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-   -   0 setback seat post? (https://www.bikeforums.net/showthread.php?t=1255604)

Helderberg 07-23-22 01:28 PM

0 setback seat post?
 
Has anyone here used a 0 setback seat post and if so how did you like it? Did it fix the issue and what was it or make things worse?
Thanks in advance, Frank.

Bald Paul 07-23-22 02:05 PM

A lot depends on bike geometry and your personal fit. I have used both zero setback and setback seatposts, depending on the bike. What issue are you trying to fix?

terrymorse 07-23-22 03:20 PM

Yes. I replaced my bikes setback post with one that has zero setback.

Why? Because I like to climb with my hands on the handlebar tops. With the saddle slightly forward, my hip angle is larger, and I can generate more force on the pedals.


https://cimg2.ibsrv.net/gimg/bikefor...11716093d.jpeg
Terry's Scott Addict R1

Helderberg 07-23-22 04:20 PM


Originally Posted by Bald Paul (Post 22585074)
A lot depends on bike geometry and your personal fit. I have used both zero setback and setback seatposts, depending on the bike. What issue are you trying to fix?

The saddle I am using now has shorter rails than my last saddle. The reach is different enough that I feel it in my shoulders and lower back.
Frank.

Bald Paul 07-23-22 05:51 PM

Is your reach too long now? You have to consider your seated position relative to your BB, as well as to the bars. If the saddle needs to be moved fore or aft to correct the BB distance, you'll have to experiment with seatposts (0 or offset). If it's just reach, maybe a shorter stem would work for you.
I went for a professional bike fitting a couple of years ago. It was amazing how small differences in saddle fore/aft and stem length made the bike much more comfortable. Well worth the money, IMHO. In fact, I'm probably going to have another done to get my new bike properly set up.

Helderberg 07-23-22 06:46 PM


Originally Posted by Bald Paul (Post 22585281)
Is your reach too long now? You have to consider your seated position relative to your BB, as well as to the bars. If the saddle needs to be moved fore or aft to correct the BB distance, you'll have to experiment with seatposts (0 or offset). If it's just reach, maybe a shorter stem would work for you.
I went for a professional bike fitting a couple of years ago. It was amazing how small differences in saddle fore/aft and stem length made the bike much more comfortable. Well worth the money, IMHO. In fact, I'm probably going to have another done to get my new bike properly set up.

I have changed from a saddle with long rails to a Brooks and can not get the saddle to BB dimension the same. My current seat post has an extension off the back that is great for rail support but hits the upward curve of the rails on my Brooks. Thought about cutting it but that would be a last resort. Thanks for your response.
Frank.

big john 07-23-22 07:49 PM

I use zero offset posts on all my bikes, have for years. I'm long legged and can't lean forward like the old days. I like the bar high, maybe an inch and a half below the saddle..
After breaking several posts I started using Thomson posts and have never had an issue with one. The exception is the mtb which has a KS dropper which is also zero offset. That bike has a slack seat tube angle which puts me way back when I get it high enough.

t2p 07-23-22 09:23 PM

https://cimg4.ibsrv.net/gimg/bikefor...8342a40d6.jpeg
Thomson

I've used Thomson zero offset posts since they were first introduced back in the day

before that used Ringle Moby and Syncros posts on a few bikes

ofajen 07-24-22 04:15 PM

Both my bikes have zero offset posts but that wasn’t why I got them. Long years with a Campy two bolt offset post and Ideale leather saddles spoiled me on having the adjustability of the two bolt design.

When I switched to more modern Volt saddles for different frames, the zero offset posts were what I could find in two bolt posts. Turns out the Volt has more range on the rails and can give similar positions on a zero offset post.

Otto

beng1 07-24-22 08:06 PM

You need this thread badly; https://www.bikeforums.net/classic-v...es-thread.html

Helderberg 07-25-22 08:01 AM


Originally Posted by beng1 (Post 22586414)

Interesting read, thanks. As is normaly the case, the posters got a bit off topic but I do get what the subject of the post is.
Thank you, Frank.

Bob Ross 07-26-22 09:06 AM


Originally Posted by Helderberg (Post 22585031)
Has anyone here used a 0 setback seat post and if so how did you like it? Did it fix the issue and what was it or make things worse?

I used one once many years ago. I didn't buy it to fix an issue, I just needed a seatpost that would fit an old frame with an odd seatpost diameter and that was the only one I could find.
Turned out riding with a 0 setback seatpost caused an issue, and so I stopped riding that bike until I could find a setback seatpost to replace it with.

Helderberg 07-26-22 10:30 AM


Originally Posted by Bob Ross (Post 22588085)
I used one once many years ago. I didn't buy it to fix an issue, I just needed a seatpost that would fit an old frame with an odd seatpost diameter and that was the only one I could find.
Turned out riding with a 0 setback seatpost caused an issue, and so I stopped riding that bike until I could find a setback seatpost to replace it with.

Could you explain what the issue is that the seatpost caused? Thank you for your post.
Frank.

Bob Ross 07-26-22 11:39 AM


Originally Posted by Helderberg (Post 22588228)
Could you explain what the issue is that the seatpost caused?

