banaltheory

I've come upon a blessing and a curse. I bought a used modified 3 years old S1E Brompton, 54t ring - 13t cog in a good condition with only a front brake. Looking at the rear wheel, it seems that it used to be a 2 speed bike and the handlebar had been changed to a riser which seems to be shaped in between an S and an M handlebar. Recently moved to a hilly area and happen to live in a perpetually rainy country so that requires me to get a bit more mountain goat capabilities out of this bike and fit it with fenders and brakes.

I'm a really lazy rider and I'd like to commute with normal clothing as my office is only 4km (2.5 mile) away. Now, this should be a relatively straight forward process if not for the sad fact that the previous owner tried to save weight by cutting off pretty much all of the cable guides as well as the mount for the pulley housing and the front fender mounting hole on the fork. Which makes it rather difficult to fit brompton's off the shelf components. But hey, luckily the previous owner managed to put carbon fibre decal on almost this entire bike making it magically super light and super fast! oh wait... not really... bummer...



Thus, I'm trying to mod this bike out of necessity not for vanity - so obviously cheaper alternative options would be welcomed, but I'm prepared to spend as required. I'm looking for utility and functionality at foremost and not looking for fancy mods or speed - Think Japanese-grandma-cruising level of speed. Oh and please don't underestimate my laziness, the lower the gearing the better. Ultimately it's for transport, leisure and exercise, in that order.

Rear mudguard - sorted with a brompton standard rear rack.

Front mudguard - My research showed that there's not a lot of alternatives for this so I have to go with Brompton mudguards. Do you think I could use a bit of cable tie to fix this? or is there any other importance in regards to the mounting hole that I am not aware of. As I'm also planning to mount a B&M dynamo Lumotec light, not sure how much it would affect the mudguard, but I think it's mounted on the brakes, oh yes about the brakes...

Brakes - Any alternatives out there to the brompton caliper brakes that can fit the brompton fenders?
Looking at the bromptontalk wiki, alternatives to the brompton standard brake levers are the shimano BLR550 or the Avid speed dial 7.
As the bike has a non standard handlebar, possibly a BLB roadrat riser bar, which one would fit better? or is it worth spending a bit more for the brompton new brake levers?
What about the length of the cable, since the handle bar is in between S and M should I be worried? I have a feeling that it matters because of the fold?
I'm planning to use normal black plastic cable ties for routing cables. But there's that other problem where brompton also uses the cable guides on the rear triangle as part of its transmission system...

Transmission - In my ideal world, it would probably be the combo of 3 speed BSR and mountain drive. 50t ring - 15t cog = 16, 22, 29, 41, 55, 74 gear inches. But without the mount for the pulley housing on the rear triangle, I have a feeling that my options for the 3 speed BSR or 6 speed BWR will be limited if it's at all possible...

So what I'm thinking is
4 speed Brompton - 2 speed derailleur plus swiss mountain drive. 50t ring - 12t/16t cog = 20, 27, 52, 69 gear inches.
Not sure if it's more hassle than it's worth, a tad expensive, requires a complete change of the bottom bracket, and more importantly I'm unsure whether the 2 speed derailleur will fit onto the current brompton with the rear cable guide missing and all that (which affects the rear cable stop assembly)

OR...

The Sturmey Archer X-RF8(W) 8 speed brompton kit from Kinetics - I haven't managed to find a lot of info on this, especially on a brompton. Any thoughts on this IGH? At almost 2kg (4pound) it's not exactly the lightest solution.
According to Kinetics, he normally uses a 33t ring - 20t cog = 27, 36, 40, 46, 52, 60, 68, 89 gear inches. Is there a way to lower the gearing on this even more? It might not be low enough, and not sure if the 20t cog means filing the rear triangle a bit, which is probably not too hard of a job. I'm unsure if it requires any of the cable guides from a standard brompton or not. Also wondering if the twist shifter will fit fine on the handlebar, which I think it would.

OR...

Electric bromptons! How about no... too expensive, too heavy, and where am I going to put my SP dynamo?
Any other alternatives?

jur

There is a vendor who sells 5-speed wheels on ebay. Combine that with a Schlumpf and you got a drop-in wide range 10-speed. I could be persuaded to part with my goodies... In Melbourne.

mastershake916

No offense if it is anyone on here, but gosh the previous owner sounds like a tool.

Edit: I'm a tool. Disregard the previous comment.

dynaryder

For cable guides,you have several options. You can buy ready-made like these:
Stick-On Guides | Jagwire
Universal Cycles -- Problem Solvers Stick On Cable Guides
Problem Solvers

...or just fab your own with zip ties,P clips,and such. P clips or zip ties with bolt holes will also sort the fender mount.

