diff --git a/src/karts/xml_characteristic.cpp b/src/karts/xml_characteristic.cpp
index 82c0b5d0d..99be54e41 100644
--- a/src/karts/xml_characteristic.cpp
+++ b/src/karts/xml_characteristic.cpp
@@ -212,8 +212,9 @@ void XmlCharacteristic::processFloat(const std::string &processor, float *value,
     std::size_t pos2;
     while ((pos2 = processor.find_first_of(operators, pos)) != std::string::npos)
     {
-        parts.push_back(processor.substr(pos, pos2));
-        operations.push_back(processor.substr(pos2, pos2 + 1));
+        std::string s = processor.substr(pos, pos2);
+        parts.push_back(processor.substr(pos, pos2-pos));
+        operations.push_back(processor.substr(pos2, 1));
         pos = pos2 + 1;
     }
     parts.push_back(processor.substr(pos));
@@ -224,15 +225,15 @@ void XmlCharacteristic::processFloat(const std::string &processor, float *value,
     // If nothing preceeds the first operator, insert x
     if (parts[index].empty())
     {
-        if (!*is_set)
+        // - is a special case: We don't take e.g. "-5" as relative, it
+        // describes a negative number. So 
+        if (!*is_set && operations[index] == "-")
+            *value = 0;
+        else if (!*is_set)
         {
             Log::error("XmlCharacteristic::processFloat", "x is unknown");
             return;
         }
-        // - is a special case: We don't take e.g. "-5" as relative, it
-        // describes a negative number
-        else if (operations[index] == "-")
-            *value = 0;
         else
             *value = x;
     }