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Zero offset seatpost?

Old 02-11-23, 01:24 PM
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VegasJen
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Zero offset seatpost?

Hey all. I have been trying to figure out what I want to do with my bikes to feel more comfortable and get more power down. The one issue I keep coming back to on all my bikes is I feel like I'm sitting too far back. I want my sitting position to be more forward, over the crank. All my bikes feel like I'm sitting behind the crank, including my Cervelo tri bike.

To that end, I have positioned the seat as far forward on the post as adjustment allows, but I think I would still like to move forward a good 1-2" (2.5-5cm). I've heard of a "zero offset seatpost" but haven't pulled the trigger on one yet. I'd like to pick one up and try it on one bike to see if it gives me what I'm looking for.

Has anyone done this? What is your impression? Where would you shop? Only real online bike store I know of is Jenson. Given this is a trial, I'm want to keep it budget-friendly and the only one they list for <$100 that fits my bikes (31.6mm[?]) is out of stock, I'm looking for alternatives.
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Old 02-11-23, 01:55 PM
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If you like your saddle further forward and you deal well with the extra weight on your arms then go for it. I'm not certain what the offset is on my Tarmac, but it's not much if any. And the saddle clamp is roughly in the middle of the rails. If your clamp is on the extreme of the rail adjustment, I'd get a seat post that puts the clamp back in the middle. Then I'd have more adjustment options open for times I might want them.

I'd buy from any online site that's been in business for a time and you might even find that your LBS sells them just as inexpensive. But that does vary. Some things they'll sell more at cost others they'll have to have their mark up on.

Universal Cycles and Jensen USA are two of the online places I use quite a bit along with Tree Fort Bikes.

But I've also had no issue with others I've used when they've had the better price + shipping. But do beware of the too-good-to-be-true prices you might find.
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Old 02-11-23, 10:16 PM
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Originally Posted by VegasJen
Has anyone done this?
Yeah, I swap in a zero setback if I want to put a set of clip-on aerobars on a road bike.
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Old 02-12-23, 12:28 AM
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I'll check out Universal Cycles. Never heard of them before. But I know of Jensen and the one cheap enough to try for an experiment is out of stock.

As far as weight on my arms, all my bikes have aero bars anyway. I don't use them for aero nearly as much as supporting my upper body. I don't have enough upper body strength to ride on drops for 20 or 30 miles without serious fatigue.
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Old 02-12-23, 11:02 AM
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Originally Posted by VegasJen
I'll check out Universal Cycles. Never heard of them before. But I know of Jensen and the one cheap enough to try for an experiment is out of stock.

As far as weight on my arms, all my bikes have aero bars anyway. I don't use them for aero nearly as much as supporting my upper body. I don't have enough upper body strength to ride on drops for 20 or 30 miles without serious fatigue.
There's plenty of inexpensive 31.6 zero setback posts on ebay from even US sellers. No reason to get wrapped up in the post's origin when it costs $20.

The upper body strength thing is why bikes have set back in the first place. You probably feel too far back because you are trying to rest on your elbows. A tri bike will give you much better geometry for that kind of weight distribution.
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Old 02-12-23, 11:18 AM
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I actually picked up a 51cm Cervelo tri bike a couple months ago. And I like it, but I still feel like I'm sitting a bit too far back. It may just be that I need to stick with a 49-50cm frame, but that's not what I have now so I'm going to have to get creative.
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Old 02-12-23, 11:42 AM
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Originally Posted by VegasJen
I actually picked up a 51cm Cervelo tri bike a couple months ago. And I like it, but I still feel like I'm sitting a bit too far back. It may just be that I need to stick with a 49-50cm frame, but that's not what I have now so I'm going to have to get creative.
Frame size has nothing to do with set back.
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Old 02-12-23, 11:49 AM
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Originally Posted by Kontact
Frame size has nothing to do with set back.
I did not know that. Thank you.
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Old 02-12-23, 12:42 PM
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Originally Posted by VegasJen
As far as weight on my arms, all my bikes have aero bars anyway. I don't use them for aero nearly as much as supporting my upper body. I don't have enough upper body strength to ride on drops for 20 or 30 miles without serious fatigue.
With most everyone else wanting to push their saddles back and "balance" themselves on the saddle with no hands on the bar, I hesitate to point you in that direction as IMO, most go too far back. I've always carried a certain amount of weight on my arms and upper body so I can have my saddle more forward and get better power to the pedals. But I don't use aerobars, however that comment is not a view one way or the other about them. I just don't need them and to me they seem awkward for the maneuverability I want.

But if you are having issues with your upper body and arms getting tired after 20 - 30 miles, then maybe you should consider moving your saddle back some. Pains of any sort will fatigue you and impair your performance in the long run. And possibly bikes that put you in a position where you need aerobars won't be the best geometry bike to move your saddle back without other issues.

