positioning two saddles of different lengths?

[Climb01742]

how do folks position a saddle (let's say a new saddle that you're trying out) that is a different length than your normal saddle?

or said another way: on two saddles of differing lengths, how do you position them so that, on both saddles, your sit bones retain their same position relative to BB setback?

am i being clear? thanks!

[e-RICHIE]

go by feel atmo.

ps

arrange disorder

:D ;) ;)
;) :p :o
:( :cool: :p

[MattTuck]

I hate to say it, but I think it is just trial and error. I think everyone's butt is slightly different, so even on the same saddle, person x may sit at a different fore/aft position than person y.

I'd probably just try to align as many of the 'anatomical' features as you can to your existing saddle, namely where the saddle 'flares' out, rather than the front or the back.

[flydhest]

I too have asked myself that question when reading on various builders' webpages about the important measurements. Saddle position relative to pedals is critical, how to measure it seems like it would depend on the saddle, and comparing across multiple seems fraught. I tend to measure to the point on the rails where the clamp is and then use Richie's technique . . . go by feel. It's usually pretty close.

[93legendti]

Count me in as another that is curious. I use the 2nd to last generation of Selle Italia trans am flite gel flow saddles and buy them whenever I find them. I have an Apside I have been meaning to try but have been too lazy to spend the time trying and erroring to get a new saddle right...:(

[zap]

Ditto what mattuck posted, take several measurements of the saddles cross section (start of flare, mid-point and widest), compare with previous saddle and adjust based on best compromise.

Then on bike feel (tilt & height has to be tweak too) and confirmed with plumb.

[David Kirk]

If you wanted to get anal about it you could drop a plumb-bob from your knee at reference it to the pedal with the first saddle and set the second one to match. Otherwise it's by feel.

Your sit bones will find the place they are happy on a given saddle (I like happy sit bones) and it may not be at all the place you may think they would be relative to the taper and flair of the saddle.

Dave

[dhoff]

I use best guess and then a 4' level instead of a plumb bob to see where I am. My ass will find its spot on the saddle but I want position to be exactly the same relative to the bottom bracket. I have seen that my knees pay the price when it's not. I usually cannot tell the difference until about 100 miles into a ride.

-d

[flydhest]

If you wanted to get anal about it

Dave

see . . . that's funny 'cuz we're talking about where your butt goes.

[Peter P.]

As Dave Kirk said, the only reliable way to duplicate the position is to set the bike up on a trainer and find the comfortable spot on the existing saddle. Then use the plumb bob and repeat with the new saddle, using the same fore/aft measurement.

It's not to imply or start a discussion on the right/wrong of KOPS, but setting up your position on both saddles, this is the way to go.

[firerescuefin]

I use best guess and then a 4' level instead of a plumb bob to see where I am....-d

This...and I'll go out for a 30-50 mile ride with multi tool and level in back of jersey to adjust mid ride if I don't have it right. All the plumb bobbing may not account that your @ss's comfort spot might be a little different on the new saddle.

[93legendti]

This...and I'll go out for a 30-50 mile ride with multi tool and level in back of jersey to adjust mid ride if I don't have it right. All the plumb bobbing may not account that your @ss's comfort spot might be a little different on the new saddle.
Me too. Plumb bob never works that well for me.

[floxy1]

I've had good luck measuring from BB to wall and widest part of seat (or where my sit bones are) to wall and take the difference. I try and keep this distance relatively close between bikes.

[Gummee]

This...and I'll go out for a 30-50 mile ride with multi tool and level in back of jersey to adjust mid ride if I don't have it right. All the plumb bobbing may not account that your @ss's comfort spot might be a little different on the new saddle.I'm with you. I end up with the multitool out on lots of rides.

I do not, however, do that on fast rides or where people are going to be waiting on me. I'll take another bike that's 'right' instead

M

[Kontact]

I've found that reach to the bar makes things pretty obvious. I have one bike that seemed like the stem was too short - then I measured set back and found that the saddle was further forward than my other bikes.

I moved the saddle back and the reach suddenly was right.


My example is with the same saddle on two bikes, but the same principle applies. A plumb line measurement is another good way.

Another method is to note how far the old and new saddles stick out in front of your shorts when seated, and use the difference to measure back from the handlebar or stem.


Whatever method, expect to make the adjustment and then readjust after you have some miles on.

[floxy1]

While I agree reach can help you determine if fore/aft is correct I don't believe you should use fore/aft to help with reach. The two should be mutually exclusive according to the fitters I've worked with.

[zap]

If you wanted to get anal about it you could drop a plumb-bob from your knee at reference it to the pedal with the first saddle and set the second one to match. Otherwise it's by feel.

Dave

I don't trust my feel in this regard.

I've invested to much time in research and adjusting and ride time to improve the health/ability of my one bum knee. Position related to kops is critical for those with osd.