I am looking for a Speedmax CF SLX with the following coordinates.
Pad Y: 700 Stack
Pad X : 510 reach
I am 183cm tall and my saddle height is about 790. I use a 172.5crank. I have attached a simple drawing.
Presently, I am using a Speedmax CF SL L size. The measurements above are taken off the the current bike.
Based on what i have seen in this thread, the 700 seems quite high for someone my height. Measured the stack couple of times, and thats what i got.
Please help me decide if the L size is what i need to go with for the SLX.
Really good drawing, helps confirm, thanks for including that.
A Pad Y of 700 is high. If I just took the numbers you gave me (height, saddle height) I'd predict your Pad Y to be 635-655. You and I are same height and our seat height is 3mm different. My Pad Y is 645. The size Large XLS maxes out at a Pad Y of 685 and I don't like to build it past 675 unless I have to (it requires some aftermarket bits to get that last 10mm).
Here is my suspicion... you're riding too shallow in seat angle. By that I mean your hips are too far behind the bottom bracket. This can be because you're on a saddle that only offers comfort when you're sitting back on rear of it. This can be because the saddle is clamped too far back on the rail or the post. If I'm right in my suspicion then something is keeping your hips back there and when you move 'em forward either with a new saddle or by sliding this existing saddle forward then EVERYTHING with change - the same comfort or more comfort (always the first priority), the same power or more power (the second priority), and your front end will move both forward and down (especially if you put a 165 crank on there, but even if you stay with this 172.5). Then you're Pad Y will be down to something more like 650-660 and your Pad X will move out to something more like 520-525.
To confirm my suspicions....I'd like to know what saddle you're using, I'd like to know the set-back of that saddle (how far behind the center of the bottom bracket it sits when bike is level - you can measure this by dangling plumb line off the nose of the saddle and measuring the gap from string to center of bottom bracket), and I'd like to see a profile pic of you riding in aero with the bike level.
Let me know if you can deliver that here, I want to investigate deeper.
Ian Murray http://www.TriathlonTrainingSeries.com
I like the pursuit of mastery
Twitter - @TriCoachIan