I got it for some mountainous areas that the Brompton accompanies me to. However, recently I also started using the Brompton mid-winter and the 20T turned out to be great for getting out of snow ditches. For that, I put the studded tires as well. The lowest and next to the lowest gears I have are actually not that useful for riding uphill at a steady pace, as you begin to run out of inertia to get you over the portions of the pedal turn where the applied torque is low. However, those gears are good where a momentary application of the low gear is sufficient, in a turn when you are zigzagging uphill or to get out of the mentioned ditch.
Making a fairly old (c15 years) 6-speed Brompton easier on hills
- Thread starter Mr_T_Wales
- Start date
Page may contain affiliate links. Please see terms for details.
I got it for some mountainous areas that the Brompton accompanies me to. However, recently I also started using the Brompton mid-winter and the 20T turned out to be great for getting out of snow ditches. For that, I put the studded tires as well. The lowest and next to the lowest gears I have are actually not that useful for riding uphill at a steady pace, as you begin to run out of inertia to get you over the portions of the pedal turn where the applied torque is low. However, those gears are good where a momentary application of the low gear is sufficient, in a turn when you are zigzagging uphill or to get out of the mentioned ditch.
Kell
Veteran
- Location
- High Wycombe/London
I know you said that going from a 50T to a 44T didn't seem like much of a difference, but I tried it a while back and found it made too much of a difference (for me). I have one steep hill on my commute and the change meant I could do it in either first of second (rather than just first), but it compromised the rest of the ride too much for me and I went back to a 50T.
I tend to change my chain and sprockets every six months and figure it's only an extra £25 to change the chainring so do that too.
When I was commuting on a full-sized bike I changed the chain and cassette every 6 months, but rarely changed the chainrings and everything worked well. It seemed to me that you could get away with a bit of chain 'stretch' on the chainrings, but almost never on the cassette.
All that said, one year I tried to make my chain last for a lot longer and had one snap on me. I landed on the crossbar and broke my Coccyx and learned a very, very painful lesson about maintenance. So now, even though most people say it's overkill, I swap my whole drivetrain out every six months - normally around the same times as I switch to winter tyres on the cars.
I tend to change my chain and sprockets every six months and figure it's only an extra £25 to change the chainring so do that too.
When I was commuting on a full-sized bike I changed the chain and cassette every 6 months, but rarely changed the chainrings and everything worked well. It seemed to me that you could get away with a bit of chain 'stretch' on the chainrings, but almost never on the cassette.
All that said, one year I tried to make my chain last for a lot longer and had one snap on me. I landed on the crossbar and broke my Coccyx and learned a very, very painful lesson about maintenance. So now, even though most people say it's overkill, I swap my whole drivetrain out every six months - normally around the same times as I switch to winter tyres on the cars.
Mr_T_Wales
Regular
I think if my chain ever starts slipping at all I'd change it and the sprockets. I dithered a bit last time as this was the first time it had happened since I got the bike and it quickly got to the stage where if I pulled out at the lights the chain slipped off every time. Since then I've not done many miles so it should be OK. Not sure if it means much but the sprockets do look in good shape.
I'm really curious to see what 39T feels like. Once I change the bottom bracket and add this crank it doesn't look too bad to chain chainring, but I'm hoping 39T is ideal as most trips are with the kids and involve fairly steep inclines. I've literally never used the top two gears and hardly ever even use the middle two so the gearing is all wrong to me. I'd just accepted it before but not I look at the front chainset it looks huge.
I'm really curious to see what 39T feels like. Once I change the bottom bracket and add this crank it doesn't look too bad to chain chainring, but I'm hoping 39T is ideal as most trips are with the kids and involve fairly steep inclines. I've literally never used the top two gears and hardly ever even use the middle two so the gearing is all wrong to me. I'd just accepted it before but not I look at the front chainset it looks huge.
berlinonaut
Veteran
- Location
- Berlin Germany
That's one of the benefits of my conversion of the BWR to 9 gears with 44-12/14/16: You gain the lower end of the 44 and don't loose as much as with 44t on a standard BWR.
About what mileage do you achieve over this period? This seems really often to me.I barely ever need to change my chainrings, many of them are 10 to 20 years on the bike. Even with chain and sprockets I seem to be on the longterm side of life - i.e. on the two-speed Brommi I typically achieve between 3000 and 5000 km with one set of sprockets and one to two chains. This is more than most people seem to achieve, still six months for everything including the chainwheel seems way over the top to me apart from if you ride thousands of miles during that period. I am btw. not maintaining the drivetrain too much in terms of lubrication. My impression is that many people that have to change frequently at the same time clean and lubricate their chains very frequently as well and possibly overdo it with both to an amount that is counterproductive in the end.
