diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,11 @@
 # CHANGELOG
 
+- 0.2.8.1 (2025-01-28)
+    * Fix performance issue in OrdPSQ relating to balancing (#61).
+    * Relax hashable upper bound to 1.5
+    * Relax QuickCheck upper bound to 2.15
+    * Relax tasty-quickcheck upper bound to 0.11
+
 - 0.2.8.0 (2022-10-27)
     * Add a number of minor optimizations and INLINE pragmas:
         - The previous `INLINABLE` pragmas were insufficient to fully specialize
diff --git a/psqueues.cabal b/psqueues.cabal
--- a/psqueues.cabal
+++ b/psqueues.cabal
@@ -1,5 +1,5 @@
 Name:          psqueues
-Version:       0.2.8.0
+Version:       0.2.8.1
 License:       BSD3
 License-file:  LICENSE
 Maintainer:    Jasper Van der Jeugt <jaspervdj@gmail.com>
@@ -68,7 +68,7 @@
     Build-depends:
           base     >= 4.2     && < 5
         , deepseq  >= 1.2     && < 1.6
-        , hashable >= 1.1.2.3 && < 1.5
+        , hashable >= 1.1.2.3 && < 1.6
 
     if impl(ghc>=6.10)
         Build-depends: ghc-prim
@@ -144,10 +144,10 @@
 
     Build-depends:
           HUnit            >= 1.2 && < 1.7
-        , QuickCheck       >= 2.7 && < 2.15
+        , QuickCheck       >= 2.7 && < 2.16
         , tasty            >= 1.2 && < 1.6
         , tasty-hunit      >= 0.9 && < 0.11
-        , tasty-quickcheck >= 0.8 && < 0.11
+        , tasty-quickcheck >= 0.8 && < 0.12
 
         , base
         , array
diff --git a/src/Data/OrdPSQ/Internal.hs b/src/Data/OrdPSQ/Internal.hs
--- a/src/Data/OrdPSQ/Internal.hs
+++ b/src/Data/OrdPSQ/Internal.hs
@@ -515,16 +515,14 @@
 lbalance, rbalance
     :: (Ord k, Ord p)
     => k -> p -> v -> LTree k p v -> k -> LTree k p v -> LTree k p v
-lbalance k p v Start m r        = lloser        k p v Start m r
-lbalance k p v l m Start        = lloser        k p v l m Start
 lbalance k p v l m r
+    | size' r + size' l < 2     = lloser        k p v l m r
     | size' r > omega * size' l = lbalanceLeft  k p v l m r
     | size' l > omega * size' r = lbalanceRight k p v l m r
     | otherwise                 = lloser        k p v l m r
 
-rbalance k p v Start m r        = rloser        k p v Start m r
-rbalance k p v l m Start        = rloser        k p v l m Start
 rbalance k p v l m r
+    | size' r + size' l < 2     = rloser        k p v l m r
     | size' r > omega * size' l = rbalanceLeft  k p v l m r
     | size' l > omega * size' r = rbalanceRight k p v l m r
     | otherwise                 = rloser        k p v l m r
@@ -653,7 +651,8 @@
     not (hasDuplicateKeys t)      &&
     hasMinHeapProperty t          &&
     hasBinarySearchTreeProperty t &&
-    hasCorrectSizeAnnotations t
+    hasCorrectSizeAnnotations t   &&
+    hasBalancedTreeProperty t
 
 hasDuplicateKeys :: Ord k => OrdPSQ k p v -> Bool
 hasDuplicateKeys = any (> 1) . List.map length . List.group . List.sort . keys
@@ -696,6 +695,21 @@
     calculateSize (LLoser _ _ l _ r) = 1 + calculateSize l + calculateSize r
     calculateSize (RLoser _ _ l _ r) = 1 + calculateSize l + calculateSize r
 
+hasBalancedTreeProperty :: OrdPSQ k p v -> Bool
+hasBalancedTreeProperty Void = True
+hasBalancedTreeProperty (Winner _ t _) = go t
+  where
+    go Start = True
+    go (LLoser _ _ l _ r) = withinOmegaFactor l r && go l && go r
+    go (RLoser _ _ l _ r) = withinOmegaFactor l r && go l && go r
+
+    withinOmegaFactor t1 t2 = u < (l + 1) * omega
+      where
+        (l, u)
+            | s1 < s2 = (s1, s2)
+            | otherwise = (s2, s1)
+        s1 = size' t1
+        s2 = size' t2
 
 --------------------------------------------------------------------------------
 -- Utility functions