Bike Fit Question: how to stop sliding forward?

Realizing bike fit is delicate and best handled by a trusty pro, could someone provide some basic options I could try? My fit has been pretty much awesome for ~year+ (only altered saddle height minimally during this time). I feel generally good on the bike and running off, bike times are progressing. I noticed lately I’ve been sliding forward on my saddle way more than before and when this happens I push my hands against the aerobar ends a little which feels off and loads shoulders. It’s not terrible and happens with some cycling bibs more than others, and definitely more of a problem on a trainer than outside, but still wanted to see if there’s anything minor I can do to see if this will help.

Drop the seat a couple mm?
Slide aerobars a few mm forward? (this might not prevent sliding forward but will maybe eliminate pushing against the aerobar ends?)

My saddle is almost parallel to the ground, a tiny bit angled forward. I could try leveling it, I guess but seems like this is more likely to upset the apple cart of the overall fit…

What kind of saddle do you have? Without seeing you in person, my first instinct is start by bringing the saddle nose up just a bit. If you have a seat post that allows for fine adjustment, a small board or book, and a digital level (smartphone apps will do), maybe tilt it up .3 to .5 degrees.

I tend to care more about the angle of the saddle where your ischial tuberosities (sit bones) are than the overall angle. You’re likely sliding (and, subsequently, feeling the load on the shoulders) because the part of the saddle where you are actually sitting is angled downward too much.

The question is “Why” are you sliding forward, not how do you prevent it.

Maybe "forward"is the correct position
Maybe you need to stop waxing your saddle
Maybe your reach to the pads is too long

Pictures are a good place to start, Fitters are a good place to finish.

The saddle is Specialized Power and the post is the Bontrager one that comes with SC. I could try raising the tip up a smidge, sounds reasonable.

saddle.jpg

try raising the tip up a smidge

This is where I’d start.

how do you like that Xlab mount? I am just using zipties for now

Worth ~$10 or however much I paid for it a few years ago, still going strong. I put that extra rubber band on the bottle holder so even a thinner water bottle won’t fall out on bumpy downhills.

It’s definitely not the lightest, but doubt it’s all that heavier than the carbon alternatives.

Took it apart and tried to raise it as much as possible, but looks like it’s already all the way up. Seems like the only way to get the tip up would be by sliding the saddle on the rails, don’t want to do that just yet…

I’d try to figure out if you’re trying to shorten the reach from the saddle to an elbow or hand contact point. Are you trying to meet your hands or your elbows with your torso or butt? Or is it the saddle tilt? You could slide the saddle forward a bit or shorten the reach at the pads/extensions/stem.

I try to put it in terms of points of reference. Do you use the arm pads in relation to your forearm/elbow or do you use the bar tips and your hands as a determining factor as to how the front end of your bike is set up. If all of that is good, and you aren’t constantly shifting your hands/elbows because one is uncomfortable, then maybe you’re sliding forward on the saddle to meet that. If that’s the case…

  • Shorten the stem, or
  • Move the pads and extension tips back the same distance, or
  • Move the saddle forward, and depending on how forward ever so slightly higher.

If you think it is the tilt of the saddle then raise the nose of the saddle but measure the saddle height to a common point (ideally where you sit most of the time) before and after you tilt it. If that point raises a few mm, then lower the saddle a corresponding few mm.