14R 

Here is the project:

At some point between now and April 14th 2010, I will acquire and modify a Brompton to fit my needs: lightweight, compact, fast enough to maintain 17-19mph and comfortable enough for 8-12 hour rides.

Here are the characteristics:

-None of the mods can compromise the final folded size. That's one of the reasons this project uses a Brompton instead of a Bike Friday, Dahon, Downtube. I need this bike to fit where a Brompton fits.

MODS

-Brakes: dual calipers upgraded brakes or Salmon pads or radioactive cables are not working. Under flat, normal conditions, they work fine, but throw in water (I often ride under rainy conditions, both in Florida and South America), some downroads and crazy traffic and now my life is in danger. I found the place to add V-Brakes to both front fork and rear triangle, and so far that's the light weight, effective mod that I am interested and looking forward to do. Price includes custom job painting on rear triangle and fork too!

-Weight: This bike cannot be as heavy as my S6L-Plus. Ti seatpost in an option (predominantly because I like the way it looks ). It will be a S-Type handlebar, but I am slightly inclined for a S1 or S2 model, most likely E type (no Fenders or rear rack). No Ti since US$700.00 I can get more performance oriented upgrades (just to include a few, carbon handlebar, grips and pedals...still keep the change). Not sure what to do in relation to hubs and wheels.

-saddle: I want this bike to be century friendly. I don't do 100 miles in a single shot often, but I want to bS able to, so...I know, saddle is a personal thing. I have very mixed feelings about Brooks saddle. They look elegant, but I see more people complaining about them than actually enjoying them. Also, I noticed that the time between new to "broken in" is about the same between "broken in" and broken down. They just look bad, like a mule back, after a while. I have very good experiences with Specialized saddles with the cut perineal region, but I want to hear and educate myseld with what is out there.

-handlebar/grips: S-Type is what I have in mind...but wouldn't bullhorns make it wind friendly, faster?

-Tyres: What's up with the Kojaks?

-Crankset and wheelchains: I need to learn more about oval shaped/assimetric ones.

Please bring your contributions. Let the fun begin!

SesameCrunch

Starting with the Brompton steel frame, weight reduction is going to be hard, isn't it?

I think LittlePixel had a lot of good ideas in his Merc/Brompton custom job. He got the lightest of both worlds. Then, add lighter wheels and tires. Rotational weight counts 4 times as much as static weight (I read that somewhere, but don't ask me where.). Ti seatpost, carbon bars. Carbon cranks.

Boy, this may cost a bundle (unless you start with the Merc frame). Have fun with this project....

Hmmmm.... I have a Merc. Maybe I should take on such a project too. Could be fun.

ChiapasFixed

maybe look at greenspeed scorchers for tires, lightweight, fast rolling and smooth out bumps similar to big apples.
how do you feel about single speed/fixed gear setups? I have done some fixed gear touring and it can be quite nice, if you have a lowish gearing (I use 65 gear inches), I don't know about maintaining 18mph... more like 14-15...

14R 

Single speed is fine, but fixed gear might not be a good idea. The crank arms get to close to the floor on agressive turns, if I hit the floor I might become part of the asfalt. Big buses do NOT stop if you fall in front of them in Rio de Janeiro lol.

That's a pretty good start, thank you for the contributions.

Edd

Hi,

I think this bike looks close to what you want:
https://sports.groups.yahoo.com/group.../message/52852
and takes you to these photos:
https://www.flickr.com/photos/2661645...57608165769367

Edd

LittlePixel

My thoughts:

Find someone that can weld Ti and then get Ti braze-ons for the lighter forks and rear triangle fitted. Costly, but lighter. Those two parts are the two things that will save a ton of weight - they are nearly half the weight of the steel counterparts.

With no mudguards or rear rack the fold is as good but less good at being wheeled about and less stable when sat in a little folded parcel (ie it falls over quite easily)

For lightness of wheels, you can go for Velocity rims, but then you have to change your hubs as the spoke count is different. You can also think about increasing the size of the wheels a little if you are definitely not going to run fenders. the '18inch' (355mm) Birdy size will fit, as will the 369 '17inch' moulton size, though you are limited to skinny tyres with the latter for reasons of clearance.

