A quick question on...
 

[Closed] A quick question on layback seat posts (of the Thomson Variety)

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Looking at seatposts for the Swift. Quite like the look of a layback but what is the actual point of one? Does it make much of a difference as opposed to an inline one?

Also, how much of the post needs to be inserted into the frame as I notice the come in different lengths.

T.I.A for any answers


 
Posted : 12/06/2012 1:59 pm
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erm, it get's you a bit further back?

sometimes you just need a bit more room up top, without having to lengthen the stem


 
Posted : 12/06/2012 2:01 pm
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will increase the effective TT length, move your weight back a bit on the frame.


 
Posted : 12/06/2012 2:03 pm
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1. They look AWFUL.
2. They effectively slacken your seat-tube. Not good for climbing.

They're an awful compromise, don't do it!


 
Posted : 12/06/2012 2:04 pm
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It depends on the length of your legs (and seatangle, cranks, saddle height)! Nought to do with top tube, or shouldn't be.

It's about getting a good angle with your leg when the pedal's are at 3 and 9.


 
Posted : 12/06/2012 2:09 pm
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1. They look AWFUL.
2. They effectively slacken your seat-tube. Not good for climbing.

They're an awful compromise, don't do it!

Yes I agree with some of that.
But most 'normal' post's that come on bikes have layback built into the clamp anyway so a layback thomson may not push your weight much further back than what your using currently...


 
Posted : 12/06/2012 2:12 pm
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they don't always look awful.

I was in the 'don't do it' school of thought, but tried one on my (large) Soul, and it suddenly fitted like a glove.. and I climb up everything on it.


 
Posted : 12/06/2012 2:19 pm
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It's about getting a good angle with your leg when the pedal's are at 3 and 9.

This...


 
Posted : 12/06/2012 2:21 pm
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I've got a Van-Nic Ti layback post on my Orange - it looks ok to me - even in silver 😉

I wanted a slightly 'longer' ride position.

[IMG] [/IMG]


 
Posted : 12/06/2012 2:21 pm
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I had an inline Thomson on my pace but with the saddle in the best spot, there was too much weight over the back and the saddle rails bent. Bought the set back version which now holds the middle of the rails and It's all been great since.


 
Posted : 12/06/2012 3:15 pm
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So, it's a mixed response. I guess the answer would be for me to try and set my bike up for the optimal riding position (whatever that is?) with my inline post and see if a layback post is needed.

[s]Is there a diagram online with the correct riding posiiton that I can use to help me?[/s] Found one [url= http://blog.timesunion.com/bike/the-perfect-mountain-bike-fit/3263/ ]linky[/url]


 
Posted : 12/06/2012 9:37 pm
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Right they:
- effectively slacken the seat angle without actually lengthening the seatstay so good for people with long thighs.
- allow you to have the saddle in the middle of the rails but still keep the distance behind the bb.
- give you more space if you need it.

Look fine!


 
Posted : 13/06/2012 12:09 am
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They look AWFUL

You are Dick Emery and I claim my £5.


 
Posted : 13/06/2012 7:58 am
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of course the fact that most new complete builds come with a layback post says nothing about the way bikes are designed i guess ?

does make me laugh when people suggest fitting a thomson to a new bike to get more cockpit length.


 
Posted : 13/06/2012 9:03 am
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Do they not increase the chance of cracking the seat tube - especially if you are a biffer?


 
Posted : 13/06/2012 9:47 am
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I think brants always frowned on fittign layback posts to his frames - due to the effective seat tube angle changes.


 
Posted : 13/06/2012 9:48 am
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I think I shall stick with buying an inline Thomson, there is too much doubt in my head now to take a chance on looks alone. I have a woodman carbon post on it at the moment but the seat mount came off and previous owner araldited it back on.... So I'm replacing it for peace of mind. The current post is about 350mm (I think), can I buy a 410mm post and then trim it?


 
Posted : 14/06/2012 8:36 am
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Some great responses 😀

slimjim78 - Member
erm, it get's you a bit further back?

Is about right but you could just as easily say that an inline post gets you a bit further forward.

As with the other thread about 'correct' setup, there isn't a correct answer. A layback post will allow some people to get the right position for them while for others it'll be pointless or put them too far back.

It's worth remembering of course that there isn't a standard for posts as such - layback or inline posts are just as valid and some frames are designed in a way that may suit one or the other (for average proportions) depending on ETT length and/or seat tube angle.

can I buy a 410mm post and then trim it?

Yes, but I wouldn't bother shortening it unless a) you're a weight weenie or b) it's too long for your frame otherwise.


 
Posted : 14/06/2012 8:54 am
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Cheers Clubber. I'm too fat to be worried about saving weight on my bike. 🙂


 
Posted : 14/06/2012 9:35 am
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It's worth noting that because the clamp is still directly on top of a Thomson seatpost, with the layback provided by the kink in the tube, that the layback isn't actually that big. Other straight tube posts have a bigger offset.


 
Posted : 14/06/2012 9:40 am
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It's worth noting that because the clamp is still directly on top of a Thomson seatpost, with the layback provided by the kink in the tube, that the layback isn't actually that big. Other straight tube posts have a bigger offset.

Good point. I guess I'm gonna have to have a fiddle with seat positions to see what will work best.


 
Posted : 14/06/2012 12:02 pm