Bike Forums

Bike Forums (
-   Folding Bikes (
-   -   Brompton seatpost decisions (

kcsaff 02-18-08 08:36 PM

Brompton seatpost decisions
Hi all,
I test-rode a Brompton a month ago and now I'm looking to buy. I am 6'0" (1.83m) and found the standard seatpost an inch or two too short for my legs. However, that was with the standard foam seat and not the Brooks saddle I will certainly prefer. It is my understanding that a real saddle will stand an inch or two higher on this bike, which may put this on the cusp of being ridable without needing the extended post. Does anyone have any ideas how well that might work? I don't think I will be able to find such a bike to test-ride here in Calgary, but I'd be willing to give it a shot if one of you has one!

(This is my first post. I hope it is appropriate in tone and content for this forum.)

LWaB 02-18-08 09:01 PM

There are actually 3 Brompton seatposts, standard, extended (about 50 mm longer) and telescopic (much longer but smaller folded than the extended). I don't think you'll get 2 inches out of the change to a Brooks saddle and normal clamp. You should get 1 inch.

My wife has an extended seatpost cut to length and custom flared at the end. The saddle always is at the right height when unfolded. Just a thought for you.

kpug505 02-18-08 09:12 PM

Do you have the intended Brooks already? If so I would take it to the shop you intend to buy from and have them slap it on there to see where you're at. The bikes a pretty high dollar item and the real differance between your LBS and an online store is service. If they won't swap a saddle for a test ride and help with proper fitting I'd go elseware.
You are correct in assuming that a Brooks will generally give an inch more height but not much more. Unless you run a double railed model like a B-72 on the lower rail only. Another consideration is pedals and shoes. Standard platform pedals and thin soled shoes could give you as much as an inch compared to clipless pedals and the appropriate shoes for them.
On the same token. If I had a bike that I had to ride on with the post at it's minimum insertion line to be comfortable I'd
A: Get a bigger bike (not many options for a compact folder)
B: Get a longer post.
Just to be on the safe side ya know?

My 2 cents'
Kelly D

P.S. Welcome to Bike Forums!

kcsaff 02-18-08 10:10 PM

Hi LWaB,
I was aware of the telescopic post, but I'm pretty sure I don't want it - it seems to add too much complexity. I was wondering if the post could be cut down. I guess cutting it is the easy part, it's the flaring that's too much for me to do.

I'm aware of the many benefits of local bike shops, and I wished there was a local Brompton dealer. Unfortunately the closest one I am aware of to Calgary is in Seattle, 600 miles away. It's a bit too far to walk when my bike's broken. :) Add to that my roommate, who's so crazy about fixing up bikes he'll start pulling them out of the trash if there aren't any broken ones handy. Please forgive me this time for being tempted by the evil that is online bicycle shopping. My other bikes were bought at local shops, I swear!

Thank you both for the advice. I'm definitely leaning towards the extended seatpost now.

bangkok 02-18-08 11:13 PM

B seappost
1 Attachment(s)
I'm an inch+ taller just fit on the extended post, but the determining factor issue is inseam; mine is 87cm (34 1/4 inch).

The standard post is about 54cm while the extended is 60 ... 6cm higher (about 2 3/8 inch).

Another option is mount the seat bracket on the top of the post, and not lower; see attached pic. This grips well with the Pentaclip and mine hasn't slipped in months of use.

Check the Brompton Yahoo forum for more dialog on the normal/extended/telescopic post subject.

kcsaff 02-19-08 12:23 AM

My pants say 32", if that's any help. I will mediate on your seat bracket pic tonight to achieve further enlightenment on this issue. I guess the clamp comes standard at the level of the black plastic bit, but can be raised another ~2cm? If so, it would seem an extra inch from the saddle and an extra inch there would give me what I need -- but that's cutting it pretty close.

I do think I was wearing hiking boots when I test-rode it, which is pretty much a worst case scenario for footwear on this bike.

I take it these seatposts are flared in some nonstandard way, but it's still possible to swap them out without super-special tools if necessary?

[Edit] I just checked out the yahoo group and it seems several people appreciate the telescopic seatpost. Perhaps I should reconsider my prejudices against it?

jefmcg 02-19-08 02:00 AM

You may find this useful:

LWaB 02-19-08 02:55 AM


Originally Posted by kcsaff (Post 6190022)
Hi LWaB,
I was aware of the telescopic post, but I'm pretty sure I don't want it - it seems to add too much complexity. I was wondering if the post could be cut down. I guess cutting it is the easy part, it's the flaring that's too much for me to do.

I use the telescopic post (always at the right height when unfolded). Flaring a cut Brompton seatpost is actually pretty easy. Put the cut end of the post over a cheap (wrench) socket on concrete and wallop the (protected) top of the post.

bangkok 02-19-08 02:56 AM

seatpost flare
The seatpost is flared at the bottom, so it is initially inserted from the bottom of the bike; pulling it up. This ensures the post cannot be raised beyond the maximum safe height etc.

My guess is you'd be comfortable on an extended post. Cost aside, the drawback on t-scope is weight!

invisiblehand 02-19-08 09:40 AM

Where are you purchasing the Brompton? They might have a few suggestions ... perhaps even letting you try out a few alternatives before settling on the final solution.

I never thought that the telescopic seatpost was that much of a hassle. Moreover, you can always remove the inner tube and insert a regular seatpost.


popsicleian 02-19-08 10:16 AM

When I test rode Bromptons, the standard seatpost felt just a little bit too short for me to get comfortable, so the shop I bought from switched out the standard for the extended at no charge. I didn't take into account that the pentaclip + Brooks saddle would add length, so it turns out I didn't really need the extended seatpost.

It's not really a big deal since I didn't pay any extra for it, but I wish I hadn't had them switch it out--the seat sticks up higher and makes the folded package bigger. Oh well...

kcsaff 02-19-08 02:36 PM

Thank you all for the advice.
Because there is not a Brompton dealer anywhere nearby, I don't have the option of trying out all the various possibilities. The one test ride I did was part of a vacation to the Pacific NW that won't be repeated soon. I have decided that I will order the extended seatpost. Here's my reasoning:

1) The telescopic post may have some nice features, but I could eventually upgrade to it if the cheaper option doesn't meet my needs.
2) The extended post will certainly be long enough for me.
3) Someone on the Brompton yahoo group suggested that there is only about an inch difference between a standard seatpost in a 'high' position as an extended one adjusted to be 'low'. Comfort is more important for my planned usage than an inch.
4) The extended post can be chopped to the perfect length, or replaced with the standard as necessary.

*Whew*, that's settled, now I just have to decide what color I want...

jagatron 02-19-08 07:54 PM

You can always upgrade the stock small seatpost by cutting off the top, inserting a shim, and a quick release. That's exactly what the generic telescoping seatpost from calhoun does. Parts to do that are around $8 (shim) + $ 8 (qr) + $15 (ext post)

All times are GMT -6. The time now is 04:39 PM.