Lets say your bicycle is setup optimally with everything perfect including your cleats. Now let's throw another set of shoes in the mix. Without touching or moving anything other than the new shoe/cleat combo, what does cleat fore/aft and stack height affect in the setup? I feel like my hip angle is closing too much at the top of the pedal stroke on my left leg. What does a more aft cleat setting do to the top of your pedal stroke? So as you move your cleat backwards or forwArds, how does that affect saddle height and saddle fore/aft settings? I've been struggling with his adjustment for a while with these new shoes.

Moving the cleat further back is like raising your saddle height a bit. Different brands of shoes have different stack heights. If the new shoes have thicker soles, then it's like having the saddle too low. Raise the saddle to fit the sole thickness.

Don't make the mistake of moving the cleat toward the front of the shoe. If anything, it's best to be further back.

My old shoes were fit with the cleats all the way forward. The soles on the old shoes are a little thicker, by about 2mm. I was under the assumption that moving the cleat backwards shortened your leg and basically made the saddle seem higher. Is there an accurate way to a) measure stack height of shoes and b) to match cleat placement on a perfect setup shoe to a new pair?

best is to systematically make adjustments to saddle height and cleat position until it feels right. There may not be ONE perfect fit, you could maybe tolerate a range.

I like to set up the cleats so my foot is positioned properly on the pedal (fore and aft, in and out, angle) then adjust saddle position to get optimal pedaling. we're talking small changes here.

I edited my post. I got the cleat change backwards. Moving the cleat back would shorten the leg length and make the saddle feel higher. I don't know of any method to measure such small differences accurately. You just have to go by feel. I can feel it if I switch shoes and don't change the saddle height to match the difference in stack height.

You can measure sole thickness using some kind of c shaped tool (when I googled "caliper" I got a result "outside caliper" that matches what I was thinking)



You may be able to replicate such a set up by using something like a table as the base (place shoe on table), put some kind of consistent bridge type item on it (like a wire shelf unit), then use something kind of pointy (chopstick?) and measure how far down the chopstick goes to hit the sole. Repeat for each shoe and you should have a good idea of the difference in sole thickness.

Use the original inner sole liner thing so that it doesn't become a factor.

I don't know why you are fiddling with cleat fore-aft adjustment. Stack height differences in the shoe sole translate into moving the seat up or down. It's as though you are increasing or decreasing the length of your crank.

If the stack height is the same on both pairs of shoes you use, then you do need to measure the distance of the slots or holes from the effective heel of your shoe to determine whether they are in fact in the same position on both pairs. Then you can decide the position of your cleats. The "effective heel" is where the back of your heel rests against the inside of the shoes -- measuring from the back of the heel on the sole is pointless, as is measuring from the toe back to the slots. Like measuring stack height, it is not an easy thing to do.

I have a similar stack height issue with a pair of Shimano sandals compared with my other shoes, but I don't bother making any adjustments -- I don't ride with the sandals for long enough distances to make the difference an issue.

From the symptom you discuss in the opening post, you may have length length discrepancies with your right leg shorter than the left. You should get this checked by a physiotherapist or if need be, through Xray. The physio check is pretty simple. The solution is a little less simple, but may involve cleat shims, orthotics or in an extreme case, using cranks of different lengths to compensate.

Do you have lower back pain in everyday life?

My issues started with the new shoes.

I had some similar issues going fro Keo's to Speedplay's. There was a slight difference in the stack height (lower) and the cletes had to be readjusted to find the "sweet-spot" under the ball of my feet as well as left to right placement. I ended up putting the bike on a trainer and fiddled with the seat and clete position until it felt right after pedaling in the new position for a while.