diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
index 05cd10095..62206c69c 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackBitmapIndexBuilder.java
@@ -115,6 +115,10 @@ public class PackBitmapIndexBuilder extends BasePackBitmapIndex {
 						JGitText.get().badObjectType, String.valueOf(type)));
 			}
 		}
+		commits.trim();
+		trees.trim();
+		blobs.trim();
+		tags.trim();
 	}
 
 	private ObjectToPack[] sortByOffset(List<ObjectToPack> entries) {
@@ -168,6 +172,7 @@ public class PackBitmapIndexBuilder extends BasePackBitmapIndex {
 	 */
 	public void addBitmap(
 			AnyObjectId objectId, EWAHCompressedBitmap bitmap, int flags) {
+		bitmap.trim();
 		StoredBitmap result = new StoredBitmap(objectId, bitmap, null, flags);
 		getBitmaps().add(result);
 		byAddOrder.add(result);