Is 9sp chain compatible with 3sp drivetrain on Brompton?
#1
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Is 9sp chain compatible with 3sp drivetrain on Brompton?
Question in subject line. Thanks! JP
#2
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The answer is..probably if your Brommie uses 3/32" derailleur-type chains, but it appears some 3-speeds use 1/8”. I suspect you wouldn't be asking if you didn't already have the chain handy, so might as well throw it on there and see what happens. Good luck!
https://www.bikebrompton.com/accesorios.aspx?Id=chains
https://www.bikebrompton.com/accesorios.aspx?Id=chains
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I'm pretty sure I need 3/32 chain for the Brompton. Problem is I can't find the width for SRAM PC-971 chain anywhere.
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You may need to adjust the chain pusher end-stop screws slightly to compensate for the narrower chain.
#5
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I have found the cheaper chains work best for me. By that I mean KMC and SRAM 7-8 speed chains.I used a higher end chain designed for 9-10 speeds which did not sit all the way down on the rear cogs although the chain ring was fine. Kept clean and lubed they last quite a while, at least here in the high desert.
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The SRAM PC-971 is a 9 speed chain so it should have a width between 6.6-6.8 mm. It is a 3/32" chain so it should work with your 3-speed Brompton.
#7
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No. ... but you could Measure it..
Now you can order S-A replacement cogs in 3 or 4/32, Brompton Stock is 1/8.
years ago Sachs of Germany made the 1st 3 by 2 hubs for Brompton UK . those were thinner, 13t and a 15t, that skipped every 4th tooth
so had (spares are still stocked) 3 incomplete teeth to help it shift between the 2 cogs.
...
Now you can order S-A replacement cogs in 3 or 4/32, Brompton Stock is 1/8.
years ago Sachs of Germany made the 1st 3 by 2 hubs for Brompton UK . those were thinner, 13t and a 15t, that skipped every 4th tooth
so had (spares are still stocked) 3 incomplete teeth to help it shift between the 2 cogs.
...
Last edited by fietsbob; 12-12-16 at 10:33 AM.
#8
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I've been using a full bushing 3/32" chain* .. the type is longer wearing than Derailleur chains.. On a skip tooth 15t, 12 full teeth, 3 short ..
* it was an OldStock find, from Harris Cycles, in Newton MA..
...
* it was an OldStock find, from Harris Cycles, in Newton MA..
...
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Looks like 3-speed Bromptons may come with 1/8" cogs after looking at SJS's website. Best off to measure your cog to see if it 1/8" or 3/32" as already suggested.
#10
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Mine came with a 3/32. it is, however,at least 3 years old. I don't know how to tell how old they are, perhaps from the SN or some such? It could have sat around the bike store for years. it was originally a single speed.
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Newer Brompton come with 3/32" chains, but I think pre-2012 or something 1 and 3-spds were standard 1/8", while 2 and 6-spds were 3/32".