Choosing the right Seat Post

Mersch
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Choosing the right Seat Post

Postby Mersch » Sat Jun 30, 2018 1:43 pm

Hi all,

So I have recently installed some mini clip-on aero bars on my road bike for Triathlon races and have decided to buy a seperate seat post and saddle which I can swap for races/ being in the aero position. However I am not sure whether to buy a straight or setback seat post and what the differences are between the two?

Cheers.

eeksll
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Re: Choosing the right Seat Post

Postby eeksll » Sat Jun 30, 2018 3:10 pm

are you asking what a set back seat post is or are you asking which is more aero?

Jmuzz
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Re: Choosing the right Seat Post

Postby Jmuzz » Sat Jun 30, 2018 3:13 pm

Get the seat first and sort out its position.
If that is forward of the mid rail point then get the setback.

Mersch
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Re: Choosing the right Seat Post

Postby Mersch » Sat Jun 30, 2018 3:28 pm

Jmuzz wrote:Get the seat first and sort out its position.
If that is forward of the mid rail point then get the setback.


Thanks for that.

So does that mean once I buy a Triathlon saddle and I am still not comfortable even with the saddle all the forward on the rails, I would need a Setback Seat Post?
Last edited by Mersch on Sat Jun 30, 2018 3:32 pm, edited 1 time in total.

Mersch
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Re: Choosing the right Seat Post

Postby Mersch » Sat Jun 30, 2018 3:29 pm

eeksll wrote:are you asking what a set back seat post is or are you asking which is more aero?


I'm asking whether I should get a straight seat post or one with a setback as I want to feel comfortable on my saddle whilst being in the aero position for triathlons.

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Derny Driver
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Re: Choosing the right Seat Post

Postby Derny Driver » Sat Jun 30, 2018 4:07 pm

Mersch wrote:
eeksll wrote:are you asking what a set back seat post is or are you asking which is more aero?


I'm asking whether I should get a straight seat post or one with a setback as I want to feel comfortable on my saddle whilst being in the aero position for triathlons.

A straight one will give you more options... slide seat back for road riding, forward when you use the clip ons. A set back post is more suited to road riding only.

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MattyK
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Re: Choosing the right Seat Post

Postby MattyK » Sat Jun 30, 2018 6:23 pm

A tri bike (or a bodge thereof) really needs an effective seatpost angle of about 78-80 degrees. The only way to emulate this with a road bike frame (typically 73 degrees seapost angle) is to offset the saddle forwards by at least 50mm.

This requires an offset post, one that can be reversed (ie has a clamp design that can rotate a LOT), and pushing the saddle well forwards on the rails as well.

As I said in your other thread, doing this on my bike still has my saddle nose well behind the bottom bracket

Mersch
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Re: Choosing the right Seat Post

Postby Mersch » Sat Jun 30, 2018 6:31 pm

MattyK wrote:A tri bike (or a bodge thereof) really needs an effective seatpost angle of about 78-80 degrees. The only way to emulate this with a road bike frame (typically 73 degrees seapost angle) is to offset the saddle forwards by at least 50mm.

This requires an offset post, one that can be reversed (ie has a clamp design that can rotate a LOT), and pushing the saddle well forwards on the rails as well.

As I said in your other thread, doing this on my bike still has my saddle nose well behind the bottom bracket


So I would have to buy an offset seat post and switch it around to give me that 78-80 degrees seat post angle potentially?

I know converting a road bike to a tt bike will never be spot on but it's just to dip my toes in triathlon and later down the track decide if I want to buy a dedicated tt bike.

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Derny Driver
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Re: Choosing the right Seat Post

Postby Derny Driver » Sat Jun 30, 2018 7:25 pm

Mersch wrote:I know converting a road bike to a tt bike will never be spot on but it's just to dip my toes in triathlon and later down the track decide if I want to buy a dedicated tt bike.

Hi again mate ... there are plenty of top notch triathletes who dont use TT bikes. I am shortly going to start helping a young guy with his bike leg training for nationals in September. Standard road bike with clip on bars. My own son is riding with a NRS development team races state A grade and has won some big TT races. He does not own TT bike. We actually use his training bike, put clip on bars on it and a disc wheel, and slide the seat forward. His aero position is perfect.
Experiment a bit with posts and seats ... despite the marketing hype you do not need a TT bike. They are horrible things to ride in anything except a straight line. You can certainly get a good position on the road bike with the right saddle and possibly a different seatpost.

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Duck!
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Re: Choosing the right Seat Post

Postby Duck! » Sat Jun 30, 2018 7:52 pm

Start with the post you have (which being a roadie is almost certainly a set-back post). If you can't get the saddle forward enough, then look at replacing the post with a straight one.
I had a thought, but it got run over as it crossed my mind.

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MattyK
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Re: Choosing the right Seat Post

Postby MattyK » Sat Jun 30, 2018 10:34 pm

Mersch wrote:So I would have to buy an offset seat post and switch it around to give me that 78-80 degrees seat post angle potentially?

Yep, exactly.

I know converting a road bike to a tt bike will never be spot on but it's just to dip my toes in triathlon and later down the track decide if I want to buy a dedicated tt bike.

You can get an excellent position on a road bike. For example, here's me on my bike with a forward seatpost, and lots of stem slammage: https://youtu.be/q6N2m4eirnA

I guess if you're not lowering the front as much then maybe you wouldn't want as much forward position on the seatpost. However if you're going to convert a bike I wouldn't NOT fit a lower stem, or you miss much of the benefit of aero bars.

My stem cost me all of $20. Between the aero bars, saddle, seatpost and stem I'd spent less than $200. Add another $150 or so for the base bar, shifters, brake levers and cables and I've got as good a position as just about anyone.

By the way, hot tip: post a video of yourself like that on slowtwitch, you'll get some excellent free feedback.

http://www.bikeroar.com/tips/5-best-mod ... tt-machine
Also read this: https://www.slowtwitch.com/Bike_Fit/Ort ... _6852.html
(It's more about bar position but that will guide your whole setup. Dan knows what he's talking about)

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Derny Driver
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Re: Choosing the right Seat Post

Postby Derny Driver » Mon Jul 02, 2018 12:10 am

ImageIMG_0848 by Derny Driver, on Flickr
You can see my son's set up here. Standard road bike, clip on bars on normal road bars, seat slid forward on the rails.
ImageIMG_0858 by Derny Driver, on Flickr
Its a good aero position. He won this TT stage in a 4 stage tour in Tasmania a few years ago.

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