Fancy seatpost for more saddle angle adjustment?

[efair]

I'm relatively new to the bike world and I'm surprised how much there is to learn about basic bike geometry. Today's challenge is my wife's seat post on her Electra ebike. Her combination of seat tube angle, seat post design, and desired saddle angle are the issue. Her saddle adjustment is of the "two bolt" variety, with one forward and one aft bolt as shown below (this is a google image, not her seat post). In order to adjust her saddle angle to her liking I had to put a shim between the cylindrical mating surfaces in the seat post - only then could I adjust her saddle nose low enough for her. The geometry at the head of the seat post seems to be the issue:

Specifically, the angle shown in red seems to be working against me here. When I "middle" the two bolts, i.e. set the saddle angle at the center of the adjustment range, the nose of the saddle points up at a ~10 degree angle. When I fully loosen the rear bolt, and fully tighten the front bolt, i.e. set it to the extreme nose-down end of the adjustment range, the saddle is about horizontal - but she wants the nose down ever-so-slightly more. To accomplish this, I inserted an aluminum shim, and that did the trick - it added just enough additional range, that she is happy. However, I am not so happy to have a shim here - I would rather have a seat post that does not require a shim.

When reading about seat posts, I see the specifications given for length, minimum insertion, and offset, but I never see specs for the angle shown in red above. I would think, ideally, the red angle here should be complimentary to the seat tube angle on the bike - i.e. if the bike has a 57 degree seat tube, this red angle should be 33 degrees (57 + 33 = 90, the definition of "complimentary"). Maybe bikes in general don't vary in seat tube angle that much, so this just usually isn't important?

I'm wondering if anybody else has faced this, and if there are "two bolt" seat posts that might offer a larger range of adjustment than hers, or if there are other seat post designs that might accommodate a larger range of adjustment? I did try a serrated one-bolt design, which did seem to have more adjustment range, but the stepped nature didn't allow me to dial it in exactly.

I also saw somewhere a seat post that offered an eccentric bolt for the saddle angle adjustment, but I can't find it now - has anybody seen one of these before?

TIA!

 

[Base]

I was thinking of the switchgrade solution

 

[juggernaut1]

I installed the fair bicycle drop best uc saddle clamp on my eMTB. I had a different use purpose in that I wanted to move the saddle further aft (provides up to 27mm rear aft adjustment). Dropper posts generally don’t have a rearward offset like most fixed seat posts and I was on the limit of the seat rails. It can also be installed the other way to give you up to 27mm forward adjustment.

The Uc saddle clamp also has the ability for some radical saddle angle adjustments through the use of shims that can be added or removed as required. Price might be offensive to some but beautifully made piece of gear - made in Switzerland.

FAIR Bicycles DROP BEST UC Offset Saddle Clamp Review: Back and Forth – Travis Engel

The FAIR Bicycle DROP BEST UC is more than just an excuse for Travis to talk about how much he really loves steep seat angles. It can add years of life to an outdated mountain bike by moving its saddle forward by more than an inch. Or, it's a solution for people who really hate steep seat...

theradavist.com

Couple of pics on my bike.

 

[zbikeman]

FWIW, I hate these two-bolt adjusting seatpost heads. It's always a guessing game to get the right torque on both relative to whatever angle you want.

With a one-bolt standard microadjust post, sometimes a more severe angle can be achieved by turning the saddle 180 degrees, typically clamp forward instead of clamp back.

I once heard someone say it's incorrect to have the clamp forward. According to Barnett's (Bicycle Institute) manual, there is no "correct" orientation - it's whatever works.

 

[stompandgo]

I don't know what's up with her seatpost, but it's not normal. You should not need a shim. The way I adjust a two bolt seatpost to be level is to lightly snug both bolts with the saddle pointing down, then crank the rear one to level it, then snug both equally. That's for level. Adjust as necessary. No shims required.

 

[Gionnirocket]

I concur.. My current Promax seat post is the same two bolt design. I can get any angle reasonably desired.
Just follow Stompś instructions. To make small adjustments I loosen one as I tighten the other alternately

 

[Stefan Mikes]

@efair didn't you orient the seat-post clamp part the wrong way?

 

[Nvreloader]

Can't the seat post be turned 180*,
That's what I had to do, my Montague seat post.
Then adjust to fit...

 

[Chazmo]

I don't know what's up with her seatpost, but it's not normal. You should not need a shim. The way I adjust a two bolt seatpost to be level is to lightly snug both bolts with the saddle pointing down, then crank the rear one to level it, then snug both equally. That's for level. Adjust as necessary. No shims required.

Yeah, I’m not getting the “shim” thing either. I’m not quite sure what @efair is talking about. Is it shown in the picture?

FWIW, I hate these two-bolt adjusting seatpost heads. It's always a guessing game to get the right torque on both relative to whatever angle you want.

I dislike them too. Takes me quite a while to get the seat angle right. But, that’s all I’ve ever had to work with. I do like that they’re adjustable, as that’s certainly a requirement for me so I’ve never tried anything else. Maybe next time I’ll look for one of those one-bolt posts.