Kell
Veteran
- Location
- High Wycombe/London
As I said - it's overkill. I know it's overkill, but I don't want to go through the painful period of being off the bike with injuries. I broke my Coccyx over 8-9 years ago and still can't sit in a car for more than 2-hours without having to stop to stand up.
I know you've commented in past about the state of my drivetrain - saying it couldn't possibly get that dirty - but ... my old commute was around Hyde Park and the bike lane is right next to the horse track - which is sand. A lot of that sand got thrown out on to the bike lane and made its way onto my chain. This ended up turning into a grinding paste that was pretty destructive. I'd clean it all out about once a month.
Video of me getting out the crud out of the chain tensioner jockey wheels: Brompton chain pusher clean out - YouTube
It probably doesn't warrant a full change, there are things I could do - especially with the chainring - like just rotate it a couple of of spokes. But I'd rather spend £50 every 6 months, than spend 3-4 months off the bike which is what happened last time. Especially when you consider that just a week off the bike costs me an additional £98 in car parking and tube fares. Three months off the bike would have paid for another bike.
I actually forgot that I did also snap a chain on the Brompton. As there's no high crossbar, I didn't smack my Coccyx, but did sprain my wrist trying to hang on. Another lesson learned.
Add in to the mix that I don't pootle along at 12mph with no pressure on the pedals. I'm very often out the saddle and putting a full 100kg through the pedals. It all adds up to a fairly tough life for my chain.
As for mileage, I was doing upwards of 2,500 miles a year on the Brompton - so changing at about 1,250.
I know you've commented in past about the state of my drivetrain - saying it couldn't possibly get that dirty - but ... my old commute was around Hyde Park and the bike lane is right next to the horse track - which is sand. A lot of that sand got thrown out on to the bike lane and made its way onto my chain. This ended up turning into a grinding paste that was pretty destructive. I'd clean it all out about once a month.
Video of me getting out the crud out of the chain tensioner jockey wheels: Brompton chain pusher clean out - YouTube
It probably doesn't warrant a full change, there are things I could do - especially with the chainring - like just rotate it a couple of of spokes. But I'd rather spend £50 every 6 months, than spend 3-4 months off the bike which is what happened last time. Especially when you consider that just a week off the bike costs me an additional £98 in car parking and tube fares. Three months off the bike would have paid for another bike.
I actually forgot that I did also snap a chain on the Brompton. As there's no high crossbar, I didn't smack my Coccyx, but did sprain my wrist trying to hang on. Another lesson learned.
Add in to the mix that I don't pootle along at 12mph with no pressure on the pedals. I'm very often out the saddle and putting a full 100kg through the pedals. It all adds up to a fairly tough life for my chain.
As for mileage, I was doing upwards of 2,500 miles a year on the Brompton - so changing at about 1,250.
Last edited:
berlinonaut
Veteran
- Location
- Berlin Germany
I'd say regarding sprockets and chain that's within range where a lot of people with derailleur Bromptons change if at the lower end of the spectrum. For you your "better safe than sorry" strategy regarding the chainwheel makes sense, maybe more for the mind than for the drivetrain or plain necessity but that's fair.
I put the 'chain check' into a calendar. The time of 9 months after I put on a new chain is reasonable for me. If the chain is still OK, I move the 'check' by 2 months and so on. Various chain checkers are ubiquitous, but there are also checkers for sprockets, starting with the original Rohloff Cog Wear Indicator. However, the rule for Brompton, of replacing the sprockets together with the chain is good enough, particularly that it can be challenging to arrive at consistent results with the checkers for sprockets.
mitchibob
Über Member
- Location
- Treorchy, Wales
6,000ish km seems to be about average for me on chains/sprockets on my Brommie, and I clean/lube pretty regularly. Chainrings go about double time or more, at least for me.
Last edited:
Mr_T_Wales
Regular
Can you tell if sprockets need replacing just by looking at them?
berlinonaut
Veteran
- Location
- Berlin Germany
I can tell you: Normally you will not be able to destroy sprockets by looking at them so that they would need to be replaced.
But yes, you can visually see if a sprocket needs to be replaced (or rather if they don't).
Last edited:
Kell
Veteran
- Location
- High Wycombe/London
TBH - it's £25 to replace a chain and sprockets. There shouldn't be any labour cost on top as it's an easy job for a home mechanic. For that price, and for me, it's almost not worth the bother of trying to get away with it.
That said, it's one of those things where you could be OK if you just change the chain. In fact if you change your chain before it's truly worn out, then it won't have introduced wear to the sprockets. Therefore a new chain will sit nicely on it. If you leave your chain for a long time so it's 'stretched' then it's more likely that you'll need to replace other parts as they'll have worn too. If you don't, your chain will get a bit jumpy.
