Author Topic: Brompton chain replacement strategy  (Read 415 times)

Brompton chain replacement strategy
« on: October 31, 2019, 06:00:18 pm »
Having done maybe 1,000-1,500km in all weathers the factory chain on my (6-speed) Brompton is starting to get a bit worn; my LBS measured it the other day and said it was probably past 0.5%. That doesn't seem like brilliant wear, but then the drivetrain catches a lot of crud and I don't baby it particularly - it gets a regular-ish wipe and a lube, with the occasional proper clean. The LBS's advice was either to change the chain soon, or to let it go to 0.75% then change both the chain and sprockets. Does this sound reasonable?

I'm minded to change the chain soon, as it's less faff than doing the sprockets as well. It looks like Brompton OEM chains are about a tenner, with cheap 8-speed KMC chains a couple of quid less and more expensive ones a couple of quid more. Are posher chains worth it? Otherwise I figure I'll just get the cheapest chains and change them a bit more often.

(As a PS, how often do people service the rear hub? I've never actually serviced an SA before, so I'm instinctively in the 'if it's not broke' camp, but I suppose it would be a useful skill to learn...)

Kim

  • Timelord
Re: Brompton chain replacement strategy
« Reply #1 on: October 31, 2019, 06:09:21 pm »
Are posher chains worth it? Otherwise I figure I'll just get the cheapest chains and change them a bit more often.

Bromptons do seem hard on chains, presumably on account of being crud-magnets.  I wore out the factory chain on mine in about 1000 miles (which is poor even compared to my other uprights).  It's currently using some of the mildly-worn PC971 that was left over when I upgraded a recumbent to 10-speed.

After a couple of rust incidents, I've concluded that nickel-plated chains are worth it if you're in the habit of exposing them to lots of salty water and then ignoring the bike for several days.  Otherwise, it doesn't really matter, buy what's cheap and/or comes with a nice quick-link.


Careful, Kim. Your sarcasm's showing...

Re: Brompton chain replacement strategy
« Reply #2 on: October 31, 2019, 06:23:52 pm »
My strategy has always been to ride until you have problems (which may rake a very long time to materialise) and then change the chain. Do a quick test ride and if the chain skips replace the sprockets too, otherwise put the new ones away for next time.

LBSes seem to love writing off parts prematurely.

Re: Brompton chain replacement strategy
« Reply #3 on: October 31, 2019, 06:35:51 pm »
Mine is a 2014 bike which, until recently when I fitted some carbon rimmed wheels (yes, really) was still on it's original brake blocks, with plenty of life left in them, but was on it's third chain.
As has been mentioned upthread, the chain tends to have a shorter life than might be expected otherwise.
Being *so much* closer to the ground no doubt compounds this, so I don't think that your mileage, in all weathers, constitutes unreasonable wear.

ETA: Grams speaks much truth.

Re: Brompton chain replacement strategy
« Reply #4 on: October 31, 2019, 06:44:27 pm »
It does seem a bit on the cautious side. Normally 0.75% is considered the point to change the chain but not the sprocket(s), and 1% or more to change both.
Quote from: tiermat
that's not science, it's semantics.

Kim

  • Timelord
Re: Brompton chain replacement strategy
« Reply #5 on: October 31, 2019, 07:44:44 pm »
Depends how many sprockets you've got, Shirley?  On a derailleur transmission, the objective is not to knacker the cassette to the point where it skips in some gears.  If it's single-speed / gears-inna-can, you can run the lot into the ground and accept much greater amounts of chain wear without issue.

Given that a Brompton derailleur system only has two sprockets, the economics might reasonably skew towards the run it into the ground end of the spectrum.
Careful, Kim. Your sarcasm's showing...