Brompton owners - how many miles do you get out of a chain / sprockets?
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annedonnelly
Girl from the North Country
- Location
- Blyth, Northumberland
Looking back at my records from when I was using mine to commute - and made a note of mileage - it looks like I changed the chain after about 5,500 miles. It's a six speed and back in those days it would get checked and cleaned weekly.
I know I've changed sprockets too but I don't seem to have made a note of that.
I know I've changed sprockets too but I don't seem to have made a note of that.
mitchibob
Über Member
- Location
- Treorchy, Wales
Whenever I've changed chain without changing sprockets, the chain slips horribly. Chainring doesn't need changing each time, but sprockets, easy and cheap enough to just replace them at the same time as the chain.
mitchibob
Über Member
- Location
- Treorchy, Wales
Interested primarily in those with derailleurs - i.e. 2 and 6 speed models.
Bonus points awarded for additional information including chain type, usage conditions, lubrication regime and chain elongation when replaced.
Cheers
Think I've managed to get 6,000-8,000km out of chain and sprockets on 2/6 speed, with regular cleaning, appropriate lubing. When commuting everyday and doing longer weekend rides, I'd clean the chain weekly, or around the 200km-250km distance, or when it sounded bad at all. Ridden in all conditions. Some off-road. Used wet-lube in winter, dry-lube in summer.
While I have bought a Brompton branded replacement chain before (as they're slightly convenient as they're correct length, but didn't find they came pre-lubed), I've mostly used SRAM PC830 7/8 speed chain, I think, as it was recommended in one LBS as good replacement and cheaper.
Couldn't tell you chain elongation... I just go by how well or badly the chain is sitting on the chainring to decide when I'm going to replace, and replace sprockets each time (learnt the hard way with that).
brommieinkorea
Well-Known Member
About 5000 miles. I always replace the outer drivetrain (chainring,cogs,chain) at the same time. Every couple of trips the chain gets oiled and wiped. Triflo, Pedro's, or olive oil doesn't seem to matter as far as longevity goes.
Kell
Veteran
- Location
- High Wycombe/London
I change mine every 6 months. Essentially before and after winter. It's overkill, but I'll tell you why I do it.
I snapped a chain on my old bike in about 2009. i was stood up pulling away from some lights when it snapped and I got dumped on the crossbar. I broke my coccyx and still have issues today. Can't sit in a car for more than two hours without having to stop, and certain chair positions are uncomfortable after minutes.
A few years later and I was trying to make my Brompton chain last a bit longer. Snapped that and while I didn’t come off, I nearly did. In the process of trying to save myself I really twisted my wrist.
Swore after that that I would never try and make a chain last longer than it should.
At that time however, I was cycling 5 days a week (these days it’s only 3) and was doing about 80 miles a week.
6-months at that mileage was just over 2,000 miles. But I guess you could add half again as I’d not gone to 6-month changes by then.
What I would say though, is that at that time I worked near Hyde Park. As part of my commute I’d do laps of the park. But the cycle track was near the horse track for The Hyde Park barracks.
I mention this as the track was sand. This would get kicked onto the cycle track by the horses and flicked up onto the bike.
My bike was always minging. Combination of the sand and oil, and general road grime.
It used to work like a grinding paste and I’m fairly sure led to the early demise of rims as well as chains.
I reckon the absence of the sand plus the fact I’m doing fewer miles means I could definitely get more time out of a chain, but I’m not prepared to risk it when the price of changing chain and sprockets is only £20 or so.
£40 a year is nothing. Especially when you consider every day I don't/can't cycle, I have to pay £10 to park at the station, and then a tube ticket at £10.50. When I broke my coccyx, I was off the bike for three months. At today's prices, 13 weeks or so off the bike at an extra £100 a week is £1300. All because I was trying to save a few pennies making my chain last longer. I could have bought a new bike for that.
So now chain and sprockets get changed every 6-months. I used to also change the chainring each time, but now I just rotate it forwards one spoke of the chainring so any worn teeth are no longer in the ‘power’ zone. Change it every two or three times I do the chain now now.
So in answer to the original question, because I do far fewer miles in those 6 months, I probably now change the chain at about 1,100-1,250 mile intervals.
Standard Brompton 6-speed chain and sprockets, but a Spa cycles 48-tooth chain ring.
Cleaning regime - might run the chain through a chain cleaner every fortnight, but then remove chain, sprockets. chainring and chain pusher to completely degrease and re-oil them once every 4-6 weeks.
I snapped a chain on my old bike in about 2009. i was stood up pulling away from some lights when it snapped and I got dumped on the crossbar. I broke my coccyx and still have issues today. Can't sit in a car for more than two hours without having to stop, and certain chair positions are uncomfortable after minutes.
A few years later and I was trying to make my Brompton chain last a bit longer. Snapped that and while I didn’t come off, I nearly did. In the process of trying to save myself I really twisted my wrist.
Swore after that that I would never try and make a chain last longer than it should.
At that time however, I was cycling 5 days a week (these days it’s only 3) and was doing about 80 miles a week.
6-months at that mileage was just over 2,000 miles. But I guess you could add half again as I’d not gone to 6-month changes by then.
What I would say though, is that at that time I worked near Hyde Park. As part of my commute I’d do laps of the park. But the cycle track was near the horse track for The Hyde Park barracks.
