SkipII

How do you equate the sitx bone measurement with actual saddles widths?

I understand you are supposed to add perhaps 15-25mm to your measurement, but is that the actually total width then of the seat?

The reason I ask is that I plan to buy a saddle from some private party -- new or used -- and I mostly see total length and width of the saddle.

For example, I have a sitz bone width of 115mm. If I add a typical 20mm to that to get to 135, do I buy a saddle of that width or something wider?

Thanks.

Mojo31

Sit bones plus 10mm = total saddle width.

nomadmax 

It really depends on the shape of the saddle. Some XXX mm wide saddles may indeed provide that amount of sit space because it's relatively flat. Another saddle listed as the same XXX mm wide may have less room because they flair down on the sides.

So the answer in my opinion is "it depends". If it was easy, cyclists wouldn't have saddles lying around in boxes.

fishboat

Sit bone width plus ~20mm = total saddle width. In your example above, I'd be looking for a 140mm wide saddle.

Between my GF and myself..we've done quite a bit of saddle searching, and purchased many saddles for various bikes we own. In the end, the comfortable ones fall into the sit bone width + ~20mm = total width category.

Carbonfiberboy 

IME the discomfort from too narrow is much greater than from too wide. A lot depends on the shape of the saddle - whether it is more pear or T-shaped in plan view, i.e. how fast does it neck down?

Cycletography

I echo the sentiments of nomadmax and Carbonfiberboy... shape matters. Your riding position also matters. Generally speaking, your saddle width will be narrower as your riding position gets more aggressive and wider as your riding position becomes more upright.

My sit bones are approximately 10.5cm, so theoretically a saddle as narrow as ~125mm should fit me. However, in a "touring" position I've ridden a 155mm Ergon saddle that felt like my butt was going to swallow it (very uncomfortable to say the least) and I own a 157mm Gilles Berthoud Aravis that fits my booty like a glove (it's perfect). On a road bike with endurance geometry a saddle width of 146mm is excellent for me. Anything less than 140mm would likely start to become uncomfortable unless I was on an extremely agressive race bike.

At the end of the day, even if you know your sit bone width and can thus estimate proper saddle width for you, you still need to ride the saddle to know if it will work or not. Once you find that correct combination of width and shape it becomes much easier to experiment going forward.

SkipII

Thanks all. With this advice, I was able to buy from private party a 143 mm Cobb RANDEE that fits my sitz just right.