FlashBazbo

Off and on, I have ridden Fizik saddles for a very long time. More accurately, I have ridden Ariones (and Brooks Cambiums). My "sit bones" are about 115mm to 120mm wide -- which, according to other fitters, means I should never have liked riding an Arione. Looking at Fizik's long-time flexibility measure, I'm not sure I ever really had the flexibility to be prescribed the Arione -- but I rode it fine, for years.

Having looked at a number of different fitting systems, including all the "sit bone" width systems, I'm not completely sure ANY of them have it completely right. But the fizik "flexibility" system seems to make the least sense of all. Why should flexibility make a person more or less comfortable on a given location on a saddle? Of course, a couple years back, fizik came up with a weight/speed/power fitting idea that they have apparently already abandoned. The fact that they adopted it, then went back to the flexibility idea hints (to me) that even fizik is grasping for a good way to select a saddle.

Am I off base here? Do you think fizik is on to something with flexibility determining saddle fit? (Why hasn't anyone else jumped on that bandwagon?)

MoAlpha

As I understand it, "flexibility" is a simplified term used to signify forward pelvic rotation, which is what you need to do to assume a low, position over the bars. The "sit bones" or ischial spines (which most roadies do not sit on) are part of the pubic rami, which converge anteriorly (upward in this drawing) in a sort of chevron. The further you rotate your pelvis forward, the closer these bones become at the point at which they contact the saddle. Therefore, the more "flexible" you are, the narrower saddle you need.

79pmooney

Try seats until you find the one that works. A fit "system" for seats is only going to get you close. We are all very different down there, probably as much so as our faces. (No, I haven't looked, but I do notice what seats people find comfortable. I remember doing a hundred or so mile ride with a fellow and were both were quite aware the seats each of us was riding would have been pure torture for the other.)

No one number is ever going to be a solid predictor of what works. Also, the more flexible we are and the closer we ride to a racer's tuck, the more we are putting serious weight on our soft tissue and the less on our sit bones. The shape of the seat forward of the sit bones are becomes critical. (Never mind that a lot of us slide forward and back so much that our sit bones spend a lot of time not on that designated spot on the seat.) The seat shape, softness, cut outs and groves add up to be often much more important than simply the sit bone width. FOr some of us, the width of the seat edges also become critical. Many seats cut off the blood circulation to my legs that would otherwise work well.

It's worth looking to see if you can find a bike shop with a good return policy so you can try seats until you get the one that works. (A Portland shop has a "library" with about 2 dozen seats on its shelves. Buy a library card for $25 and you can take out seats for a week at a time, as many times as you want. Find one you like and that $25 goes toward a new, boxed one.

Ben

FlashBazbo

I agree. But fizik DISAGREES! When they say "more flexible," they actually mean more flexible -- as in, so flexible that a very flexible person doesn't have to rotate their hips forward and an inflexible person DOES have to rotate their hips forward. So, when you look at their charts for flexibility, the most flexible person's hips don't rotate forward and, therefore, they put more of the pressure on the widest part of the "sit bones." And their chart for the least flexible person shows the hips rotated well forward. Yet they prescribe the narrowest saddle for the person who sits on the widest part of their supporting bones and vice versa.

Hence my question. The fizik system does not make logical sense, as they present it.

FlashBazbo

Good, practical advice, Ben. My question is more conceptual. In a nutshell, I'm asking if fizik has it all wrong. I'm not saying that taking flexibility into account is a bad thing. I suspect that it's not really very relevant, though.

MoAlpha

Sorry, I should have looked first. The chart I found does indeed appear to have the concept backward.

Seattle Forrest

I think it's just a guideline to help people narrow it down when they're at the store looking at a bunch of saddles? It makes a little bit of sense, but you're going to need more flexibility to use more saddle-to-bar drop and their system doesn't take that into consideration.

MoAlpha

So, this piece of copy has pelvic rotation (presumably the angle in red) tracking with spine flexibility, but captions it wrong. However, the saddle width seems to be assigned correctly. I have no idea what happens in real life. I can't touch my toes, but do lots of dead lifts and can ride a healthy drop by rotating my pelvis.

Do we care? It's not chemo for cancer and all saddles make my ass hurt and my pecker go numb after a while.

79pmooney

Hip rotation should be a matter of what works best for your body. It is governed in part by your flexibility and ability to comfortably do it and ride (by your back and body; the seat should NOT be telling you what angle your hips have to be). I like to have my hips well forward much of the time to have my abdomin comfortably extended for good, deep diaphram breathing. (This makes the fit to my soft parts critical and the sit bome width much less so.)

If you look at pro riders there is significant difference in hip rotation between riders. But once you know where your hips work best in terms of being a core part of the "engine", you then have to find a seat that is comfortable for that rotation. Sadly, many never get there because their seats will not comfortably allow it. Hence my advice to try a lot of seats. And, I didn't say, but stay alert. This changes as we grow as riders, as we age and for other reasons.

Ben

FlashBazbo

No, they mean what they're saying. It's about SPINE flexibility. (Hence, the name.) And if your spine is flexible (like a snake), you don't have to roll your hips forward. It's only the stiff of spine who have to "cheat" forward by rolling their hips / sit bones forward. That's what they're saying.

And as for why care? If all saddles did to me what you're describing, I would CARE! (I count myself blessed!)

MoAlpha

I understand about the spine and I think we agree on the mechanics.

Maybe I'm interpreting the pictures wrong, but the snake guy on the left has an acute bend in the red line, presumably indicating the femoroacetabular (hip) joint, which is where pelvic rotation takes place, despite a caption saying "little hip rotation." He's also clearly hinging at the hip, with very little spinal flexion. I think it's just bad copy.

My problems with racing saddles are a cross I've born these 30 years.

redlude97

I think the fizik infographic is incomplete or lacking context because it doesn't take into account saddle to bar drop ie back position for a given rider type. Even the ability to touch your toes doesn't necessarily indicate how much your hips rotate on the bike. I can go almost flat palm on the ground. I have used all 3 fizik saddles in the normal widths (130, 142, 142 L/R respectively) on different bikes with different saddle to bar drops. I rotate my hips less than most and round the back to get in an aggressive position and have over 10,000 miles on an antares saddle with moderate drop and position. I've used an arione and its only comfortable in an aggressive position, there is some hip rotation to be comfortable on that saddle. The Aliante with the raised nose is only comfortable in a more upright position for me and I get some numbness riding in the drops for an extended period of time either with a rounded back or rotated hips. Antares fits best with its wider width in the back and a more flat construction

chainwhip

Doesnt keeping the recommended "flat back" require the hips to rotate?




The acute angle of the "snake" rider might be a useful shop- floor check, but I have difficulty picturing that angle being useful in a bike fit.

August West

Can't really comment on their fitting system but my Giant Defy came with a bottom of the line Aliante Gamma and by good fortune it turned out be a great saddle for me. Best I've ever tried. When I purchased my Domane I moved the one from the Defy to it then bought another one in black so the colors matched and kept the white one as a spare.

Seattle Forrest

For what it's worth, Antares has been the most comfortable Fizik saddle I've used, LBS had every kind to demo (had as in they went under). Fabric Scoop is even better.