Warped Bass Bridge

Just what causes a bass bridge to warp?  There can be a few different reasons, though even the best, most dense and most seasoned bridges can warp.

We've noticed over the years that even some of the best known (better)  brand bass makers often will go on the 'cheap' when it comes to their bridges.  Most people (musicians and bass players alike) will often never think of or consider what kind of bridge they get or have until way after there are problems.

First, a bridge has to be a well seasoned (dry) wood of maple.  Maple has the proven quality of being one of the most dense woods and best conductors for sound and vibration.  In so many cases, when we get a new bass in our workshop, we are sometimes shocked by the lack of quality in some otherwise, expensive basses.  The best bridges are seasoned and stored for years before use.  That means that since all of the excess moisture has naturally evaoporated from the wood, it won't be subjected to drying type issues: premature shrinkage, warping, twisting etc... as the wood dries out while on the bass!

On a typical bass bridge with hundreds of pounds of force from the bass strings, if the wood is not dense and/or strong enough, it too will eventually warp and often quite quickly. 

Even the best French made bridges (like Aubert or Despiau) on the most expensive basses can warp.  This is often not caused by bad or inferior quality, but the cause in this case is usually when the bottom flat side of the bridge does not maintain a 90 degree angle to the top of the bass.  (For example, look at the side view of a bass and examine the angle of the bridge.  (Should always be 90 degrees.)  When players buy new strings and they are changed one at a time, the new strings will quickly stretch, which requires much tightening.  By tightening, you are pulling the string upwards in the direction of the scroll.  This constant direction eventually pulls the tip of the bridge over to an off balanced, off centered and puts incredible pressure on the middle of the bridge, causing it to bend over time.

Sometimes, the seasonal changes will naturally release the strings in one direction (in the winter) or pull them tighter (in the summer).  Players only need to lay the bass on its side and examine the angle again to make sure that the bridge remains at 90°.  If the angle seems to lean upwards (towards the fingerboard), or the other direction, you only need to carefully pinch or press the tip down (to correct the angle again).

Somestimes particular brand of strings can easily pull the bridge over too much, just by using the strings or tuning.  The Innovation strings (slap style) are a loose tension (so not pushing down too hard on the bridge) therefore make it easier to move and also because these strings all have round wound wrapping,  tend to hook or grab the bridge tip over very easily.

So there can be several causes for a bridge too warp: Thin, unseasoned wood, or cheap (light) wood will bend far easier.  Again, even the best bridges will warp if players don't keep an eye on the angles to make sure that they are still at 90°.