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Saddle Position and Tilt for Power and Comfort
A change to bike fit was discouraging and painful for the better part of a week, but it seems to be worked out now, involving saddle position and tilt.
The main issue remains my right leg, which over the years has always been the grumpy one, never entirely happy and always unhappy about changes in position or shoes. That leg has always liked to rotate outward (heel in, toe out), whether road or mountain bike, and sometimes it is grumpy one and fine the next. At present, the main issue is muscle pain and some patella achiness, but it all seems to be adaptation-related and not anything ugly like internal joint point. So I am cautiously optimistic.
Bike fit for me is an ongoing project, but I’ve gotten a lot of the twist out of my hips caused by an asymmetric crank in 2012 that resulting in a “windswept” riding position. Still, it is a complex challenge, relating to symmetry on the saddle, foot support and years of baked-in miles.
3DBikeFit.com is patiently helping me through this process. I say “patiently” because I myself am frustrated with my annoyingly reactive right leg. The issue being that neither of my legs likes significant changes all at once (significant for me means anything more than a few millimeters!), so that the “best fit” might mean “can’t handle the change all at once”. Very few people are likely to have my sort of reactive body, but with so many miles and approaching 50 and unrelenting training, that’s just my body to deal with. Moreover, my trouble is that I am attempting to train hard and adapt at the same time, which cannot be recommended for anyone.
Changes with a previous bike fitter a few years prior were equally challenging for me: my body is reactive to changes.
Since I don’t have six months to slowly adapt (aggressive training schedule), I took it upon myself to modify the 3DBikeFit position by taking an intermediate saddle position (e.g., backing out a ~12mm change to a ~5mm change), with the plan of making an additional incremental to the recommended fit with some adapter time in between).
Fit changes
A change to saddle position (~+12mm forward and ~2mm down) caused painful and very discouraging effects for a few days. Though it looked felt fine and good in the lab as per videos (my total agreement on the spot!), on the road my right leg seems to be highly reactive to changes. Something about the way I ride; I seem to weight myself differently depending on slope and power output.
So I backed-out out the change to ~+5mm forward (still ~2mm down), and that is now working very well, once I found the right saddle tilt (see below). That change might not sound like much, but has these measurable benefits:
- Cadence is settling in at about 5 rpm higher; it’s a smoother place to spin.
- Power is up by ~15 watts (probably saddle tilt benefits).
- Hip rotation and stability/support on saddle is now just about perfect.
The point is that position matters a great deal. The 5mm freed me up noticeably, though the saddle tilt was clearly the most critical thing.
Saddle position
The tilt of the saddle and the saddle itself allow the pelvis to rotate into (or not) a powerful position that allows fully (or not) use of the powerful gluteal muscles. If that hip rotation is blocked then the gluteal muscles cannot be fully utilized and power is sub-optimal. Moreover, the gluteal muscles resist fatigue and recover quickly, so using them fully is critical.
As I discovered, the complicating factor is that a bike in the lab (with video) is not the same as on the road for me. I have to tweak the position precisely to be comfortable. In particular, my long torso means that small saddle-angle changes are a big deal for comfort and power:
- Saddle angled down too much and my hands quickly get uncomfortable from taking too much weight;
- A change of 0.5° is significant for me especially in my hands; it has to do with the balance point of my long torso. With up/down/level terrain, there is no perfect position so I literally have to find the right spot to within about 0.1° to feel satisfied.
- Saddle angled up too much and I can’t rotate my hips for optimal power (“blocked”). This presumes a saddle that doesn’t itself block out hip rotation (which kills power from the gluteus, many saddles prevent this hip rotation).
- Saddle position fore/aft (reach) has to match the tilt for just the right balance/support point!
But I finally seems to have gotten the saddle just right:
- Specialized Romin EVO, 155mm width (I have sit bones that are 10-15mm wide than usual, standard saddles do not support my butt properly).
- 532 mm from tip of saddle to center of bar clamp.
- 2.5° downward tilt as measured by an digital inclinometer @AMAZON placed on a flat thin stiff board on saddle for repeatable accuracy of 0.1°. (don’t try to relate this number another saddle; mine looks to be close to level but the rear of saddle rises slightly and that is part of the measurement for this saddle).
As little as 0.2° of saddle tilt is noticeable for hand comfort or hip rotation.
The troublesome factor is that tightening the bolts can make the saddle tilt up to ~1.5°! So tweak and measure with an inclinometer.