It was simply impossible to get the saddle into a position where I could fully engage the larger leg muscles (quads & glutes) during the power portion of the pedalstroke. I was too "on top of" the cranks. Getting a seatpost with ~25mm of offset resolved the issue nicely, allowing me to feel more comfortable during hard efforts and generate more perceived power (though I don't have any objective data to back up that last assertion).

fwiw nowadays all my bikes are set up with about 8cm of saddle setback [nose of saddle behind center of bottom bracket] but back then with a Thomson straight 0-offset seatpost, a Selle Italia SLR saddle, and this old (circa 1986) Bridgestone frame, I simply could not achieve that much setback.

davester 07-26-22 12:02 PM

In general, it's a mistake to alter the saddle fore-aft position to correct the reach to the bars. The fore-aft saddle position relative to the bottom bracket should be determined based on the proportion of the rider's weight supported by the handlebars (i.e.move the saddle back to reduce the weight on the bars, move it forward to increase the weight, bearing in mind that too much weight on the bars often leads to back, neck and shoulder pain). Only after that weighting has been determined should you adjust the reach to the bars by altering stem length.

Polaris OBark 07-26-22 12:14 PM

Having recently made that very mistake on my wife's bike, I have a nice Salsa carbon 30.9 mm zero-setback seat-post that hasn't been ridden on yet.

Oldguyonoldbike 07-29-22 04:36 PM

I have a zero offset post on one of my bikes. The frame is about half a size too big for me and I seem to have short thighs for my height. The post puts me in a position more on top of the pedals. My knees are happier that way.

Road Fan 07-29-22 09:37 PM


Originally Posted by Bob Ross (Post 22588310)
It was simply impossible to get the saddle into a position where I could fully engage the larger leg muscles (quads & glutes) during the power portion of the pedalstroke. I was too "on top of" the cranks. Getting a seatpost with ~25mm of offset resolved the issue nicely, allowing me to feel more comfortable during hard efforts and generate more perceived power (though I don't have any objective data to back up that last assertion).

fwiw nowadays all my bikes are set up with about 8cm of saddle setback [nose of saddle behind center of bottom bracket] but back then with a Thomson straight 0-offset seatpost, a Selle Italia SLR saddle, and this old (circa 1986) Bridgestone frame, I simply could not achieve that much setback.

Hi, Bob, I sympathize! I have the same desire, to have more saddle setback for better comfort and to better use the meager “old guy” strength that I have. I found a small collection of saddles which help me a lot to get a good setback position. The saddles are Specialized Toupe Gel, Selle AnAtomica with rails that have 10 cm of straight saddle (on the newest family of models, the long rail is defunct :notamused:), a Ideale 92 which offers 2 cm more than a Brooks B17. I also have a Rivet Independence with 8 or 9 cm (Rivet says 9 cm but I'm not sure yet! But right now i like it!

For any saddle the limit of setback is when the position of the forward end of the straight saddle rail is up against the front edge of the saddle rail clamp on the seatpost. The saddle cannot be slid back any farther than that point. So getting setback is also about moving the seat post’s saddle clamp back. For this I use the Nitto S-84 seatpost, to get about 20 mm more setback than a Campy two bolt Microadjust offers. Additionally using an older Toupe saddle or a steel-rail Selle AnAtomica can place your butt significantly behind the seatpost, on frames with a 75 degree or steeper seat tube. One of my bikes with that steep angle is my classic 1980 Masi, and I worry that the extra bending moment may stress the frame. For me a 70 degree seatpost seems very suitable.These two measures result in a weird-looking bike.

To have a less weird looking bike you just need a frame which has i highly laid back seat tube, such as the mentioned 70 degree. This is why I’m experimenting with a 1952 Redge 27” Clubman-style bike. This one and the Raleigh Super Lenton were the top “racer-boy” (translation: aspiring long-distance time trialers, such as Lands' End to John O'Groats or London to Edinburgh. The way amateur cyclists now think they may be able to show the talent to go to TdF, amateurs tried to work up their skills to conceive of running such great and classic time trials.

In any case I’m building up my Rudge to thrust it into service for another aspirational (I guess there's a fine line between aspiration and fantasy ... ) TT rider, me. But it has a 70 mm seat tube angle! In any event it should make a suitable perch for local rides, 10 to 40 miles reasonable this year!

As a measurement I look at setback as the distance from a plumb line to the BB axis to the widest point of my saddle. This number lets me set up any saddle to satisfy my setback criteria, choosing a seatpost which will allow it, if I can find such a seatpost.

A few take-always: use a saddle with a long straight rail, use a seat post where the saddle clamp is “pretty-far back” from the seat tube axis, and use a frame with a shallow seat tube angle, maybe 72 or less as a target range. Between those three I can find a 28 to 29 cm setback from my contact point and the BB plumb line for quite a few frames. It lets me see if the particular solution looks reasonable and safe for the frame. This measuring works for odd saddles like
Selle AnAtomica, Rivet, and others with long rails, and more conventional racy saddles like Specialized Toupe, and classics like Brooks and Ideale, and Selle Italia.

I can also set reach practically by measuring from the widest point of my saddle to a line connecting the front of the hoods. I can see if I need a different top tube, stem extension, or handlebar reach, and match the riding properties across my collection of frames.

If folks want I can work up some pictures.


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