It's not an exact science, but it's one of the parts of Bromptons that actually cheap to replace so I just do it anyway.
Last edited:
mitchibob
Über Member
- Location
- Treorchy, Wales
Well, you can tell when you change the chain, then when you put any power through the pedals, the chain skips over the sprockets.
As they're pretty cheap, I just get sprockets at same time as replacing chain.
Mr_T_Wales
Regular
Thanks. It wasn't really the cost I was worried about, just the hassle of doing so much in one go - plus I think the sprockets I have are older types or something so I'd have to think about what to do about that and there is only so much bike stuff I can handle at once as I'm not great at the mechanical stuff.
I did buy a 39T chainset/crankset and it came with a hollowtec bottom bracket. This is all installed but I can't test yet as I don't have the tools to get the folding pedal off the old crank arm (it needs a 24mm socket, which I got hold of, but the other side is 1/2 inch and I only have 3/8 inch adaptors).
One annoying thing is that when parked I can't turn the pedal at all as the chain presses a tiny bit against a bit of metal. As far as I can see the front chain ring is lined up perfectly to one of the rear cogs, when I guess it should be in the middle, but it looks so close I don't think it's going to be a problem with riding - but I can't test until I have both pedals on and can try to ride up a hill. All I can do I think is undo it all and try to find some kind of 3mm washer to make the chainring slightly more outside or just be careful to note where the pedals are when folding.
Update - I asked in Halfords about this and the guy there really knows his Bromptons. He said that I need spacers so he gave me a couple for free (Halfords don't sell them but he uses them for repairs etc). It looks like they are 3mm and he said that if it's a road bike hollow bracket the drive side thread is the same as the other and you can really only put one spacer in there. What a guy!
So I have to undo everything. Blah.
I did buy a 39T chainset/crankset and it came with a hollowtec bottom bracket. This is all installed but I can't test yet as I don't have the tools to get the folding pedal off the old crank arm (it needs a 24mm socket, which I got hold of, but the other side is 1/2 inch and I only have 3/8 inch adaptors).
One annoying thing is that when parked I can't turn the pedal at all as the chain presses a tiny bit against a bit of metal. As far as I can see the front chain ring is lined up perfectly to one of the rear cogs, when I guess it should be in the middle, but it looks so close I don't think it's going to be a problem with riding - but I can't test until I have both pedals on and can try to ride up a hill. All I can do I think is undo it all and try to find some kind of 3mm washer to make the chainring slightly more outside or just be careful to note where the pedals are when folding.
Update - I asked in Halfords about this and the guy there really knows his Bromptons. He said that I need spacers so he gave me a couple for free (Halfords don't sell them but he uses them for repairs etc). It looks like they are 3mm and he said that if it's a road bike hollow bracket the drive side thread is the same as the other and you can really only put one spacer in there. What a guy!
So I have to undo everything. Blah.
Last edited:
Kell
Veteran
- Location
- High Wycombe/London
I describe myself as mechanically retarded.
Although my bike is newer than yours, it's a fairly easy job even for me.
So I always figure if I can do it, anyone can.
Although my bike is newer than yours, it's a fairly easy job even for me.
So I always figure if I can do it, anyone can.
Last edited:
Mr_T_Wales
Regular
So here is the result, showing all the Shimano goodness. The crankset and chainring really do feel top quality, and it's kind of cute that they load them with green grease as it comes. I tried on the steepest hills near me (some are very steep in parts) and it was way way easier than before.
I'd say that the biggest hassle is knowing what parts and tools are needed, and how much to adjust the chain or what length to get if getting a new one, and then it's mainly just having patience. Oh, and not trying to take a crank arm off before removing the bolt (seriously...).
Adding a 3mm spacer wasn't too bad but I couldn't put 3mm on the other side as the thread for the crank would look a little short (so it's offset from the centre by a tiny amount). Also, even that 3mm adjustment meant that the plastic screwcap thing that helps to keep the crank tight was much harder to get in and find the thread.
All works now and it rides superbly. The pedals fold properly and the bike can be parked as before with the wheels not jammed (it was probably only 1mm off working before really).
I'd say that the biggest hassle is knowing what parts and tools are needed, and how much to adjust the chain or what length to get if getting a new one, and then it's mainly just having patience. Oh, and not trying to take a crank arm off before removing the bolt (seriously...).
Adding a 3mm spacer wasn't too bad but I couldn't put 3mm on the other side as the thread for the crank would look a little short (so it's offset from the centre by a tiny amount). Also, even that 3mm adjustment meant that the plastic screwcap thing that helps to keep the crank tight was much harder to get in and find the thread.
All works now and it rides superbly. The pedals fold properly and the bike can be parked as before with the wheels not jammed (it was probably only 1mm off working before really).
