Double Bass Bridge Slipping with Labella Jazz Strings

[The_Greek_Flame]

Hello,
I've been having some issues being able to reinstall my bridge. Every time I tighten the strings to tune them, I play the bass for no more than 15 minutes and the bridge slips upwards towards the top of the bass. I'm using Labella Jazz Black Nylon Wound strings and they've been working great for a good couple of months until they started making the bridge slip. If anyone has any ideas why this is occurring that would be amazing.
Thank you!

 

[KUNGfuSHERIFF]

Are you holding the crown of the bridge in place while you tune?

How well are the bridge feet fitted to the top?

Is the bridge warped?

Photos would be helpful.

 

[DoubleMIDI]

Maybe the bridge grooves for the strings are a bit narrow or not rounded. So the string might be clamped or an edge grips into the string. The string needs to be able to slip over the bridge. Putting graphite on the grooves helps, but only when the slots are wide enough and well rounded.

 

[robobass]

I once found my bridge gradually tilting north after I got it back from the shop. There had been much work, including new strings, bridge, and tailgut. Over weeks the tuning would always be slightly flat when I unpacked it each morning. I couldn't figure it out. One day I started tuning up and the tension totally dropped. Turned out that the new fancy synthetic tailgut had been gradually failing, and eventually let loose. Your problem might have nothing to do with the strings themselves.

 

[JoeyNaeger]

I once found my bridge gradually tilting north after I got it back from the shop. There had been much work, including new strings, bridge, and tailgut. Over weeks the tuning would always be slightly flat when I unpacked it each morning. I couldn't figure it out. One day I started tuning up and the tension totally dropped. Turned out that the new fancy synthetic tailgut had been gradually failing, and eventually let loose. Your problem might have nothing to do with the strings themselves.

Yikes! It actually broke? I've seen some tailpieces explode, but have yet to encounter a broken tailgut...

 

[The_Greek_Flame]

I finally figured it out, I sanded out deeper grooves into the bridge and it completly fixed the issue. Thank you all for the advice!