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Road Bike Fit..thoughts....inputs please
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Using the FIST road protocol with and exit fit bike...

1. A common feedback input after the bike is ridden on the road is that there is too much weight on the bars. I'm thinking that the fit bike gives an illusion level of comfort that the bike on the road does not convey.

2. How to decide how much saddle setback / seat angle is too far? My clients like it as far as it will go, but that does not necessarily transfer to a bike. When at the maximum on the road, riders tend to push themselves off the saddle and use a lot more upper body to stay in place. The relaxed angle seems to cancel out a thigh/saddle lockup on a level saddle. Is stem length the answer? Drive a rider to a smaller frame with a long stem? Then there is maximum seat tube extension...if the customer is comfortable, where does it stop?
Thinking too much...
Thanks, Ron

http://www.mybicyclefit.com
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Re: Road Bike Fit..thoughts....inputs please [Ron Hacker] [ In reply to ]
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I'm trying, but I have no idea what you're asking or looking for.
Saddle position (fore/aft) is purely a function of knee position in relation to the ball of the foot. handlebar position is a function of torso length/flexibility/riding style. If the rider is pushing themselves all over the saddle, the fit is wrong.


Brian Grasky
Grasky Endurance: World Championship Triathlon Coaching; Professional Training Camps
RETUL fitter, Biomechanist, USAT Level 3 Coach, USAC Level 2 Coach
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Re: Road Bike Fit..thoughts....inputs please [seebritri] [ In reply to ]
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' Saddle position (fore/aft) is purely a function of knee position in relation to the ball of the foot


That's one way of doing it, but it's not really based on any science...

Jonathan Blyer,
ACME Bicycle Co., Brooklyn, NY
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Re: Road Bike Fit..thoughts....inputs please [jonblyer] [ In reply to ]
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Ok. Do tell.


Brian Grasky
Grasky Endurance: World Championship Triathlon Coaching; Professional Training Camps
RETUL fitter, Biomechanist, USAT Level 3 Coach, USAC Level 2 Coach
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Re: Road Bike Fit..thoughts....inputs please [seebritri] [ In reply to ]
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show me the research and explain why thousand of triathletes ride with their knee well in front of the ball of their foot with no issue at all.

I'm not saying that I have a better answer, just that KOPS is based on nothing other than convenience and observation.

Jonathan Blyer,
ACME Bicycle Co., Brooklyn, NY
Last edited by: jonblyer: Jun 16, 12 14:24
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Re: Road Bike Fit..thoughts....inputs please [jonblyer] [ In reply to ]
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You really did misunderstand me, didn't you. I support riding with knees in front of the foot on TT/Tri. I won't toss out a number as everyone measures from different places, but you're right. All I said was the knee position is a function of (i.e. measured from) the foot position.

The OP was talking about stem length and weight on the bars in relation to saddle position fore/aft.

Carry on.


Brian Grasky
Grasky Endurance: World Championship Triathlon Coaching; Professional Training Camps
RETUL fitter, Biomechanist, USAT Level 3 Coach, USAC Level 2 Coach
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Re: Road Bike Fit..thoughts....inputs please [seebritri] [ In reply to ]
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I don' think I misunderstood you at all....
If KOPS really had any biomechanical merit why would it apply to road bikes and not to tri bikes? One could easily argue that riding a road bike in the drops simulates riding a tri bike with a slack seat angle from a muscle recruitment stand point, at least as far as the legs are concerned.

Wouldn't you agree that weight on the bars of a road bike is a function of saddle fore/aft as well as a few other factors?

Jonathan Blyer,
ACME Bicycle Co., Brooklyn, NY
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Re: Road Bike Fit..thoughts....inputs please [jonblyer] [ In reply to ]
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1. sure. But the rider in the drops rotates the hips and slides forward as on a tri bike. And you're not as concerned with hip angle on the road bike as the rider is in the drops for less time typically than he's in the aero bars on a tri bike. (one reason...there are many)
2. chicken and egg. Set the saddle off of the bottom bracket first. Then set the bars off of torso/core/flexibility. Only minimal adjustment the other way if at all.

Done here.


Brian Grasky
Grasky Endurance: World Championship Triathlon Coaching; Professional Training Camps
RETUL fitter, Biomechanist, USAT Level 3 Coach, USAC Level 2 Coach
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Re: Road Bike Fit..thoughts....inputs please [seebritri] [ In reply to ]
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I don't understand why you are being so dismissive here...
Yes there are obvious application differences between riding a road bike in the drops and riding a tri bike in aero such as time in the position, purpose, amount of discomfort one is willing to tolerate, etc.
I was simply trying to point out that if the recruitment is similar as a result of somewhat large hip flexion in both positions, then it doesn't make sense to use one metric for setting fore/aft on a road bike and another on a tri bike.

Jonathan Blyer,
ACME Bicycle Co., Brooklyn, NY
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Re: Road Bike Fit..thoughts....inputs please [jonblyer] [ In reply to ]
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It's not 2 metrics. That's what I'm trying to say. Your premise is incorrect on the primary metric. The fit is for the position that is held the most. You don't fit a road bike for the minority of time that is spent in the drops, but for the majority of time that is spent on the hoods.


Brian Grasky
Grasky Endurance: World Championship Triathlon Coaching; Professional Training Camps
RETUL fitter, Biomechanist, USAT Level 3 Coach, USAC Level 2 Coach
Last edited by: seebritri: Jun 16, 12 20:28
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Re: Road Bike Fit..thoughts....inputs please [jonblyer] [ In reply to ]
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jonblyer wrote:
show me the research and explain why thousand of triathletes ride with their knee well in front of the ball of their foot with no issue at all.

Because they are rotated forward on the bike...

If you take bike and rider and rotate both back for the same amount of cm you rotated the rider forward, his knee will align with the ball of his foot again.
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Re: Road Bike Fit..thoughts....inputs please [Ron Hacker] [ In reply to ]
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I have found that saddle fore/aft positioning is a function of femur length; while KOPS can be a starting point, finding the correct pivot point/torque level at the joint has to do with the femoral head center at the hip (trochanter), and the lateral condyle of the femur.

At two points of your pedal stroke the femur is in parallel with the crank (4 0'clock and 10 o'clock, thereabouts). The foot length is also part of the lever system, so ankle flexion is part of the setup. If the femur/crank parallel isn't is 'sync', something has to give - usually at the saddle, but the knee joint can also move to accommodate one lever being too long. For example if the location of the lat condyle is too 'long' for the pivot (ie, saddle to far forward), the ligaments are impinged and there can be excess torque on the Vastus Med or Vastus Lat; also likely that there is pain at the top of the tibia or around the kneecap - in flexion the femoral condyles push the patella forward, asthere isn't enough room for the joint to function properly.

Anne Barnes
ABBikefit, Ltd
FIST/SICI/FIST DOWN DEEP
X/Y Coordinator
abbikefit@gmail.com
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Re: Road Bike Fit..thoughts....inputs please [Ron Hacker] [ In reply to ]
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Captain Ron - here is a good read.

http://www.bikefit.com/s-13-road-bikes.aspx

Swifty

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