measuring sit bones

[sundial]

Well.......the easiest way is to go to your local bike shop and ask them if they have a butt-o-meter. It's a cool device that you sit on and it measures your sit bones. Then you can determine what saddle is the right width for you.

A more difficult way is to take a piece of typing paper, place it on a stool or chair and see if you can make indentions with your sit bones. One TE'er had luck using Play Do to make her sit bone impressions.

Good luck and let us know what you find out.

[velogirl]

whatever you sit on (a little piece of foam would work), you need to elevate your feet to make your sit bones protrude. to do this, just place your feet on a chair at the same height as you are sitting. make sense?

btw, the "saddle measuring tool" is a specialized product, so you need to go to a specialized dealer to use it.

[lattae]

Thank you for the info. Once I obtain my 'sit bone size' is there a certain rule of width that the saddle should be? Should it be a inch or so wider than the sit bone measurement, or exactly the same size?
Hope you understand what I mean. Thank you ladies so much

[velogirl]

measure your sitbones in mm. there are ranges that will be most comfortable for your width and your style of riding.

here's the guideline from the "butt-o-meter" (yes, I have one because I use it for bike fits). the range on the narrow end is intended for those who ride in a more aero position (ie riding forward on the soft tissue), while the range on the wide end is intended for those who ride in a more upright position (ie sitting on their sit bones).

SIT BONE WIDTH -- SADDLE WIDTH RANGE

130-160mm -- 143mm -- 155mm and wider
100-130mm -- 143mm -- 155mm
70-100mm -- 130mm -- 143mm

I've been fitting women (and men) on Specialized saddles for over a year now. I have a saddle demo program with my bike fits. I'd say 60% of the women I fit on a 143mm saddle, 30% on a 155mm and 10% on a 130mm.

[Thorn]

But...that chart doesn't make sense to me. For the narrower measurements, they suggest saddle widths that are wider. If you're built wide, they suddenly switch over and say you can fit a saddle that is narrower than your sit bone width.

I don't mean to be contrary, but do women with wide sit bones actually ride saddles that are narrower than the bone width? By being uninformed I have done so with extremely negative consequences. So, in your experience is that valid or is that marketing from companies that dont' really have non-tractor saddles for wider widths? And I'm not picking on Specialized--I've read this elsewhere. Just curious.

[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.

[TxDoc]

I've been fitting women (and men) on Specialized saddles for over a year now. I have a saddle demo program with my bike fits. I'd say 60% of the women I fit on a 143mm saddle, 30% on a 155mm and 10% on a 130mm.

10% only?
I guess I belong to the minority!!! My saddles are 124 and 130...

[dianne_1234]

Found this in my old uni notes and wanted to post it here for easy reference:

Ischial Tuberosity Spacing among women:
5th percentile 112 mm
50th percentile 130 mm
95th percentile 148 mm

Ischial Tuberosity Spacing among men:
5th percentile 100 mm
50th percentile 118 mm
95th percentile 137 mm

I don't remember the population this data was taken from, but I remember being under the impression that it was a very large number of individuals and it was considered "safe" to assume it might represent the whole world.

I've used this info to help narrow the search - once I learned I was wider the 95th percentile(!) I stopped bothering with a lot of narrow saddles.