I mention this as the track was sand. This would get kicked onto the cycle track by the horses and flicked up onto the bike.
My bike was always minging. Combination of the sand and oil, and general road grime.
It used to work like a grinding paste and I’m fairly sure led to the early demise of rims as well as chains.
I reckon the absence of the sand plus the fact I’m doing fewer miles means I could definitely get more time out of a chain, but I’m not prepared to risk it when the price of changing chain and sprockets is only £20 or so.
£40 a year is nothing. Especially when you consider every day I don't/can't cycle, I have to pay £10 to park at the station, and then a tube ticket at £10.50. When I broke my coccyx, I was off the bike for three months. At today's prices, 13 weeks or so off the bike at an extra £100 a week is £1300. All because I was trying to save a few pennies making my chain last longer. I could have bought a new bike for that.
So now chain and sprockets get changed every 6-months. I used to also change the chainring each time, but now I just rotate it forwards one spoke of the chainring so any worn teeth are no longer in the ‘power’ zone. Change it every two or three times I do the chain now now.
So in answer to the original question, because I do far fewer miles in those 6 months, I probably now change the chain at about 1,100-1,250 mile intervals.
Standard Brompton 6-speed chain and sprockets, but a Spa cycles 48-tooth chain ring.
Cleaning regime - might run the chain through a chain cleaner every fortnight, but then remove chain, sprockets. chainring and chain pusher to completely degrease and re-oil them once every 4-6 weeks.
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neilrichardson55
Active Member
- Location
- Hemel
done about 220miles on mine the chain is still less than 5 % i did not expect to be honest lolol in did change the sprocket at the time to. as I'm a heavy rider I'm expecting tires and chains to ware quiet quick.
EltonFrog
Legendary Member
Which, as it turns out was a mistake. I’m currently in Vancouver with the Brompton, had a ride around downtown and Stanley Park and the chain kept slipping, as @Gunk and others said it would. Fortunately for me a couple of hours ago I found an excellent bike shop / Brompton dealer who had sprockets in stock, and fitted them for me then and there! On a Saturday afternoon! I could have done it myself, but it would not have been a good idea in a hotel room. Lesson learned.
They seem to be made out of monkey metal
Thanks all - that's a massive range of service lives! I guess it all comes down to usage, maintenance and criteria for deciding when replacement is necessary..
For what its worth I'm running two alternating waxed chains on mine; each has about 1.6k miles on while the bike / sprockets are obviously on about 3.2k miles.
Last time I measured the chains the numbers suggested I'd get about 4.5k miles out of each before I hit 0.5% elongation. Sprockets are visibly worn but apparently not excessively so..
I suspect running two alternating chains is probably easier on the sprockets as I think chain elongation exacerbates sprocket wear as it effectively moves the contact patch forwards / upwards on the teeth to a less-optimal location.
To be honest as much as I have a downer on the quality of some of Brompton's components and their design choices, I don't think the sprockets deserve too much stick as they evidently have a hard life. They're pretty small, there are only two of them and the small wheels need to rotate nearly twice as many times as a 700C to cover the same distance..
This result is that each tooth sees far more loading / unloading cycles. It's a crude comparison, but if one considers an 8sp 11-34 cassette with (for the sake of ease) equally-spaced tooth count, this suggests a total of 180 teeth. Conversely the 2/6sp Brompton setup has 29; or around six times fewer. Add to this that the wheels have to turn around twice as fast at any given speed, and we potentially have twelve times as many load / unload cycles per tooth on the Brompton; are arguably correspondingly twelve times the rate of wear. A somewhat crude and flawed example but I think gives a ballpark idea of how hard these sprockets have it..
For what its worth I'm running two alternating waxed chains on mine; each has about 1.6k miles on while the bike / sprockets are obviously on about 3.2k miles.
Last time I measured the chains the numbers suggested I'd get about 4.5k miles out of each before I hit 0.5% elongation. Sprockets are visibly worn but apparently not excessively so..
I suspect running two alternating chains is probably easier on the sprockets as I think chain elongation exacerbates sprocket wear as it effectively moves the contact patch forwards / upwards on the teeth to a less-optimal location.
To be honest as much as I have a downer on the quality of some of Brompton's components and their design choices, I don't think the sprockets deserve too much stick as they evidently have a hard life. They're pretty small, there are only two of them and the small wheels need to rotate nearly twice as many times as a 700C to cover the same distance..
This result is that each tooth sees far more loading / unloading cycles. It's a crude comparison, but if one considers an 8sp 11-34 cassette with (for the sake of ease) equally-spaced tooth count, this suggests a total of 180 teeth. Conversely the 2/6sp Brompton setup has 29; or around six times fewer. Add to this that the wheels have to turn around twice as fast at any given speed, and we potentially have twelve times as many load / unload cycles per tooth on the Brompton; are arguably correspondingly twelve times the rate of wear. A somewhat crude and flawed example but I think gives a ballpark idea of how hard these sprockets have it..
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Kell
Veteran
- Location
- High Wycombe/London
It's good to try it though...
If you hadn't you'd always have wondered if we were just spending money for the sake of it.
I think Wafter's method of running two chains would mean you can probably get twice as many miles as long as the chains are swapped very regularly.
As I've said elsewhere recently, it's still a fairly cheap swap so to me it's not worth the additional hassle of trying to remember to swap the chain. But, as I do remove it all to clean wouldn't actually be any extra work as such.