BTW,the stem setup looks interesting,could we see a better pic of that?

blakcloud

Front fender, P clips will possibly work.

Brake levers, yes the ones you mentioned will work, I use the 550's but I wished I used the latest Brompton brake levers. The reason is the Brompton brake lever has the housing and cables exit the lever at an angle that is conducive to the Brompton. With the 550's the housing has sharper bends which doesn't help in braking. Not the end of the world but if you have to buy levers anyway.

For the back brake, just buy the Brompton it works well and fits perfect.

Your bar and stem look like it approximates the height of the M bar, so that is the cable length I would use. You can always cut it shorter if need be.

As for the gearing, your idea of mountain drive and two speed rear sounds expensive. Two speed shifter, cable set plus mountain drive to get great range but crappy transitions. The 8 speed idea again is expensive. You have to have the rear triangle widened to fit the hub or you buy the whole kit from them with a new rear triangle.

Is it possible you just don't have the right Brompton? Could you sell the one you have and put the money towards a 6 speed and with -12% gearing? Someone else might appreciate what the original owner did for a light weight Brompton.

In the end it just sounds like a lot of work but maybe that is something that appeals to you.

Joe Remi

Whoever fiddled with that Brompton is barking mad. It seems to me you'd be better off buying a proper 6-speed Brommie than trying to undo...whatever that is.

fietsbob

2 speed hub and the Speed drive 34-'54', or just 2 chain rings ? a derailleur up front (on one of the custom clamp on brackets to fit a Braze on FD. )

I use a 54t MD and a 15t cog on the BSR. 17-85 GI 6 useful gears.

cable to both brakes come up from beneath to still fold you can try other things

kinetics in Glasgow, makes whole rear ends and custom forks to take disc brakes .. put the 8 speed in that
maybe the 25 t cog will clear that one?

mulleady

And that makes you what? A troll perhaps?

Just because the previous owner modded the bike to their needs and liking doesn't make them a 'tool' or 'mad'. It appears they modded the bike to be a very lightweight commuter in urban areas perhaps? It's best not to disrespect what you don't understand. Some people get by just fine with one brake and all the mods and chosen tyres make this a very light folder suited to a particular individual's needs. Perhaps not for some people and certainly not for me as I need mudguards living in London!

The op knowingly bought the bike 'as is' and made a choice. It would have been easier to get a more standard Brompton without many modifications or at least ones that suited their needs.

mulleady

What weight is the bike? How much did you pay for it? Where are you based?

I'd hazard a guess that this bike is under 9kg and you might be able to resell it for a good price to a buyer with a flatter urban commute who desires an ultralight Brompton. There is a niche market for these bikes.

It would be more expensive to remod this bike to your needs. I would say that a Brompton wide range 3 speed hub is the neatest solution if you decide to work with this bike. It will give you enough range to climb as well as descend or gain good momentum on the flats.

Joe Remi

The previous owner put carbon-look stickers all over a Brompton. That's barking mad.

fietsbob

Love it or Flip it.

banaltheory

Thanks for the responses and suggestions people.

@Jur
Yea I saw those, it's an SRF5(W) I believe? I'm just not sure if it will fit onto my brompton as the mounting bit for the pulley housing on my rear triangle had been cut off and no longer available unfortunately. see photos attached.

@Dynaryder
Thanks for the ideas, I think the P-clips would work fine.
Sure I'll take some pics of the stem for you when I get spare time this thursday.

@blakcloud
Thanks for the tips, you're correct. It is a lot of work but I don't mind getting my hands dirty if I can get close to the gears and range that I need, plus I will understand a bit more about the build and maintenance of a brompton. I could potentially sell it and buy a new 6 speed but what concerns me with the BWR and 44t combo is the fact that it might not be low enough for me so I will have to end up customising it again anyway and 39t ring from Tiller Cycles is the lowest I've seen so far.

I had another look at the 8 speed kit from kinetics and apparently it does not require any modification of the frame. Looking at the picture, it also doesn't seem to use the mount for the pulley housing so this might be the way to go.

Otherwise as you suggested I might sell it, get a used 3 speed and add mountain drive but that might end up costing more than the 8 speed kit above. I'll do a bit more research.

