If the seat you received with your used kart isn't big enough, or you slop around in it and need something more snug, then buying a new seat is probably the best solution. While larger seats can be padded out with seat padding (you can find plenty of options in our store by CLICKING HERE) this is only achievable if the difference is small, and using too much padding or padding without enough support won't solve the issue. You also can't make a small seat bigger (although you can remove some of the seat spacers between the seat and bars to try to stop the seat from being compressed) this usually doesn't provide very much extra room.
The best way to determine if a particular seat in our range will fit, is to sit on a flat seat and measure the distance that you take up on the seat. This will approximately equal the measurement C in our pictures.