I took the stock grips off straight away, they're terrible. I've got Ergons here too; best grips I've tried.

I found my Dahon Vitesse ludicrously harsh when I first got it and I wasn't really too happy with the ride until I put a massive 20 x 2.15 Big Apple Liteskin on the front plus a Thudbuster ST.

They are built like tanks. Im wondering if it has to do with the older models you and chagzuki are talking about that flex. One thing i dont like is flex,id be the first to tell you if my newer model did it.
Perhaps email Brompton and ask about the older model re: flex. Ive found them quite good to chat with about questions. Your not buying it from them so they would have no reason to fib.

I've already asked Brompton about this and they implied that there's no difference with more recent models in this respect. I'd like to test ride another Brompton to see if it might be something peculiar to mine. If there were, for instance, a tiny bit of play in one of the headset cups/bush that'd lead to extra handlebar movement.

If you sit on your bike ddez and alternate between pushing your bars forwards then pulling backwards, surely you see some obvious travel? I can get close to a centimeter, perhaps 8m or so and it's clearly not coming largely from the handlebar as the top of the stem moves also (of course you have to keep your head as still as possible.)

Yea, the join of hinge and tube is sound on both techniques, they are just different.

the current design is adaptable to a torch array jig,
where the Mk2 is a skilled hand done fillet braze.

Only if your fork is in line with your steering axis (or out in front, as in a rake).

But there's no reason the fork couldn't be pointing down at a steeper angle than the steering axis. You could put practically any trail you'd want on that thing.

Thing is, the Brompton has a significant rake, for (so far as I can tell) absolutely no good reason. The B's trail is 24mm, the tikit's (which still has a very slight rake for no good reason, though quite a bit less) is 28 or 29mm, and I think if you have a perfectly straight fork at that steering angle you'd get about, oh, maybe a 35mm trail, which would be a lot better. Bend the fork backwards and you could easily get up to 60mm or higher.

Two good, or at least defensible positions, for the Brompton's trail:

Small wheels do poorly with potholes; a 'twitchy' ride makes avoiding them easier in practice.

Also, subjectively, the Brompton travels much more smoothly with a loaded front bag. Something about the large moment of intertia over the front wheel. I could see it feeling a bit sluggish if it had a 'normal' responsiveness when unloaded.

Both of these are adaptations to the Brompton's core purpose, urban cycling for the multimodal.

brompton to swift here. don't regret it. my goal with the brompton was to have extremely smooth integration with everything else i do, and every other mode of transit. i never really achieved that, a bike, even folded, still is awkward in many situations - inside stores, tight transit situations, inside libraries. now, with a swift, i just aim to park it outside of wherever i am, and just deal with the few akward moments of having to put it on a train or bus. in exchange, i get a nicer ride, many more options for customizing.

biggest thing i miss about the brompton is the front block mount. frame mounted luggage is vastly superior to stem mounted luggage. i suspect the same can be said for luggage mounted on front risers/rack of the fork

Okay i did it your way and got about 4m. Perhaps its not so noticeable with the flat bars when riding. But it dont come close to my Speed D 7 i used to have,feels way more solid. Im surprised actually cause no way do i feel it when riding. So now maybe we have the answer it flexes. I would test ride a S- type if you can though.
Just slightly off topic but speaking of Dahon. I saw my first Speed TR today up close and personal. Dang thats a nice bike and price is good too. Sheesh 24 gears. Too bad i got it in for Dahon.

chagzuki
Just thought of something. My B-17 Brooks is quite far forward,Penta Clip bolt is facing forward as i like my knees directly over the pedals. Thats the reason i have the Aber Halo so i can push it forward to get stretched out. Perhaps thats why i dont feel any flex although i find what little it has as minor even when testing it the way you suggested. Just a after thought.

It probably does have a lot to do with riding position.

Dahon bikes particularly from the mid range upwards are very nice, I think. Good components, nice wheels and rims etc.. But they do have their quirks.

As it happens, I'm looking to do the reverse. We'll see how I get on.

I suspect I may just keep both

Would that be the first signs of folderitis?

I tend to agree that having one bicycle, the Swift is very nice. If I had a hybrid mountain bicycle the OP was referring to, the Swift *could* be jettisoned. And I could get something smaller.

But I don't think I could deal with the Bromptons. I need gears, and the odd gear shifters on the Brompton I tried threw me a bit. Also the brakes, the rack-as-a-kickstand feature are not for me. I like that Brompton seems to have good customer service for parts though. Unlike (cough) Dahon (cough). Lastly, compared to the Swift, the limitations with compatible accessories would annoy me. e.g. can't use this accessory, because it interferes with the fold etc etc.

If I really wanted a fold-to-small bicycle for a train, I would consider a Brompton, but also a Birdy, maybe.

Horses for courses.

So far, here's the things I'm less than thrilled about with the Brompton (in relative order):

1.Brakes
2.Proprietary luggage system -- I have to buy all new bags to bring stuff on the bike?
3.It's hard to put things like bottle cages on the things without it messing with the fold
4.Cramped riding position
5.Bit of flex in stem / handlebars

I'll need to address the brakes. The luggage issue will resolved with some workshop bodging. The rest, I'll live with as compromises that come with such a friendly fold.

