Flatwound String Height

[garyt]

I just changed strings on my Stingray V for a set of Rotosound flats .  I’ve never tried flats before so am a complete novice, however when trying to set up, the lowest string height I can get is 2.75mm on the G, and 3mm on the low B.  This is with the G and B string bridge saddles wound right down.  Neck relief is 0.25mm at the 7th fret.   All strings appear to be sitting in the nut and bridge correctly, and I have pushed the strings down to check there is no movement.  
Is this normal?  Why should flats affect string height? 
 

[hooky_lowdown]

Because flats are higher tension than rounds. Roto flats are the highest tension strings of all flats.

Tension and guage can affect string height. However, your action (string height) is a personal preference. There is no right or wrong string height.

The higher the tension, the lower the string height can go without fret buzz.

[Bigguy2017]

Try tightening the truss rod a quarter turn - any better at all? 

Neck should (!) now be nearly straight... check the neck bolts are not loose.

If the action is still too high, ) you will need a small shim in the neck pocket to tilt the neck back a little bit.

[garyt]

21 minutes ago, Bigguy2017 said:

Try tightening the truss rod a quarter turn - any better at all? 

Neck should (!) now be nearly straight... check the neck bolts are not loose.

If the action is still too high, ) you will need a small shim in the neck pocket to tilt the neck back a little bit.

Thanks - neck bolts are tight.  I did have to tighten the truss rod, and noticed I will need to do this again as the neck is more concave after settling overnight. 
I also had to make some major adjustments to the intonation.

The string height is playable, but just wondered why flats would prevent them going any lower.  If I had to resort to neck shims, I’d just go back to rounds. 

[garyt]

9 hours ago, hooky_lowdown said:

Because flats are higher tension than rounds. Roto flats are the highest tension strings of all flats.

Tension and guage can affect string height. However, your action (string height) is a personal preference. There is no right or wrong string height.

The higher the tension, the lower the string height can go without fret buzz.

Thanks - the string height is playable, but is higher by default than rounds so just wondering if this was common.  
There is no fret buzz but I can’t get the strings any lower as the bridge saddles are at their lowest setting.   I don’t think 2.75mm is too high, just find it odd, that it’s the lowest they can go.

 

[Reggaebass]

I’m no expert btw 🙂, I only use flats and I like an incredibly low action, it sounds like the higher tension has pulled the neck a bit further forward, a few tweaks to the truss rod should do the trick