Brompton how light can it go

[chriscross1966]

Someone has just put pictures up on one of the Facebook Brompton Groups of a 5.7Kg Bromopton that still has the standard frame.... the rest of it (even the hubs) is mostly carbon fibre

 

[Flying Dodo]

Ooooo....I wonder how much?

 

[Fab Foodie]

Ooooo....I wonder how much?

5.7kgs I reckon ;-)

 

[deptfordmarmoset]

5.7kgs I reckon ;-)

5.7 Kilodollars

 

[TheDoctor]

If I could lay my hands on enough pre-preg (and an autoclave) I'd love to try making a Brompton frame out of carbon.
The hinges would be difficult. Making hardpoints in carbon is, well, hard.
Although, the only time I've ever had an issue with the weight was when SNCF made me fold and bag my M6R before I got onto the platform at Gare du Lyon.
Two TGVs coupled together are surprisingly long, and lo! I cursed without hesitation, deviation or repetition for almost 1/4 of a mile.

 

[mustang1]

I don't think brompton will make the bike lighter for the foreseeable future. Right now i.reckon they're concentrating on developing an electric version.

I'd love to get a lighter version at a fair price but I can't see that happening until some other wonder material, we , materialises

The X version isn't light enough and already costs more than what I want to pay.

 

[Cycleops]

The thing is Brompton is not really a bicycle company, it facilitates urban transportation. They have developed it as far as they want to in that role. Its already very expensive and making a slightly lighter model wouldn't increase sales to people that want to ride it across town and store it in their office.

As mustang says the holy grail for them now is the electric version.

 

[Kell]

I think perhaps you're looking at the situation from the wrong end.

The problem is that the Brompton is heavy to carry long distances.

One solution could be that you make it lighter so it's easier to carry. But in my experience it's not the weight in and of itself that's the problem, but the awkwardness of the bike once folded. Also, as others have mentioned, so much kit is OEM and non-standard sizes that this would be horrendously expensive for very marginal gains.

So another solution could be one in which you make it easier to transport while folded.

This *could* be by making proper rollers that would allow you to push/pull it with ease.

If something like the Sidewinder (3rd party add on) could be incorporated into the bike, then it wouldn't need to be lighter.

(Sidewinder: http://www.wheeelz.co.uk/)

Or it could be some sort of rucksack or strapping that would make it easier to use your shoulders to distribute the weight. Though, I have to say folding it up, putting it in a bag or then having oil or road grime drip down your back probably wouldn't work for everyone.

 

[reppans]

It is an awfully awkward thing to carry, if held like a suitcase/briefcase down by your legs. But the Brompton's compactness and locking fold makes it easy to carry on top of my shoulder(s) - water container style. While touring, I usually carry mine ~1/4 mile into woods for wild camping, and have carried it up a ~30 story staircase (to the top of a 300' dam) - T bag with full touring kit carried in backpack mode. Also being on the short side I can carry it comfortably at a normal walking pace though my entire house - narrow staircases and hallways incl., with a free hand to open/close doors along the way. ~20 yards is about my limit for suitcase-carry style, then it goes up on 1, or across 2, shoulder(s). Fully kitted, my Brommie is up to 35lbs and is my heaviest bike.... yet is by far the easiest to carry distance.

 

[bikegang]

Yet another record (5.24 KG). Nothing from brompton I am afraid. But the possibility ... .

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[steveindenmark]

I am thinking that some of these people must carry their bikes more than they ride them.

 

[rogerzilla]

One of mine is 23 1/4 lb with SPDs - just weighed it. Ti frame bits and seatpost, Flite saddle and no mudguards but it has proper cranks and bigger sprockets than a normal Brompton, plus bar ends - those put some weight back on.

The other one is probably 35 lb as it is an M-type with SON-XS, lights and Marathon Plus tyres. I daren't weigh it.

 

[rogerzilla]

Although aesthetically the Brompton is a wonderful thing, it is just so massively over-engineered in places. The main tube just doesn't need to be as big and bulky as it is.

If they made it from a stronger steel it could be thinner and/or butted. I think the current frame is just hi-tensile steel. Fillet brazing would need to be looked at too: they do that because no-one makes lugs to suit but a good air-hardening chromoly steel could be TIG welded.

You'd see more rusted-out main frames if they were thinner gauge, though - Brompton rear frames are known to rust through and the bikes often have a hard life.

 

[Flying Dodo]

Yet another record (5.24 KG). Nothing from brompton I am afraid. But the possibility ... .

Wow! Where can I get one?

 

[doginabag]

Will those EZ wheels last more than one fold?