Strictly just my 2 cents. I don't know anything about the reasons that might well be very valid for why you have for going that route.

Last edited by Iride01; 02-12-23 at 12:49 PM.
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Old 02-12-23, 03:51 PM
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I can appreciate your perspective, but there was a different reason I gave in my OP, the arm fatigue issue was an aside. I want to be more vertical, at least I want to try it and see how it feels. I've noticed every time I'm trying to put the power down, aside from just standing up and mashing, that I scooch forward, but it doesn't take long before I end up sliding back. So I end up with this tiring routine of scooch forward, slide back, scooch forward, slide back....
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Old 02-12-23, 07:30 PM
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Both of my bikes have zero offset posts. I prefer two bolt posts. The ones I could find for my cheap, old frames with odd seat tube diameters were both zero offset.

However, Im using newer saddles with long rails and I can still get both into a decent fore-aft setting for my needs.

Otto
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Old 02-12-23, 09:37 PM
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Link

My kid has one of these for triathlons.
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Old 02-12-23, 11:04 PM
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Originally Posted by Polaris OBark


Link

My kid has one of these for triathlons.
Dude, that is awesome! It is also cost prohibitive for me. $200 is almost as much as I paid for a couple of my bikes. No ****** here.
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Old 02-12-23, 11:28 PM
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I think I got it on sale, but it is a bit pricey. It is very robust and well-made, so I think you at least would get what you pay for.
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Old 02-13-23, 12:01 PM
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That's funny. Forum software edits the expression "b@ller", which colloquially has no sexual connotation.
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Old 02-13-23, 09:33 PM
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Be careful to keep your cadence up. With your center of gravity directly over the peak power phase of your stroke, it's easy to turn your legs into "pile drivers".
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Old 02-13-23, 09:46 PM
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Originally Posted by Polaris OBark


Link

My kid has one of these for triathlons.
That is...interesting.
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Old 02-14-23, 10:41 AM
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Originally Posted by VegasJen
I've noticed every time I'm trying to put the power down, aside from just standing up and mashing, that I scooch forward, but it doesn't take long before I end up sliding back. So I end up with this tiring routine of scooch forward, slide back, scooch forward, slide back....
That's physic's telling you where you need to have your butt based on your current power output and position you maintain on the bike via all the different geometry and measurements involved. Changing the seat post won't cure that since it seems like the position you have set up on the bike for yourself is telling you to move the saddle back.

Unless I'm misunderstanding what you described. If you want your butt to stay forward then you need to increase your reach to the bars/aerobars and maybe increase your saddle to bar/aerobar drop to a lower position.

Last edited by Iride01; 02-14-23 at 10:45 AM.
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Old 02-20-23, 05:45 PM
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[UPDATE]
Since this was just an experiment, I decided to try a cheap seat post from Amazon. Got it yesterday and put it on my K2. I made an initial adjustment, moving the seat as far forward on the post as allowed and checked the fit. I would say it moved my seating position at least 1 full inch further forward, maybe a little more. I know that doesn't sound like a lot, but it put me more over top of the crank rather than behind it. I also noticed I was able to bring my aero bars forward a good cm and still have good position on the bike.

So I took the bike out today. This was a different route than I did on Saturday. Conditions were different too. This was shorter and a bit flatter, however, I also had a lot more wind today than on Saturday, so that's going to corrupt real data. What I can say is my "seat of the bike shorts" impression is I was able to put a lot more power into the bike. Previously, I felt like I was losing leverage because I was behind the crank. Now I feel much more over top of it, so on my power stroke, I'm pushing down and not forward. I have to say, I really like it. And, again, the data is suspect since it was a different route under different conditions, but my pace today was 1.4mph faster than on Saturday. I actually spent a considerable amount of time in the 20+mph range.

Having said that, I think I would still like to be just a bit further forward, like maybe another inch or two. But eventually you get to a point of diminishing returns. At least right now, for this bike, I'm really happy with where it is.
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Old 02-21-23, 07:41 PM
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I ride bicycles that tend to have pretty slack seat tube angles, like 70. I pieced one together from scratch, gave it a zero-offset seatpost and have started using it this Winter season. So far it's been great. If what people are saying here is true, that my hands will be supporting too much of my weight, I suppose I'll find out on my first longer ride on the bicycle. I can always push the seatddle farther back on a zero-offset, and feel more secure than if I was using a layback seatpost with the seatddle pushed all the way forward, no? Having the seatddle pushed all the way forward on a layback seatpost causes the clamp to eventually loosen up while riding, which is no fun at all.
This Dimension 2-bolt seatpost is what I'm using. I'm pretty happy with it.

