# Double Chainring combos for touring an S6L in a hilly area ....



## Fab Foodie (22 Jun 2016)

I may have asked this before out of interest ... But now out of need!

I may need to take the Brompton on my Outer Hebrides cycle tour if I can't get the Rourke in a Citroen C1
It's a good excuse to get on with the mod anyhow.
I use the 44t chainring as std but if went double would not mind the 50t back on.
So, if I'm to buy a new chainset, what chainring combos do you recommend for lumpy 2 week tour?

Also, will I need to get a wider BB.
I may do a derailleur mod later ....

Cheers
FF


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## Rohloff_Brompton_Rider (22 Jun 2016)

Fab Foodie said:


> I may have asked this before out of interest ... But now out of need!
> 
> I may need to take the Brompton on my OH cycle tour if I can't get the Rourke on a Citroen C1
> It's a good excuse to get on with the mod anyhow.
> ...


I've done this on a few B's. A 50t has the holes in the right place to mount down to 28t and the tensioner can handle the delta. You'll only need to space the BB out by 3mm to mount inside the 50t and a Hope spacer does this nicely. Spa cycles has the rings and bolts.

Heel strike to drop and a stick to get back onto the big ring.


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## Arellcat (22 Jun 2016)

I have a FSA double chainset on my Brompton, with an Octalink v1 BB with a 2mm spacer behind the right-hand side cup. I have it set up with a 40t inner and 53t outer, but to be honest I hardly use the 53 because most of my riding is in hilly places, and for me the ratios from the 40t work nicely with the BWR hub, particularly in direct drive mode.

At the York Rally I saw @kimble 's Brompton with the Kinetics/Sturmey 8spd hub, plus a triple on the front, using the outer mount for a chainguard.


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## 12boy (22 Jun 2016)

I was using a 54 and 38 combo for a while both with a single speed and with a regular SA 3 speed. I like having my 38 on the outside, because it made switching the chain easier. I could not find a chain ring smaller than 38 for a 130 BCD crank. Since you have a 2 cog rear wheel it would probably be best to go with the smaller chain ring on the inside. I found that if I left it on the 38 when I folded the bike the chain would come off but it isn't hard to just put it on the big chain ring. I did not need to change the 119 mm JIS BB is now use. i do not know what an OH tour is but for my riding when I have a lengthy climb it is no big thing to stop, move the chain and go on or vice versa. Using a wax or drilube type chain lube means your fingers stay a lot cleaner.


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## Fab Foodie (22 Jun 2016)

Arellcat said:


> I have a FSA double chainset on my Brompton, with an Octalink v1 BB with a 2mm spacer behind the right-hand side cup. I have it set up with a 40t inner and 53t outer, but to be honest I hardly use the 53 because most of my riding is in hilly places, and for me the ratios from the 40t work nicely with the BWR hub, particularly in direct drive mode.
> 
> At the York Rally I saw @kimble 's Brompton with the Kinetics/Sturmey 8spd hub, plus a triple on the front, using the outer mount for a chainguard.


Ooo, she's never shown that to me!


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## Fab Foodie (22 Jun 2016)

12boy said:


> I was using a 54 and 38 combo for a while both with a single speed and with a regular SA 3 speed. I like having my 38 on the outside, because it made switching the chain easier. I could not find a chain ring smaller than 38 for a 130 BCD crank. Since you have a 2 cog rear wheel it would probably be best to go with the smaller chain ring on the inside. I found that if I left it on the 38 when I folded the bike the chain would come off but it isn't hard to just put it on the big chain ring. I did not need to change the 119 mm JIS BB is now use. i do not know what an OH tour is but for my riding when I have a lengthy climb it is no big thing to stop, move the chain and go on or vice versa. Using a wax or drilube type chain lube means your fingers stay a lot cleaner.


Ta .... Outer Hebrides ( and Skye).


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## Fab Foodie (22 Jun 2016)

Mmmm 50/28 would give 19" to 100" That's a fair range!


