questions: seatpost, saddle position changes w/ fitting

[azfiddle]

Okay knowledgeable gals out there-

Last week I went in for the way cool 3D Retul computerized bike fit I won from Carmichael Training systems (2 hours, 2 guys, 3 cameras, many angles and overall very interesting experience). I have had the bike 4 months, had a pretty careful fit at the bike shop, but wanted to try it in case there was anything else that could be improved, given that I have had physical issues (arthritis L4-L5, and a whole series of problems with my hip going out of alignment and other areas in my leg responding with problems when they try to compensate).

Possibly relevant info: I'm 5'1", with a very short torso, have a 44 cm frame Specialized Ruby, with the stock seat post but Jett saddle replaced the Lithia saddle that came with it.

Net result, they wanted to move the saddle up and forward a bit to improve the angle at my knees and hips. However, my saddle was as far forward as it can be and the only way they could move it further forward was by turning the seat post 180 degrees. (which they did)

So, I do like the change in position but....my saddle won't stay level anymore. It started to tilt up and my DH tightened it back down, but it started creeping up again.

questions
Do I need a different seatpost if I want to keep this set up? We were concerned that tightening it too much might be a problem...

Thanks for your insights

[OakLeaf]

I don't know exactly what your seatpost setup is, but the MacGyver method of making a seatpost clamp micro-adjustable is to shim the serrated part with a piece of metal cut from a can. I've had the best luck with steel (aluminum is too soft and compresses pretty quickly) folded over once to make a double thickness. It takes a little fiddling, but it can be done. Use snips to cut it and pliers to fold it (so you don't cut yourself).

Still, a micro-adjustable seatpost sure is nice, and between that and your issue with setback, I guess it depends on your budget.

[Becky]

Is it a zero-setback seatpost? If not, that would be an easy enough fix.

[azfiddle]

Sorry, can you explain what "zero setback seatpost" means?

[withm]

A zero setback seat posts is completely straight, with the mounting mechanism at the top. A set-back seatpost is shaped sort of like a reversed number "7" or rather an inverted letter "L". The mounting mechanism is "set back," typically about 25mm (but they vary) or from the actual seatpost thus extending the reach, and also changing the angle of your leg while pedaling.

A picture says 1,000 words - there are photos at this website

http://en.wikipedia.org/wiki/Seatpost

[indysteel]

Sorry, can you explain what "zero setback seatpost" means?

As I understand it, it basically means that the seatpost clamp is directly above the post itself, rather than offcenter or "set back." Your seat tube has an angle (say, 74 degrees) that effectively changes when you use a seatpost with an offset clamp. By using a zero-setback seatpost, you keep your seat tube angle the same. Some of us (most of us, I'd wager) use an offset seatpost because we need to get farther behind the pedals/bottom bracket than the STA allows. I, for one, usually need a lot of setback.

[nscrbug]

Probably a dumb question here...but exactly how does one know how much setback they need (or don't need, if that is the case)? I've had many fittings (include Retul), but the fitter never mentioned "setback" to me, so I have no clue. FWIW, the seat post on my Cannondale Synapse is one of those teardrop-shaped aero posts, so it's not like I can easily swap it out for something with more (or less) setback. Infact, I really dislike the entire seatpost/clamping system on the Synapse because small adjustments are virtually impossible to make.

[OakLeaf]

If turning the seatpost around 180° did anything at all, then it has some setback. If it were zero setback, then the clamp would be centered over the shaft.

You have some fore/aft adjustment by where you clamp the saddle on its rails, but if you need to go beyond that, then you need a seatpost with a different setback. That's what azfiddle's fitter did. nscrbug, if your fitters never mentioned it, then (hopefully) they were able to place you in the correct relationship with your pedals with the setback you have.

The seatpost on my '07 Synapse is round - I really need more setback and one of these days I'm going to get around to ordering one of those $eatpo$t$ I was asking about - but in the interim I've done fine changing the tilt with shims.

[Hi Ho Silver]

The problem might be that one (or both) of the saddle angle adjustment screws is just hanging on by a thread or two (because the clamp is no longer at the designed usage angle) and therefore can't really fasten securely.

Jean

[Kathi]

Probably a dumb question here...but exactly how does one know how much setback they need (or don't need, if that is the case)? I've had many fittings (include Retul), but the fitter never mentioned "setback" to me, so I have no clue. FWIW, the seat post on my Cannondale Synapse is one of those teardrop-shaped aero posts, so it's not like I can easily swap it out for something with more (or less) setback. Infact, I really dislike the entire seatpost/clamping system on the Synapse because small adjustments are virtually impossible to make.

I knew when the fitter said, "Your femur is so short I can't get your knee over the pedal". He immediately swapped the seatpost with the setback for a zero degree seatpost.

If your fitters were happy with the position of your knee over your pedal then you don't have to worry about it.

[azfiddle]

Okay, so it's definitely a set back seat post.

I'm not too mechanically minded...but my DH wil look at the angle adjustment screws - if that is the problem, can they be replaced with some that would work? And/or we will look at the shim option.

I just want to be sure that it is okay to have the seat post turned around 180 degrees. I never had a problem with the angle of the saddle changing when it was in the original position. I also want to be sure I will not be damaging the seat post in trying to clamp it down.

Thanks for the input.

[Hi Ho Silver]

Okay, so it's definitely a set back seat post.

I'm not too mechanically minded...but my DH wil look at the angle adjustment screws - if that is the problem, can they be replaced with some that would work? And/or we will look at the shim option.

I just want to be sure that it is okay to have the seat post turned around 180 degrees. I never had a problem with the angle of the saddle changing when it was in the original position. I also want to be sure I will not be damaging the seat post in trying to clamp it down.

Thanks for the input.

If your seat post has the "pave" clamp like on my 2011 Ruby Elite below, it will have two bolts. One is normally in the back and is easily accessible - it might be replaceable. The 2nd bolt is directly under the saddle and is barely accessible since the large serrated bolt head is situated between the saddle and the top of the clamp - this bolt may be hard to replace.

I was unhappy enough with the "pave" clamp seat post that I looked around for a replacement, but I couldn't find a zero-setback seat post within my meager budget.

[pll]

Infact, I really dislike the entire seatpost/clamping system on the Synapse because small adjustments are virtually impossible to make.

I do, too. It is working out for me, but I dislike idiosyncratic designs that make it impossible to swap the part with something you can find readily in the market. I saw that in the 2012 models, there is more of the same, except now you can have different 'toppers' on the seatpost, with varying amounts of offset (perhaps that new seatpost is backward compatible with 2010 and 2011 modesl?).

[nscrbug]

I do, too. It is working out for me, but I dislike idiosyncratic designs that make it impossible to swap the part with something you can find readily in the market. I saw that in the 2012 models, there is more of the same, except now you can have different 'toppers' on the seatpost, with varying amounts of offset (perhaps that new seatpost is backward compatible with 2010 and 2011 modesl?).

Hmm...interesting thought. I'll have to check into that. Thanks!

ETA - Ok, I just went to the Cannondale site and I couldn't find any info on different toppers for the seatpost. Looking at the pictures, it looks exactly like the seatpost and clamp that I currently have. Maybe I'm not understanding what you mean by "toppers". Can you explain?

[nscrbug]

Oh nevermind...I think understand now...after clicking on your link to Bike Rumor. I may just have to stop in at my dealer and see if they can tell me if that seatpost would retro fit my 2010 model. I don't see why it wouldn't, since it is still teardrop-shaped to fit the frame and then morphs into a round post towards the top. Now I'm really curious.....