# 8 string Truss rod



## Empryrean (Dec 11, 2009)

How many do 8 string guitars need? My friend was very persistent in convincing me that since 5 string basses(apparently) use 2 truss rods, that 8 string guitars would obviously need 2. Honestly I thought bs, but I'd rather be informed than ignorant.


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## CooleyJr (Dec 11, 2009)

My Intrepid has 2. I believe the rg2228 has 2. I think the reason most 8s nowadays have 2 truss rods is for more stability for both sides of the neck instead of having just 1 truss rod doing the work that 2 should be doing.


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## Galius (Dec 11, 2009)

I know the schecter I had for awhile had only 1. Mabey its needed for the longer scale length instruments.


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## Empryrean (Dec 11, 2009)

Would you need 2 truss rods for a baritone 8 string?, Do they have to be parallel?(I'm just curious; if not perfectly parallel, would it cause serious problems?)


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## troyguitar (Dec 11, 2009)

My 9-string only has one but it's got a very thick neck. I don't know if 2 is necessary, but it can't hurt.


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## Empryrean (Dec 11, 2009)

troyguitar said:


> My 9-string only has one but it's got a very thick neck. I don't know if 2 is necessary, but it can't hurt.



Ah, I was hoping you would chime on this Troy. How thick would you say?


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## MaxOfMetal (Dec 11, 2009)

I think there are a lot of factors to consider, such as width of neck, thickness of neck, and length of scale to say the least. Another factor would also be if the neck had any carbon/steel support rods in it.


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## metalfoundry (Dec 11, 2009)

If this can help, I know that Blackdroid guitars only use a single rod...

But its adjustable from the heel portion of the neck... 



Edit: I believe also blackmachine only use a single rod...


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## Ben.Last (Dec 11, 2009)

From what I've heard, the main reason to go with 2 rather than 1 on a guitar with a wider neck is not for stability but rather to allow for the possibility of adjusting the highs and lows slightly differently. Since there's a wider range there's a bigger possibility that a truss rod, properly adjusted to optimize the low F3, for example, will not be optimized for the high E


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## GazPots (Dec 11, 2009)

The Rg2228 only has 1 truss rod.


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## Durero (Dec 11, 2009)

I've not heard of any 5-string basses that use two rods. Can your friend name any models?


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## Elysian (Dec 11, 2009)

Definitely not necessary.


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## Adam (Dec 11, 2009)

Elysian said:


> Definitely not necessary.




The two 8 strings I built only needed 1 and they both had thin necks, but my 11 needed 2.


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## troyguitar (Dec 11, 2009)

Empryrean said:


> Ah, I was hoping you would chime on this Troy. How thick would you say?



Just over 1", like 1.05"

I plan to make the next one very thin (probably ~.75") with one truss rod just to test this very concept.


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## Elysian (Dec 11, 2009)

troyguitar said:


> Just over 1", like 1.05"
> 
> I plan to make the next one very thin (probably ~.75") with one truss rod just to test this very concept.



I still need to finish my 8, but the neck is around that, maybe slightly thinner(due to fretboard mainly), but it seems pretty strong right now. It's been out in the shop for months, and is still straight.


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## plyta (Dec 11, 2009)

I think it depends on the construction of the neck itself, is it one piece or laminate, maturity and breed of the timber used, length of the neck (scale), presence of any additional reinforcements (carbon strips)...

I doubt 2 rods are for extended adjustment though. Somehow I'm thinking you'll end up with fractured or deformed neck if you try to set the rods for different concaveness on the bass and treble sides, I keep concaveness +/- the same on bass and treble sides of my Intrepid neck.


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## canuck brian (Dec 11, 2009)

I just use the one.


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## Elysian (Dec 11, 2009)

plyta said:


> I doubt 2 rods are for extended adjustment though. *Somehow I'm thinking you'll end up with fractured or deformed neck if you try to set the rods for different concaveness on the bass and treble sides*, I keep concaveness +/- the same on bass and treble sides of my Intrepid neck.



Not at all.


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## flo (Dec 11, 2009)

My eightstring neck is about 19mm, and has got one trussrod, the tension is far from the limit. 
I haven't heard about fivestring basses with two rods either...


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## Empryrean (Dec 11, 2009)

Durero said:


> I've not heard of any 5-string basses that use two rods. Can your friend name any models?





flo said:


> I haven't heard about fivestring basses with two rods either...



That's why I thought he was just bsing me, so single truss should be fine and dandy no?


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## AlexThorpe (Dec 11, 2009)

The only five string bass I can think of with two truss rods would be the Rickenbacker 4003s5. But hell, even there four string models have two truss rods.


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## Ram150023 (Dec 15, 2009)

Where would one go to get a truss rod for and 8 string??? i'm venturing into custom building on my own since a manufacturer who will remain un-named, took my ideas i sent to them for a one off custom 8 for myself and is now mass producing it... and im certainly NOT gonna pay for it!!!


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## Tom Drinkwater (Dec 15, 2009)

I get most of my trussrods from www.stewmac.com and www.wdmusic.com. 

I don't believe that an 8 string would need more than 1 rod unless it had a really wide neck 3.5" or more. The truss rod holds the neck in the correct relief, if you need the neck to be stronger use carbon fiber rods. They are also available through stewmac. 

Some advice regarding ERG's and adjusting the truss rods-
1) Clamp the guitar to a table or workbench
2) Loosen the truss rod completely so the rod isn't tensioned
3) String and tune the guitar
4) Manually adjust the neck by hand or with a clamp or shims, not by tensioning the rod or rods
5) Take up the slack in the rods slowly until they hold the neck which should be in the correct relief
6) Unclamp the guitar and retune

This is how I adjust my own guitars and the guitars that I build for customers.


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## Ram150023 (Dec 15, 2009)

Awesome! Thx Tom!! I will definitely have to investigate further to get ALL the notes i need. Question though... is there specific lengths or truss rods for an ERG?? Or will... say a strat truss rod... work for my custom?? My idea (without going into detail) will be a neck through 8 string... either a Maple/wenge or ash/wenge mix... 27" scale, 24 fret... i will definitely take pix of the build process and get them posted here! again thanks!


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## hairychris (Dec 16, 2009)

My 2 cents...

Agile use 2 on the Intrepid but that's based on a 6 string bass.
Doug Blackmachine used (99% sure) 2 on his 1st prototype but _all_ other 8 have been single, both fan and 30 inch scales. Not enough extra tension from the bass string to move a rigidly constructed neck IIRC.

The Agile is IMO overkill, especially with a laminated neck.


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## ViK-master (Dec 26, 2009)

Durero said:


> I've not heard of any 5-string basses that use two rods. Can your friend name any models?



Ibanez BTB5 series.

BTW, I'll be using two truss rods on Black Lotus 8 Baritone just in case to be able to make more suitable adjustments on both sides of the neck.


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