Cracked frame

Typically when you get a warranty replacement item the warranty is NOT reset.

Good result

Glad you got a good result. TBH I'd be very suprised at any reputable brand not replacing the frame as the cost to them is minimal particularly when compared to the cost of good or bad publicity. When you think how much advertising costs the cost of doing the right thing as in this case is peanuts.

Will the new frame get an extended warranty?

The crack seems to be located at a potential stress point where the rear stays meet the seat tube.

result, will it only have the remaining warranty period of the original frame or reset?

It is just possible that the seat post (as supplied) is the wrong diameter. I know that has happened before, they go up in .2mm increments, and that will certainly lead to the issue you're seeing. It should be a pretty firm fit in the frame. Either way, still not your problem, get the retailer involved...

So where does the seat post end relative to the crack? If it’s way below, then that rules it out. If it’s right by the crack, that raises the suspicion of it being short. 

Alternatively, it just occurred to me on looking at the photos again,  this could be clamp damage from being in a bike stand if someone was silly enough to clamp it on the seat post.....

Under the consumer rights act, the manufacturer is not your problem, whoever you bought the bike off bears the responsibility (as it is them  you had the contract with). 

Other poster's opinion that the seat post length appears to be an issue looks correct to me. It appears that the bottom of the seat post has coincided with the connection in the frame with the seat stays. There's a number of reasons this might be an issue, but the important point here is that if you were sold the bike as a unit and advised by the shop it was the right size for you, a lay person can not be expected to know that the seat post was sitting at the wrong place for that frame if it was the right height for the person.  Seat posts have a minimum insertion mark, but carbon frames also have a minimum insertion depth as well (normally contained in the paper work with the new bike). This may be a manufacturing issue with the bike, or not. The acid test is:

Was it:

• suitable for purpose,
• as described (in advertising or claims by the seller)
• free from defects
• and last for a reasonable time (which is nothing to do with the warranty period).

Speak to the retailer you bought the bike off, mention the consumer rights act, and see if you can come to an arrangement about a replacement frame. Ideally, under the law, this should be at no cost to you, but all negotiations require both parties to be reasonable, so you might need to be prepared to bear a portion of cost going toward getting a new frame, but realistically the retailer should stand all costs of moving old componints etc to the new frame.

Alternatively you could find a good carbon frame builder / repairer as this looks to me to be a very repairable problem. Cosmetically it won't be perfect, but it looks repairable. I had a seat stay broken right through on my cannondale evo. I had it repaired. It's not visible, but you can feel the difference in tube diameter if you run your hand over it. The frame builder (who builds frames for olympic teams) was happy to guarantee the frame against failure at the point of his repair. Contrary to common opinion, carbon fibre is very repairable in many instances.

My first mountain bike (GT Tequestra) had a similar , but bigger, crack in the same place, caused from the bottom of the seat post trying to escape through the seat tube. That was helped by a crash though. 

I had a reinforcing sleeve welded on, and I kept riding for years more. 

Anyway, the point I was making is it looks like the bottom of the seat post, and I think a warranty claim would be bounced on that basis. 

The photos look like there was at least 3" in the hole (steady)...

Really?

Wouldn't that mean most riders with a lot of seatpost showing would be risking the same?

Looks like the reason is a too short seatpost you used. It’s a very common mistake.

That is very frustrating. You might try contacting someone higher up in the company concerned as they are more likely to be concerned about any bad publicity this could bring as well as any good publicity a positive response could engender.