After reading thru the bike fit articles I have a question regarding stack and reach versus bike size. I was fitted in the past on bikes in the 56cm range, I am 6 ft with a 33 in inseam. Currently on a p2 size 56 with 3 cm of spacers and 80 degree stem flipped to get high enough. Went to a fist certified fitting and was told front still not high enough, would agree based on comfort etc. Can’t make this bike any higher in front so recommended looking at bike with a higher stack. He measured me at 58 stack and reach of 42.5 When I look at tables the xl scott plasma would seem to fit. What else do I need to consider since this seems to me like a move up in size? Can I ignore the size and base fit strictly on stack and reach? Any other recommendations, I know I need a tall and narrow bike? Go easy on me as this is my first post
Sounds like you’ve got it about right.
What seat angle are you riding the bike at thoug? If you’re real slack, there might be room to move forward and down and ride the bike the way it’s supposed to be ridden. If you’re already pretty steep, then a taller bike is needed.
you seem to have pretty short legs from your inseam; and i would infer from this that you would need bikes with proportionately longer reach for relative stack, which does not jive well with the stack and reach numbers that your fitter has come up with for you. I don’t know how your fitter came to your stack and reach requirements, but it just seems odd to me that someone who would need a ~70cm saddle height should need that much stack to achieve reasonable comfort.
saddle height is 73.5 cm and riding cervelo as far forward as I can go on arione saddle, stem length is 110mm.
It sounds strange but right to me. Throw “normal” thinking and numbers out the window when you are dealing with long legs and short torso. I need a bike with a short reach but tall stack due to long legs, long arms and short torso. Its difficult to get “low enough” with a short torso. The hip angle closes down really fast as you go low due to the length of the seat tube. With long legs, your seat is “really” high compared to the top tube. A tall head tube is needed with a short reach. Its a tough combination. My top of the seat is like 33" from the bb, nearly 20cm of drop and I’m not close to flat with lots of rise in the stem. Even with a “huge” head tube I still have lots of rise.
When most manufacturers make L and XL sizes they increase stack as well as reach and this does nothing to help the long leg/short torso person. If only they could make a bike frame with us in mind it would be wonderful!! I know there are a few out there but the pickings are slim. My 596 is working out well as I adjust my position to go further forward as I rotate the stem forward and down. I’m getting more stretched out as I go lower as I can’t move the seat any further forward, yet I’m not close to a flat back or anything that is semi ST approved. My reach measurement would rival someone about 5-8 to 5-9, yet my inseam is 37" and I’m 6-3. I cut only 1" of the seat mast off of my “large” Look 596 and even then I had to use about 5mm of spacers to raise the Epost to the required height. With the seat that high, a huge head tube is needed just to reach that far down, even with a long humerous.
Note the angle of these 2 examples: The first line is the seat and the next line is the elbow pads. Imagine the angle of the riders back in each case even with the same amount of drop and same length humerous:
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The angle from the tip of the seat to the pads of example 1 is greater then the angle from the tip of the seat to the pads on example 2. This would allow the rider in example 2 to be flatter then the rider in example 1 with a humerous of the same length but a short torso compared to a long torso. I know this is a very basic and simple example but it gets worse when you add long legs and the extra seat height to that short torso. Its gets really wierd. Numbers from a fitter will look rather weird when you are dealing with a short torso and long legs.
I don’t know if I explained that very well, sorry.
but this gentleman has short legs and needs a high stack, which is what i find odd. It’s not the same as having long legs and needing a tall stack.
Your dimensions are similar to mine - 37" inseam and a shade under 6’4"
I ride a 58 P2C with slammed 120x-17 stem and low stack pads. You can’t make generalisations just on torso:inseam proportionality, too many other factors involved. Everyone is different - nothing weird about it.
The OP needs to see a different fitter before buying a new bike.