled completely through the top board, and partially into the second board (and then finished drilling completely through the second board.

Step 7: Assemble on Rack Using Hitch Pins

• Assemble the lumber from Step 2 and 4 with the PVC roller from step 3 using two hitch pins on your rack. This is done to make sure everything fits and is aligned before moving on to any subsequent steps.

Step 8: Cut your last Two Pieces of 2x6 Lumber

• Cut two pieces of the 2x6 Lumber that are as long as the distance pictured below. Mine were approximately 5” long each.

Step 9: Glue and screw everything together

• 9A: Start off by ensuring that the pieces from Step 2 is perfectly centered on the piece from step 1, and glue it together, and secure with screws that are 2.5” long. Also make sure that you drive the screws in deep enough so that the heads of the screws are recessed in the wood. If you stick out – they will scratch up your rack.

• 9B: Add one of the pieces from Step 4. Use plenty of glue. I drilled through the pieces from step 1 and into the pieces from step 4 using 3” deck screws.

• 9C: Add one of the pieces from Step 8 – which will secure the piece you just added in 9B. Again use plenty of glue. I used 4 2.5” Screws for this. NOTE: After the Glue dries you will likely need to remove the 2 screws furthest to the edges. Consider these 2 screws to be only temporary screws. They are unnecessary after the glue dries. The Bolts used to mount the bearings (done in a subsequent step) will help keep everything together.

• 9D: Now add the remaining piece from Step 4, and then the remaining piece from Step 8.

• 9E. Now let the glue completely dry – which can take up to 24 hours.

Step 10: Drill Holes for Mounting the Pillow Block Bearings

• Once the glue is dry – now we can now drill the holes for our ½” bolts that will mount the ¾” pillow block bearings. We will also drill 1 1/8” wide counterbores so that the nuts and washers on the back side are recessed into the wood.

• To determine hole placement, assemble the 24” long ¾” threaded rod and your two ¾” Pillow Block Bearing. Use the mounting holes into the Pillow block bearing determining your hole positions. Make sure that the bearings are completely parallel before drilling your holes – and this is why we are inserting the threaded rod – and tightening the bearing’s set screws – to get the bearing as parallel as possible in order to  determine the hole position.

• The width of your washers will also influence your hole position. I used ½” washers that are approximately 1” in diameter. If I used wider washer, the counterbores would also have to be wider. Therefore, be sure to get washers that are no wider than 1”.

• If your are drilling counterbores - I recommend doing that first before you drill the longer holes. To drill the counterbores,  I used a 1 1/8” Forstner bit to accommodate my roughly 1” wide washer, and to drill the longer hole for the bolt – I used a ½” bit since I am using ½” bolts. The bolts I used are 3” long – but I should have used 3.5” so that I would not have to drill such a deep counterbore.

Step 11: Now Drill Holes for the Rope Cleat

• Temporarily mount one of the Pillow Block Bearings on one side of the unit, and then insert one hitch pin through the opposite side through the PRIMARY holes (the ones aligned with your rack’s holes).

• This will tell you where you can mount the rope cleat without interfering with the Bearings or hitch pin. Once you determine the position, mark it with a pencil (i.e., draw a widthwise line on the front and back of the 16 long piece of lumber). Trace the hole position of the rope cleat onto the line you just drew.

• The Rope Cleat I used was designed for  ¼” bolts. I used 4” long bolts so that they do not stick out.

• Now that you have marked the hole position, use a Forstner bit so that the washer and lock nut we will add later will be recessed in the wood.

• Since the ¼” washers I used are approximately ¾” wide – I used a ¾” Forstner bit, and then drilled through the center of the hole made with the ¾” Forstner bit, using a smaller bits, but gradually increasing in size until I was using a ¼” drill bit.

Step 12: Now you can paint or stain the wood

•  I only painted the outside area. I did not paint the area which will rub up against the rack – because I don’t want paint blemishes on my rack. Duh!

Step 13: Mount the Rope Cleat

• Again – I used ¼” Bolts. Therefore I also used ¼” Washers (Approximately ¾” in diameter), and ¼ Nylon Lock Washers.

Step 14: Assemble to flywheel mechanism

• Rather than writing all this out here -  refer the graphic below. The BLUE triangles represent the order of the steps. The purpose of each component is explained in the YouTube video.

Step 15:  Cut off excess length on the Threaded rod

• Leave enough space to add more plates if you like. That being said, you do not have to cut off any excess if you don’t want to – But I suggest that you do.

