[Closed] STW seatpost law

Up to the max mark on a 400mm post. Any more and you have the wrong size frame!

as much as you want so long as it isn't

A) carbon composite
or
B) Chrome

Dunno, I always need a 400mm post though, why do bike companies supply 350mm ones, they're useless!

PeterPoddy - Member
Up to the max mark on a 400mm post. Any [s]more[/s][b][i] less[/i][/b] and you have the wrong size frame!

FIFY. 😉

seatpost length = bar width/pi

doesn't matter as long as it's Thomson
but not the bent one

depends on if you are going up or down.

as long as the post goes at least an inch below the bottom of the seat-tube/top-tube junction, you can have an arm length of post out the frame.

I'd say about 1/3 to 1/2 of the seat tube length.

why?

There's a complex system of rules depending on bike size, whether top tube slopes or not, type of bike etc.

I'll configure a matrix and post it up.

doesn't matter as long as it's Thomson
but not the bent one

...... wassa madder with the bent one!? 😐

Both ends of the spectrum:

[img] [/img]

[img] [/img]

...... wassa madder with the bent one!?

It's wrong, because you can do this with it.

[img] [/img]

However, fitted the right way, on certain bikes, it can look alright.

I think all really long people should have small frames with loooooads of seatpost sticking out (whilst claiming they have the correct frame size 😆 ), as they look really odd on their bikes and it amuses me. 🙂

What about freaks like me with long legs and a relatively short body? It has to be a long seatpost on a short toptube frame. Not quite up to the maximum mark on a 410mm Thomson, though!

What about freaks like me with long legs and a relatively short body?

Larger 'women's geometry' frame?

My 250mm protruding is pretty normal then!

[img] [/img]

I like a small frame as it's "chuckable" 🙄

mine but i have a reverb now.......
[img] [/img]

do i detect mockery MrP?

normally, i'd probably agree with you, but...

i could be wrong, but i think that's a 19" cotic soul, and that's as big as they come, despite Cy being some kind of giant.

or, is it your bike? and i've got the wrong end of the stick again?

this, however, looks stunning:
[img] [/img]

(sshhh! - it's got them funny new 29" wheels...)

i think the wheel height/saddle height ratio is more critical to aesthetics than 'amount of seatpost out of frame'

Not a great picture but that's how much I run when I'm riding XC. I'm not going to lie, the frame is too small but I like it, I am half-looking out for one in L (16.5"!) though.

[img] [/img]

PeterPoddy - Member
Up to the max mark on a 400mm post. Any more and you have the wrong size frame!

Mister P - Member

I like a small frame as it's "chuckable"

What is the maximum amount of seatpost one can show, according to STW law?

4" 8) . How the heck I used to ride with the recommended 6" bitd I have no idea 😆 (my frames were bigger then too)

Larger 'women's geometry' frame?

I don't think so.

No, I like running a long seatpost. When I first started in this game the bike shop advised me to run the smallest frame I could get away with, and I still see no reason to question that advice.

The mark on a seatpost is to try to limit the bending moment on the seatpost, not protect the frame. They have to make an assumption on the weight of the rider and include a safety margin so you're obviously getting away with it!

small hardtail + long seatpost = more comfy that large hardtail + short seatpost ..

Surely when going downhill, having the seatpost way higher than the handlebars can't be too good for your centre of gravity?

Stw law #3

You should choose a frame that is way to small for you, ride it with a excessively long seatpost, and claim you prefer riding smaller bikes because they are more "chuckable".

Then, in true Stw style, start a thread cluelessly asking why your top tube has departed from your seat tube.

Edit: Special needs, the max height is to make sure you have enough post in the frame to stop you cracking it at the seat/top tube weld.

Edit: Special needs, the max height is to make sure you have enough post in the frame to stop you cracking it at the seat/top tube weld.

That makes an assumption about all frames having similar layout and being designed around a similar post insertion.

Surely its up to the frame manufacturer to suggest minimum insertion depth for frame integrity ,and post manufacturer for post integrity?

[img] [/img]

I managed to snap this one off last week.
There was around 25mm off post above the min. insert line in the frame.

I assumed that if a seatpost was sold as 400mm length including a min insertion line that anything more than that would be fine. I am not the lightest rider though at 87kg.

Perhaps I have shouldn't have used such a lightweight seatpost but I guess I've learnt this lesson now.

So my saddle is level with my bars. I do have a low and long steel frame 29er and I'm partial to a bit seatpost showing....
[img][url= http://farm6.static.flickr.com/5186/5681291222_351a2dc2b4.jp g" target="_blank">http://farm6.static.flickr.com/5186/5681291222_351a2dc2b4.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/56594563@N07/5681291222/ ]Stealth[/url] by [url= http://www.flickr.com/people/56594563@N07/ ]tangwyn[/url], on Flickr[/img][img]http://[/img]
This looks good.

That makes an assumption about all frames having similar layout and being designed around a similar post insertion.

Surely its up to the frame manufacturer to suggest minimum insertion depth for frame integrity ,and post manufacturer for post integrity?

I forget which # the stw law is that states "Flow" will usually add something retarded to most bike forum threads .

[i]Goes off to sit on the naughty step[/i]

400mm post but a layback ..... but more than 100mm in the frame - does that make it right?

[img] [/img]

Still a bit high on this 20'' frame too I guess:

[img] [/img]

Ahhh, because all frames come with minimum seatpost insertion marks dont they, dumbass.

mine stays slammed most of the time 🙂

[img] [/img]

common sense, simple common sense! Flow 🙄

@Marge - that seatpost (if it's a KCNC) does have an 85kg limit for XC. Are you 87kgs in the morning or fully kitted up and ready to ride?

Ahhh, because all frames come with minimum seatpost insertion marks dont they, dumbass.

1 > no need for the name calling
2 > most *do* actually come with a note in the owners manual about making sure Xmm inserted below point Y

further proof - I have three Intense frames in the loft which actually have a little hole drilled in the back of the seat tube (so you can see where the seatpost is) with a sticker around it saying 'minimum seat post insertion'

My old Proflex had the same, the seat tube was about half a foot long and didnt continue to the bottom bracket so it was no where near as strong. Its dangerous and pretty expensive to assume people have any common sense.

Whyte manual states to refer to seatpost manufacturers min insertion markings (Thompson)

And there was GW questioning my superior knowedge.

From now on its Mr Flow to you.

I'm no engineer, but I guess that running a 31.6mm dia 410mm seat post at its limit will be safer than, say, a 27.0mm dia post at the same extension - all other criteria being equal, that is.