Bike Fit and Knee Angles

most guys measure at rest. (as in you were pedaling and they had you stop and hold it static)

toe dipping doesn't mean anything (or rather, it CAN mean that you're too high, but it can also mean that you naturally do that.) so mainly it comes down to what feels right.

How is your power at 160 compared to when the saddle was lower?

Edited by Leegoocrap 2013-12-24 6:13 PM

I don't have my bike completely back together, still wokring on position... I'll post up some pics here then everyone can give me hell... LOL.

I put the 170mm cranks in my road bike from 172.5... I HAVE noticed the loss in leverage on hills. I was a good spinner with the longer cranks, but I noticed that I spin at around 95 with the 170 as feeling the same as 91 ish with the 172.5. Otherwise, on hills I've lost some real top end grinding power. I've fiddled with the position too and tried to get in that magical range... I may have had my previous setup too high also... but I like the way it felt, now I feel like I aint got the power, we'll see if my body adjusts to the changes.

In these 2 pics... the saddle is too high, I figure that I have to lower it about another 5 to 6mm... I can't pedal the bike, since the crankshaft is in the BB softly and no chain...

I've lowered my bars 1.5 cm from the previous position, and figuring out whether to use a 165 or 160mm crankshaft.

My torso angle went from 100 to 94-95, so that's good.

How does my back look? is that the way it's supposed to be, flat and the open hip?

How do my arms look from the shoulder, they're at 90 degrees.

I've narrowed my elbow pads by 3cm also... getting ready for testing in Jan and then training to get used to the new position, hopefull I'm going in the right direction.

Merry Xmas.

Edited by tomspharmacy 2013-12-25 8:53 AM








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Move your seat forward....and down a bit. (although I wouldn't move it down before I moved it forward to see what that looked like)  I don't like the angle from your shoulder to your elbow.  Your torso is not rested on your skeleton.  I bet if you move your seat forward you can come down a bit more in the front and close that angle up,,,,,and flatten your back more.

Edited by Left Brain 2013-12-25 9:26 AM

*as always, feel is more important than looks, (and feel always overrules look) but just going on looks...

first thing is your upper body is too stretched out. You don't look to be supporting your upper body with your skeletal system.

Looks a lot like your saddle is pushed WAY too far back. Did you slide it forward when you raised it? (You need to as a rule)

Your knee lines up with your pedal about where my road bike does, it should probably be forward a bit.

Your upper body is stretched... almost leaning towards a "deep diver" position. If that's something you were going for, worth trying, but most guys can't hold that position for long races. When you slide the saddle it might clear that up so don't change anything there yet, but your shoulder to elbow should make a straight line down, and currently yours is sloping pretty hard (will cause shoulder fatigue)

The other thing is that for the bars you've picked it's usually a lot more comfortable if the elbow pad lines up with the "trigger" (pointer) finger if you drew a straight line between them. Your pads are a bit lower... you might try a spacer under them to raise them up a few mm.

-again, all just what I see.

Tom,

2 things

I would bet Mat Steinmetz measure that angle, in motion, using Retul

Your knee angle is probably even greater than that. If you measured it when your pedal is a between 5 and 6'o'clock you would probably get and even greater open knee angle

From Dan Empfield's article

BDC is not at the absolute bottom of the pedal stroke (with the crank arm at 6 o'clock). It's with the crank at 5:25, or 5:27 (let us say) as is the case in the illustration.

Edited by marcag 2013-12-25 10:36 AM

Ok, if I make the seat the same height as my road bike, the center of crankarm to top of saddle distance - 91.3mm. I'll have to lower it about 5mm.

Funny, I just moved the saddle back 5mm before this picture.

Chris, as for the arm extensions, I can angle them down without making them higher, that's the beauty of the shiv system, it's very adjustable.

As for my arm angle from the shoulder, I read that it's supposed to be at 90 degrees, this is about where I have it now as it is perfectly perpendicular... that is why I moved the saddle back... lol.

Marc, ok, that's what I thought in motion...

Another question to yous: is there a rule for the effective seat angle? currently in the picture it's about 79.5... If I move forward, say a centimeter, it will be around 81... is that ok?

My goal is to either go faster on the same watts, being more aero, but to produce more by beginning of next season. So far, I'm getting the latter down, now got to get a nice, new comfortable lower position.

I'll post up a new pic...

I think that I have to sell my new SRAM Red 165 cranks b/c they're incompatable with my Rotor Aero Q rings. I didn't know this prior to getting them. I'll have 5 freakin cranksets to sell here soon.... jeesh. 4 road and 1 mtb.

Sorry, the house is a mess, it's Xmas time and the daughter is reaking havoc...

Edited by tomspharmacy 2013-12-25 4:36 PM

DP

Edited by marcag 2013-12-25 4:55 PM

I would not necessarily move my seat forward to correct my arm angle. Yes you can move you seat forward or your pads back but you want to get you seat right first then adjust the pads accordingly.

Remember that as you shorten cranks you are supposed to move your seat back.

Very steep should work better for flats, slack better for climbing

Moving seat forward/back will affect power generation and muscle recruitment

You do appear to be riding slack so yes there is probably room to move forward but I would not do it to adjust your arm angle. I would figure out how steep I want to ride then adjust pads/bars/cockpit


Remember, you are gaining something like 1.5watt per cm you are dropping, so don't compromise power for it.