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## 12boy (23 Jun 2016)

I am sure you may have explored this but it would be cheaper and easier to change the rear cogs if you haven't maxed already


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## Rohloff_Brompton_Rider (23 Jun 2016)

Fab Foodie said:


> Mmmm 50/28 would give 19" to 100" That's a fair range!


And it's the cheapest option by far. The yahoo Brompton wiki page has a list of the parts required, which is basically; a ring, 5 spacers (or 10 if they've not got the right ones in stock), 5 long ring bolts, BB spacer and an hour of your time.

Words of warning though, once you you can get into the hills because of the increased gearing - you will start contemplating more expensive options - and yearn for a Rohloff, been there done that. It's like a manual move double chainring starts you off down a path of addiction.


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## Fab Foodie (23 Jun 2016)

Rohloff_Brompton_Rider said:


> And it's the cheapest option by far. The yahoo Brompton wiki page has a list of the parts required, which is basically; a ring, 5 spacers (or 10 if they've not got the right ones in stock), 5 long ring bolts, BB spacer and an hour of your time.
> 
> Words of warning though, once you you can get into the hills because of the increased gearing - you will start contemplating more expensive options - and yearn for a Rohloff, been there done that. It's like a manual move double chainring starts you off down a path of addiction.


Just realised that my spider won't take a 28T I'm certain. I'll check the BCD when I have a mo ...


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## Fab Foodie (23 Jun 2016)

User14044mountain said:


> FF - the other option is to stick to the 44 ring and walk up the occasional steep hill. Obviously you'd need some flat shoes - remove the SPD pedals. That way you'll get to spend some more time contemplating the beautiful scenery without expensive surgery.


WHAT??? And miss an upgrade opportunity? What are you thinking ....


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## cisamcgu (23 Jun 2016)

User14044mountain said:


> You could buy some of those fancy Italian leather touring shoes




Or even two pairs


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## swansonj (23 Jun 2016)

User14044mountain said:


> You could buy some of those fancy Italian leather touring shoes





User14044mountain said:


> You could buy some of those fancy Italian leather touring shoes


One for each foot?


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## Rohloff_Brompton_Rider (23 Jun 2016)

Fab Foodie said:


> Just realised that my spider won't take a 28T I'm certain. I'll check the BCD when I have a mo ...


Ah, do you have the new one? I'm talking about the old pie dish one, sorry I should have clarified. 

The new ones will work but it means grinding the lip off.


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## Fab Foodie (23 Jun 2016)

Rohloff_Brompton_Rider said:


> Ah, do you have the new one? I'm talking about the old pie dish one, sorry I should have clarified.
> 
> 
> The new ones will work but it means grinding the lip off.


I can always get a Stronglight double for not too much.


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## Rohloff_Brompton_Rider (23 Jun 2016)

Fab Foodie said:


> I can always get a Stronglight double for not too much.


Yep, that's what I did on the wife's previous B and ebayed the oem B one for same price.


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## TheDoctor (23 Jun 2016)

I thought long and hard about what double to fir to the M6R before taking it touring Provence. In the end I couldn't be arsed. If a 33" bottom gear was too high, there's always walking...
I'd throw a cheap compact on, myself.


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## Fab Foodie (23 Jun 2016)

TheDoctor said:


> If a 33" bottom gear was too high, there's always walking...
> .










A 50/34 would give me a 22" to 68" on the 34 which is pretty useable for about £50. With the 50T all the way to 100".
I think that is sorted.
Ah, just double checking BB width .... I'm not averse to fitting a new one ....


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## TheDoctor (23 Jun 2016)

I didn't end up walking *all* that much.
To be honest, I did actually have a chainset to hand, so I could have fitted it. But I went for a ride to the pub instead. It seemed like a better idea at the time...


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## Fab Foodie (23 Jun 2016)

Rohloff_Brompton_Rider said:


> And it's the cheapest option by far. The yahoo Brompton wiki page has a list of the parts required, which is basically; a ring, 5 spacers (or 10 if they've not got the right ones in stock), 5 long ring bolts, BB spacer and an hour of your time.
> 
> Words of warning though, once you you can get into the hills because of the increased gearing - you will start contemplating more expensive options - and yearn for a Rohloff, been there done that. It's like a manual move double chainring starts you off down a path of addiction.


