Bike fit / correct riding position

I have a slammed 130mm -6deg stem. If I swapped it for a 130mm -17deg stem, how much would it reduce my stack height by ?

Or if anyone can point me to an handy online tool where I can punch the numbers in to get an answer ? (i've forgotten most of my a-level maths...)

2mm more reach and is 25mm lower, assuming a 73 deg head angle.

http://yojimg.net/bike/web_tools/stem.php

Cheers, just what I was after. Will get the -17 stem and put a 1cm scoblebrick underneath to start with

Still a very big drop in one go, your back may not appreciate it!

Trying to tame a mamil friendly geo Cervelo road bike for TT'ing, used to a bigger drop on my more traditional geo bikes.

I can see why the Pro's used to ride these with 140 -17 stems with the headset top cap off.

Has anyone ever used cleats with less float to correct a knee-tracking issue? My left knee wanders all over the shop during the pedal stroke, wonder if less float might keep it under control...?

get a bike fit

I've had so many.

then refer to what the fitter suggested you

My left knee wanders all over the shop during the pedal stroke

Does that cause you any discomfort, or do you just think it looks 'wrong'? If it doesn't hurt, leave it alone :-)

If it is causing pain, then go back to the fitter. It's more likely that your wandering knee is caused by something above it, in the hip/lower back area.

I am broadly imbalanced, says my fitter and have been going to the gym for squatz & core strengthing etc. Hoping this will sort it.

It does lead to inflammation and discomfort. Wondered if floatless cleats might keep the knee locked into more rigid tracking.

'floatless' 0º cleats mean that you have to be very confident about your cleat position (angle included) no? So that could sort it or could go very wrong. Float is just a bit of wiggle room.

Float is just a bit of wiggle room.

Yep. Even though I have plenty of float, I still ensure that my correct cleat position sits somewhere in the middle of that.

Speedplays let you choose exactly how much float you have and where exactly the 0º point is. For example I've got mine locked down with no float, but positioned with heels very slightly out because that's what my knees like.

Wondered if floatless cleats might keep the knee locked into more rigid tracking.

It's one of those things I'd probably try, out of curiosity. I've got the advantage of never really riding hard and having the opportunity to adapt to these changes. If you're training/racing/prommuting, you could just end up doing more damage.

Personally I used to have lots of float because I heard it's good for your knees but found when pushing hard my heels would twist out slightly and my knees would start to hurt, so locking down the float has meant my feet can't move and my knees are more supported.

This is what I'm hoping. Ill give it a go.

@Croft - what pedal system do you use?
I use SPD-SL and instead of going zero float with the red cleats, I was thinking about going in the middle with blue (3deg) cleats instead of the yellow (6deg) I normally use.

I've got Keos. the grey ones I use have 4.5 deg of floatage.

if it helps @croft i found my left knee wandering around and foot twisting outward on the turbo and pain was developing from it, the movement didn't feel right to me at all because i know when walking my left foot tends to go pigeon toed.
I adjusted speedplay cleat to only allow pigeon toe rotation but still give it some float in that direction, knee stopped swaying and i felt better ever since.
All that said I've got a bike fit session on 30th and im half expecting a full pedal/cleat overhaul
will be prescribed as this is my first pro fit.

Also @croft , I've found my knee-tracking helped by switching to a more supportive footbed. You may have something fancy/custom already, but if not, definitely worth looking at.

Thanks :). Have tried that with limited joy, but not fully custom insoles. Guess I'll throw money at it until it's fixed.

Considered throwing said money at Scherrit?

He's a bit out the way for me. Have done both holistic and computerised biek fits.

I personally don't think it's wise to lock the bottom of the leg to keep the knee straight. If your knee wants to twist there's probably a good reason for that, and since it's not a ball joint, forcing it to bend in only one plane is going to put stress on it and give you trouble.

I would say you're better off working on the physical reason why it's happening, with the help of a sports physio. And also if it doesn't hurt then just letting it be.