Well, my Planet X Stealth Pro Carbon was irreparably damaged by airline baggage handlers, so I’m looking for a replacement and have settled on the P2 SL. I was riding a Medium Stealth (size 51), which had a 53cm top tube and 11cm stem, with the seat jammed pretty far forward. The size 54 P2 SL lists a 53cm top tube with the seatpost in the forward position, so I think this might be the right size. Anybody out there who wouldn’t mind giving me a steer in the right direction?
Thanks, but none of what you’ve suggested is necessary in my case. My PX fit perfectly the way I had it set up, so there’s no need for a fit calculator, FIST, etc. A test ride isn’t possible since I’m purchasing the frame from abroad. I was looking for someone who is familiar with both products to indicate whether a 54 P2 SL and size M Planet X Stealth are similar in terms of size. The top tube appears to be similar. The headtube on the P2 is 2cm longer, but I had 2cm of spacers on my PX, so that should work out fine. Other than that, I’m just not sure how to go about making sure the frame will fit.
Now THAT is a massive help! Thanks very much. To my amateur eye, it looks like I’d end up with an awful lot of spacers on the 51 P2SL, and that I should probably go with the 54, albeit with a slightly shorter stem. Is this about right?
Note that spacer figure includes the headset top cap so if the 20mm of spacers you quoted on the P-X is plus a 15mm cap then the 51 would have a bit of a skytower unless you also changed aerobars to get a higher pad stack.
I would incline towards the 54 and shorten the stem by 20mm