Tight Seatpost Installation I'm having a bit of a problem installing my seatpost. I have a 31.6mm carbon-wrapped aluminum seatpost which fit perfectly fine in my previous aluminum frame. Unfortunately, that frame cracked, but I found the exact make, model, and size frame on eBay to replace it. The only problem is that the seatpost doesn't fit into the seat tube very well. It is a very tight fit, and I can only get it down 1 1/4" before it gets really difficult, even with a bit of grease. The top of the seat tube doesn't appear to be crimped, so I'm not sure what the problem is. I'm a bit gun-shy since I've already broke a frame this year. So, I'm not sure whether to force it down, use a rubber mallet, or buy a new seatpost. How do I determine if it's possible to fit this seatpost in this frame safely? Is it possible there's something else interfering with the installation, or will I need to buy a new seatpost?

If they are the same make, model, and year frame and the proper sized seatpost will not insert into the frame more than 1-1/4" **then something is wrong.**
This one's hard to diagnose over the internet so I suggest you head down to a reputable bike shop and let them have a look at the frame before something gets mucked up irreparably.