For what its worth,try the Two Fish water bottle holder mounted to the frame top or to the handle bar stem. Mine is on the stem works fairly good easy to reach and can still be folded. Velcro straps didnt last long so i used hose clamps.

I can't recall taking a good look at whether there were any physical restrictions to a backward bending fork. You'd get a shorter wheelbase and the fold would be ... bigger since the handlebar is still facing forward after the folding the main tube. I guess the wheel might hit the right pedal if it were further back. (sorry, doing this from memory since we don't have a Brompton anymore) Anyway, bike handling is sort of a fuzzy discipline. You might be right that more trail would produce a better handling bike.

35 mm of trail would be consistent with most big-wheeled front loaders from memory.

I've got a Minorua water bottle mount that I fit on the stem for my test ride. Worked ok, but it stuck out a bit when the bike was folded. I might try the top tube and see if leakage is a problem.

I have a Mk2 bike, the brakes on it, single pivot, were made by CLB of France.
After fitting a set of Kool Stop 'Continental' I have no braking issues,
they Stop me fine.

I don't know what the braking you consider (in) adequate for your
(pro racing like?) speeds,

Given: the dual pivot brakes type, have been adopted
by the race Bike Component Manufacturers
So, would be a significant change, for the better, It would seem.

Perhaps you could update to the newer style brakes if you choose. Ive said it before but worth repeating i can put myself over the bars on my 2009 anytime i want to with little effort. With the original pads still on it i should add.

I happened to find a (UK) shop doing the fibrax pads at a much cheaper price than they retail at as 'Brompton' pads. £10 got me front and rear pads + holders and 2 spare sets of pads.

The brakes have been upgraded to the latest 2009 version. I suspect that mostly an issue of the bike sitting in a shed for two years unused. That, and I'm used to how well the drums work on my Swift.

I just did a food shop with brompton as trolley, which is probably about the 5th time I've done the trolley thing. It was a pleasure today, perhaps partially because I'm a bit better at maneuvering it, partially as the shop was fairly empty so I didn't have to be to vigilant about not bumping into people. Left the shop feeling extremely happy and bonded with the bike.

Flex aside there's something I particularly like about the way it rides too. And I even managed to carry both bike and full basket up a flight of stairs (1st floor flat) without touching the newly painted walls. I'd previously been doing two journeys which rather detracted from the utility of the thing, and was thinking I'd probably have to sew a shoulder strap into the folding basket so I could use two hands to carry the bike. Perhaps I don't need to.

1. - minor, just swap with other brakes you prefer
2. - people swear by the brompton pannier bag. costs a lot, but beautifully integrated. alternateively you can by the front frame and figure out a cheap way to strap your exsiting panniers onto the frame. (kind of similar to how the new klickfix frame plus strap works). best option is to get carradice saddle bags, and multiple sqr mounts for your various bags.
3. - minor, lots of work arounds for that. lurk around yahoo brompton talk group
4. - major problem, make sure you figure out a way around this - modifying/customizing handlebars, or whatever you can think of
5. - never noticed this, put some luggage on there, and its stuff. i never biked wihtout at least some luggage

Brakes - yes they are not the best. I replaced my front brake lever with Avid SD-7 I adjusted it so max hand force was just before the lever gets to the handlebar so max force and max control. The tight bend in the brake is a big part of the problem. If you only ride Bromptons you adjust via more force.
Luggage is excellent, I cut handle off the stock C-bag frame and replaced with shoelace weaved handle, so the handle does not foul the brake levers. The C-bag is ample space for all I need, e.g. can go camping with it in summer.
Bottle cages, agreed, but you can put a main-tube velcro-strap type thing on and carry bike via saddle, only a 0.6L size though. Unfolded you can put them all over the place. For short rides I have 0.5L in C-bag rear pocket, longer rides I can fit bottles on the seatpost and the front stem. The pannier can carry pouch to top-up or instead of bottle but bottles easier to carrry.
Cramped? Well if you push the saddle all the way back, flip the pentaclip so its front of the saddle, it can go welllll back. The S-bars need a longer model (newer or replacement)
Flexing, well with S-bars there is very little flexing. Are you suffering from some play in the steering or brakes and need to adjust? I also have a Brooks Switft which is stiff saddle but shaped to my contours so comfortable and I replaced with stiffened suspension. I don't find it flexing.
I have S6L-X the older 6-speed with 6 close-gears and I customised front gearing, either a manual-move double-chainring when I'm generally in flat areas or I swap for Mountain Drive Brompton model which self-fits easily, if I need to go through a long undulating route.
I used Ergon grips to compensate for the harsh hand shocks from S-bars that solves the issues but my next modification is a longer S-bars, its cramped on the bars between grips and gear shifters but I have the 2007-model with shorter bar than newer model (48cm vs 51cm).

Thanks for all the suggestions. The bike is truly mine now, so let the tinkering begin!

I suppose that's a call for another thread. I'm not going to try to get the Brompton to ride like my Swift. Instead, I'm going to try to maximise its "Brompton-ness", while minimising the impact on my wallet.

First upgrade: Easy Wheels, or skate wheels.

To be continued...