@fietsbob
I think the gearing on your bike is pretty much the gearing that I'm after really. The only issue is mounting the BSR pulley onto my brompton decapitated triangle.
I'll see if it's possible to go with a 25t with the 8 speed. I know someone had done it with a 23t though. Do you know if the chainring can go any lower than 33t?

@mulleady
Yes you're right, it's important to respect the owner as they each have their own personalities, quirks and priorities.
I bought the bike as is because it had been maintained pretty well and it was in a great condition, a lot of the used bromptons I saw were rather... for the lack of a better word, rusty & crusty. I also liked the added adjustability of the modded stem which gives it an inbetween an S and an M bar height. But honestly if it wasn't for the missing "limbs" on the bike's frame, I would've just bought a 3 to 6 spd wheel upgrade and I'd have myself an almost brand new 6 spd brompton at 3/4 of the price. I just didn't realise it at the time and unlike you, I am not lucky enough to live anywhere close to the Brompton motherland.
The BWR hub you suggested unfortunately would require the use of the mount for the pulley housing on the rear triangle which I don't have. Unless you have an idea on how to affix the pulley housing onto the triangle securely by any chance?

mastershake916

@mulleady
You're right, my bad.

CliffordK

You could always get the proper frame cable stops and nuts and braze them back on and repaint. It would be a lot of work, but you'd get the bike you want (and even your color choice). You don't really have the original paint anyway.

mulleady

Fair play!

cpg

It will make good money on the second hand market. It would be far easier and probably cheaper to sell it and buy a used 6 speed Brommie. A used 9 or 10 speed Mezzo could be had for a lot less than a used Brommie.

fietsbob

different cranks entirely .

SRAM 2 speed IG Crank https://www.sram.com/truvativ/produc...dt-am-crankset .. 22 or 24t ..
https://pattersonbike.com/ has a 28t(45) on it Schlumpf HSD its a 27t (67.5)


or consider granny gear only using a triple or a smaller BCD crank ..

dynaryder

Will only work on frames that have ISCG 03 or ISCG 05 Tabs

LittlePixel

Curious Stem is the "Aberhallo" hack - as preluded by me - at least on the Brompton (tootles own trumpet!)
It's basically an adjustable stem attatchment that allows fitting of non standard bars if you combine it with some sort of quick release and adjustments in height or reach.

The reason standard "M" bars look so dorky (sorry M bar lovers) is that there are no compound curves in them - for the reason that they'll fold flat against the wheel when you fold the bike.

Combining an Acor or Satori "Aberhallo" stem with a QR means you can fit more ergonomic or flamboyant bars and then flip the bars back when you fold it meaning you can still close the stem into it's clip without the more 3-dimensional bars fouling the wheel.

You can actually do this handlebar hack without the aberhallo with just a Quick release bolt, but the using this stem adapter allows for height or reach adjustments to dial in the ride ergonomics a little more towards your own taste.

Here's an image - not of mine but you get the idea:

cpg

I use the same stem and a QR on my Mezzo. Better ergonomics, a bit more reach and when folded, the bars can be rotated to keep it compact. Works very well and the handling improved.

banaltheory

Yep the stem is exactly like what LittlePixel said. Although in this case it does not have a quick release.



Curiously the weight of this brompton is not even that light. Without the rear rack it's about 10.7kg (23.6 lb)
I think it's because it doesn't have titanium parts on it at all.

I emailed Kinetics regarding 8 speed brompton a few days ago and still have not received a reply. I heard that it is common knowledge to have to wait patiently for replies from him? In other words, are there any other supplier for an 8 speed brompton kit out there?

fietsbob

Ben Cooper (Kinetics proprietor) posts in the Frame Builder forum .


perhaps some one Local can take the hub down narrower, [take it off the Left end] and pry the Rear end open to suit .
then build a Wheel ..

Ben, it seems, builds a new Rear end, 135 wide*, that will also take Disc Brakes , and also scratch builds a Fork, 100mm wide(disc mount,too) not 74.
*also fits Rohloffs..

depends on what crank you buy .. 110 and a Limit is the bolt circle . A 34t typically

Old TA the crankarm bolts to the Outer chainring. then the bolt circle is much smaller.

banaltheory

Thanks fietsbob, actually the xrf8(w) hub apparently does not require any adjustments to the rear triangle, but rather a modified version of the chain tensioner/derailleur. As seen in this blog More on the Brompton 8-speed conversion?.room for improvement? | Pedalitis

fietsbob

Yea the smallest cog is a 20t on those.. bolting down a Derailleur claw and using a Non Brompton chain tensioner may work Too .. single pulley

looks like the Blogger wanted to use a Double crank Too.