A couple questions about my recent bike fitting… First, a few things about me, I am novice age grouper (44), a couple half and numerous shorter distance Tri’s and Du’s under my belt. I am training for my first IM this Oct at Beach to Battleship. I currently ride a 2012 Trek Speed Concept 9.9 and was recently fitted by my LBS using the Specialized Body Geometry method.
I am generally very happy with the fit and saw an improvement in my last half, but have some concerns regarding a few adjustments I still have not made.
The BG fit still uses KOP measurements and recommends about +40mm KOP in front of spindle and my LBS guy wants me to push my saddle and cockpit back to accommodate the KOP range. I am about +80mm KOP and still have good angles at the shoulder and hip.
Should I go through the stem and seat post cap changes to bring me back the +40mm?
Can you really be too far forward ? (seems like most are going away from KOP measurement)
What gains/losses can I experience between the 2 positions?
Thoughts?
My general thought is that if you’re comfortable in your current position, why change? What are the projected benefits of moving your saddle rearward 40mm? My guess is more power. But doing so will close your hip angle and you may not be able to stay as low as you currently do. So your aero drag increases. The real question is does the increase in your power exceed the increase in aero drag. If so, then you’re going to be faster. If not, you’re not.
I fit a friend on a Shiv. A couple of months later I noticed he was much higher up front. I had set him low, but he wasn’t flexible enough. His power loss was more than the aero gain. So there are cases where moving back makes sense.
I also think it’s possible to be too far forward. The front wheel becomes overweighted and downhill switchbacks become very sketchy. If you’re using a 120 stem or greater, you may be too far forward. The operative word being “may”.
hth,
FaS
I am not a fiiter, but all the people I trust say KOP is to be ignored on a tri bike.
From this article by Dan
"You can also see from the photo that “knee over pedal spindle (KOPS) can be thrown out the window for this application (tri bike fit)”
In theory, to preserve all angles, to move backwards you will need to move cockpit up and back, potentially less aero.
If someone says anything about KOP to me when it comes to fitting a tri bike, I pretty much stop listening. It has no relation to a good fit.
Yes, the suggestion was to move me up and back (I needed the up due to flexibility and my lower back) and my saddle has been moved so far back that I was shopping for a +/- 35mm seat cap to re-postion my clamps back closer to the center of the rails…
So if I am more comfortable and still retain proper body angles, being +80mm forward of my pedal spindles at the knee should not be an issue.
I can keep the rise of the new stem, move my bars forward back to closer to where they were and adjust my seat fore/aft and redo my saddle height…
If someone says anything about KOP to me when it comes to fitting a tri bike, I pretty much stop listening. It has no relation to a good fit.
Would you agree that moving further and further forward eventually reaches a state of negative effect?
How would you propose to define that?
KOPS is just a measurement, making sure you apply that measurement appropriately is what matters