Bridge replacement-Not exactly the same size=help

[panos]

Hi all,
I want to replace my bridge because the string height at the end of the fingerboard is too low. My current bridge is a 3/4 Auber having the exterior leg width 145mm.
I ordered a 3/4 Despiau bridge, and these days I've started to prepare this bridge for the replacement.

I realised that the new bridge has the exterior leg width 150mm (5mm more than the old one). The distance also from one center to the other center of the foot is 103mm for the old one and 109mm for the new one.

I'm wondering what is the right thing to do.
If I proceed to the replacement finally, this will cause any problems, changes or possible damage to the top?
I'll greatly appreciate your help!

[RCWilliams]

I would suggest installing adjusters, that way you can adjust as the seasons change.

[Eric Hochberg]

Yes, adjusters will let you increase the height of the old bridge, maybe to a satisfactory level. You need a luthier to check out whether or not the new larger bridge will "fit" your bass and sit correctly over the bass bar area. Assuming your old bridge is of the correct size for your bass, adjusters on it may be the best way to go. Of course, fitting a new bridge will be more costly than adding adjusters to your old bridge.

[panos]

Originally Posted by ehochberg

You need a luthier to check out whether or not the new larger bridge will "fit" your bass and sit correctly over the bass bar area. Assuming your old bridge is of the correct size for your bass, adjusters on it may be the best way to go.

I read that the correct position of the bridge foot is to sit on the middle of bass bar (assuming that the bridge is posed symetrically on the top).
If this is right generally, then it seems that the middle of the E foot of the new bridge comes closer to the middle of the bass bar. (After measurements I did, I found that the distance from the middle of the bar to the mid-point of the bass is 57mm,
old bridge is 103:2= 51,5mm and
new bridge 109:2= 54,5mm).
Maybe new bridge is more proper?

About adjusters: I don't want to install them at this time, and if I decide to do it, the only one luthier in my country is 400 miles far from the island I live...

[Jake deVilliers]

Panos, either way you're not going to destroy your bass.

It sounds as though the original bridge may be a little narrow for your bass too. If you don't like the way the new bridge works, you can always put your old one back on, right?

[KSB - Ken Smith]

One thing here I don't see mentioned is the upper eyes of the F holes. It is important that this measurement be taken into consideration as well as the Bass Bar.

I will show 3 examples below.

One (a S.Gilkes), the Bridge is correctly centered and the Bass Bar was recently replaced by the same Luthier so he was familiar with the Bass and its tonal needs as well as structural.



*Notice how the outer feet of the Bridge line up perfectly just inside the upper eyes of the FFs.

The second had a Bridge that was way too wide for it and it contributed to pushing the Top in and opening up one of the Top cracks udder the G side F wing. The eyes of this Italian Bass are close together measuring only about 145mm. The Bridge measured 180mm. Way to wide for this Top. The string length was 44 1/2" so the previous owner put a 4/4-5/4 size bridge on it ignoring the FF widths and damaged the Top. 145-150mm is the maximum this Bass should have at the feet.




*Note how many cracks are visible to the naked eye in this pic above. This Bass seriously needs the correct sized bridge. To use the Bass temporarily while it awaits its restoration, I have trimmed the outer feet 5mm each to take some of the excess pressure off the Top. This little bit has actually helped in the sound.

The third is actually a 4/4 sized Bass with the upper F eyes to match measuring about 190mm+. The Bassbar however is in quite a bit so the estimated bridge feet width will be 165mm. This is what it needs to center over the Bassbar. Perhaps this is best as this Top is over 200 years old and had never sunk in at all. Its tight grain also contributes to its strength.



*On this Bass currently Bridgeless and in restoration, it is clearly seen that the previous placement of the Bridge was well inside the width of the upper F eyes almost 10mm each side of the upper F eyes. The Bridge that came with the Bass was about 180mm. With the Bass bar further in, this Bridge while not at all to0 big for the Bass was too wide for the 'bar placement.




Panos, on your Bass 145mm or 150mm is not as important as which fits your Bass best. With such a small difference (2.5mm per side) I don't think it's much of an issue. Measure the upper Eyes and go from there. Better too narrow than too wide. However your measurements from the center of 103mm-109mm on the bigger bridge tell me the difference might be 5mm per side and not 5mm overall. Check again but also, 5mm total over it not a huge problem.

[panos]

I thank you all for your posts.
Ken, the distance between the upper eyes is 150mm, so I think it's ok to proceed. I also verified again all my others measurements.

[KSB - Ken Smith]

Originally Posted by panos

I thank you all for your posts.
Ken, the distance between the upper eyes is 150mm, so I think it's ok to proceed. I also verified again all my others measurements.

Sounds like you are set to go. Either bridge should work physically but it's possibly that one will sound better depending on the Bar and Post placement under the feet. Only the Post can be adjusted hence the reason for the correctly sized Bridge.. Best of luck.