Last edited by Nyah; 02-21-23 at 07:45 PM.
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Old 02-21-23, 07:55 PM
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Originally Posted by VegasJen
[UPDATE]
Having said that, I think I would still like to be just a bit further forward, like maybe another inch or two. But eventually you get to a point of diminishing returns. At least right now, for this bike, I'm really happy with where it is.
Depending on the style of your old seatpost, turn it the opposite direction. I've done this to help shrink a bike down for a kid and to move people forward for aerobars. Not every post will allow it but quite a few will allow just enough angle adjustment to allow a saddle to be flat to a few degrees nose down. Otherwise, profile makes a post for putting aero bars on a road bike that moves the seat forward, Thomson's angled post can be turned around for the same purpose.
https://profile-design.com/products/...orward-alloy-1
https://www.retro-gression.com/produ...tback-seatpost
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Old 02-21-23, 08:11 PM
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Ya, I looked at that option first, but the original K2 post doesn't have enough adjustment. It would be pretty significantly nose-up if I tried turning it. My Specialized, OTOH, I might be able to do that, but I'm sure I'll need to swap out at least one, if not both bolts to get enough adjustment.
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Old 02-21-23, 08:52 PM
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Originally Posted by VegasJen
Hey all. I have been trying to figure out what I want to do with my bikes to feel more comfortable and get more power down. The one issue I keep coming back to on all my bikes is I feel like I'm sitting too far back. I want my sitting position to be more forward, over the crank. All my bikes feel like I'm sitting behind the crank, including my Cervelo tri bike.

To that end, I have positioned the seat as far forward on the post as adjustment allows, but I think I would still like to move forward a good 1-2" (2.5-5cm). I've heard of a "zero offset seatpost" but haven't pulled the trigger on one yet. I'd like to pick one up and try it on one bike to see if it gives me what I'm looking for.
Has anyone done this? What is your impression? Where would you shop? Only real online bike store I know of is Jenson. Given this is a trial, I'm want to keep it budget-friendly and the only one they list for <$100 that fits my bikes (31.6mm[?]) is out of stock, I'm looking for alternatives.
Try rotating your seat post 180 degrees, I have done this on more than one bike and it has worked great. I have used a round file to modify the clamp on one seatpost that was not designed to be rotated 180 degrees, to get it to work anyway. Of course you have to be a bit of a mechanic/engineer to know what to do and how much material removal will not weaken the part, but having your weight right over the seatpost instead of hanging behind it, puts a lot less stress on all of these parts.....

I have been experimenting with moving the seats forward on all of my bikes for a few years now. Especially on older bikes, or bikes not designed for power like a TT or track bike is, I think this can help a lot. I think there are a lot of advantages to having your body forward on a bike and also to being closer to the bars. Here is my thread on the subject with photos of my bikes; The seat forward on old road-bikes thread....

Last edited by beng1; 02-21-23 at 08:57 PM. Reason: adding info...
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Old 02-22-23, 08:23 AM
  #24  
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Originally Posted by Nyah
I ride bicycles that tend to have pretty slack seat tube angles, like 70. I pieced one together from scratch, gave it a zero-offset seatpost and have started using it this Winter season. So far it's been great. If what people are saying here is true, that my hands will be supporting too much of my weight, I suppose I'll find out on my first longer ride on the bicycle. I can always push the seatddle farther back on a zero-offset, and feel more secure than if I was using a layback seatpost with the seatddle pushed all the way forward, no? Having the seatddle pushed all the way forward on a layback seatpost causes the clamp to eventually loosen up while riding, which is no fun at all.
This Dimension 2-bolt seatpost is what I'm using. I'm pretty happy with it.
If you're starting off with a 70 degree STA, using a zero setback post is just going to get your saddle back into the normal setback range. A 70 STA is going to put your saddle 3cm further back than a 73 STA. Subtracting the normal 25mm of seat post setback by using a zero still puts your saddle 5mm further to the rear.
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Old 04-06-23, 03:43 PM
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I'm more comfortable on a zero setback post, but I think it's mainly because I have very short legs - 5'10", and 30" inseam pants (the shortest you can typically find off the rack) often drag. As such, a setback post puts my knee too far behind the pedal... I think. I've never been able to get into a comfortable spinning cadence with a setback post, but can with a straight.

Also, for future reference, if you have a 31.6mm seat tube, you don't necessarily need a 31.6mm post - there are adapter shims that will adapt a common 27.2mm post to 31.6, which opens up options a bit. Current trends are to have a skinnier post that'll have more 'give' over bumps; 31.6mm seatposts are used for more frame stiffness under power.

As someone above mentioned, two bolt posts are great - I've sheared the bolt off of a single bolt post in the past. My preferred option is a Thomson - my Elite is 22 yrs old (replaced the single bolt that sheared), and is now on its second bike.
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