# Brompton Adapted for Hills



## The Jogger (18 Jul 2017)

I'm seriously thinking of bring my Brommie over to the village i have a house in Spain but it is seriously hilly around here, so what adjustments will I be able to make or get my LBS to do to make it a bit easier to get up the hills. Also what would i expect to pay for the adjustments.


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## raleighnut (18 Jul 2017)

Theoretically you just need a crank with less teeth so about £80 max.


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## Cycleops (18 Jul 2017)

I'm sure Brompton enthusiasts will give you a run down on how to get ultra low gears but its basically a urban commuter not a hill climber. Unless you have an alternative role for it in its intended use you might be better off selling it and buying something that would cope properly with the hills.


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## TheDoctor (18 Jul 2017)

I threw a cheap compact onto mine.
Going onto the 34T ring instead of the 50T means essentially you lose the top two gears and gain an extra two at the lower end.
It's now an M12R


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## rualexander (18 Jul 2017)

Stick a cheap Spa triple chainset on it http://www.spacycles.co.uk/m2b0s109p2000/SPA-CYCLES-XD-2-Touring-Triple-Chainset 
stop when you get to a hilly section and move the chain to the inner ring by hand. You'll probably only be able to use the middle and inner rings as there isn't enough scope in the chain/tensioner to use all three rings. Outer ring can act as a chainguard.
Depending on which hub you have on your Brompton that should give a decent range for very little outlay and you can swap it back easy enough when you take it back home.


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## oldwheels (18 Jul 2017)

I put on a 40t chainring on my 6 speed. Good for hills and top is ok unless you want to race.


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## CopperBrompton (18 Jul 2017)

There are lots of options, from a smaller chainring all the way through to Rohloff gears. I currently have the SA-8 hub, which I can highly recommend, but decided to treat myself to a Rohloff for the replacement currently being built for me by Kinetics.


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## pjd57 (19 Jul 2017)

http://www.kinetics-online.co.uk/category/folding-bikes/brompton/


Few ideas in here.


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## Fab Foodie (19 Jul 2017)

TheDoctor said:


> I threw a cheap compact onto mine.
> Going onto the 34T ring instead of the 50T means essentially you lose the top two gears and gain an extra two at the lower end.
> It's now an M12R


This is what I did with mine.
50/34 stronglight compact fitted to my S6L gave me nough bottom end gearing to haul a touring load over the hills of Harris.
No other mods required.


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## The Jogger (19 Jul 2017)

Fab Foodie said:


> This is what I did with mine.
> 50/34 stronglight compact fitted to my S6L gave me nough bottom end gearing to haul a touring load over the hills of Harris.
> No other mods required.



Thanks FF

Is this an easy modification to make bearing in mind I don't do much mechanics or best with my lbs?


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## Cycleops (19 Jul 2017)

You'll need a 14mm socket, a crank extractor and a 15mm open ended for the pedals.


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## mitchibob (19 Jul 2017)

If you're not commuting with it, and don't mind the slight compromise of a pedal sticking out when folded, decent pedals make ascents a bit easier too. And if you still want to be able to ride with sandals, you can actually get sandals with SPD cleats, or just use those where one side is for the cleat and the other for any old shoe.


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## GrumpyGregry (19 Jul 2017)

8 speed conversion from Kinetics. Bottom gear climbs cliffs.


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## Fab Foodie (19 Jul 2017)

User said:


> Can you remove a crank arm and a bottom bracket? If so easy. If not easy for a bike shop.


@The Jogger as above. With the tools and know-how it's a 10 minute job.

I too use single sided SPD pedals which help on the hills.
I also find that when folding the bike the chain needs to be on the 50T ring as it falls off the 34.
@TheDoctor is this your experience too?


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## TheDoctor (19 Jul 2017)

Fab Foodie said:


> I also find that when folding the bike the chain needs to be on the 50T ring as it falls off the 34.
> @TheDoctor is this your experience too?



I've got a 44/34 on there at the minute. The tensioner will just about manage things if the chain is on the 34, but it's better on the 44.
TBH, it's perfectly fine with just a 44T chainring, but I didn't have any single chainring bolts!


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## Fab Foodie (19 Jul 2017)

User said:


> View attachment 362971
> 
> Mine has 52 and 38 teeth. It is a Spa touring double chainset that cost something ludicrous like £20 without rings. I had to experiment with the bottom bracket to get the right length and wish I had thought to write that down somewhere.


