Two New Tenors have Upbow - Are Factory Strings Too High Tensioned?

[Wiggy]

I recently returned a new tenor "A" due to neck upbow.
I then purchased tenor "B" which has the same issue but not quite as bad.
Both are well-established brands in the $300 range. Both are solid cedar tops.

In both cases, the factory "Aquila" strings were very tight.
In both cases, I changed to a custom (by me) lower tension set.

Neck A did not improve with lower tension, thus it had to be returned. It was severe.
Neck B got visually flatter with lower tension strings, but upbow still exists as can be easily seen with a metal straight edge.

Are the factory (what I consider) high-tension strings the culprit?
I will likely have to return tenor B. I don't want to send it back because it sounds heavenly, but... there is a definite time limit.

 

[Larry U]

A well-built ukulele should be able to handle normal ukulele strings, either high or low tension, without physically distorting the neck. Unless you're stringing it with steel guitar strings(!), it's either a design flaw or a construction defect. I'd return both instruments.

 

[Wiggy]

A well-built ukulele should be able to handle normal ukulele strings, either high or low tension, without physically distorting the neck. Unless you're stringing it with steel guitar strings(!), it's either a design flaw or a construction defect. I'd return both instruments.

I agree. I returned one. I'll have to return the other. Sadly

 

[anthonyg]

There is nothing, technically wrong with a little up bow in a neck. Some may say that its an advantage. It comes down to just how much up bow we are talking about.
There's no guarantee that a neck that is dead flat now will always remain dead flat, and if in fact it back bows, then this is particularly BAD.

So, is there something you can't play because of the up bow?
Is the nut height correct?
Is the saddle height correct?
Lots of questions, yet I'm all good with a little up bow in a neck.
So, just how much up bow are we talking about?

EDIT: For the record, Tenor ukulele's are always over tensioned at g,C,E,A tuning. That goes without saying.

 

[Wiggy]

I was adjusting the nut slots, where I loosen each string to file, when I noticed the upbow. With all strings loosened the clearance started at 2.5mm. But "at tune" it went a little over 4 under string #1 and about 3 under #4. That is upbow with a twist and was too flexible for me. Lowering the saddle will not fix that. If it were minimal, even, and stable, I certainly would have kept it.

It feels really good in hand and cedar has become my most-played. I will purchase Ordered another with the refund.

 

[anthonyg]

OK, well a twist isn't good.
Giving good advice in these situations, all comes down to the numbers.

 

[ploverwing]

cedar has become my most-played

I am definitely in the cedar fan club. I'm glad you'll get a replacement.

 

[70sSanO]

Most steel string guitars have neck relief, upbow. Electrics are around .009” if I recall correctly. It is adjusted with the truss rod.

I vaguely remember years ago in the luthiers sub-forum that “if” there is any neck relief built in, it is around .004” (?). I don’t remember exactly but it was basically flat.

Relief is usually only an issue if you run the string height low, sub 2mm.

John