Best Layback Seatpost for Brooks

[robc02]

they make the seat tube angle steep on small frames in order to shorten the top tube.

At one time it was common for small racing frames to have steep seat angles because it was said that shorter riders had body dimensions that necessitated them sitting further forward. If you subscribe to this belief, then the steep seat angle does the job. The designer then selects a top tube length so that a reasonable handlebar stem extension will give the rider the right position. If the rider had a shallow seat angle the saddle would need to be so far forward that it would create the opposite problem to the OP's!
The whole philosophy behind this has been challenged recently, though - as already pointed out - it doesn't stop a lot of manufacturers using steeper angles on smaller frames. I can't really judge from experienced as I'm 6ft tall!
I have noticed that the portion of Brooks rails suitable for clamping is further back than on many modern saddles. As a result I need a layback seatpost on my Brooks Professional but inline posts on My Specialized sadddles (same frame geometry).

[531colin]

Hi Colin,

Spa don't currently show geometry figures for the new frame. Any idea what the seat tube angle, headtube and standover heights are on the 54cm?
http://www.spacycles.co.uk/products.php?plid=m1b17s21p2307&z=2753

Jason

Hi Jason
I basically designed the 54 to fit me (got to be some perks, right? 5 feet ten, 31" Trouser).
The 54 has 625mm. front centres, 455mm chainstays, and 60mm. top tube slope, and designed around 170mm cranks.(for ground/ toe clearance)
Angles for all sizes are 71 head, 72 seat. All have 54mm. fork offset. and a minimum of 60mm. stem spacers.
Steering characteristics are you can look over the hedge to see what that bird is without ending up in the ditch, or ride uphill "no hands" if you feel like it.
Beauty of a slack head angle and long offset is you get toe clearance and a 63 year old can still have a 90mm stem.

[horizon]

viewtopic.php?f=5&t=37587

This is a parallel thread.

[horizon]

Hi Colin,

Spa don't currently show geometry figures for the new frame. Any idea what the seat tube angle, headtube and standover heights are on the 54cm?
http://www.spacycles.co.uk/products.php?plid=m1b17s21p2307&z=2753

Jason

Hi Jason
I basically designed the 54 to fit me (got to be some perks, right? 5 feet ten, 31" Trouser).
The 54 has 625mm. front centres, 455mm chainstays, and 60mm. top tube slope, and designed around 170mm cranks.(for ground/ toe clearance)
Angles for all sizes are 71 head, 72 seat. All have 54mm. fork offset. and a minimum of 60mm. stem spacers.
Steering characteristics are you can look over the hedge to see what that bird is without ending up in the ditch, or ride uphill "no hands" if you feel like it.
Beauty of a slack head angle and long offset is you get toe clearance and a 63 year old can still have a 90mm stem.

I think I just need to establish again what we mean by a steep frame angle. Is 72 OK?

[531colin]

I think I just need to establish again what we mean by a steep frame angle. Is 72 OK?

If I was designing my own bike, it would have been 70deg.
However, some customers will be influenced by what is common throughout the bike trade (fashion?).
In the end I went for 72 because I can get comfortable at 72, and thats as slack as I thought I could go without putting people off and losing sales on an off the peg frame.

[yelfordrover]

I recently bought an Ambrosio Momentum which has 45mm set-back & a brilliant infinitely adjustable rail clamp. I think it's only available in 27.2. Bought it off e-bay from what I think is Dave Hindes emporium but had no issues.

[yostumpy]

i've got a VO post, excellent, but does suffer fom some verical slippage in my 631 pearson, but not in my old 531 raliegh lightweight. I seem to remember , in old adverts of about '82-84 ish from maddison in the ctc mags, something called 'RAILZ' these were effectively another set of seat rails, , double decker if you like, so lower deck fixed to post, and seat fixed to upper 'setback' set., never seem them since, good idea for brooks though. i do find tilting nose up helps though.

[yostumpy]

I recently bought an Ambrosio Momentum which has 45mm set-back & a brilliant infinitely adjustable rail clamp. I think it's only available in 27.2. Bought it off e-bay from what I think is Dave Hindes emporium but had no issues.

I had an ambrosio post like this, Most post are like a cupped hand'/ cradle type thing, but this was like a pea on a snails back. Opposite. couldn.t ever get it tight enough to stop it tilting backwards. the VO one has good layback , but is ifinitely adjustable via a for and aft allen bolt. superb.

[531colin]

i've got a VO post, excellent, but does suffer fom some verical slippage in my 631 pearson, but not in my old 531 raliegh lightweight. I seem to remember , in old adverts of about '82-84 ish from maddison in the ctc mags, something called 'RAILZ' these were effectively another set of seat rails, , double decker if you like, so lower deck fixed to post, and seat fixed to upper 'setback' set., never seem them since, good idea for brooks though. i do find tilting nose up helps though.

VK adapter?....http://forum.ctc.org.uk/viewtopic.php?f=5&t=7406&hilit=saddle&start=15

[yostumpy]

wats the link to these VK adapter jobbies, cant read the red writing on the picture.

[531colin]

wats the link to these VK adapter jobbies, cant read the red writing on the picture.

St John Street cycles do them

[yostumpy]

yeah just found them, does seem like an excessively large amount of leverage on a small bolt, dont think I;d trust it with my svelte 15 stone!

[The Mechanic]

I have a VO grand cru post waiting for me at the post office (wasn't in when delivered). Only 30 quid plus postage from Freshstrip in Ireland. Any one interested in a carbon Chorus seapost 250mm 27.2?