S-type stem is definitely the way to go, but you might want to get some bars with more options than the 'straight' s-types. Some slight risers might be good, or as you suggest bullhorns (though imo they aren't too good for long rides. Flipped North Road bars are good as shallow drops, or you could consider Moustache or 'On-One's Mary, Mungo or Midge bars. Any bar that isn't flat in the x dimension will foul your fold in some way though so you may need to think about the Aberhallo or Syntace stem extender fix so you can QR the bars and flip them up into the vertical axis for folding and clipping the stem to the forks.

Saddles - personal choice. My Brooks has become a very funny shape (probably as a result of butchering the sides to look like a swift). Have just swapped it out for a Charge Spoon affair which seems pretty nice, if a little hard for light use.

Chainrings. Never tried Bio / Eggs so can't comment. Going fixed is interesting but I think a little too much trouble for a day to day bike. Singlespeed should be good though. Nice and light without extra cabling, big hubs, extra lever.

invisiblehand

Why is weight important to you? I ask since the point of this thread seems to be about performance and I suspect that you will not be riding many pacelines on the Brompton (but I could be wrong). Although your requirement could be about carrying the bike -- the urban mobility part in the title. If you don't need the extra gear range, I would stick with the two speed since just about everyone can use a low gear on long rides. And swapping the rear cogs and chainring for appropriate gearing is not hard.

The 349 Kojacks or Scorchers are probably what you should use for long distance rides. Although if you really want to trick your bike out and are thinking about doing something with your wheels, then you could look at Moulton or Birdy options.

I think v-brakes in the front make a lot of sense. But I don't think that the exercise is worthwhile in the rear unless you are looking for more tire clearance. Note that if you are really considering bull horns then you have to use levers with enough cable pull or travel agents. If you went with larger wheels without fenders, you might be able to swap short/standard reach caliper brakes instead of the long reach Brompton models and improve the stopping power and shed weight.

I think you will be hard pressed to find a Merc frame at this point. But if you are going to invest a lot of money and time into the project, I would stick with the Brompton and its warranty. From what I understand, going with the ti fork and rear triangle kills the v-brake modification. How much weight do you think one could lose only through components? One reason to go with the ti option is that one could still incrementally upgrade components over time.

14R 

Weight is important to me when the bike is folded and being transported: carrying it, having it on my lap or checking it in inside luggage.

I couldn't care less about tire clearance since this will be an E type: no fender, no rack.

Correct me if I am wrong, but fitting larger wheels will allow me to use standard road bike calipers without any "littlepixel amazing mods" to make them fit? hmmm, that might be better than V-Brakes.

Thank you for the contributions...keep them coming.

invisiblehand

That is what I figured. But why not ask?

Maybe. Short reach brakes would be awesome ... but they are considerably shorter than the Brompton dual pivot brakes. I no longer have a Brompton to take the measurements for you, but if you went with ERTO 355 wheels you would move the rim 3 mm closer and perhaps modern long reach/former standard reach (47-57 mm) brakes could fit. Shimano sells a set that they consider equal to Ultegra.

I believe that the classic Moulton uses ERTO 369. That would get the rim 10 mm closer and perhaps compatible with short reach brakes.

Caliper brakes are quite powerful when properly set up.

14R 

I knew good stuff would come out from this forum.

I did my homework, and I did find someone that can play with Ti. It requires a chamber filled with Argonium since Ti reacts with O2 in a bad way. It is expensive and very technique sensitive (I might have to destroy a fork or 2 to get the results I want, or send it out of the state #for a lot more $# to have it done).

Ti + V-Brakes is out.

The next option is to invest on wheel size that will allow different brake calipers to be used. If the Molton size IS compatible with short reach brakes, that's a good way to go. LP, do you have experience with those sizes?

