String gauge when moving from round wound to flats

[bigfishsmallworld]

Just recently bought my first set of flat wounds. I bought the same gauge as my last round wounds 105-45. As the tension feels higher on these strings do I either need to adjust the truss rod or should I have bought a gauge lighter?

[BlueMoon]

My advice would be to change the strings and then check if the truss rod needs adjusting. Actually, it may not need adjusting. If you have never adjusted a truss rod it will be a great time to learn. It really is not that difficult.

 

Welcome to the flat-side!!

[Reggaebass]

I’d try them first and see how your action is, you might not need to adjust anything depending on your bass , some flats are higher tension than others , which ones did you get 

[fretmeister]

I always go lighter on flats if I can.

[PaulThePlug]

What Brand?..

I've only ever used Adagio and Olympia Flats, (which i think are the same) 45-100...

Described as Standard Tension... maybe a little higher than a 45-105 set.

Stick em on... might need to back of the truss rod a smidge.

Welcome to the Smooth Side...

[chris_b]

I switched from DR Lo-Riders to TI flats on my PJ5 and didn't have to touch the truss rod. That's 130's on the round wounds and 136 for the TI low B. I always use the fattest strings I can find. I think they give me a better tone.

 

I play lightly so tension and string size isn't an issue for me. 

[garyt]

You can see if you need to adjust the truss rod by checking the neck relief.  
I had to adjust action and truss rod a tad when changing to flats , but had to make big adjustments to the intonation.