Do I need to measure the existing seat tube? I bought a GT avenger mtb.
To ensure compatibility, we would recommend measuring the existing seat tube in order to see if this would be a compatible match. The diameter of the seat post measures to be 1 inch. The length of the seat post is 1.25 inches long. Please note that if the seat post on your bike happens to be slightly smaller in diameter, this seat post does come with bolts that will enable the seat post to be adjusted onto the new seat. You will be able to secure it tightly into place so the new seat will not wobble or move out of place.