4mm Allen Nut Hot Rod Truss Rod

  • 96 Reviews
  • Write a review

A smaller 4mm (5/32") Allen nut for most instruments. Smooth two-way action corrects upbow and backbow, giving complete control over the neck.

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12-1/4" overall length

Item # 2550
In stock, ready to ship!


6 or more $13.74
12 or more $12.95

14-1/4" overall length

Item # 2551
In stock, ready to ship!


6 or more $13.91
12 or more $13.11

18" overall length

Item # 2552
In stock, ready to ship!


6 or more $14.78
12 or more $13.93

24" overall length

Item # 2553
In stock, ready to ship!


6 or more $18.26
12 or more $17.21
Quantity Discount Prices apply when you buy multiples of the same item number.
Total: $0.00
Quantity: 20


A smaller 4mm (5/32") Allen nut for most instruments. Smooth two-way action corrects upbow and backbow, giving complete control over the neck.

Easy to install. The Hot Rod® fits in a straight channel. For proper operation, this truss rod must be installed so that the active rod (the rod with the adjustment nut) is below the passive rod. A wooden filler stick is not required.

Smooth 2-way action with superior strength for stubborn necks.
Our Hot Rod neck adjustment system features twin rods in threaded brass collars. The stainless steel active rod turns for smooth neck alignment, with 2-way action to correct upbow and backbow.

The Hot Rod requires an access cavity for the adjustment nut, and a straight 7/32"-wide x 7/16"-deep slot (measured from the bottom of the fretboard) for installation.

Pick the Hot Rod Truss Rod size you'll need:
(overall length includes the nut)

Resonator guitar
Acoustic guitar with 12th fret at the body
Acoustic guitar with 14th fret at the body
Electric guitar

We've designed the Router Bit for Hot Rod Truss Rods especially for routing your neck to fit our truss rods.

Product Instructions

Hot Rod Adjustable Truss Rods

Installation and adjustment instructions for Hot Rod Adjustable Truss Rod.

    • Item #
    • Weight
    • 2550
    • 0.197 lbs. (0.09 kg)
    • 2551
    • 0.232 lbs. (0.11 kg)
    • 2552
    • 0.296 lbs. (0.13 kg)
    • 2553
    • 0.385 lbs. (0.17 kg)

Ratings & Reviews

4mm Allen Nut Hot Rod Truss Rod

  • Based on 96 Reviews
Displaying 9 of 10 1 2 3 4 5 6 7 8 9 10
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Do the truss rod effect the sound?

By Mack Guitarworks from Hungary/Europe
(Customer's Reviews) Wednesday, February 16, 2011

Good truss rod for the beginner, because of the easy installation and routing. I built 3 of this design, but I like the original, gibson style much more. For my taste this design needs a very deep channel. If you hit the strings very hard, you can hear some truss-rod rattle from the neck. I can't figure out, how to eliminate this. I also don't like, that the fingerboard glue surface must be reduced, compared to the traditional method. I think, this effects the sound and the sustain.

I don't use any other brand now...

By B. Jesson from Chandler, AZ, USA
(Customer's Reviews) Wednesday, February 02, 2011

I used to use the martin style truss rods until I used the two-way hot rods. With the ability to adjust in both directions I don't have to worry about any curvature. The best part is if the rod gets damaged in anyway they are not too difficult to remove and replace if the neck and slot were built correctly. All my builds now use the Hot Rod truss.

Good thing I bought this one

By Steve Skinner from Kokomo, IN
(Customer's Reviews) Sunday, January 30, 2011

After finishing my last neck I noticed it has lost it's straightness in the direction away from string tension. By turning the nut counterclockwise I was able to take the curvature out of the neck in just a moment. First time I ever had a neck bow in that direction.


(Customer's Reviews) Saturday, January 29, 2011

I use the Hot Rod truss rod in all my guitars for me it is easy to install and works like a champ every time and has never let me down. I will continue to use it in all my custom builds Electric or Acoustic hands down its the best.

Thank you stewmac

By Michael Grannis from Phoenix, Az
(Customer's Reviews) Wednesday, January 19, 2011

A truly affordable product. Good size and adjust ability. Will certainly use again.

allen head truss rod

By D.M.Holzer Banjos from West Fargo, N.D.
(Customer's Reviews) Monday, January 17, 2011

i really like this truss rod and use it extensively in all my banjos. it's the ease of installing which i like. For the truss slot i know a router bit is suggested but what i do is use 3 circular saw blades on the table saw and make only one clean pass down the center of the neck. then i just drop the rod in and fill the rest of the truss rod channel. it is a nice fit and the allen head ensures no slippage when adjusting the rod. i want quality in my instruments and this rod is the one i prefer.

14-1/4" truss rod

By DhaenensGuitars from Aarschot, Belgium, Europe
(Customer's Reviews) Sunday, December 12, 2010

After trying out a few brands of other truss rods, I've used this type on all of my guitars. Excellent stuff!

not really happy ....

By Utopia Custom Shop from Alessandria -Italy
(Customer's Reviews) Tuesday, November 23, 2010

Sorry but I find the nut anchorage to the bar not enough resistant.

Others truss double action rod are more resistant in that zone

Hot Rod truss

By R Guess from North Florida
(Customer's Reviews) Tuesday, October 26, 2010

Well made, easy install and perfect fit using the Stew Mac truss rod router bit. I have used 6 now with very good results.


By James B. from Ontario Canada
(Customer's Reviews) Thursday, September 30, 2010

I have built 8 electrics with these and I find them convenient to install since they use just a flat bottom channel.

I had one shear at the adjuster once, which made me livid, but I was able to save the neck and replace the truss rod without removing the fretboard. Always lubricate the threads and test it before installing. Proceed with caution while adjusting any truss rod.

On Fender style necks, with the adjuster oriented just under the fret board, the tightening/loosening direction is opposite to conventional so watch out for that!!

Finally, I'm glad there is now metric adjuster sizes!!

Displaying 9 of 10
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Shown on page 72 of our latest catalog.
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