• Try to cut straight so that the existing  threads are not damaged – so that you can remove the nut in order to add/remove plates.

• There are multiple ways to cut it – but the easiest way (for most people) is to cut using a metal cutting disc on a grinder. Once you have cut off the excess swap the cutting disc with grinding wheel. Grind it so that there are no sharp edges – but again try not to damage the existing threads.

Step 16: Add Rope

• Use whatever type of rope that you want. I used paracord (AKA 550 Cord) because thinner rope is easier to tie TIGHT knots with. However, I may experiment with other rope types and do an update video in the near future.

• The length of this rope is entirely up to you. The determining factor will b : What is the maximum distance you want to stand away from the unit. Whatever that number is – double it (and add some extra inches to tie the knots). In other words,  you want to stand 15 feet away – then you need 30 feet of rope.

• After cutting your desired length or rope, burn the ends with a lighter to prevent fraying.

• Take one end of the rope, tie it to the rope cleat, and then wrap up the excess rope onto the cleat.

•  Now take the other free end of the rope and  tie a good, tight knot in between the two rubber grommets on the threaded rod.

• Finally, tighten the nut labeled “A” in the GRAPHIC ABOVE so that the rope is pinched/secure. Then tighten nut “B” so that the washer in between Nuts A and B cannot move.

• To tighten nuts – you can use some “grippy” shelf liner or rubber gasket and a pair of Vise Grips. The Rubber Gasket/Shelf liner will protect the threads from getting damaged. The Vise Grips keeps the threaded rod in place so that you can tighten the nuts down with a wrench.

• Question: Instead, could you drill a hole in the threaded rod for the rope to go through - instead of pinching it with the grommets/nuts — In other words: Feed the rope through the hole and tie a knot?

  • Answer: This is what I was originally going to do, but then I thought about a sharp metal hole constantly rubbing against the rope….so I came up with another method. That being said…it would likely be easier (no tools required) to add rope than using my method. Each method has its pros and cons.

Step 17: Add Pulley

• The pulleys I used are great because they swing open to add it to your rope. Once added secure it with a carabiner, add your favorite attachment to the carabiner…and exercise!

• As described in the video – you can also keep the unit mounted low – but pull DOWNWARD– by mounting the pulley to your upper cross member with a hitch pin, welded ring, a washer (wrapped in electrical tape), and lynch pin. Rather than describing it all over again – just watch the video. I think I did a good job explaining it there.

SHOPPING

 To Purchase the supplies for this project via Amazon, click here: https://amzn.to/3XTOjhj

Here: is a List for the basic setup:

• ONE 24” Long ¾” Threaded Rod

• TWO ¾”Pillow Block Bearings

• FOUR 3.5” Long ½” Bolts (with EIGHT ½” ID 1” OD WASHERS and FOUR ½” Lock Nuts)

• TWO HITCH PINS (Racks with 1” Holes need 1” Hitch Pins, 5/8” Holes need 5/8” Hitch Pins

• TWO Lynch Pins (For Hitch Pins)

• THREE ¾ Rubber Grommets

• Paracord

• TWO Welded Rings

• ONE Rope Cleat (with appropriate Fasteners, I used ¼” Bolts, ¼” ID ¾” OD washers, and ¼”Lock Nuts)

• FOUR ¾” ID Washers, and at least 2” OD

• SIX ¾” Lock Nuts

• Grippy Shelf Liner (2-3 feet)

• ONE-TWO Weight Plates with 1” Holes

• ONE Snatch Block Pulley

• ONE Carabiner

• ABOUT 45” of 2x6 LUMBER (With Wood Glue, 2.5” Screws, and 3” Screws)

• Forstner Bits/Spade Bits/Standard Wood Bits (Sizes depend upon you Hole Sizes, I used 1 1/8” and 3/4” Forstner/Spade Bits)

• Electrcial Tape

• ¾” Schedule 40 PVC (Just a few inches worth to make spacer for the 1” holes in the plates)

• 1” Schedule 40 PVC - 2-3” inches (I This is to make the roller if using 1” hitch pins. Again - don’t use 1.25” PVC like I did. Further, if you are using 5/8” hitch pins - I am not sure what size of PVC fits tightly on them. Next time I go to the Hardware store I will figure this out and update this article.

• Paint/Stain

• Metal Cutting Disc for Grinder

• Metal Grinding Disc for Grinder

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