George

When I drop the plumb line, from the top tube, to the center of the BB and then from the nose of the saddle, to the chain stay, I have 23mm, where and how do I apply this measurement ? Thanks for any replys.

card

**********????

How are you wanting to apply the numbers, George. I'm confused.

stonecrd

Hmm, saddle setback is measured by dropping a plumb line from the saddle nose and measuring from the BB center to the plumb line. Is that what you are doing? If so some fit programs like the one on Competitive Cyclist will provide a optimum setback based on your measurements. I think mine is like 4.1 - 4.5 cm.

George

Yes that's what I'm talking about. I have a setback seatpost coming and I wanted to know how far to go. From the BB to the chain stay where the plumb line rest is 23mm. Do I have to find a place on the saddle rail and measure back so much or what. I don't know if I'm readind this right or not. I've read you have to get the center of your rail, and do what with it, I don't know. Is the mark on the center of the rail, plus 23mm, for set back. That's what I'm trying to figure out,thank again.

BluesDawg

Engineers are so entertaining.

stonecrd

For setting up a new seat or post I do the following:

Level seat with a carpenters level so that it is flat
Adjust the height by measuring BB center to saddle top

Adjust the fore aft position by measuring:
Saddle nose to front of bars
Saddle setback via plumb bob

If you don't know your measurements a good place to start is: https://www.competitivecyclist.com/za...LCULATOR_INTRO

Like anything when it comes to calculators this is a reasonable place to start and then go ahead and tweak you seat if you find issues. The measurements that they ask for are pretty much what a LBS will do when they do your fit. the advantage of a fit though is that you can be on the bike and have someone else looking at your body position and also doing things like measuring the angles of your legs at various pedaling positions.

George

Thanks stonecrd, I've read that web site before. I know how far I have to be back, and I have my saddle at the correct height. I have the setback seatpost coming and it's going to give me 23mm setback. I was trying to figure out if that's going to be enough or not. I guess I'll just have to try it out, thanks again, George

pdq 5oh

This may not be very scientific but, I've found the best seat position by riding my bike and making adjustments based on comfort and what I feel to be most efficient.

stonecrd

Sorry I was not real clear at what you were getting at, so I just covered all of the bases. I think if you measured the setback with the seat rails all of the way back on your current post and then added the 23mm you would have your maximum setback.

Hask12

Yipes

MNBikeguy

+1
Make sure the plumb bob is ripe and washed before eating......

Camilo

I've found the plumb bob to be easier than the apple bob.

George

I guess I'm second guessing myself, I did add the 23mm to the setback as well, but I was wondering if that was going to give me enough. I order it from Spicer and he was trying to talk me into something with more setback, but after reading about seatpost, on Peter White's site, and he said he liked the Salsa, because of the way it adjusted, I wanted to go with that one. Anyhow I'll just leave it at that and hope it works. Thanks again everybody.