In one way or another, I am inclined to get the Ti + bigger wheels instead of conventional wheels. Any good source to buy them?

Once again, thank you for your contribution.

14R 

It seems that Mr. Rubin is working on making some parts of the UFB available. Check the recently updated (and still crap) website:

https://www.ufbusa.com/

Dynocoaster 

I just purchased a Terry Liberator Ti saddle very light and comfortable.

LittlePixel

I don't have experience myself of those sizes, but the dutch guy on BromptonTalk (sorry can't recall his name right this second) who sells and modifies them has fitted 17" moultons in the past - perhaps search the archives or knock out a quick question to see what experience people over there have.

Shame to hear about the TI brazing. Somehow I knew this wouldn't be a simple thing. Seems to be the reserve of the uber-rich, the military and F1 teams then haha.

invisiblehand

You can probably get a decent estimate from LP's work.

I recall that Campy brakes tend to have 40-50 mm of reach. If true, then the center-to-center distance of the holes will tell you how much vertical adjustment is needed for the modification.

IMO, you will probably be pretty happy with standard reach (47-57) Shimano brake calipers. They are pretty powerful in my experience.

invisiblehand

BTW, I have been thinking about the front wheel all of this time. I also seem to recall that the rear tire clearance -- with the frame bridge -- is minimal.

14R 

A single speed with minimal cables (maybe single speed) and S&S Couplers can't be that hard to put inside the luggage, can it?

Just kidding, but I really like the idea of a Bianchi Mini. maybe one day the garage will feature everything I want hanging from the wall...

Joako

- Velocity Aerohead + American Classic 58g front hub 14H laced radial (not sure if they make the 28h in 74mm OLD, but Dahon uses the 20H one).
- Velocity Aerohead + brompton rear hub 14h laced 1x
- Ditch the IGH and go single speed or two speed
- Carbon/hollowtech Crank and carbon handlebar
- Hollow bottom bracket
- Aluminum seatpost to save weight and $$$. It also depends how tall you are as I have not seen long 31.8 seatpost.
- Ti saddle or carbon if you don't mind replacing it. Ti charge spoon is an option. I just got a chromo one after waiting a month and it is very comfortable.
- Kevlar folding tire
- Light presta tube

Bullhorn = extra weight. Keep the straight bars since you are concerned about the weight.

bhkyte

Can somone post a picture of a Brompton with bullhorns.Thanks

BruceMetras

bykerouac

Very cool and informative thread! If you would like a somewhat stretched out position without going the bullhorn route (which I think is uber cool by the way), I would suggest getting the M stem, a 2 1/2 inch MTB riser bar, short stubby bar ends, and perhaps a Brompton saddle adaptor pin. The M stem is lower than the S stem so it gives a lower handlebar position. The 2 1/2 inch riser (Azonic makes one) can be angled forward a bit without affecting the fold, and the stubby bar ends offer a more forward riding grip. At the rear, you can reverse the saddle clamp (or Pentaclip if you are using one) to place your saddle further back an inch or so. If you would like more offset, the saddle adaptor pin does the job quite nicely. With all these, the result would be a stretched out riding position without affecting the fold.

Great project, please keep all of us up to date!

bhkyte

Thanks Bruce, (good day my name is Bruce) (also)),seen this one before however. some more pictures please. I have not seen a Brompton with bulls that the fold does not seem compromised, I would like to see any other solutions,thanks.

LittlePixel

bhkyte

Thanks "LittlePixel", can I see it folded? I am really interested in folding solutions for drops and bullbars. You have been mentioned several times before for your mods, but I have struggled to find the excate details of the stem. I am aware of the "atoris?" solutions ,but I am not sure they are QR. The other versions I have seen are Jurs QR on an adjustable stem.(sorry not trying to Hijack the thread).

LittlePixel

@bhkyte Read this thread (from post 16 onwards)- it should illuminate things a little:
https://www.bikeforums.net/folding-bikes/400500-best-looking-brompton-i-ve-seen-so-far.html

bhkyte

Thanks!