Ok here is the deal with "Long Scale" strings on a "Short Scale" Bass.
In short... The strings are the same* The difference is from the scale length of the instrument. If you have a .105 string 60" long, and have two points in which the string pivots (call it a Nut and a Saddle) this will create a vibrating length in the middle of the string. If that Vibrating Length was 36" long the string would be a specific tension to vibrate in E. If you reduce that length to 34" the string will be a little lower tension to vibrate in E. Reduce it even shorter to 30" and the string will be even lower to vibrate in E. Keep in mind the over all length of our 60" string has not changed, only the "Vibrating Length" has changed. This is the same on a bass.
This is a fun thing to do if you have a Capo: Tune your instrument down a half step and place the capo on the 1st fret. Now your instrument will have the tension of close to a medium scale instrument! Tune down another half step and place the capo on the 2th fret and you now have a tension similar to a Short scale! (See how it works now?).
So really the strings on a Short Scale instrument and Long Scale instrument are the same it is just the vibrating length of the string (distance between nut and saddle) that determine the overall tension.
The reason for different strings between short and long scale instruments? Plain and simple... Fitment. If you put a string too long on a short scale instrument (even a long scale instrument) if the full winding of the string begins to wrap around the tuning post the string can and most likely will snap** and break.
There are some instrument manufacturers that claim that having an extended B-String is going to add more tension to the string, while really it is debated that it just helps with the installation and fitment of the B-string. This way you can use any B-String pretty much that is out there and you do not have to worry about the full winding going around the tuning post and breaking (extended b-string instruments usually have the B string tuning post where the A string tuning post is (at the end of the headstock rather than closest to the nut).
So the reason for * number 1? In the case of Thomastik-Infeld their strings have different gauges depending on the scale length of their flatwounds. They do this because they want the user to experience a similar feel of their strings regardless of the scale instruments they have them on. The Short Scale set has a .106 E, the Long Scale has a .100 E, the Super Long has a .096 E. Each E-string will have a similar tension to one another while installed on a Short, Long or Super long... (.106 Short Scale Instrument will feel like a .100 on a Long Scale instrument or feel like a .096 on the Super Long instrument... dig?)
**On the bass it is important with most string types that the full winding lengths do not go around the tuning post. Not all bass strings are very flexible so they can break when bent to much. Low-B strings are notorious for breaking when the full winding is wrapped around a tuning post.
So overall the main reason for having the correct length strings on an instrument is for fitment. If you put long scale strings on a short scale instrument of say a 45-105 set, the .105 E-string will most likely break doing around the tuning post. But keep in mind the same .105 gauge string in a shorter length will yield the same result.
If you want your short scale instrument to similar tension of a 34 or 35" scale instrument you are going to need to up the gauges. Use the Thomastik-Infeld Jazz Flat set as a guide as to what I am getting at.
If you like a .105 on your 35" instrument, you will most likely need a .115 on your Short Scale instrument to have a similar tension. But that .115 is going to need to be the correct winding length for your short scale instrument otherwise it most likely will break going around the tuning post.
- overall string length does not determine tension, the vibrating length of the string (distance between nut and saddle) determines the tension.
- want a short scale to feel less rubbery? up the gauges!
- make sure the winding lengths are correct for your instrument
- more information on the correct winding lengths for your instrument here