Velo Orange Grand Cru Seatpost.

[FatLad1980]

Current seat post doesn't have enough setback.

Genesis recommend a 400mm long seat post for the XL frame.

Grand Cru seat post seems to have the amount of setback I need but it only comes in a 300mm length.

Having measured from the saddle rail, will I get away with a 300mm long seat post?

https://www.instagram.com/p/BfJvRdSFsFD/

[531colin]

See the similar offering from planet X....https://forum.cyclinguk.org/viewtopic.php?f=1&t=104331&hilit=seatpost

Looks like you will have almost 100mm insertion, which should be enough, I feel, despite the seat tube extending some way above the top tube.
You might have, and be able to feel, an externally-butted seat tube....in which case, if the seatpost goes down as far as the end of the external butting, I would be happy.

[FatLad1980]

See the similar offering from planet X....https://forum.cyclinguk.org/viewtopic.php?f=1&t=104331&hilit=seatpost

You might have, and be able to feel, an externally-butted seat tube....in which case, if the seatpost goes down as far as the end of the external butting, I would be happy.

Ummm?

Planet X don't seem to have one in black.

[PH]

Velo Orange spec says - Maximum height (above the min. insert line) is about 23cm
Looks like you'll be well within that.
I'm not sure where Genesis get the recommendation from, I'd have thought it was the length of post in the frame that mattered rather than the overall. Whatever the variables I'd trust the minimum insertion line.

[531colin]

Time to fondle your seat tube,,,,they can't touch you for it!
My first look, I thought it looked like a steel frame, but maybe not?
Anyway, a steel seat tube is likely to be more than a millimeter wall thickness at the top, where they weld it and ream it for the seatpost; in the middle it can be nearer half a millimeter wall thickness, and the hole in the middle is a constant diameter to fit the seatpost......So, if you run your fingers up the seat tube starting in the middle, you may feel where the seat tube outside diameter increases by about a millimeter.....this is the external butting, and I would be happy if the seatpost reached down as far as that.....with the caveat that the external butting should reach at least as far below the top tube as your seat tube extends above the top tube.

[freeflow]

Time for a Nitto S84. You know you want one.

http://freshtripe.co.uk/nitto-s84-lugge ... st-27-2mm/

[FatLad1980]

Time to fondle your seat tube,,,,they can't touch you for it!
My first look, I thought it looked like a steel frame, but maybe not?
Anyway, a steel seat tube is likely to be more than a millimeter wall thickness at the top, where they weld it and ream it for the seatpost; in the middle it can be nearer half a millimeter wall thickness, and the hole in the middle is a constant diameter to fit the seatpost......So, if you run your fingers up the seat tube starting in the middle, you may feel where the seat tube outside diameter increases by about a millimeter.....this is the external butting, and I would be happy if the seatpost reached down as far as that.....with the caveat that the external butting should reach at least as far below the top tube as your seat tube extends above the top tube.

Yes, steel frame.

I'm with you now, can definitely feel it change and the new seat post should definitely reach it, or at least be not far away from it.

Having had another measure and feel the extra thickness seems to start where the Q is on the ruler.

[FatLad1980]

Time for a Nitto S84. You know you want one.

http://freshtripe.co.uk/nitto-s84-lugge ... st-27-2mm/

Lovely post, but at 250mm it's way too short.

[fossala]

Time for a Nitto S84. You know you want one.

http://freshtripe.co.uk/nitto-s84-lugge ... st-27-2mm/

Lovely post, but at 250mm it's way too short.

But it weighs 0g!

[531colin]

If the butting goes all the way down to the "Q" of B&Q then that's a good long but, and if the seatpost goes that far too I don't think you will have any worries.
....Of course, they only make a limited number of different seat tubes, with different lengths of butting.....so that same seat tube could easily be used in a smaller frame, where some of the butted length will be cut off.
I can envisage a situation where on a very small frame to get adequate standover you might need a dropped top tube (ie. the seatpost extends a long way above the top tube) and the top tube could be welded right at the end of the seat tube but; on the other hand you could expect a light rider, and the seatpost should have a long insertion.....
Anybody know of any bike where the smaller sizes have a smaller diameter seat tube than the big sizes?....or even seatposts made differently for heavy or light riders?

[FatLad1980]

If the butting goes all the way down to the "Q" of B&Q then that's a good long but, and if the seatpost goes that far too I don't think you will have any worries.

As the seatpost is only 300 long it won’t quite go to the Q. Probably only as far as the 30cm mark

[pwa]

If the butting goes all the way down to the "Q" of B&Q then that's a good long but, and if the seatpost goes that far too I don't think you will have any worries.

As the seatpost is only 300 long it won’t quite go to the Q. Probably only as far as the 30cm mark

When I install a seatpost that is longer than it needs to be I cut it to size. And in your pic I would normally be aiming for about the 31cm mark. But I am conservative, and I would be content with the 30cm mark. I reckon that more or less replicates where the minimum insertion mark is likely to be. The worst case scenario is that you have a bit of the minimum insertion mark showing at the collar.

EDIT Actually, as these posts have 23cm above the min insert line, you can clearly see that 23cm is below the collar by a good margin, so no problems.

[FatLad1980]

If the butting goes all the way down to the "Q" of B&Q then that's a good long but, and if the seatpost goes that far too I don't think you will have any worries.

As the seatpost is only 300 long it won’t quite go to the Q. Probably only as far as the 30cm mark

When I install a seatpost that is longer than it needs to be I cut it to size. And in your pic I would normally be aiming for about the 31cm mark. But I am conservative, and I would be content with the 30cm mark. I reckon that more or less replicates where the minimum insertion mark is likely to be. The worst case scenario is that you have a bit of the minimum insertion mark showing at the collar.

EDIT Actually, as these posts have 23cm above the min insert line, you can clearly see that 23cm is below the collar by a good margin, so no problems.

I’m more concerned about damaging the frame due to the post being too short.

[Brucey]

FWIW I think it is an excellent idea to have a good deal more than the stipulated minimum inside a frame, especially when you are using a long seat pin inside a big frame. Chances are that if the rider is upscaled everywhere, not only will there be more leverage but there will be more weight too.

Thus depending on the frame design, I'd want 3-4" of the seat pin inside the frame, regardless of what is marked on the seat pin itself.

cheers

[FatLad1980]

FWIW I think it is an excellent idea to have a good deal more than the stipulated minimum inside a frame, especially when you are using a long seat pin inside a big frame. Chances are that if the rider is upscaled everywhere, not only will there be more leverage but there will be more weight too.

Thus depending on the frame design, I'd want 3-4" of the seat pin inside the frame, regardless of what is marked on the seat pin itself.

cheers

I'm a big chap (6' 3" and 21 stone) so I am concerned about the length. I have the Grand Cru here and I'm going to send it back.

A friend has suggested I may need to increase the height of my seat post a little after seeing me on the bike. I'll give that a go first before considering finding something else. Doing it by eye he says the bottom of my knee looks like it's pretty much over the pedal axle so it's more likely that I just need a bit more height.

The Grand Cru is beautiful though.