How does the BB spacer work then?


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## Fab Foodie (23 Jun 2016)

User said:


> And a proper BB.


What do you recommend oh learned one?


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## Rohloff_Brompton_Rider (23 Jun 2016)

Simples, remove BB, slide a 3mm spacer onto drive side cup of BB and refit. Sounds too small to make a difference on (older) bb's but it's enough to clear the fold.


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## albion (23 Jun 2016)

I really cannot see there being a problem getting the Rourke into a C1, especially if you have no passengers.

Push the, tilted towards window, passenger seat fully forward, and remove the bike front wheel. If need be, remove the saddle post.


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## TheDoctor (24 Jun 2016)

That is a good point well made. We recently got three people, three cases and a road bike into a Toyota Yaris, so a road bike and driver into a C1 shouldn't be impossible.


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## Fab Foodie (24 Jun 2016)

TheDoctor said:


> That is a good point well made. We recently got three people, three cases and a road bike into a Toyota Yaris, so a road bike and driver into a C1 shouldn't be impossible.


I'll let you know! Full guards and rack fitted just for fun ....


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## Fab Foodie (5 Jul 2016)

albion said:


> I really cannot see there being a problem getting the Rourke into a C1, especially if you have no passengers.
> 
> Push the, tilted towards window, passenger seat fully forward, and remove the bike front wheel. If need be, remove the saddle post.


Yep it fits just fine .... Options options ....


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## Fab Foodie (5 Jul 2016)

Guys
Gonna get a Stronglight compact double and might as well fit a new BB and chain while its in pieces.
Can I just check ... What lengthy Shimano or similar BB do I need to order?


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## 12boy (5 Jul 2016)

You can fit the new Stronglite to the existing BB and see if the chain line is right. Then measure the old one and, if needed add or subtract from its length until you feel it is right and buy that. The crank arm really drives the BB length. I replaces my single speed with a 119 and it has worked fine with both a Sugino RD2 and the original Brompton 52 tooth. There is a calculation for chain line that goes: Measure the width of the seat tube and divide divide by half. Measure from the left side of the seat post to the chain ring and subtract 1/2 of the width of the chain ring from that number which gives the exact distance from the center of the seat post to the chairing. Measure from the inside of the rear chain stay on the right to the cog and subtract that number from 1/2 off the total width of the distance between the chain stays. In the case of 2 chain rings and 2 cogs I would probably go to the distance between the 2.


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## Arellcat (5 Jul 2016)

According to Spa Cycles, a Stronglight Impact (and the similar Spa/Sugino XD-2) uses a 107mm BB. I'm pretty sure it's a JIS taper. Of course, the thing to watch out for is the chain getting jammed on or behind the swing arm bolt and bracket as you fold your Brompton, or indeed as you try to unfold it. The inner chainring must sit a minimum distance out.

As an example, I measured my original Brompton BB spindle as 119mm, and the chainline was 43.2mm. My FSA double (ISO taper) cranks onto a 110mm (JIS) bottom bracket, plus a 2mm spacer behind the right-hand BB cup, gave a chainline of 43.5mm for the inner chainring, on which I do 95% of my riding. The chainline for the outer chainring was awful, but it didn't really matter.

I ended up having to replace the cranks with similar but using the Octalink v1 interface, and I can't remember the BB spindle length for that.


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## 12boy (6 Jul 2016)

i have a Xootr Swift as well as a Brompton, and was curious about crank weights so I checked. The Swift has some 130 BCD no-name crank and I weighed it, a Campy Nuevo Record, an old Avocet triple and a Sugino RD, all without chain rings. I was surprised to learn the were all within 10 grams of each other. I have not weighed it but for the Brompton I've returned to the original swaged crank and it feels quite a bit lighter than the other 4. to compare I would have to weigh them all with 52 teeth chain rings since the B's is one piece.


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## Fab Foodie (8 Jul 2016)

BOOM!

Dunnit.
No spacers required and as long as it's in the 50T there are no fold issues. Cheers all!


