I bought this with my new upgraded trailer tires (Goodyear Endurance). Overall trailer length is 30 feet (hitch with spare tire) and the monitors work great. My only (very small) issue is that it's too easy to switch it from PSI to Bars - just hit the wrong button once. When this first happened I thought the tire pressure suddenly dropped from over 60psi to 44psi (actually it was 4.4 but you can't see the decimal while driving). Worse, once I found out what happened I couldn't find how to get it back into PSI. The document that came with the kit doesn't mention this and the instructions available online are wrong for this model. In the end I managed it through trial and error.