Seatposts, layback, and a daft idea

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gilesjuk
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Re: Seatposts, layback, and a daft idea

Postby gilesjuk » 19 May 2010, 10:23pm

32mm layback option with this:

http://www.wiggle.co.uk/p/cycle/7/FSA_K ... 360042302/

Not cheap and carbon might look silly with a Brooks.

tour59
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Re: Seatposts, layback, and a daft idea

Postby tour59 » 20 May 2010, 8:03am

Gilles Berthoud in France offers a CLB post in several different diameters.

I have a VO post on one bike, and a CLB on another. The CLB has a longer layback.

http://www.gillesberthoud.fr/anglais/fiche_detaillee/fiche.php?refArticle=191PRD272/CLB

Tom

Mackerel
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Re: Seatposts, layback, and a daft idea

Postby Mackerel » 19 Oct 2010, 9:30pm

Nitto have started producing the S-84 which is a nice looking lugged steel seatpost with somewhere between 37mm and 45mm of setback (different figures are quoted on the various sites selling it).

I think this is at the instigation of the guys at Rivendell Bikes in the US who retail it:
http://www.rivbike.com/products/show/ni ... 0mm/11-048

Jamie at Freshtripe now sells them in the UK (@ 19/10/2010).

They are only in 27.2mm diameter, 250mm (and sometimes 300mm) length, weighing 317.5 grams.

Anyway, it's looks like it could be a good solution for would be Brooks users. Maybe Santa will bring me one to test...

11-048_waybackfullshovedbak.jpg

11-048_waybacksv.jpg
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horizon
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Re: Seatposts, layback, and a daft idea

Postby horizon » 20 Oct 2010, 12:27am

I just wanted to add something about frame angles. The Galaxy in 1985 had a frame angle of 72 degrees, compared with anything up to 75 degrees today but that is in the smaller frames. I am not convinced that frame angle per se however is the problem (although it may have made matters worse): I would say that for most people, 72 - 73 is OK. However, like many other things about mass production bikes, it is a compromise - worked out to suit the average person (and in this case the average male).

I cannot and do not believe that Dawes made a bike that didn't fit the average person and I am happy to believe that it would have been impossible for them to make it fit everyone (after all, if Dawes can happily sell me a bike with size 8 toe clips, then I am sure that they are going for average). For most folk, the bike is right, for a few not. These people are the small proportion of the population that don't have an averagely proportioned body and whose thighs/pelvis/hips or whatever are in a different proportion to their height, perhaps not even by very much. And hence this thread. We've got carbon fibre but we haven't got a comfy bike.

The very comfortable answer to this problem is the custom-built frame, made to suit the individual, and costing £2,000. The more economical but equally effective answer is the VK adaptor costing £20. VK adaptors exist because there is a need for them. But people don't buy them and are not offered them because they believe that they should be able to fit their bike - after all, lots of other people manage it. But if you want to sit further back than the frame/saddle will allow, fit a VK - it will transform your riding experience and provide exactly what you are looking for.

I cannot say more than this: I wanted to sit further back, I bought a VK, I tried it, it worked exactly as I hoped, it has no known disadvantage apart from a small weight penalty. It costs just £20. But if you don't want one, (or prefer the Nitto S 84 :D) fine.
Last edited by horizon on 20 Oct 2010, 12:44am, edited 2 times in total.
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

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horizon
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Re: Seatposts, layback, and a daft idea

Postby horizon » 20 Oct 2010, 12:30am

Mackerel wrote:Nitto have started producing the S-84 which is a nice looking lugged steel seatpost with somewhere between 37mm and 45mm of setback (different figures are quoted on the various sites selling it).

I think this is at the instigation of the guys at Rivendell Bikes in the US who retail it:
http://www.rivbike.com/products/show/ni ... 0mm/11-048

Jamie at Freshtripe now sells them in the UK (@ 19/10/2010).

They are only in 27.2mm diameter, 250mm (and sometimes 300mm) length, weighing 317.5 grams.

Anyway, it's looks like it could be a good solution for would be Brooks users. Maybe Santa will bring me one to test...

11-048_waybackfullshovedbak.jpg

11-048_waybacksv.jpg


mackerel: great post but a VK will do the same for £20 not £90. But at least they are on the same lines and recognise that some people want to sit further back! A VK goes back in the same way, it just isn't so elegant!
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

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horizon
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Re: Seatposts, layback, and a daft idea

Postby horizon » 20 Oct 2010, 12:42am

gilesjuk wrote:32mm layback option with this:

http://www.wiggle.co.uk/p/cycle/7/FSA_K ... 360042302/

Not cheap and carbon might look silly with a Brooks.


