Winfried

As seen on the web, one way to mount a Brompton luggage block on a saddle + seatpost.

Apparently, you won't notice you're carrying several kilos back there.

Parts:

• Brompton luggage block — original or third-party
• Saddle cage holder
• Seatpost clamp with rack mounts
• Two punched flat straight braces
• A few bolts (and nuts).

2_i 

Thanks for the transcription and finding links to the parts

3speedslow

Interesting! Would like to see it folded up with the mech still attached. Is the front bag a L borough Brompton model?

Schwinnsta

Very nice. Ingenious really. Would like to see the detail of the piece from the clamp to metal strap pieces. I guess it is just thu bolted and no extra piece. I never really noticed any load from the Swift Cross Rack on the Swift. Curious that having weight higher up does not seem to effect handling.

Winfried

Yes, it's just bent and bolted.

Apparently, the weight isn't felt, thanks to the seatpost clamp.

It'd be interesting to test ride that solution and Carradice's.

Winfried

Either the T-Bag or the Borough L.

tds101 

Here's the link to an alternative the the Xootr Cross Rack seatpost mount: V-Rack Seatpost Carrier – Vincita Co., Ltd.

Winfried

However, it won't take a Brompton bag, and, although it sticks out a lot, offers no quick-release lever so the adapter can be removed when folding the Brompton.

reppans

HERE’s another example using the standard Brompton brackets - but seat post luggage mounts give me the Willies. There’s a lot mechanical leverage involved when you mount weight so far back and/or so high up on long arms. The OEM set-up works well because it’s frame mounted and tips the bag backward which places the bag’s CoG over the mount, or at least quite close.

Weight + long levers + ‘bouncing’ over road imperfections = additional stress to both the plastic luggage brackets and the seat post, and in directions they weren’t really designed for. IIRC, Brompton even advised not to attach large/heavy seat bags due to the leverage of the long seat post.

Anyways, just my $0.02, YMMV and all - it’s your bike to use as you please.

Winfried

I agree, which I why, in addition to the frame-mounted front bag, I use the rear rack to carry the rest 1) on the frame 2) as low to the ground as possible for maximum stability, like this guy did below — I carry less stuff myself.

I just mentioned that option above for science's sake :-)

2_i 

I am thinking about an attachment for Andersen Shopper or B-Tourist there .

Winfried

Good call.

A while back, I emailed Andersen to suggest a seatpost clamp for bikes that either don't have a rear rack or have small wheels… but they don't seem interested, and I don't know of a third party solution.

People's/Poor man's Burley Travoy:
https://www.bikeforums.net/utility-c...l#post14704329

biker101

Simple DIY solution:
see https://mybikesite.org/#CarrierBlockMount

Winfried

There's a business opportunity right there.

Winfried

New pics