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## Fab Foodie (9 Jul 2016)

Boom!

New rear sprockets, chain. Easy-Peasy.
Loaded for 35 mile test-run tomorrow!


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## Fab Foodie (9 Jul 2016)

User14044mountain said:


> Go for it FF


I'm pumped!


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## 12boy (9 Jul 2016)

So fabulous one, what cogs & chain ring did you end up with?


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## TheDoctor (12 Jul 2016)

Kinda curious about that myself.It looks like a 50/34?
I've just cobbled together a compact from the spares heap, or at least I thought it was. Turns out it's actually a 44/34. Why have I got a 44T chainring? I'm not fitting it this evening as I'd get drowned going to the BikeCave. Again.


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## TheDoctor (2 Aug 2016)

Yay!! My own fettlage has been successful. Newish 44/34 chainset, new chain and new sprockets, as the old ones skipped like anything with a new chain on.
My Brompton now has 12 gears, with 88" 71" 56" 46" 36" 29" on the 44 ring, and 68" 55" 43" 35" 28" 22" on the 34 ring. This compares with the standard gearing, which is 100" 81" 64" 52" 41" 33". I never needed the 100" gear. So I've now got a general knocking-about set that I can spin up to about koff-koff mph if I have a downhill or tailwind, and a set for touring or climbing. Anything I can't climb on a 22 inch gear I shall walk or get a bus.Or possibly a chairlift,as I have plotted for a putative tour of the Alps including an ascent of the Col de Mont-Cenis.


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## Trickedem (1 Jun 2017)

Fab Foodie said:


> BOOM!
> 
> Dunnit.
> No spacers required and as long as it's in the 50T there are no fold issues. Cheers all!
> ...


Thinking of doing the same, can you confirm what parts you needed and where you got them from


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## clockworksimon (2 Jun 2017)

If any non-Brompton folding bike owners are wondering whether a double chainset might work, I fitted an old 52/39 to my BTwin Hoptown the other week. Along with a 24/13 six speed freewheel this got me up Kirkstone Pass in the Lakes during an unplanned after work, evening jaunt. Gear changes at the front used the manual change technique described in earlier threads. Thought it might be a pain stopping but the brief breaks were welcome. Think my lowest gear is about 33 inches which was low enough on an unladen bike. 
This was my first time trying a ride this serious on a folder and perfectly doable. If repeating I would reduce the low gearing to below 30 inches and be prepared to sacrifice my top gear a bit.


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## Fab Foodie (2 Jun 2017)

Trickedem said:


> Thinking of doing the same, can you confirm what parts you needed and where you got them from


IIRC IT's a standard square taper 50/34 stronglight double. Around £50. Can't find where I got it from.
My chain is slightly long and it falls off on the 34T when folded but am led to believe that with the shortest chain for the 50T is should be OK folding on tge 34.
Either way, it's a straightforward swap with the std and works a treat!


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## Pale Rider (2 Jun 2017)

Fab Foodie said:


> IIRC IT's a standard square taper 50/34 stronglight double. Around £50. Can't find where I got it from.



Spa keep quite a lot of Stronglight stuff.

http://spacycles.co.uk/brands/stronglight_chainsets_headsets_bottom_brackets.php


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## BromptonChrispy (31 Jul 2018)

Hello there y'all. I'm new to the Cycle Chat Net and found it and this thread from searching for info about double "chainringing" a Brom S6L. As it is over two years ago since the original post I was wondering if FabFoodie's mod is still alright or whether it proved to be troublesome.

Before shelling out £75 for a stronglight chainset, I thought i'd ask. Thanks for any assistance.

My Brom is a 2014 S6L with the newer JIS taper BB.


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## TheDoctor (4 Aug 2018)

I've been using a double for a couple of years, with no problems.
It doesn't specifically have to be a Stronglight one, I just used a compact from the spares pile.
It's a 44/34 IIRC, although I may change it to a 50/34 sometime.
Hope this helps.


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## BromptonChrispy (5 Aug 2018)

Thanks very much. I'm hoping to fit my new chainset today......
......bit of a pain having to go in for a knee operation on Wednesday though


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