It makes the point though. A better (and very elegant) option though I think would be mackerel's suggestion (and with more lay back) albeit also with more weight. The VK will still do the same though at a fifth of the price and of course will fit any post diameter.
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

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531colin
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Re: Seatposts, layback, and a daft idea

Postby 531colin » 20 Oct 2010, 7:50am

horizon wrote:I just wanted to add something about frame angles. The Galaxy in 1985 had a frame angle of 72 degrees, compared with anything up to 75 degrees today but that is in the smaller frames. I am not convinced that frame angle per se however is the problem (although it may have made matters worse): I would say that for most people, 72 - 73 is OK. However, like many other things about mass production bikes, it is a compromise - worked out to suit the average person (and in this case the average male).


Sorry, I dont believe 75 deg seat angle is either a compromise, or worked out to get the average person comfortable.

There is a (small?) proportion of the population (which incidentally includes both Horizon and me) who cannot get our Brooks saddles far enough BACK on anything steeper than 72 deg. with the longest layback seatpost we can find. If 75 deg. is a compromise, where are the people who cant get their saddles far enough FORWARD with 78deg angle and an in-line seatpost? They aren't posting on this forum.

I think steep seat angles on a touring bikes are a nonsense, I think it has been blindly copied over from racing fashion by people who should know better.

The known downside of steep seat angles is some people wont be able to get some saddles far enough back. What is the downside of slack seat angles?

snibgo
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Re: Seatposts, layback, and a daft idea

Postby snibgo » 20 Oct 2010, 8:12am

531colin wrote:What is the downside of slack seat angles?


It depends on the geometry to the bars, doesn't it? If we keep the distance and angle (from the horizontal) to the bars constant, but slacken the seat angle (moving it down and back), the body will be bent more. some of us are getting older, and can't bend as easily as we did once.

However, my hips have difficulty when getting on and off. So I want a slacker angle (much slacker, say 60 degrees) so the saddle is lower, and further back so my legs are extended. The bars would have to be correspondingly further back and higher.

That might give me less power to the pedals, but I would live with that.

Incidentally, I've just measured 75 degrees on the tourer and 77 degrees on the racer. Both Raleigh, 1987. Each has the saddle back as far as they will go. Haven't tried Brooks saddles yet.

MartinC
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Re: Seatposts, layback, and a daft idea

Postby MartinC » 20 Oct 2010, 9:36am

531colin wrote: What is the downside of slack seat angles?

:) I think at some point you answered your own question! The downside is that they aren't fashionable and they mean you'd have a shorter stem which isn't fashionable either. It's not for us customers to interfere with the marketing guys, what do we know!

fatboy
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Re: Seatposts, layback, and a daft idea

Postby fatboy » 20 Oct 2010, 9:45am

531colin wrote:What is the downside of slack seat angles?


I think that a steeper seat angle makes the legs more behind you allowing a lower tuck position for racing. So for racing slacker angles would be "slower". However for the average stiff, middle aged person this is much less of an issue!
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

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horizon
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Re: Seatposts, layback, and a daft idea

Postby horizon » 20 Oct 2010, 10:51am

531colin wrote:
horizon wrote:I just wanted to add something about frame angles. The Galaxy in 1986 had a frame angle of 72 degrees, compared with anything up to 75 degrees today but that is in the smaller frames. I am not convinced that frame angle per se however is the problem (although it may have made matters worse): I would say that for most people, 72 - 73 is OK. However, like many other things about mass production bikes, it is a compromise - worked out to suit the average person (and in this case the average male).


Sorry, I dont believe 75 deg seat angle is either a compromise, or worked out to get the average person comfortable.

There is a (small?) proportion of the population (which incidentally includes both Horizon and me) who cannot get our Brooks saddles far enough BACK on anything steeper than 72 deg. with the longest layback seatpost we can find. If 75 deg. is a compromise, where are the people who cant get their saddles far enough FORWARD with 78deg angle and an in-line seatpost? They aren't posting on this forum.

I think steep seat angles on a touring bikes are a nonsense, I think it has been blindly copied over from racing fashion by people who should know better.