IMO


Edited by marcag 2013-12-25 4:56 PM

it's hard to tell from that one picture

Yes, he does not look steep. The guys really steep are on the tip of their saddles nd you see a big part of the seat tube
But for example if you look at Rapstar's profile, you will see him on a Shiv and he is not steeper than Tom.
On the front, look at the line along his arm and project it along the fork. Tom would achieve that by moving his pads back

I am not saying he should keep the seat the same, move forward or move pads

He should not be trying to replicate someone's position. He should adjust his seat for maximum power and then adjust his front end accordingly. IMO



Edited by marcag 2013-12-25 5:34 PM

yeah, he does look pretty lax in the SA. not always a bad things though, but as mentioned he does need to move forward as he is way too stretched out. I would also say he needs to move the saddle down at least a cm

I moved the seat 1 cm forward, and do the pics again... see how the looks on the front bars. Tell you honestly, I'm used to riding steep, around 80 to 82 on all previous setups, so that appears to be a good position... I moved back soley to get my arms in that raked position... my legs would hang better in a steeper position and I'd be able to sit on the seat instead of being on my soft parts.... my LBS gave me a SITERO to demo, but I'm not sure so far from just sitting on it that it feels good... but I like Marc's suggestion about making things comfortable on the seat then adjusting the front to be appropriate. I think that I was doing it backwards.

IMO
You want to start with the seat on a road bike fit
You want to start with the bars on a tri/tt bike fit.

I'm sure you can get success either way... but that's how I've always done it.

Lots of good advice already.

Based on my non-expert opinion: The combination of your heel-high foot position, pedal not at 5:25ish, and open knee angle you need to move your seat forward and/or down a bit. Do you get any rocking in your hips in the current position?

You said your elbow position puts you close to 90 but to me your pads are not where they need to be. You're not resting on bone. Once you get the seat where you want it, play around with the pad position some more.

for the short of it...

you end up with a saddle too far back and body too stretched out usually. Sort of the reasoning behind buying the cockpit before you buy the bike.

Your contact points in the front being "precise" is much more important on a tri bike than on a road bike (not saying they aren't important on a road bike)

Edited by Leegoocrap 2013-12-26 11:56 AM

no worries, I'm not selling.

We've been through it a million times already... 10 people, 10 different opinions on fit.

What's weird about this... is this; my saddle height to center of pedal crank on the road bike is 91.4mm (which is were my FIST fitting from 1.5 years ago placed me) and it's near perfect, with a nice knee angle of 140 in motion, about 144 static.... so if I set the same height of 91.4mm on the SHIV, I get a stretched out leg.... then I realize that my hamstrings are pulling tight and effectively straightening my leg, or raising my heel if I keep it flexed, when I tilt my pelvis forward to get into the bars... so should I lower the seat more?

Either I have to get 160mm cranks and keep saddle height the same to lose 5mm, or cut my seat post down by 5mm (not going to do) and close my hips more with the 165mm.

I have a 11.5cm (4.5 inches) drop now, from 9.7cm (3.7) from the previous setup.

I have to get this crap down soon, I have a 3 day stage race in Feb with a TT component, and I need to get acclimated, dialed in... I use this race to gauge my progress for the beginning of the year... then I have the Leadman 125k and St. George as the first races.

Edited by tomspharmacy 2013-12-26 1:22 PM

Why not cut the seat post another 5mm? If it's the right thing to do, then it's a lot simpler than going out and buying new cranks.

My guess on the tri vs road bike fit question, is that on the road bike you are sitting up a bit more. Therefore your hips are rotated down and back. On the tri bike you are rotating forward which raises your hips up a bit.

This reminds me of "critique my swim" lol! I am NEVER putting up pics or vid of me on my bike or in the pool! I would be crucified.

Yes, you're right.. actually made me think and test about the hip angles vs. the two bikes. The hip rotates and the it changes the top of the femur bone higher and thus shortens slightly my leg length.

Ok, I bit the bullet and cut 1 cm off my seat post, and set it at the stop, I lowered my seat 8mm... voila, my foot fell naturally into place with a nice angle, my butt fits better on the seat and arms hang naturally, I also moved my arm pads back about 5 mm, unfortunately I lost the 1 cm of drop, so back to 10.5 cm. But, I've gained 1 cm from the previous and with the 1 cm of space from the 165's, my hip angle is where it was from previous, generous space I felt at TDC...I will get some new pics out this weekend.

I can see that I lowered my front profile donw about 1.5 cm with this between butt, back and front body.

After all this, from my previous saddle height and looked at my pics where I'v been for a couple of years, and man I was riding tall and stretched in the legs (and probably when I looked at my pics, something didn't look right)... I don't understand how my previous tt fit got so whacked up. Now I get why I've developed upper hamstring tendonitis.

I've also may have realized that I might have fit on the small SHIV over the medium, that would give me more range to play with. Well, I guess that I'll have to look at that aspect next. I was right on the cusp of being too big for small, but centered on medium from my previous setup.



Edited by tomspharmacy 2013-12-27 2:05 PM

that's one of the things I really dislike about the new shiv (one gripe of an otherwise awesome bike)

that thing requires you to REALLY size down if you wanted to get low/steep. Now the Shiv TT... that thing is perfect for a fella like me