I have apparently found an issue with the design. My seat is set in the back position and the top tube has worn through the plastic where the seat frame contacts the tube. When the large chain ring is used on the front and rear pressure is put on the top tube causing the chain to wear through the plastic exposing the chain and then rubbing on the metal seat bracket. This is a new issue and there is not a fix at this time. I found this when I removed the seat to wash the trike. I have 980 miles on my RAT as of Oct. 6. Check your top tubes for wear.