The known downside of steep seat angles is some people wont be able to get some saddles far enough back. What is the downside of slack seat angles?


There are two possibilities here:

1. Steep frame angles (are we talking about 72 or 75??) are a deliberate change to emulate racing bikes. The Dawes range in 1986 had 73 for their top end racing bike, 72 for their touring and 70 for their MTB. (I had a 1985 Galaxy and cannot remember whether I had the same problem with it.) The latest figures I have are for 1999 which gives the angles as 72 - 75 across both the touring and racing ranges so you could say there has been a change (the Galaxy in 1999 was 73).

2. Steep frame angles are tolerated to reduce sizing issues and to simplify manufacture. The information I have doesn't say whether the frame angles varied in 1985 but they don't appear to do so.

I think #1 is inexcusable but #2 is "you pays your money....".

By the way Colin, I am not suggesting that 75 is the compromise, 72 is - it's the starting point. 75 occurs nowadays presumably to reduce the variety of tube components. So what did we have before? Was it 70 or was it in any case the 72 offered back then by the likes of Dawes? To make a non-custom bike now with a shallow frame angle would mean more components or some people being less well served in the steeper range. My own answer is the VK but the new seat posts on offer show there is a demand.
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

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horizon
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Re: Seatposts, layback, and a daft idea

Postby horizon » 20 Oct 2010, 10:55am

fatboy wrote:
531colin wrote:What is the downside of slack seat angles?


I think that a steeper seat angle makes the legs more behind you allowing a lower tuck position for racing. So for racing slacker angles would be "slower". However for the average stiff, middle aged person this is much less of an issue!


fatboy, I'm thinking it's body proportion not age (though I don't claim youthful vigour!). And can you then explain the carbon fibre set back seat posts on Wiggle - for oddly proportioned youngsters or "mamil"s? I think they are for both.
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

robc02
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Re: Seatposts, layback, and a daft idea

Postby robc02 » 20 Oct 2010, 12:50pm

fatboy wrote:
531colin wrote:What is the downside of slack seat angles?


I think that a steeper seat angle makes the legs more behind you allowing a lower tuck position for racing. So for racing slacker angles would be "slower". However for the average stiff, middle aged person this is much less of an issue!


Spot on! See slowtwitch.com (bikefitting) for a good explanation and relevant data. It is a triathlon/timetrialling site, but the explanation does have some relevance to all cyclists.
What it boils down to is that the more upright your body, the further back you sit. This why road race bikes have seat angles around 73 degrees, timetrial bikes 76+, and roadsters 70 or less. Why a specialist touring frame should mimic road race geometry, I am unsure - it will doubtless suit the "fast touring" type who probably used to be, or still is, a racer.

In my case I have a timetrial bike with 76 degree seat angle and the saddle slightly forward of middle on an inline seatpost, a road race and a fast commuting bike with 73.5 and saddle in the middle with inline post, and a roadster with 70 degrees and its B66 as far back as it will go on setback clip! All are very comfortable for their respective uses. I initially tried the roadster with its saddle further forward but couldn't get on with it. From this one might conclude that 76 degrees is a bit too shallow and 70 degrees too steep!!

Needless to say, I have decided that trying to replicate one riding position on all my bikes is not the way to go.

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531colin
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Re: Seatposts, layback, and a daft idea

Postby 531colin » 20 Oct 2010, 7:41pm

Snibgo and Martin C are saying a slack seat angle will make you sit farther back.
It wont. Riders on this thread go to great lengths to sit just where they want to. Slack seat angles simply make it easier to get the saddle as far back as you need.
Look at the picture of the Spa tourer somebody posted on the other seatpost thread. Its a 54cm set up for a 63 year old 5 feet 10 bloke , with a 9cm stem and no toe overlap.

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531colin
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Re: Seatposts, layback, and a daft idea

Postby 531colin » 20 Oct 2010, 9:04pm

Horizon
Sorry, I misinterpreted you , (it was before breakfast), when I read it again you say 72/73 deg is an average sort of figure. I agree that it is, although i (we?) prefer 72 over 73 .

At Spa we had no issues at all getting frames made with 72 deg seat tube, and I cant see why it would be cheaper or easier to make steeper angled frames, these days the tubes are all cut and mitred by robots. I also think steep angles create rather than solve bike fit/sizing issues.

I am forced to conclude these steep angles on TOURING bikes have simply been "copied over" from racing fashion.