measuring sit bones

[velogirl]

actually, Specialized has wider saddles in their line-up.

but I'm not sure I understand your question completely. try to remember that these are ranges of sizes and simply recommendations. however, Specialized has done a ton of medical-based biomechanics research, so I believe they know what they're doing in this respect.

Lorri (no, I am not a Specialized employee)

[Thorn]

Sorry, Lorri, confusion is, unfortunately, contagious and I apologize for the thread digression....of course, I'm a statistical outlyer. My sit bones measure at about 140mm. I struggle to find a saddle that is wide enough, firm enough and "gets out of the way" where it needs to "get out of the way".

Anyway, I read the specialized chart and for narrow widths, the saddle widths they recommend are much wider than the sit bone measurements. For example, for 100-130mm, the saddle width (143-155mm) is wider than the widest range. Makes sense. You want to sit on saddle, not the edges.

But then when the sit bone width gets into my range, the saddle width is not always wider than the sit bones. So, I guess my question is, given that you've been fitting people, have you ever fitted someone in the wider sit bone range successfully on a 155mm? My question is more curiousity (e.g., how far of an outlyer am I?) than anything else.

I guess this is the same as lattae's question. The chart gives ranges. Do you start there? Or do you have a rule of thumb you use?

I've toyed with trying one of the 155mm saddles, but I've been unsuccessful on wider Terry's so I'm more than a bit wary.

[Beane]

Couple of things:

1) Trek has a butt-o-meter now too (a friend of a friend was on the design team for their new saddles)

2) I did the specialized measurer thing and was told to buy a 143. I liked it for a while, but no more. The saddle is really uncomfortable. At first I thought it was that there wasn't enough padding for the sit bones, but now I'm thinking that the saddle is a bit too narrow. So I guess my question is: what are the chances that the size they sold me was wrong?

[KnottedYet]

My sits are 170-180mm wide. (depending how forward tilted or "aero" I am)

No kidding.

I work in pelvic rehab, I am friends with many sit bones. Mine are not terribly unusual.

Got to have a nice talk with a very popular brand division head for road bikes this week at a seminar in San Francisco: their widest women's performance saddle isn't even going to be as wide as my sits, let alone give me 1-2 cm wiggle room to each side. Their idea is that women should be sitting on the rami, not the sit bones. Ummm, lets talk about soft tissue damage, shall we? (pelvic rehab training will scare you right out of the idea of weightbearing on your rami, if you can possibly help it!)

I'll be sticking with my 210mm wide Brooks B67.

[velogirl]

I don't think Specialized is recommending you fit on a saddle narrower than your sit bones. You'll note, the top right of the scale indicates "and wider."

I honestly have never measured a woman who had sit bones wider than 160mm. Most have been in the 130-140mm range.

And yes, these are only guidelines. For example, Specialized would fit me on a 143mm saddle. I've been riding a 130mm saddle since 2004. I like it. When I tried the 143mm saddle I ended up with saddle sores.

The fit process doesn't end when someone leaves my office. I guarantee my fit so if someone isn't happy with their fit or satisfied with their saddle, I will see them again until I can make them happy. And in all the years I've been performing fit, I've only ever needed to see someone again twice.

BTW, I've only been demo-ing Specialized saddles for a year but I've been performing bike fit for the past six years.

Now Knotted, tell me more about pelvic rehab. I sit firmly on my soft tissue (not my sit bones) and have been since I started riding about 10 years ago. I've noticed no negative issues.......what should I be looking for?

[KnottedYet]

If you are comfy on your soft tissues it's likely you are on the rami, which is exactly what the new saddles I saw are designed for. They are curved (top surface) to match the "ideal" rami angle for each sitbone width. (in their case, the sitbone width is only used as an indicator of rami angle)

The guy didn't have their widest new saddle for me to try, to see if it did match my rami angle, darn. (my rami are going to have a VERY shallow angle) It isn't in production yet.

There are an awful lot of important muscle attachments and nerves and blood vessels running around in the rami's neighborhood. If the seat top curve doesn't match the rami right, someone will be weightbearing on just a portion of the rami (not the whole thing, just a small contact point) and battering that point and yanking on the soft stuff. Or if it's completely off, they will be off the rami and into the tender goodies or even the pubic bone.

This weekend I rode a borrowed bike with a different brand women's saddle, which was way too narrow. I was definitely weightbearing on the rami, mostly on just one little spot. I'm a hurtin', and it was only a 10 mile ride. If someone tried one of the newer saddles and didn't know what it should feel like (comfy, like you are VG) I would worry about things like pudendal nerve entrapment and blood flow.

The guy was demo-ing with a female pelvis model and a sample of the 146mm saddle, and I was cringing at the thought of damage to those of us who don't match the statistics.

I was impressed that saddle designers are finally getting away from the oat-bran trendiness of over padded saddles and cut outs for women.

[OakLeaf]

I was impressed that saddle designers are finally getting away from the oat-bran trendiness of over padded saddles and cut outs for women.

Do you think that cutouts are always inappropriate? Or just for some women? (I have a hard time picturing where I'd put my very large, um, parts on a saddle without a cutout.)

[Cindyloo]

Their idea is that women should be sitting on the rami, not the sit bones.

OK, I finally gave up an googled "rami". I wasn't sure if it was a slang term that would pop up something to get me in trouble at work.

This explains it nicely: http://en.wikipedia.org/wiki/Superior_pubic_ramus

[VeloVT]

OK, I finally gave up an googled "rami". I wasn't sure if it was a slang term that would pop up something to get me in trouble at work.

This explains it nicely: http://en.wikipedia.org/wiki/Superior_pubic_ramus

Thanks Cindyloo, I tried finding a diagram too but for some reason I couldn't.

I think this must be where I sit. My Fizik Arione is very, very comfortable to me, but I'm quite sure it's narrower than my sitbones. I've never measured them, but I'm a pear shape with a wide pelvis (even when I'm thin ), and I'm sure they're not on the narrow side. But I find this saddle more comfortable than wider ones I've tried, particularly wider saddles that have less of a smooth transition from nose to rear (if there's a pronounced flare I tend to "run into it"), and wider saddles that are less convex than the Arione from side to side. My bf has a 143mm Specialized Alias, which is both significantly wider and has a cutout, and it's much less comfortable to me. This has puzzled me for a while, but maybe this explains it. The Arione must be the perfect shape for my rami !

[Beane]

Andrea: from your description, we are looking for similar things, so if you find anything great, let me know.

Knotted: I had my anterior pubic ramus removed ~8 years ago when I had an aneurysmal bone cyst grow in it and break it. (I'm assuming that anterior p.r. and superior p.r. are the same thing) .. So, what does my asymmetry mean for my seat comfort, do you think?