berlinonaut
Veteran
And so we are travelling in circles back to page one of the thread (https://www.cyclechat.net/threads/prototype-20-brompton.289842/post-6898104 and following postings)...
Prototype 20" Brompton
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T4tomo
Legendary Member
Why would he?
The fork and rear triangle are obviously bespoke parts, the mainframe remains unchanged. various options on Kinetics website, 16" fat tyres, 18" & 20" wheels.
For me, I’m interested more in a standard Brompton scaled-up, wheels, mainframe and all to give a bit more reach and still folding neatly with the 20” wheels. Otherwise I feel like a circus bear on a tricycle - exaggeration but you get the idea.
This is the constant battle with modifying the Brompton - the mods have to work when the bike is unfolded and when folded. So, as a good as Ben’s 20” options are they’re not for me, personally.
Not to say that Ben’s 20” variant doesn’t still fold well, it’s just a halfway house to my dream Brommie
This is the constant battle with modifying the Brompton - the mods have to work when the bike is unfolded and when folded. So, as a good as Ben’s 20” options are they’re not for me, personally.
Not to say that Ben’s 20” variant doesn’t still fold well, it’s just a halfway house to my dream Brommie
Drago
Legendary Member
Because larger wheels put more torque loading through the frame under brakint and hard pedalling for a start. The frame may be up to it, but you can bet it was thought about carefully before trying.
Schwinnsta
Über Member
Really, because the gear ratios are more or less similar to large tire bikes. So you think the forces are higher in the frame? I mean, the forces in the frame come from us peddling.
Drago
Legendary Member
Have you never heard of a thing called 'braking'?
True as far as your statement goes, but.
The leverage from a force being applied by a 20" lever to the frame, or from The frame to the ground, will be different than for a 18" lever. Very different.
On the front forks in particular, the distance between brake pads is consequently greater and wheel centre will transmit more torque back into the headstock, and hence frame, under heavy braking.
And this pedalling whereof you speak, our imaginary rider is now transmitting the forces through the wrong end of a 2" longer lever.
And so on and so forth.
And it's good that you mention pedalling forces. A standard flame already flops and twists like a MP being caught in a lie when my 1/8th of a tonne lays down the power through the pedals hard, and that's why I do not buy one (that and its a little cramped, but I could probably with the sizing alone.) This is why I am hoping that Brompton will see that a larger wheeled bicycle - not just a conversion of an existing frame - might attract larger riders, so might stiffen the frame to suit.
I do not know that they will go that route, but that is the hope. I don't think that basic premise is at all difficult to u derstand?
True as far as your statement goes, but.
The leverage from a force being applied by a 20" lever to the frame, or from The frame to the ground, will be different than for a 18" lever. Very different.
On the front forks in particular, the distance between brake pads is consequently greater and wheel centre will transmit more torque back into the headstock, and hence frame, under heavy braking.
And this pedalling whereof you speak, our imaginary rider is now transmitting the forces through the wrong end of a 2" longer lever.
And so on and so forth.
And it's good that you mention pedalling forces. A standard flame already flops and twists like a MP being caught in a lie when my 1/8th of a tonne lays down the power through the pedals hard, and that's why I do not buy one (that and its a little cramped, but I could probably with the sizing alone.) This is why I am hoping that Brompton will see that a larger wheeled bicycle - not just a conversion of an existing frame - might attract larger riders, so might stiffen the frame to suit.
I do not know that they will go that route, but that is the hope. I don't think that basic premise is at all difficult to u derstand?
T4tomo
Legendary Member
all has negligible effect on the mainframe....as mentioned prior to your comment the rear triangle and forks are bespoke on Ben's kinetic large wheel conversions...
the forks will clearly need to be beefier as the large wheel conversions are disk brake not rim brake.
Brompton is increasingly an exporter, in the Asian market considerations of larger riders wont be a concern, but a growing US market might bring that into play as a beacon of hope for you, depends whether the overlap on "bigger yanks" and "yanks who want a folding bike" is of sufficent size on the Venn diag.
berlinonaut
Veteran
Not really. Export quotes have been in the 70+% range for the last decades already. Nothing has changed in that regard.
T4tomo
Legendary Member
exactly, supporting my point that the UK/European market isn't their prime target.
BTW which "decades" as WBA has only been there 2 and before he arrived they were a fraction of the size they are now.
PS can you do the maths for Drago, he's run out of fingers
tinywheels
Über Member
wondering how many kinetics sell.
I think the uptake might be quite small,if brompton produce a similar one.
I think the uptake might be quite small,if brompton produce a similar one.
Schwinnsta
Über Member
I agree with you to the extent that as the beam length goes up, the stresses in the parts go up. So to some extent a longer Brompton (with same size tubes) will see higher stresses.
berlinonaut
Veteran
Well, as I said: The percentages for export have been pretty similar since the start, just that the weight of certain export markets has changed. In the early years the main export markets have been Benelux, Germany and Japan. Only a couple of years ago the US have started to gain more intensive traction and recently China has been on the rise. For a couple of years in the 2010s South Korea has had a massive growth in numbers. And in general the number of countries that Brompton does export to has massively risen over time.
The exact numbers are outlined in the yearly financial statements. Just that only since 2010 those are way more elaborate than before and i.e. also include the export numbers. Before that one had to rely on random press articles. From official numbers it looks like that (Brompton's financial year goes from April to March, so is not a calendar year Jan-Dec).
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ukoldschool
Senior Member
I hope this photo has been staged because this is one of the most annoying things that I see regularly on my commute into London. Idiots with folding bikes taking up 3 seats when they could take up none by taking 30 seconds to fold a bike that is designed to be folded.
Idiots.
a.twiddler
Veteran
Yebbut Nobut Yebbut. If the train is not packed and it's not bothering anyone...though I realise that the term "empty London commuter train" is probably an oxymoron. How would you know before you got on even if it was your regular journey? Since to me Londoners seem to be an angry lot it would make sense to have it folded ready to get on, to avoid confrontation.
Perhaps a) it's not a London train
b) it's staged
c) something else.
