Measuring saddle setback on different saddles

[FastforaSlowGuy]

I'm using my CX bike to experiment with some different saddles. Given the differences in shape and length, is there a reliable way to measure saddle setback? When moving the same saddle across bikes, I use the nose. But the nose on some is longer than on others, and where on the saddle a rider sits can also vary. My historical go-to saddle has been the SMP Evolution, but I'm interested in trying some Prologo and Specialized saddles.

[Climb01742]

I've always used the nose too, but I've seen folks use the center of the saddle, measured nose to tail, as the constant point from saddle to saddle to align behind the BB.

[e-RICHIE]

Rest a 6 inch or 8 inch square on the top tube and back it into the saddle nose. Mark the area where it stops.
Then compare marked spots with each other as you select other models, and place them in different areas
over the bicycle atmo.

[guido]

I've been using the spot where my 140mm sit bones (or measurement of same distance...) come to rest as the reference point.

[bluesea]

Ymmv but the nose (or tip of the nose) doesn't determine where my sit bones gravitate on different saddles. With that in mind and for a starting point, I initially place the newer saddle over the existing mounted saddle to determine the new setback.

[believe]

I use the angle between the greater trochanter and BB when helping clients try multiple saddles. Without a mocap/retul system, you could have someone take a measurement from your GT to the stem or bar for easy position replication.

[MattTuck]

From a saddle trial standpoint, this is a very frustrating issue. Ideally, everyone would sit on a given saddle the same way, the saddle could have some sort of "sit bones here" indication, that you could replicate on different bikes and different saddles.

Unfortunately, that isn't the case as different people sit on different saddles differently. Still, you'd think that there would be some bell curve around which the population is centered, and that mean could be indicated on the saddle.

Using the nose of the saddle as an alignment tool across different saddles is silly. The nose gives absolutely no information about where on the saddle you actually sit.

I like the idea that eRichie suggests, if you have several known saddles that work for you, you can use the different in the nose positions to figure out where you sit on the saddles, and maybe use that to extrapolate to a new saddle. Still, it is a guess.

[zap]

I don't measure to the nose.

I measure to the widest point of the saddle. I also "overlay" the saddles to compare the flair and then also look at the profile and adjust accordingly.

This should get you pretty close.

[MikeD]

I measure from the back of the saddle to the bars. My Fitstick measures from the back of the saddle too.

[buldogge]

It may be silly...but...I use the saddle tip (with the speed square on TT method) and then simply make fine adjustments after real world testing/riding. I tend to use "similar" shaped saddles on most bikes, so it has not been a huge issue.

I think any fit adjustments need real world fine tuning, really.

-Mark in St. Louis

[Black Dog]

It has to be where your sit bones are located for the majority of your riding. Easy to find on some saddles not so easy on others. Measuring from the GT is a good idea.

[Gummee]

I remember reading somewhere that the pro team wrenches use a spot on the saddle that's 100mm wide. ...at least I think I read that somewhere.

Could be wrong tho, so 2x check that info

M

[davidcha64]

I do what someone else also suggested: put the new saddle atop an existing known good setup. Then I take a look at the setback and nose position and then I use that to position the new seat. I ride around 5 - 10 miles and then adjust if needed. YMMV

[Ti Designs]

Given that riders sit differently on different saddles, I'm going to make the bole statement that it doesn't matter where the saddle is, only the rider. Measuring from the tip or tail only works if you're using the same saddle. The Arione and the Gobi (both my Fizik) have the same shape, but the Arione is much longer, measuring from the tail would clearly be wrong...

Here's an idea that doesn't involve buying a Retul system, but is just as accurate: Set up a trainer, put the bike on it with a known saddle and position. Place a maker on your hip - I use stickie dots, you can use a gold star if you want. Put a laser pointer (makes a great cat toy) on a tripod - you don't have to get fancy here, using a chair and duct tape works just fine. Set up the laser pointer so it hits the marker on your hip when you're on the trainer. Don't move the trainer, switch saddles, get the saddle height the same, guess at fore/aft. get back on the bike, pedal for a while, if the laser isn't on the marker, move the saddle.

If you want to make this easy in the future, make a mark on the chainstay at a known distance from the bottom bracket, then drop a line down from the saddle and use a sharpie to mark where that line is on the side of the saddle. From then on, use the line as your measuring point - problem solved.

Added bonus: You're going to notice that the dot moves up and down more with some saddles than with others. I'm not saying this is an indication of a better or worse fit, but if you're chasing lower back or hip or knee issues, it's worth knowing.

[John H.]

I agree with Ti.
Saddle setback itself can be really different with different saddles and different bikes.
What matters is that the saddle setback puts the rider in their preferred position in terms of setback and leg extension.
A goniometer and plumb works great for this if you have an experienced helper or fitter.
I am not advocating KOPS, but KOPS is a good landmark to see if you are fore or aft vs. your original bike and saddle.

[wallymann]

I remember reading somewhere that the pro team wrenches use a spot on the saddle that's 100mm wide. ...at least I think I read that somewhere.


i use the same saddle everywhere so this is a non-issue for me, but ID'ing a common width somewhere in the middle or 2/3 back from the nose of the saddle as your point-of-reference makes alot of sense.

[classtimesailer]

Guess and Check. Then, write the numbers down for the Best Guess for that bike and that saddle. My saddles (4 different models on 3 bikes) play musical chairs from time to time and I measure saddle tip to center of bars for each combination.

Jeff

[Lewis Moon]

Ima gonna resurrect this thread. I've been struggling with saddle position on my Raleigh RXC. I have always measured from the nose to a plumb line at the center of the BB and set up the rest of the measurements from that. It's always been pretty good, but on the RXC, I feel that I need to be up on the nose of the saddle all the time, putting weight on my hands. I measured my "gold standard" bike (My Masi 3V) and the measurements are spot on except that the RXC has about 2cm less drop from the saddle to the bars.
The Masi has a previous generation Prologo Scratch saddle and the RXC has a new Fizik Aliante. I'm going to swap saddles and use the same measurements to see if that helps. I'm pretty sure it's an issue as to where my sit bones should actually be on each saddle. The Aliante has a droopy/pointy nose that may make the nose functionally longer.
PS: does anyone else hate the pointy noses manufacturers are putting on the new saddles? I really have to be careful when I sit down after being out of the saddle. If I don't get it exactly right, my shorts can get caught on the nose and I have to get back up. I also hate that I now have something pointy in my back at stop lights. Seems to be their answer to nobody's question.