Mine seems to work fine on the standard BB.

OK so 10 and 14T difference seems to be OK for the rear tensioner but 16T (50/34) is possibly a step too far for foldability on the inner ring.


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## The Jogger (19 Jul 2017)

User said:


> Can you remove a crank arm and a bottom bracket? If so easy. If not easy for a bike shop.


Bike shop me thinks, Adrian................thanks


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## chriscross1966 (20 Jul 2017)

If you have the current crank it's a 130BCD, so you could just fit a 39T chainring. Slightly more exotic would be fitting a different crank, I do it for aesthetics purposes, but it wouldn't be expensive to get a double chainring in the front and have say 50/34 compact loaded onto it, assuming a 3-speed then maybe go up a tooth or two on the rear sprocket. It's not hard to get a Sturmey 8-speed into the standard rear triangle, once again go down to the smallest chainring you can on the front.... in a more exotic world you can fit a Vostok rear triangle and either a Rohloff 14-speed or Shimano Alfine 11-speed hub, If you had 39-18 chanring and sprocket on an Alfine you'd be able to climb pretty much vertical faces, that bottom gear would be around 20", and you'd still have a top gear that would allow you to play SB's down the hills...


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## The Jogger (28 Nov 2017)

My LBS said they would fit if I sourced it as apparently because they're not a Brompton agent they can't. Would this do the trick

https://www.sjscycles.co.uk/chainsets/alloy-compact-double-square-taper-chainset-5034t-170mm/

Mind I did ask them to fit a marathon + and I've just picked it up with just a marathon on it, never mind, they are a nice bunch in there.


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## 12boy (28 Nov 2017)

The 50/34 will be fine. You haven't said how old the bike is. Before they went to the 130 bcd crank with removable chain rings they were ISO. However, I used a JIS 119 mm bottom bracket with a 54 and 38 and it worked fine except for throwing the chain when folded on the 38. I had to stop to change the chain from one ring to the other but it only takes a few seconds. Others have said they can do the down shift with their shoe but not the other way around. I have used ISO crank arms with a JIS spindle but I am not sure you can use JIS cranks on an ISO spindle. A better BB than the original is not a bad idea anyway. The only tools needed to switch chain rings is a 5mm allen key and perhaps a wrench made to hold the nut side still. https://www.parktool.com/product/chainring-nut-wrench-cnw-2 is an example.


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## The Jogger (29 Nov 2017)

Thanks 12boy, I got the bike about three years ago. I'm not confident enough or technical enough to carry out the work so I'll get the lbs to do it. Just good to know that compact is the right one. I know @Fab Foodie has a similar one.


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## chriscross1966 (29 Nov 2017)

12boy said:


> ..... A better BB than the original is not a bad idea anyway. ....



It isn't hard to find a better BB than the old Brompton one :-).... I like the Campagnolo Ultratorque, but recognise there is a significant technical challenge in getting one into a Brompton, the Shimano UN55 is available in many lengths, although one method that might work very well is to investigate the use of 73mm (Mountain Bike) Hollowtech2 cranks with a 4mm spacer under the drive side and a 1mm spacer under the NDS... that would give clearance for the inner ring, and you could look at adding a front derailleur mounted on a 40mm derailleur hanger https://www.ebay.co.uk/itm/322544758574


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## Kell (29 Nov 2017)

You're probably the right person to ask @chriscross1966 - has anyone successfully added a front derailleur and shifter to a Brompton?


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## chriscross1966 (29 Nov 2017)

Kell said:


> You're probably the right person to ask @chriscross1966 - has anyone successfully added a front derailleur and shifter to a Brompton?


There's a fair number on the far-Eastern Brompton fan pages on Facebook, Steve Parry built a few too. I'm in the process of trying to get one together ATM, mostly late 80's or early 90's Campagnolo parts, including the bottom bracket. I plan on using that 40mm clamp to work out positioning for the front mech then have a mount brazed on when the frame goes off for repaint. For the rear mech I have the hanger that came with the Vostok triangle on another bike so will use that with the modified stock triangle I'm fitting. She's called Francesca because of all the Italian parts.


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## Fab Foodie (29 Nov 2017)

Kell said:


> You're probably the right person to ask @chriscross1966 - has anyone successfully added a front derailleur and shifter to a Brompton?


Yes, it’s been done and it’s not to complicated. Ask on the London Brompton Club forum.


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