Hello!
After replacing the chain on my early 2000s Brompton (2×3 gearing), the chain is now jumping—but only on the outer/smaller chainring, and only under load.
Some details:
• The chain has no stiff or locked links.
• The derailleur is properly adjusted, and the chain isn’t being pulled sideways or caught by the larger chainring.
• It seems like the chain is slipping over the teeth, not shifting or moving side to side.
• Chain dimensions: 1/2” x 3/32”
Is this a common issue?
Thanks!
Chain jumping on small chainring after replacement (early 2000s Brompton, 2×3 gears)
byu/_tentakel inBrompton
by _tentakel
4 Comments
If the bike was used a lot with the stretched chain, the rear cogs probably got worn and will cause skipping with a new chain. They will need to be replaced too.
Change the sprockets, they will have worn in with the old chain.
Given the age the whole drivetrain should be replaced at the same time the chain was replaced.
did u change the cogs too? if not , do it ASAP. old cogs on new chain will wear the chain prematurely, waste of money